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started in 1995 for a second water reservoir in the area, which was built between 2011 and 2014. The new reservoir is underground, buried under topsoil and native plants, and it has a volume of 50 millionUS gallons (190 million L). With the new reservoir came improvements to the Powell Butte park, including resurfaced and realigned trails, reduced environmental impacts, better accessibility measures, and reduction of steep grades. The government also built a visitor center, caretaker's house, public restrooms, maintenance yard, and a permeable parking area that permitted filtration of rainwater through asphalt to an underground stone bed, where it could be absorbed by the soil and then into the nearest aquifer.
321:
80 °F (27 °C), and the average minimum for
January is above 32 °F (0 °C). Yearly, precipitation averages between 35 and 45 inches (890 and 1,140 mm) in most river valleys, with a mean of 42.04 inches (1,068 mm) from 1871 through 1952. It shows variability, with a historic low of 26.11 inches (663 mm) at Portland in 1929 and a maximum of 67.24 inches (1,708 mm) in 1882. More than 75 percent of this precipitation occurs between October and March; July and August mark the driest months with means below 1 inch (25 mm), while November, December, and January represent the wettest with averages greater than 6 inches (150 mm).
335:
196:
1125:
434 feet (132 m) of silt from the
Troutdale Formation. Running along the tube's arc are five depressions, which were created through the collapsing roofs of the lava tubes within a subsegment that is 6,000 feet (1,800 m) in length. The characteristics of the tube system are not well documented, since only the collapsed segments are accessible. Some of the channels have been reduced to rubble, and analysis has revealed that they trended northwest, had widths up to 40 feet (12 m) and depths no more than 60 feet (18 m), and required special engineering procedures to permit the construction of a 15-story building above them.
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Activity spread out over the area, extending to its current expansive state about one million years ago. In addition to spreading out geographically, the lava composition in the field's vents became more diverse. This period continued until about 500,000 years ago, with no activity until about 350,000 years ago, after which activity continued through roughly 60,000 to 50,000 years ago according to several sources, or about 120,000 years ago according to I. P. Madin (2009). R. Evarts and Fleck originally reported that lava flows at the Barnes Road deposit of the field represented the youngest eruptive products in the Boring area, with a
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in 1974. The Catlin Gabel tubes lie among cinder cones and lava flows from the
Pliocene to Pleistocene, and they are the oldest known lava tubes in Oregon, older than the Holocene. The tubes were produced by a small vent at the southern end of the northern segment of the field, extending 2.5 miles (4.0 km) from its base to the south and then the west. They originated from the uppermost lava flow from a series of eruptions that ran into a valley on the western slope of the Portland Hills. The Catlin Gabel tubes have a width of 2,500 feet (760 m), with slopes averaging 150 feet (46 m) per mile for an average grade of 3
761:
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42:
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1559:. Activity took place during the late Tertiary and early Quaternary, in what is now the Portland area as well as the surrounding area, with a particularly concentrated pocket of activity to the east. Nearly all of these eruptions were confined to single vents or small vent complexes, with the exception of a lava plain southeast of present-day Oregon City. Boring Lava generally consists of flowing lava; only one eruptive deposit contains tuff, ash, and tuff breccia, and one vent to the northeast of the Carver area displayed evidence of explosive eruptions that later became
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Willamette River, 19 vents east of the
Willamette River and north of Powell Valley Road, and 45 vents east of the Willamette River and south of Powell Valley Road (Highway 26). Of these, 42 were unnamed, and several volcanoes contained multiple vents. Generally, all lava flows in the field can be traced to specific vents in the field, but documented source vents have mostly been confirmed through chemical analysis or
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aluminum reduction, and shipyards can be found in the region. Industrial chemical production represents an important industry in
Portland. Most of these industries rely on resources outsourced from other areas, except for the paper industry; business is driven by low power costs and the local industrial mineral market. Other important manufacturing industries in the nearby region include food processing and logging.
1100:(located 20.5 miles (33.0 km) north of Portland); Mount Scott also has an intact summit crater. Many of its vents retain the shape of a volcanic cone, with loess extending above an elevation of 400 feet (120 m). The Rocky Butte plug, which reaches a height of 330 feet (100 m) above its surroundings, was dated to 125,000 ± 40,000 years old by R. Evarts and B. Fleck from the
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deposition of volcanic ash that could lead to serious infrastructural consequences, covering large areas. A larger eruption, like the ones that built Larch
Mountain or Mount Sylvania, could span years to decades. It is unclear where exactly a future eruption might take place, but it would probably occur in the northern portion of the field.
1580:, the field itself is not considered extinct. The probability of future eruptions in the Portland–Vancouver metropolitan area is very low. It is rare that more than 50,000 years pass without an eruption in the region; given the past eruptive history of the field, an eruption is predicted to occur once every 15,000 years on average.
1072:. Boring Lava was erupted by vents in the volcanic field, and it has been exposed at elevated topographic levels in intact volcanic cones and dissected lava plains. There is likely more lava deposited under Quaternary sedimentary mantle throughout the region, though activity was confined to a relatively concentrated area.
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and Curtis, and these intrusions have been associated with normal faulting at
Parrett and Petes Mountain, Aurora, Curtis, and Swan Island (along the Molalla River). Faults together with igneous intrusions are usually accompanied by stretching and doming as a result of magma influxes or collapses from
1036:(rock fragments enveloped in a larger rock during the latter's development and solidification) can be observed among local cinder specimens, dating from Miocene to Pliocene Troutdale deposits. While the volcanic rock of Boring Lava was being emplaced over rock from the Troutdale formation, there was
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at Mount
Sylvania, Highland Butte, and Larch Mountain. The Boring Lava Field marks the densest volcanic vicinity in this group, encompassing an area of 36 square miles (93 km). It includes more than 80 known small vents and associated lava flows, with more volcanic deposits likely present under
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In contemporary times, clearing of forests for housing development has left about half of the Boring Lava region un-forested. As a result, water quality has decreased due to higher sedimentation and turbidity, and flooding has worsened over time. Streams within the area are of either first or second
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originate from the south during winter and from the northwest during the summer season, with the exception of prevailing winds at the mouth of the
Columbia River Gorge, where winds predominantly move to the east. The southern winds have the highest velocities of the three, only rarely occurring with
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In addition to the nature park on Hogan Butte, a number of smaller cinder cones are also publicly accessible. The
Gresham Saddle Trail traverses Gresham Butte and Gabbert Butte, running for 3.3 to 3.7 miles (5.3 to 6.0 km). The trail is considered to be of moderate difficulty, and it offers no
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Many seismic faults in the northeastern section of the northern Willamette Valley formed as a result of intrusions of Boring Lava, as supported by their orientation, lengths, displacements, age, and proximity to Boring Lava intrusions. Though intrusions from any future eruptions at the Boring field
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Sometime less than 100,000 years ago, magma at Battle Ground Lake in Washington state interacted with water to form the eponymous maar volcano, destroying a lava flow dated to 100,000 years ago. The last volcanic center to form in the field was Beacon Rock, a cinder cone produced by eruptions about
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percent. On average, these tubes have a thickness of 235 feet (72 m) near their center, with an upper lava unit thickness of 90 feet (27 m) that has since been modified by erosion and the deposition of up to 30 feet (9.1 m) of Portland Hills silt. The Catlin Gabel tubes also sit atop
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along the western slope of the Portland Hills. These formations, created by lava flows cooling at the surface while their hot interior kept draining, were first identified by R. J. Deacon in 1968, then analyzed by L. R. Squier in 1970; they were studied in greater detail by J. E. Allen and his team
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In 1952, after a local vote, the Kelly Butte Civil Defense Center was built between 1955 and 1956, costing about $ 670,000. The center was constructed to host local government agents should a nuclear attack on Portland occur; it had an area of 18,820 square feet (1,748 m), intended to host 250
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Portland's climate is moderate, with long growing seasons, moderate rainfail, mild winters, and warm, dry summer seasons. The area has more than 200 frost-free days annually. Temperature can vary widely, reaching a historic maximum of 107 °F (42 °C), though the usual July maximum is below
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volcanic cones that appear as hills throughout the area, reaching heights of 650 feet (200 m) above their surroundings. The collection includes more than 80 small volcanic edifices and lava flows in the Portland–Vancouver metropolitan area, with the possibility of more volcanic deposits buried
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million years ago, eruptive activity resumed to the north of the previously active area, with alkalic basalt lava flows generating the Mount Scott shield volcano. As eruptions shifted to the east over time, the Larch Mountain volcano was produced by eruptions in the foothills of the Cascade Range.
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million years, the volcanic field has irregularly rotated clockwise and migrated to the northwest at an average rate of 0.37 inches (9.3 mm) ± 0.063 inches (1.6 mm) per year relative to the surrounding crust. This northwest trending is consistent with other faults in the nearby area. The
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The Portland area has a moderate climate, and precipitation is not typically very heavy, allowing for significant growth of vegetation, which can hamper fieldwork in the area. Many forests that covered the area were partly cleared for agriculture, timber, or cemetery applications in the early 20th
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Trails in the city of Gresham travel over parts of the Boring Lava Field and its cones. Mount Tabor and Powell Butte are better known for their recreational uses than other cones; Powell Butte Nature Park has 9 miles (14 km) of trails. The Mt. Tabor Park is open to bicyclists and pedestrians
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Eruptions at Boring Lava Field occur in a concentrated manner, often in clusters of three to six vents, as at Bobs Mountain and Portland Hills. These types of vents typically produced similar types of magma in relatively short periods of time, and they also frequently show alignment. Vents in the
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At points where the Boring Lava sits over Troutdale Formation deposits, landslides are frequent, producing steep head scarps with heights of up to 66 feet (20 m). These scarps tend to have grabens at their bases and Boring Lava blocks at their tops, and they show variable slide surfaces from
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In the eastern part of the Boring cluster, volcanic vents have average diameters less than 1.6 miles (2.6 km), with average heights less than 1,090 feet (330 m) from base to summit. The lava flows from Highland Butte and Larch Mountain, both shield volcanoes, encompass a wide area, the
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The Portland area has historically been a center for trade since the city was founded in 1845. With time, commerce has diversified. Iron mining and smelting was common between 1867 and 1894, with paper mills becoming established as an industry in 1885. Plants manufacturing cement and conducting
183:, recreation, and nature parks. Because of the field's proximity to densely populated areas, eruptive activity would be a threat to human life and property, but the probability for future eruptions affecting the region is very low. The field may also influence future earthquakes in the area, as
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Boring Lava deposits averaging thicknesses of 100 to 200 feet (30 to 61 m) not considering areas next to volcanic cones in the field. Most of the summit craters have been destroyed, though there are partial craters at Bobs Hill (located 20.5 miles (33.0 km) northeast of Portland) and
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formation that has been changing since the Miocene. The Boring Lava Field sits on the floor of the Portland Basin, residing in the forearc setting between tectonic extension to the south and compression to the north. The uneven distribution of vents within this forearc suggests a local zone of
700:
In 1981, the Portland city government built a reservoir at the north end of Powell Butte (part of the Boring Lava Field), which still serves the city. In 1987, Portland government created Powell Butte Nature Park, covering 600 acres (240 ha) of meadows and forest within the city. Planning
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included footage of the Defense Center. The center was left obsolete after a 1963 Portland City Council vote to abolish it passed; in 1968, just one permanent employee remained. Eventually the building was converted into an emergency services dispatch center from 1974 through 1994, when it was
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culture is poorly understood as a result of disturbance of archeological sites and artifacts by erosion and human development. Oral history, limited archeological evidence, and ethnographic research inform current knowledge about local Native American communities. The area surrounding Portland
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About half of the Boring Lava Field eruptions took place in what are today densely populated areas of the Portland–Vancouver metropolitan area. Though the formation of a small cinder cone vent might not extend far beyond its surroundings, depending on location, similar eruptions could lead to
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million, despite opposition from local environmental groups like the Friends of the Reservoirs. Historically, the park has also housed a police firing range, and Kelly Butte remains a recreational space today, administered jointly by Portland Parks and Recreation and the Portland Water Board.
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The Boring Lava Field covers an area of about 1,500 square miles (4,000 km), and has a total volume of 2.4 cubic miles (10 km). This region sustains diverse flora and fauna within its habitat areas, which are subject to Portland's moderate climate with variable temperatures and mild
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D. E. Trimble (1963) argued that the Boring Lava Field was produced by eruptive activity at 30 volcanic centers; these include shield and cinder cone volcanoes. J. E. Allen reported 95 vents in 1975, dividing them into four clusters: 17 vents north of the Columbia River, 14 vents west of the
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was designated upon a petition from the Portland City Council. The park is public land 6 miles (9.7 km) to the southeast of downtown Portland named after a pioneer family, covers an area of 22.63 acres (9.16 ha), including part of the Boring Lava Field. Historically, it sustained a
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under sedimentary rock layers. The borders for the Boring Lava Field group are clear, except on the eastern side where distinguishing between Boring deposits and those from the major Cascade arc are less clear; many geologists have arbitrarily placed the eastern border at a longitude of 122
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operated at Kelly Butte from September 1920 until 1960, supporting patients with communicable disease. A 10 million-US-gallon (38 millionL) water tank stood in the area from 1968 through 2010, when it was replaced with a 25 million-US-gallon (95 millionL) underground reservoir that cost $
215:. The deposits were given this name by R. Treasher in 1942. In 2002, as geochemical and geochronological information on the Boring deposits accumulated, they were designated part of the larger Boring Lava Field. This grouping is somewhat informal and is based on similarities in age and
752:, and the Buttes Conservancy organization. Gresham is one of just a few places in the United States with volcanoes contained in its city limits. Mount Sylvania and Mount Scott lie within the limits of Portland, in the southwestern and southeastern parts of the city, respectively.
3884:
Evarts, R. C.; Conrey, R. M.; Fleck, R. J.; Hagstrum, J. T. (January 2009). O'Connor, J. E.; Dorsey, R. J.; Madin, I. P. (eds.). The Boring Volcanic Field of the Portland-Vancouver area, Oregon and Washington: Tectonically anomalous forearc volcanism in an urban setting.
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million years ago, yielding far-reaching basalt lava flows, the Highland Butte shield volcano, a number of monogenetic vents, and one andesitic lava flow. These took place near the southern Portland Basin, and were followed by about 750,000 years of quiescence. About
712:, the deepest train station in North America, located 260 feet (80 m) underground. The station displays a core that exhibits Boring Lava deposits. For the first 3,900 feet (1,200 m) of the tunnel, the core shows Boring lava flows with cinder, breccia, and
625:. They also developed skill as craftspeople in making clothing, baskets, tools, and architecture. Local indigenous populations were greatly reduced after forced displacement and disease, but a small Native American community persists in Multnomah County.
992:, but they are similar in age. There is a small amount of andesite in the lavas from the field, mostly erupted from monogenetic vents or Larch Mountain. Sometimes, Boring Lava overlaps with volcaniclastic conglomerate from other Cascade eruptions in
720:
million to 120,000 years ago, which have been deformed by the Sylvan fault. With the Oatfield fault, the Sylvan fault trends to the northwest, extending 9.3 miles (15 km) northwest and 16 miles (25 km) southeast of the tunnel. It is of
728:
In 2000, the nonprofit Friends of Mt. Tabor Park was formed to help maintain the Mount Tabor Park area, located 3.5 miles (5.6 km) east of downtown Portland. They have an organizational website and publish a bi-annual newsletter called the
159:
million years ago, with long periods of eruptive activity interspersed with quiescence. Its last eruptions took place about 57,000 years ago at the Beacon Rock cinder cone volcano; the individual volcanic vents of the field are considered
857:(a depressed block of the Earth's crust bordered by parallel faults), and activity at the Boring field and throughout the Portland area may be associated with deformation of the block. Portland lies within the Portland Basin, part of the
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the evacuation of the magma flows. Similarly, faults north of Oregon City might have resulted from subsidence after magma chambers emptied or lava was extruded as a result of Boring Lava eruptions. Some of the Boring Lava vents cut off
865:, which consist of Eocene to Miocene marine sedimentary rock deposits and Eocene intrusions and extrusions of basalt that were emplaced on the Siletz terrane. The eastern boundary for the Portland Basin is the Cascades, while the
179:, including suburbs, is one of the few places in the continental United States to have extinct volcanoes within a city's limits, and the Boring Lava Field plays an important role in local affairs, including the development of the
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age of 105,000 ± 6,000 years. These eruptions followed a relatively even age distribution over time; younger vents and associated deposits lie in the northern portion of the field, while older deposits are confined to the south.
740:, encompassing an area of 46 acres (19 ha) that includes the extinct Boring Lava Field volcano Hogan Butte. This park opened after more than 25 years of processing, supported by a 1990 bond from the city and two regional
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sedimentary rock deposits from the Missoula Floods (also known as the Bretz or Ice Age Floods), which took place between 21,000 and 15,000 years ago and probably destroyed small cinder cones (including those made from
952:; these sub-alkaline basalts and basaltic andesite predominate among Boring Lava deposits. The olivine basalt deposits have fine to medium textures, and the basaltic andesite lava flow deposits have relatively little
1024:, which at the Boring Lava Field has reached depths of up to 25 feet (7.6 m), altering the upper 5 to 15 feet (1.5 to 4.6 m) of soil to a red, clay-like material. At the cinder cone in Mount Tabor Park, an
852:
The High Cascades, a segment of the Cascade volcanic arc that includes the Boring Lava Field, is characterized by basaltic lava flows with andesite, tuff breccia, and volcanic ash. The High Cascades may lie over a
3738:
Blakely, R. J.; Wells, R. E.; Yelin, T. S.; Madin, I. P.; Beeson, M. H. (September 1995). "Tectonic setting of the Portland-Vancouver area, Oregon and Washington: Constraints from low-altitude aeromagnetic data".
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from 5 a.m. through midnight and to motorized vehicles from 5 a.m. through 10 p.m. each day, except for Wednesdays when the park roads are not open to automobiles. The Hogan Butte Nature Park offers views of
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data available for the lava field, and despite the field's proximity to an urban area, little was known about its composition until recent years. Weathering, fine grain size, and glassy content further limit
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provided a list of potentially threatened or endangered species in the Boring Lava area, labeling them "sensitive" species. Among plant species, they determined the following species to be sensitive:
3858:
Conrey, R. M.; Uto, K.; Uchiumi, S.; Beeson, M. H.; Madin, I. P.; Tolan, T. L.; Swanson, D. A. (November 1996). "Potassium-argon ages of Boring Lava, northwest Oregon and southwest Washington".
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eruptive products. Some of the low-K tholeiite deposits likely originated from vents closer to the High Cascades, and they are overlain by Boring Lava materials. J. M. Shempert, a geologist at
255:
reaching elevations of 400 feet (120 m). The Willamette Valley is marked by hills reaching heights of more than 1,000 feet (300 m), and it is also physically separated from the lower
1056:
due to the Boring Lava pushing down on rock from the Troutdale formation. Intrusions of Boring Lava formed outcrops at Highland Butte, La Butte, and potentially in the subsurface regions near
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meets with a subduction zone and plate divergence at the ridge and convergence at the subduction zone continue, causing the ridge to be subducted), they likely interacted with the regional
809:. The Global Volcanism Program reports that the field includes somewhere between 32 and 50 shield volcanoes and cinder cones, with many vents concentrated northwest of the town of Boring.
4121:
Le Corvec, N.; Spörli, K. B.; Rowland, J.; Lindsay, J. (September 2013). "Spatial distribution and alignments of volcanic centers: Clues to the formation of monogenetic volcanic fields".
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3800:
Chan, C. F.; Tepper, J. H.; Nelson, B. K. (July 2012). "Petrology of the Grays River volcanics, southwest Washington: Plume-influenced slab window magmatism in the Cascadia forearc".
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821:, the Boring Lava Field lies about 62 miles (100 km) to the west of the major Cascade crest. It marks one of five volcanic fields along the Quaternary Cascade arc, along with
1104:(USGS). Mount Tabor is also prominent in the area, dated by the USGS to 203,000 ± 5,000 years old, as are Kelly Butte, Powell Butte, and Mount Scott. Scott has been dated to 1.6
305:
aquifer, is also made of sandstone and conglomerate and bears water well. It also supplies water to domestic wells in the Mount Norway area. Boring Lava is known to have formed
3986:"Paleomagnetism and 40Ar/39Ar geochronology of the Plio-Pleistocene Boring Volcanic Field: Implications for the geomagnetic polarity time scale and paleosecular variation"
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780:
There are 90 volcanic centers within a 20-mile (32 km) radius of Troutdale and more than 32 vents within a 13-mile (21 km) radius of Kelly Butte. Mostly small
41:
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in the Lava Field area host diverse species, and they are influenced by uplands that serve as migration connections for birds, mammals, reptiles, and some amphibians.
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degrees west. In total, the Boring Lava Field covers an area of about 1,500 square miles (4,000 km), and it has a total volume of 2.4 cubic miles (10 km).
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Evarts et al. (2009) list only 80 centers but acknowledge there are likely more buried vents; Le Corvec et al. (2013) list 88 volcanic centers at Boring Lava Field.
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657:(under guard supervision) to gather crushed rocks for building roads in Portland until the 1950s. In general, rocks from the Boring Lava Field have been used for
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Direction of maximum horizontal compression in western Oregon determined by borehole breakouts. Structure and tectonics of the northern Willamette Valley, Oregon
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people in case an emergency government became necessary. It was known throughout the United States as a model facility for local governments, and in 1957, the
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rocks. Despite the prevalence of quarrying activity in historical times, there is no ongoing mineral or aggregate resource mining near the Boring Lava Field.
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abandoned due to rising costs for renovation and space limitations. That same year the building was vacated, and then it was sealed off in 2006. A sixty-bed
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field have generally produced basalt and basaltic andesite, with some andesitic eruptions, including those that produced the Larch Mountain shield volcano.
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Boring Lava Field represents the youngest episode of volcanism within the Cascade forearc, and while there is no evidence that they were associated with a
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villages and encampments near what is now East Portland, trading with members of the community and describing their plank houses, language, customs, and
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4345:"Olivine and Spinel Systematics of Boring Volcanic Field (BVF) Basalts: Evidence for Magma Source Variations and Interaction Among Basaltic Magmas"
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211:. The term "Boring Lava" is often used to refer to the local deposits erupted by vents in the field. They are located in the western portion of
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Multnomah Creek drains from Larch Mountain, one of the volcanic cones in Boring Lava Field. Local streams near the community of Boring receive
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are "probably minimal", Boring Lava might play a role in determining the intensity of ground shaking during future earthquakes in the area.
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A stratigraphic-geochemical study of the Troutdale Formation and Sandy River Mudstone in the Portland basin and lower Columbia River Gorge
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amenities. It includes the Gabbert Loop Trail, which extends for 1 mile (1.6 km) through forests of maples, alders, ferns, and firs.
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degrees, as well as minor faults. The landslides range in thickness from 20 to 79 feet (6 to 24 m). Portland's wet climate leads to
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Eruptive vents on the western edge of the field formed along a fault line that trended to the northeast, located north of present-day
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constituted one of the most densely populated communities in the Pacific Northwest, made up predominantly of Chinook people including
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The Boring Lava Field shows a similar composition to the High Cascades that run through Oregon and southern Washington state, with
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Low-K is a geological term used to describe lava with low amounts of potassium, while high-K describes lava enriched in potassium.
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474:
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Lowry, W. D.; Baldwin, E. M. (January 1952). "Late Cenozoic Geology of the Lower Columbia River Valley, Oregon and Washington".
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laths that show a pilotaxitic texture with spaces between them that show a diktytaxitic texture. The Boring Lava exposures show
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937:, proposed that mantle sources for the two different lava types may be different and that the calc-alkaline sources are more
234:; most vents reach an elevation of 660 to 980 feet (200 to 300 m). Located in the Portland Basin, the field consists of
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for the field. Recent argon–argon dating suggests that eruptive activity at the Boring Lava Field began between 2.6 and 2.4
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Boring Lava Domes: Supplement To The Johnson Creek Basin Protection Plan And Minor Amendments to Environmental Regulations
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1971:
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A self-guided tour of the geology of the Columbia River Gorge – Portland Airport to Skamania Lodge, Stevenson, Washington
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magma, and the subducting Juan de Fuca plate may be as shallow as 50 miles (80 km) in depth at their location.
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A core sample showing Portland's geological history, which includes Boring Lava Field deposits, is exhibited on the
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4158:"Variability of the 0–3 Ma palaeomagnetic field observed from the Boring Volcanic Field of the Pacific Northwest"
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3947:"40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA"
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The Boring Volcanic Field of the Portland Basin: Diverse Primitive Mafic Magmas Erupted in a Frontal Arc Setting
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percent. Cool and clear, many sustain macroinvertebrates, and a smaller number support amphibians and fish. The
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anomalies with short wavelengths and high amplitudes suggestive of their relatively young geological ages.
155:. Boring lies southeast of the densest cluster of lava vents. The zone became volcanically active about 2.7
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age and lacks surface expression, possibly as a result of its extensive burial by loess along its length.
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into the early Quaternary. Within the field, lava shows a diverse composition overall, varying from low-
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The buttes of the Boring Lava Field are visible toward the center of this panorama of Portland, Oregon.
930:
841:, but it has a different tectonic position, with its eruptive activity more likely related to tectonic
606:
360:
235:
176:
5685:
5095:
5079:
5024:
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4344:
3876:
2313:
1644:
Refractory refers to any material that does not easily convert from liquid to gas via the process of
1037:
934:
749:
3918:"The Boring Volcanic Field of the Portland, Oregon Area: Geochronology and Neotectonic Significance"
3917:
5781:
5420:
5410:
4971:
3887:
Volcanoes to Vineyards: Geologic Field Trips Through the Dynamic Landscape of the Pacific Northwest
1962:
1598:
1183:
997:
993:
969:
733:. Membership requires dues, and they also rely on donations and a gift shop for financial support.
645:
622:
554:
223:
5847:
5501:
5456:
5029:
4538:
4171:
4027:
Lithology, thickness, and extent of hydrogeologic units underlying the East Portland area, Oregon
2308:
1967:
984:. The Boring Lava reaches thicknesses of more than 400 feet (120 m). Boring Lava has a more
926:
829:
chain, and Caribou in California. Like the Cascade Range, the Boring field was also generated by
688:
5725:
5660:
5556:
5405:
5236:
5226:
5221:
5195:
5191:
5187:
5183:
5159:
5090:
4931:
4875:
4791:
1743:
1534:
621:. They imported slaves, traded among villages, and acted as intermediaries for the English and
490:
4479:
Treacher, R. C. (1942). Geologic History of the Portland Area: DOGAMI Short Paper 7 (Report).
5927:
5745:
5740:
5695:
5655:
5377:
5047:
4951:
4757:
4231:
4123:
3945:
Fleck, R. J.; Hagstrum, J. T.; Calvert, A. T.; Evarts, R. C.; Conrey, R. M. (December 2014).
3597:
3337:
3233:
3195:
1683:
494:
334:
4400:
1520:
Eruptions took place in areas that are now populated, such as this community on Mount Scott.
6138:
5798:
5720:
5481:
4918:
4678:
4271:
Geologic Map 119, Geologic Map of the Oregon City 7.5' quadrangle, Clackamas County, Oregon
4210:
4175:
4136:
4003:
3962:
3846:
3813:
3752:
1279:
862:
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773:
482:
284:
8:
6057:
6005:
5995:
5980:
5516:
5262:
5178:
4701:
3602:
1116:
1005:
745:
558:
550:
526:
518:
506:
447:
428:
259:
valley. The Columbia River flows west from the eastern Portland region, merging with the
70:
4214:
4179:
4140:
4007:
3966:
3850:
3817:
3756:
6044:
5872:
5645:
5589:
5561:
5286:
1548:
960:
were uncommon within the field. Dark gray to light gray in color, Boring Lava produces
957:
866:
834:
769:
586:
542:
510:
498:
404:
388:
364:
195:
144:
59:
3685:
6015:
5898:
5793:
5675:
4567:
4507:
4455:
4385:
4316:
4281:
4094:
4045:
4037:
3902:
3776:
3646:
1560:
961:
949:
534:
530:
416:
412:
400:
299:
252:
203:
The Boring Lava deposits received their name based on their proximity to the town of
136:
4148:
3718:
1572:
57,000 years ago, which was eroded by the Missoula Floods to leave only its central
5972:
5913:
5705:
5700:
5584:
5392:
5382:
5299:
4981:
4831:
4497:
4445:
4410:
4218:
4183:
4144:
4084:
4011:
3970:
3894:
3821:
3772:
3760:
2367:
1606:
953:
846:
845:
throughout the region. The Boring Lava Field has erupted material derived from hot
705:
618:
610:
599:
595:
591:
444:
420:
396:
344:
322:
310:
260:
208:
180:
152:
128:
117:
75:
2832:
2830:
2675:
2673:
2102:
2100:
2098:
2096:
6010:
5942:
5937:
5822:
5771:
5367:
5272:
5231:
4986:
4438:
A description of hydrogeologic units in the Portland Basin, Oregon and Washington
4437:
4026:
1839:
1837:
1835:
1833:
1831:
1829:
1556:
1529:
1260:
1045:
1000:. The Boring Lava also contains tuff, cinder, and scoria; it is characterized by
965:
884:
737:
566:
514:
424:
380:
280:
276:
251:
With a variable topography, the Portland area ranges from river valley floors to
3898:
3497:
6052:
5887:
5857:
5809:
5785:
5665:
5476:
5251:
5241:
5216:
5201:
5154:
5143:
5135:
5130:
5074:
5055:
5000:
4946:
4913:
4908:
4893:
4870:
4844:
4839:
4772:
4762:
4673:
4645:
4156:
Lhuillier, F.; Shcherbakov, V. P.; Gilder, S. A.; Hagstrum, J. T. (July 2017).
4016:
3985:
3564:
2827:
2752:
2670:
2093:
2081:
1957:
1516:
1267:
1069:
1057:
826:
789:
682:
662:
582:
538:
478:
440:
306:
272:
256:
204:
184:
148:
120:
32:
1826:
263:
near Portland before moving north. Tributaries for the Willamette include the
6097:
6040:
5908:
5903:
5877:
5827:
5730:
5619:
5571:
5541:
5491:
5486:
5451:
5430:
5334:
5282:
5267:
5042:
5034:
4936:
4811:
4637:
4511:
4489:
4459:
4285:
4098:
4073:
3984:
Hagstrum, J. T.; Fleck, R. J.; Evarts, R. C.; Calvert, A. T. (January 2017).
3780:
3487:
3485:
2202:
2200:
1602:
1573:
1291:
822:
818:
708:
runs for 2.9 miles (4.7 km) through the Tualatin Mountains. It contains
603:
467:
451:
392:
268:
264:
63:
4436:
Swanson, R. D.; McFarland, W. D.; Gonthier, J. B.; Wilkinson, J. M. (1993).
4320:
4049:
3833:
Conrey, R. M.; Leeman, W. P.; Streck, M. J.; Evarts, R. C. (December 2003).
3621:
3538:
3536:
3003:
2607:
2163:
2161:
2159:
2146:
2144:
6082:
5867:
5862:
5852:
5763:
5715:
5650:
5637:
5521:
5324:
5206:
5125:
5120:
5115:
5100:
5069:
4976:
4941:
4923:
4903:
4860:
4855:
4826:
4816:
4801:
4777:
4767:
4752:
4737:
4724:
4709:
4683:
4668:
4655:
3916:
Fleck, R. J.; Evarts, R. C.; Hagstrum, J. T.; Valentine, M. J. (May 2002).
3026:
3024:
3022:
3020:
3018:
2597:
2595:
1993:
1991:
1989:
1854:
1852:
1645:
1555:
The products of the Boring Lava Field were erupted discontinuously over an
1207:
1062:
1053:
944:
Like the surrounding High Cascades, Boring Lava Field erupted lava made of
888:
654:
486:
459:
124:
46:
Mount Sylvania in Portland, Oregon, one of the major volcanoes in the field
3482:
2344:
2197:
2185:
1895:
1785:
1783:
1781:
1779:
1777:
1775:
427:
can be observed. Other trees that sometimes dominate forest areas include
6077:
6072:
6067:
5962:
5670:
5531:
5526:
5354:
4961:
4956:
4865:
4796:
4719:
4714:
4650:
4188:
4157:
3533:
2479:
2173:
2156:
2141:
1577:
1219:
1089:
1001:
977:
904:
880:
806:
781:
666:
613:. Chinookian villages married amongst themselves and with members of the
570:
546:
522:
408:
384:
352:
314:
161:
3015:
2991:
2740:
2592:
2416:
1986:
1849:
1080:
1048:
blocks to the southeast of Portland. Along the Washougal River, a large
431:
and red alder. Forest communities have many additional shrubs including
5832:
5690:
5680:
5461:
5446:
5246:
5167:
4966:
4688:
4660:
4041:
3975:
3946:
2543:
2541:
1772:
1021:
989:
981:
830:
765:
760:
722:
562:
368:
287:. The Columbia River has significantly shaped the geology of the area.
4594:
4450:
4415:
4089:
2776:
2497:
5837:
5309:
4821:
3825:
2441:
1112:
1049:
1029:
922:
910:
870:
785:
736:
In September 2017, the Hogan Butte Nature Park opened in the city of
678:
372:
302:
227:
216:
132:
2538:
1931:
462:, with moderate to low flows and average gradients between 10 and 12
343:
century. These cleared and burned land plots sustain rich stands of
4132:
3999:
3719:
East Portland Historical Overview & Historic Preservation Study
3470:
2658:
2624:
2622:
1033:
918:
914:
900:
614:
502:
432:
4502:
4155:
3721:(Report). City of Portland Bureau of Planning and Sustainability.
3503:
4625:
4435:
2836:
2758:
2679:
2106:
2087:
1843:
1041:
1025:
1013:
945:
858:
658:
632:
295:
97:
2634:
2619:
988:(rich in magnesium in iron) composition than the nearby volcano
4629:
2898:
2304:"Kelly Butte Civil Defense Center and Kelly Butte Natural Area"
1919:
1663:
1661:
1610:
973:
907:
854:
670:
650:
356:
212:
199:
A hiker atop Larch Mountain, the highest elevation in the field
140:
55:
4490:
Geology of Portland, Oregon, and adjacent areas: Bulletin 1119
4343:
Shempert, J. M.; Streck, M. J.; Leeman, W. P. (October 2009).
4315:(Report). Washington Division of Geology and Earth Resources.
1576:. While the known volcanic vents in the Boring Lava Field are
4120:
3627:
985:
713:
653:, prompting the creation of the Kelly Butte Jail, which used
436:
376:
222:
The Boring Lava deposits lie west of the town of Boring. The
4074:
Quaternary Magmatism in the Cascades – Geologic Perspectives
3915:
3771:
2613:
2601:
2350:
2206:
2191:
2179:
2167:
2150:
1658:
3765:
10.1130/0016-7606(1995)107<1051:TSOTPV>2.3.CO;2
3036:
842:
802:
798:
794:
348:
3983:
3944:
3491:
1901:
1858:
3883:
3542:
3030:
3009:
2997:
2746:
2474:
1997:
1864:
1789:
1744:"The Boring Volcanic Field – Hills of the Portland Basin"
1648:, which includes elements and compounds made from metals.
801:
craters, burying them under up to 98 feet (30 m) of
207:, which lies 12 miles (20 km) southeast of downtown
3832:
3161:
3159:
3157:
3155:
3153:
3151:
3149:
3147:
3145:
3080:
2925:
2915:
2913:
2876:
2874:
2872:
2859:
2857:
2558:
2556:
2547:
2234:
2232:
2219:
2217:
2215:
2071:
2069:
2067:
187:
from its historic eruptions may affect ground movement.
168:
precipitation. The highest elevation of the field is at
16:
Plio-Pleistocene volcanic field in Oregon, United States
4223:
10.1130/0016-7606(1952)63[1:LCGOTL]2.0.CO;2
3178:
3176:
3174:
3143:
3141:
3139:
3137:
3135:
3133:
3131:
3129:
3127:
3125:
3112:
3110:
3097:
3095:
3070:
3068:
3066:
3053:
3051:
2942:
2940:
2805:
2803:
2516:
2514:
2512:
2131:
2129:
2127:
2054:
2052:
2050:
2037:
2035:
2033:
2008:
2006:
1885:
1883:
1881:
1879:
1816:
1814:
1812:
1810:
1016:
to flat. A number of these exposures show dips up to 35
980:
with olivine phenocrysts that have been transformed to
279:
Rivers; tributaries for the Columbia River include the
172:, which reaches a height of 4,055 feet (1,236 m).
3873:
Downstream Effects of Glaciers on Stream Water Quality
3857:
3775:(Report). Portland Bureau of Planning. November 1997.
3737:
3521:
3476:
3376:"Feature Detail Report ID 1136814: Mount Tabor Summit"
2782:
2712:"Description: The Boring Lava Field, Portland, Oregon"
2503:
2332:
2018:
1566:
968:, which can be seen in Oregon east of Portland and in
883:(a gap that forms in a subducted oceanic plate when a
744:
bonds. Collaborators for opening the park include the
151:, located 12 miles (20 km) southeast of downtown
4375:
4349:
Geological Society of America Abstracts with Programs
3509:
2910:
2886:
2869:
2854:
2842:
2815:
2685:
2553:
2526:
2268:
2256:
2244:
2229:
2212:
2064:
1937:
1795:
423:; within swamps and moist areas in creeks, the shrub
4342:
4232:"Portland, Oregon, geology by tram, train, and foot"
3922:
Programs with Aspects: Geological Society of America
3171:
3122:
3107:
3092:
3063:
3048:
2937:
2800:
2764:
2664:
2646:
2580:
2568:
2509:
2394:
2280:
2124:
2112:
2047:
2030:
2003:
1876:
1807:
4481:
Oregon Department of Geology and Mineral Industries
4278:
Oregon Department of Geology and Mineral Industries
4247:
Oregon Department of Geology and Mineral Industries
3698:
Oregon Department of Geology and Mineral Industries
3662:
Oregon Department of Geology and Mineral Industries
2788:
2372:
The Landscape Architect's Guide to Portland, Oregon
1907:
371:. Myriad species of fern, as well as rapid-growth
4052:. Water-Resources Investigations Report 88-4110.
4024:
2904:
1925:
976:, though one sample from Rocky Butte consists of
6095:
3799:
2640:
2628:
2470:"Gresham opens Hogan Butte Nature Park Saturday"
894:
784:vents, these volcanoes also include some larger
764:Volcanism in the Boring Lava Field results from
3911:. Geological Society of America Field Guide 15.
3350:National Oceanic and Atmospheric Administration
3246:National Oceanic and Atmospheric Administration
3208:National Oceanic and Atmospheric Administration
2957:
2955:
2436:
2434:
2411:
2409:
1696:National Oceanic and Atmospheric Administration
4376:Siebert, L.; Simkin, T.; Kimberly, P. (2011).
581:The nearby Portland area was inhabited by the
4610:
383:are also frequent. Forests support stands of
4307:
4196:
3991:Physics of the Earth and Planetary Interiors
3330:
3042:
2952:
2431:
2406:
1870:
1079:
557:have been identified as species of concern;
4308:Norman, D. K.; Roloff, J. M. (March 2004).
1678:
1676:
4617:
4603:
4557:
4025:Hartford, S. V.; McFarland, W. D. (1989).
3593:"Hogan Butte Nature Park to open Sept. 23"
3188:
2706:
2704:
2702:
2700:
2301:
1667:
1609:, as well as running trails and sites for
147:. The field got its name from the town of
4501:
4449:
4414:
4187:
4088:
4015:
3974:
3560:"A hidden hike among Gresham's volcanoes"
3308:"The Boring Lava Field: Portland, Oregon"
3226:
2467:
2297:
2295:
1738:
1736:
4478:
4071:
3716:
3686:"Volcanoes of the Portland Area, Oregon"
3584:
3553:
3551:
3456:United States Department of the Interior
3420:United States Department of the Interior
3286:United States Department of the Interior
2963:"Volcanoes of the Portland Area, Oregon"
2532:
2376:American Society of Landscape Architects
2274:
2262:
2250:
2238:
2223:
1801:
1734:
1732:
1730:
1728:
1726:
1724:
1722:
1720:
1718:
1716:
1673:
1515:
759:
631:
333:
194:
4624:
4545:from the original on September 26, 2020
4487:
4398:
3870:
3787:from the original on September 18, 2016
3527:
3515:
2931:
2919:
2848:
2821:
2697:
2691:
2562:
2361:
2359:
2338:
2320:from the original on September 28, 2018
2286:
2135:
2118:
2075:
2041:
2024:
2012:
1974:from the original on September 28, 2018
1820:
1760:from the original on September 30, 2018
1329:The following vents are in Washington:
475:United States Fish and Wildlife Service
6124:Extinct volcanoes of the United States
6096:
5883:John Day Fossil Beds National Monument
4530:
4268:
4229:
3741:Geological Society of America Bulletin
3609:from the original on November 29, 2017
3590:
3057:
2892:
2880:
2863:
2809:
2794:
2652:
2586:
2520:
2463:
2461:
2459:
2400:
2292:
2058:
1952:
1950:
1948:
1946:
1913:
1333:Boring Lava Field Vents in Washington
6109:Volcanic fields of Washington (state)
5843:Fort Rock-Christmas Lake Valley Basin
4598:
4423:from the original on October 11, 2018
4363:from the original on October 11, 2018
4330:from the original on January 31, 2017
4256:from the original on October 30, 2020
4108:from the original on January 31, 2021
3932:from the original on December 4, 2008
3683:
3644:
3548:
3386:from the original on January 31, 2021
3182:
3165:
3116:
3101:
3086:
3074:
2946:
2770:
2574:
1889:
1713:
1528:Prior to the 1990s, there was little
246:
4518:from the original on August 16, 2018
4466:from the original on August 16, 2018
4295:from the original on October 5, 2018
3725:from the original on January 1, 2016
3704:from the original on August 25, 2018
3572:from the original on October 3, 2018
3557:
3434:
3354:United States Department of Commerce
3250:United States Department of Commerce
3212:United States Department of Commerce
2485:from the original on October 3, 2018
2468:Rafanelli, R. (September 23, 2017).
2382:from the original on October 3, 2018
2365:
2356:
1700:United States Department of Commerce
1092:comparisons, with a few exceptions.
874:crustal expansion. Over the last 2.7
3671:from the original on March 15, 2017
3447:Geographic Names Information System
3411:Geographic Names Information System
3380:Geographic Names Information System
3277:Geographic Names Information System
2724:. November 29, 1999. Archived from
2456:
1943:
1938:Siebert, Simkin & Kimberly 2011
1567:Recent activity and current threats
1511:
1324:
1133:The following vents are in Oregon:
972:in Washington state. It is usually
812:
338:Old-growth forest at Larch Mountain
226:lists the volcanic field's highest
13:
3864:Nevada Bureau of Mines and Geology
2665:Shempert, Streck & Leeman 2009
1137:Boring Lava Field Vents in Oregon
443:. Ground layer plants include the
14:
6165:
4583:
4163:Geophysical Journal International
3591:Keizur, C. (September 20, 2017).
3318:from the original on July 1, 2011
2444:. Friends of Mt. Tabor Park. 2018
2419:. Friends of Mt. Tabor Park. 2018
2302:Blackbourn, N. (March 17, 2018).
1640:
1633:
1626:
704:Built between 1993 and 1998, the
298:. This unit, part of the greater
230:as 4,055 feet (1,236 m), at
4558:Wood, C. A.; Kienle, J. (1990).
4059:from the original on May 1, 2019
2975:. April 23, 2008. Archived from
2351:Portland Bureau of Planning 1997
2207:Portland Bureau of Planning 1997
2192:Portland Bureau of Planning 1997
2180:Portland Bureau of Planning 1997
2168:Portland Bureau of Planning 1997
2151:Portland Bureau of Planning 1997
1495:
917:. It was active during the late
313:, and thus it may guide flow of
40:
6154:Volcanoes of Washington (state)
4494:United States Geological Survey
4442:United States Geological Survey
4149:10.1016/j.earscirev.2013.05.005
4081:United States Geological Survey
4034:United States Geological Survey
3684:Allen, J. E. (September 1975).
3645:Allen, J. E. (September 1974).
3452:United States Geological Survey
3416:United States Geological Survey
3398:
3368:
3312:United States Geological Survey
3300:
3282:United States Geological Survey
3264:
2973:United States Geological Survey
2722:United States Geological Survey
2417:"The Friends of Mt. Tabor Park"
1754:United States Geological Survey
1128:
1102:United States Geological Survey
1065:units in the surrounding area.
573:are also considered sensitive.
326:potentially destructive force.
164:, but the field itself is not.
4382:University of California Press
3871:Dougall, J. A. (August 2007).
2641:Chan, Tepper & Nelson 2012
2629:Chan, Tepper & Nelson 2012
1075:
551:Pacific western big-eared bats
525:. For animal and marine life,
1:
6144:Geography of Portland, Oregon
4590:USGS Map of Boring Lava Field
4357:Geological Society of America
4207:Geological Society of America
3959:Geological Society of America
3926:Geological Society of America
3891:Geological Society of America
3810:Geological Society of America
3749:Geological Society of America
3717:Anderson, Susan, ed. (2009).
3647:"The Catlin Gabel Lava Tubes"
2905:Hartford & McFarland 1989
1926:Hartford & McFarland 1989
1652:
1591:
895:Composition and local setting
839:North American tectonic plate
817:Considered an outlier of the
774:North American tectonic plate
617:tribe as well as the coastal
5895:Lava Butte (Basin and Range)
5815:Devils Garden Volcanic Field
5691:Lava Butte (Newberry/Tumalo)
5610:Willamette National Cemetery
5111:Sand Mountain Volcanic Field
3558:Hale, J. (October 3, 2017).
2968:Cascades Volcano Observatory
2717:Cascades Volcano Observatory
1749:Cascades Volcano Observatory
190:
7:
5986:Columbia River Basalt Group
5868:Harney Basin Volcanic Field
5567:Southern Oregon Coast Range
5212:Tom Dick and Harry Mountain
4101:. Professional Paper 1744.
835:Juan de Fuca tectonic plate
770:Juan de Fuca tectonic plate
585:, though much of the local
10:
6170:
5711:Oregon Badlands Wilderness
5600:Upper and Lower Table Rock
4885:Little Chinquapin Mountain
4564:Cambridge University Press
4560:Volcanoes of North America
4017:10.1016/j.pepi.2016.07.008
3843:American Geophysical Union
3839:AGU Fall Meeting Abstracts
3636:
2368:"Powell Butte Nature Park"
1200:4,061 feet (1,238 m)
869:lie to the west, along an
755:
669:, especially oxidized and
576:
329:
177:Portland metropolitan area
6104:Volcanic fields of Oregon
6063:Cobb-Eickelberg Seamounts
6039:
5971:
5780:
5618:
5281:
4743:Davis Lake Volcanic Field
4636:
4407:Portland State University
3877:Portland State University
3568:. Oregonian Media Group.
2314:Oregon Historical Society
1481:
1471:
1461:
1451:
1441:
1431:
1421:
1411:
1401:
1390:
1380:
1370:
1360:
1348:
1343:
1340:
1337:
1312:
1302:
1290:
1278:
1266:
1250:
1240:
1230:
1218:
1206:
1194:
1182:
1172:
1162:
1152:
1147:
1144:
1141:
1115:were documented near the
996:and the northern part of
956:in them, suggesting that
935:Portland State University
750:The Trust for Public Land
748:, local citizens, Metro,
555:northern red-legged frogs
527:northwestern pond turtles
96:
85:4,061 feet (1,238 m)
81:
69:
51:
39:
30:
23:
5759:Wildcat Mountain Caldera
3346:National Geodetic Survey
3242:National Geodetic Survey
3204:National Geodetic Survey
3043:Norman & Roloff 2004
1963:Global Volcanism Program
1871:Lowry & Baldwin 1952
1692:National Geodetic Survey
1620:
1485:1,400 feet (427 m)
1455:1,395 feet (425 m)
1445:1,113 feet (339 m)
1435:1,465 feet (447 m)
1425:1,010 feet (308 m)
1415:1,111 feet (339 m)
1384:1,690 feet (515 m)
1374:1,775 feet (541 m)
1364:2,110 feet (643 m)
1316:2,450 feet (747 m)
1306:1,275 feet (389 m)
1256:1,093 feet (333 m)
1234:1,380 feet (421 m)
1176:1,594 feet (486 m)
1052:occurred as a result of
825:, Tumalo in Oregon, the
646:Kelly Butte Natural Area
483:golden Indian paintbrush
224:Global Volcanism Program
6073:Devils Elbow State Park
6021:Saddle Mountains Basalt
5848:Four Craters Lava Field
5472:Mount Scott (Clackamas)
4539:Oregon State University
4488:Trimble, D. E. (1963).
4399:Swanson, R. D. (1986).
4172:Oxford University Press
3899:10.1130/2009.fld015(13)
2309:The Oregon Encyclopedia
1968:Smithsonian Institution
710:Washington Park station
638:Washington Park station
143:and adjacent southwest
5938:Squaw Ridge Lava Field
5928:Powder River Volcanics
5924:Powder River Volcanics
5557:Siletz River Volcanics
5431:Little Butte Volcanics
5237:Tumalo Volcanic Center
4899:Lost Lake Cinder Cones
4531:Werner, K. S. (1991).
4378:Volcanoes of the World
4269:Madin, I. P. (2009b).
4230:Madin, I. P. (2009a).
3845:. pp. V31E–0981.
1668:Wood & Kienle 1990
1530:potassium-argon dating
1521:
1475:555 feet (169 m)
1465:610 feet (186 m)
1405:804 feet (245 m)
1394:680 feet (207 m)
1354:509 feet (155 m)
1296:715 feet (218 m)
1284:630 feet (192 m)
1272:978 feet (298 m)
1244:995 feet (303 m)
1224:612 feet (187 m)
1212:614 feet (187 m)
1188:400 feet (122 m)
1166:718 feet (219 m)
1156:890 feet (271 m)
1084:
777:
641:
519:Nelson's checkermallow
339:
200:
82:Highest elevation
6134:Pleistocene volcanism
5746:Smith Rock State Park
5656:Crooked River Caldera
5633:Bald Mountain Caldera
4996:Mount Scott (Klamath)
4881:Little Cache Mountain
4124:Earth-Science Reviews
4072:Hildreth, W. (2007).
3628:Le Corvec et al. 2013
3504:Lhuillier et al. 2017
1756:. November 13, 2017.
1519:
1083:
763:
635:
337:
198:
139:of the U.S. state of
114:Boring Volcanic Field
6114:Subduction volcanoes
5953:Strawberry Volcanics
5502:Oregon's Matterhorns
5056:Pine Marten Mountain
5030:Oregon's Matterhorns
3893:. pp. 253–270.
3442:"Battle Ground Lake"
3382:. October 11, 2018.
2979:on December 14, 2012
1859:Hagstrum et al. 2017
863:Pacific Coast Ranges
665:, garden walls, and
598:. In 1805 and 1806,
559:pileated woodpeckers
543:long-legged myotises
6149:Volcanoes of Oregon
6058:Brown Bear Seamount
6006:Hat Rock State Park
5991:Grande Ronde Basalt
5948:Strawberry Mountain
5661:Deschutes Formation
5263:Williamson Mountain
5179:Three Fingered Jack
5148:South Pinhead Butte
5018:North Pinhead Butte
4734:Cupit Mary Mountain
4702:Chinquapin Mountain
4215:1952GSAB...63....1L
4180:2017GeoJI.211...69L
4141:2013ESRv..124...96L
4008:2017PEPI..262..101H
3967:2014Geosp..10.1283F
3851:2003AGUFM.V31E0981C
3818:2012GSAB..124.1324C
3757:1995GSAB..107.1051B
3603:Pamplin Media Group
3234:"Rocky Butte Reset"
3089:, pp. 149–151.
3012:, pp. 256–257.
2837:Swanson et al. 1993
2783:Blakely et al. 1995
2759:Swanson et al. 1993
2680:Swanson et al. 1993
2504:Blakely et al. 1995
2442:"Visiting the Park"
2107:Swanson et al. 1993
2088:Swanson et al. 1993
1844:Swanson et al. 1993
1670:, pp. 170–172.
1381:Bob's Mountain (S)
1371:Bob's Mountain (N)
1334:
1138:
1117:Catlin Gabel School
1108:million years ago.
958:explosive eruptions
746:U.S. Forest Service
661:projects including
535:long-eared myotises
507:Bradshaw's lomatium
112:(also known as the
6129:Pliocene volcanism
6045:Juan de Fuca Ridge
5873:Hole-in-the-Ground
5750:Tea Table Mountain
5590:Tualatin Mountains
5287:Oregon Coast Range
5256:West Pinhead Butte
4889:Little Nash Crater
4866:Little Aspen Butte
4189:10.1093/gji/ggx288
3976:10.1130/GES00985.1
3841:. Vol. 2003.
3543:Evarts et al. 2009
3477:Conrey et al. 1996
3458:. October 11, 2018
3422:. October 11, 2018
3356:. October 11, 2018
3288:. October 11, 2018
3252:. October 11, 2018
3214:. October 11, 2018
3031:Evarts et al. 2009
3010:Evarts et al. 2009
2998:Evarts et al. 2009
2747:Evarts et al. 2009
2548:Conrey et al. 2003
1998:Evarts et al. 2009
1790:Evarts et al. 2009
1549:radiometric dating
1535:argon–argon dating
1522:
1350:Battle Ground Lake
1332:
1136:
1098:Battle Ground Lake
1085:
867:Tualatin Mountains
778:
689:isolation hospital
642:
623:American fur trade
531:willow flycatchers
523:Oregon sullivantia
340:
247:Physical geography
201:
98:Last eruption
6119:Cascade Volcanoes
6091:
6090:
5899:Mahogany Mountain
5676:Gearhart Mountain
5435:Little Pilot Rock
5345:Crescent Mountain
5320:Boring Lava Field
5131:Sheridan Mountain
4797:Greylock Mountain
4573:978-0-521-43811-7
4451:10.3133/wri904196
4416:10.15760/etd.5604
4391:978-0-520-26877-7
4280:. pp. 1–46.
4090:10.3133/wri884110
3908:978-0-8137-5615-8
3492:Fleck et al. 2014
2934:, pp. 36–37.
2614:Fleck et al. 2002
2602:Fleck et al. 2002
2366:Faha, M. (2018).
1902:Fleck et al. 2014
1491:
1490:
1482:Tum-Tum Mountain
1322:
1321:
1153:Chamberlain Hill
950:basaltic andesite
413:cascara buckthorn
275:, Abernethy, and
137:Willamette Valley
110:Boring Lava Field
106:
105:
25:Boring Lava Field
6161:
5973:Columbia Plateau
5914:Mutton Mountains
5754:Wildcat Mountain
5706:Ochoco Mountains
5701:Newberry Volcano
5686:Grizzly Mountain
5620:Eastern Cascades
5330:Chamberlain Hill
5283:Western Cascades
5039:Peavine Mountain
5006:Mount Washington
4982:Mount McLoughlin
4928:Maklaks Mountain
4909:Lookout Mountain
4832:Howlock Mountain
4785:Frog Lake Buttes
4706:Clear Lake Butte
4619:
4612:
4605:
4596:
4595:
4577:
4554:
4552:
4550:
4527:
4525:
4523:
4505:
4484:
4475:
4473:
4471:
4453:
4432:
4430:
4428:
4418:
4395:
4372:
4370:
4368:
4339:
4337:
4335:
4329:
4314:
4304:
4302:
4300:
4294:
4275:
4265:
4263:
4261:
4255:
4236:
4226:
4193:
4191:
4152:
4117:
4115:
4113:
4107:
4092:
4078:
4068:
4066:
4064:
4058:
4031:
4021:
4019:
3980:
3978:
3941:
3939:
3937:
3912:
3880:
3867:
3854:
3829:
3826:10.1130/B30576.1
3796:
3794:
3792:
3768:
3734:
3732:
3730:
3713:
3711:
3709:
3680:
3678:
3676:
3670:
3651:
3631:
3625:
3619:
3618:
3616:
3614:
3588:
3582:
3581:
3579:
3577:
3555:
3546:
3540:
3531:
3525:
3519:
3513:
3507:
3501:
3495:
3489:
3480:
3474:
3468:
3467:
3465:
3463:
3438:
3432:
3431:
3429:
3427:
3402:
3396:
3395:
3393:
3391:
3372:
3366:
3365:
3363:
3361:
3338:"Sylvania Reset"
3334:
3328:
3327:
3325:
3323:
3304:
3298:
3297:
3295:
3293:
3268:
3262:
3261:
3259:
3257:
3230:
3224:
3223:
3221:
3219:
3192:
3186:
3180:
3169:
3163:
3120:
3114:
3105:
3099:
3090:
3084:
3078:
3072:
3061:
3055:
3046:
3040:
3034:
3028:
3013:
3007:
3001:
2995:
2989:
2988:
2986:
2984:
2959:
2950:
2944:
2935:
2929:
2923:
2917:
2908:
2902:
2896:
2890:
2884:
2878:
2867:
2861:
2852:
2846:
2840:
2834:
2825:
2819:
2813:
2807:
2798:
2792:
2786:
2780:
2774:
2768:
2762:
2756:
2750:
2744:
2738:
2737:
2735:
2733:
2728:on March 2, 2000
2708:
2695:
2689:
2683:
2677:
2668:
2662:
2656:
2650:
2644:
2638:
2632:
2626:
2617:
2611:
2605:
2599:
2590:
2584:
2578:
2572:
2566:
2560:
2551:
2545:
2536:
2530:
2524:
2518:
2507:
2501:
2495:
2494:
2492:
2490:
2465:
2454:
2453:
2451:
2449:
2438:
2429:
2428:
2426:
2424:
2413:
2404:
2398:
2392:
2391:
2389:
2387:
2363:
2354:
2348:
2342:
2336:
2330:
2329:
2327:
2325:
2299:
2290:
2284:
2278:
2272:
2266:
2260:
2254:
2248:
2242:
2236:
2227:
2221:
2210:
2204:
2195:
2189:
2183:
2177:
2171:
2165:
2154:
2148:
2139:
2133:
2122:
2116:
2110:
2104:
2091:
2085:
2079:
2073:
2062:
2056:
2045:
2039:
2028:
2022:
2016:
2010:
2001:
1995:
1984:
1983:
1981:
1979:
1954:
1941:
1935:
1929:
1923:
1917:
1911:
1905:
1899:
1893:
1887:
1874:
1868:
1862:
1856:
1847:
1841:
1824:
1818:
1805:
1799:
1793:
1787:
1770:
1769:
1767:
1765:
1740:
1711:
1710:
1708:
1706:
1680:
1671:
1665:
1643:
1636:
1629:
1607:Mount St. Helens
1545:
1540:
1512:Eruptive history
1499:
1335:
1331:
1325:Washington vents
1139:
1135:
1123:
1107:
1019:
998:Clackamas County
994:Multnomah County
954:pyroclastic rock
877:
813:Regional setting
790:shield volcanoes
719:
706:Robertson Tunnel
695:
619:Tillamook people
611:material culture
600:Meriwether Lewis
539:fringed myotises
511:Kincaid's lupine
499:Willamette daisy
495:peacock larkspur
465:
429:black cottonwood
421:Oregon white oak
393:western redcedar
345:secondary forest
323:Prevailing winds
311:sedimentary rock
242:
181:Robertson Tunnel
158:
135:in the northern
129:shield volcanoes
118:Plio-Pleistocene
102:57,000 years ago
76:Plio-Pleistocene
44:
21:
20:
6169:
6168:
6164:
6163:
6162:
6160:
6159:
6158:
6094:
6093:
6092:
6087:
6035:
6016:Pendleton Vents
6011:Hermiston Butte
5967:
5943:Steens Mountain
5921:Poker Jim Ridge
5918:Pillars of Rome
5823:Diamond Craters
5819:Dooley Mountain
5782:Basin and Range
5776:
5772:Yamsay Mountain
5614:
5547:Saddle Mountain
5512:Pepper Mountain
5443:Lost Lake Butte
5421:Laurel Mountain
5402:Indian Mountain
5383:Harter Mountain
5368:Elk Rock Island
5277:
5273:Zigzag Mountain
5232:Tumalo Mountain
4987:Mount Multnomah
4972:Mount Jefferson
4852:Le Conte Crater
4720:Crater Mountain
4632:
4623:
4586:
4581:
4580:
4574:
4548:
4546:
4521:
4519:
4469:
4467:
4426:
4424:
4392:
4366:
4364:
4333:
4331:
4327:
4312:
4298:
4296:
4292:
4273:
4259:
4257:
4253:
4234:
4111:
4109:
4105:
4076:
4062:
4060:
4056:
4029:
3935:
3933:
3909:
3790:
3788:
3728:
3726:
3707:
3705:
3674:
3672:
3668:
3649:
3639:
3634:
3626:
3622:
3612:
3610:
3589:
3585:
3575:
3573:
3556:
3549:
3541:
3534:
3526:
3522:
3514:
3510:
3502:
3498:
3494:, p. 1312.
3490:
3483:
3475:
3471:
3461:
3459:
3440:
3439:
3435:
3425:
3423:
3406:"Mount Talbert"
3404:
3403:
3399:
3389:
3387:
3374:
3373:
3369:
3359:
3357:
3336:
3335:
3331:
3321:
3319:
3306:
3305:
3301:
3291:
3289:
3270:
3269:
3265:
3255:
3253:
3232:
3231:
3227:
3217:
3215:
3194:
3193:
3189:
3181:
3172:
3164:
3123:
3115:
3108:
3100:
3093:
3085:
3081:
3073:
3064:
3056:
3049:
3045:, pp. 3–4.
3041:
3037:
3029:
3016:
3008:
3004:
2996:
2992:
2982:
2980:
2961:
2960:
2953:
2945:
2938:
2930:
2926:
2918:
2911:
2903:
2899:
2891:
2887:
2879:
2870:
2862:
2855:
2847:
2843:
2835:
2828:
2820:
2816:
2808:
2801:
2793:
2789:
2785:, p. 1055.
2781:
2777:
2769:
2765:
2757:
2753:
2745:
2741:
2731:
2729:
2710:
2709:
2698:
2690:
2686:
2678:
2671:
2663:
2659:
2651:
2647:
2643:, p. 1336.
2639:
2635:
2631:, p. 1334.
2627:
2620:
2616:, p. 1305.
2612:
2608:
2600:
2593:
2585:
2581:
2573:
2569:
2561:
2554:
2546:
2539:
2531:
2527:
2519:
2510:
2506:, p. 1052.
2502:
2498:
2488:
2486:
2466:
2457:
2447:
2445:
2440:
2439:
2432:
2422:
2420:
2415:
2414:
2407:
2399:
2395:
2385:
2383:
2364:
2357:
2349:
2345:
2337:
2333:
2323:
2321:
2300:
2293:
2285:
2281:
2273:
2269:
2261:
2257:
2249:
2245:
2237:
2230:
2222:
2213:
2205:
2198:
2190:
2186:
2178:
2174:
2166:
2157:
2149:
2142:
2134:
2125:
2117:
2113:
2105:
2094:
2086:
2082:
2074:
2065:
2057:
2048:
2040:
2031:
2027:, pp. 5–6.
2023:
2019:
2011:
2004:
1996:
1987:
1977:
1975:
1956:
1955:
1944:
1936:
1932:
1924:
1920:
1912:
1908:
1904:, p. 1283.
1900:
1896:
1888:
1877:
1869:
1865:
1857:
1850:
1842:
1827:
1819:
1808:
1800:
1796:
1788:
1773:
1763:
1761:
1742:
1741:
1714:
1704:
1702:
1682:
1681:
1674:
1666:
1659:
1655:
1623:
1594:
1569:
1557:erosion surface
1543:
1538:
1514:
1509:
1508:
1507:
1505:
1500:
1472:Prune Hill (W)
1462:Prune Hill (E)
1422:Mount Pleasant
1402:Green Mountain
1361:Bob's Mountain
1327:
1261:Harvey W. Scott
1173:Highland Butte
1131:
1121:
1105:
1078:
1017:
897:
885:mid-ocean ridge
875:
833:of the oceanic
815:
768:of the oceanic
758:
717:
716:dated from 1.47
693:
663:retaining walls
579:
567:cutthroat trout
515:Howell's montia
463:
452:stinging nettle
417:Pacific madrone
397:Pacific dogwood
389:western hemlock
332:
294:from the local
249:
240:
193:
156:
92:
47:
35:
26:
17:
12:
11:
5:
6167:
6157:
6156:
6151:
6146:
6141:
6136:
6131:
6126:
6121:
6116:
6111:
6106:
6089:
6088:
6086:
6085:
6080:
6075:
6070:
6065:
6060:
6055:
6053:Axial Seamount
6049:
6047:
6037:
6036:
6034:
6033:
6031:Wanapum Basalt
6028:
6023:
6018:
6013:
6008:
6003:
5998:
5993:
5988:
5983:
5977:
5975:
5969:
5968:
5966:
5965:
5960:
5958:Tower Mountain
5955:
5950:
5945:
5940:
5935:
5930:
5925:
5922:
5919:
5916:
5911:
5906:
5901:
5896:
5893:
5890:
5888:Jordan Craters
5885:
5880:
5875:
5870:
5865:
5860:
5858:Hager Mountain
5855:
5850:
5845:
5840:
5835:
5830:
5825:
5820:
5817:
5812:
5807:
5804:
5801:
5796:
5790:
5788:
5786:Eastern Oregon
5778:
5777:
5775:
5774:
5769:
5766:
5761:
5756:
5751:
5748:
5743:
5738:
5733:
5728:
5723:
5718:
5713:
5708:
5703:
5698:
5693:
5688:
5683:
5678:
5673:
5668:
5666:Hager Mountain
5663:
5658:
5653:
5648:
5643:
5640:
5635:
5630:
5624:
5622:
5616:
5615:
5613:
5612:
5607:
5602:
5597:
5592:
5587:
5585:Three Pyramids
5582:
5577:
5574:
5569:
5564:
5559:
5554:
5549:
5544:
5539:
5534:
5529:
5524:
5519:
5514:
5509:
5504:
5499:
5497:Olson Mountain
5494:
5489:
5484:
5479:
5477:Mount Sylvania
5474:
5469:
5464:
5459:
5457:Mount Defiance
5454:
5449:
5444:
5441:
5436:
5433:
5428:
5423:
5418:
5416:Larch Mountain
5413:
5408:
5403:
5400:
5398:Hunsinger Peak
5395:
5390:
5388:Highland Butte
5385:
5380:
5375:
5373:Grass Mountain
5370:
5365:
5360:
5357:
5352:
5347:
5342:
5337:
5332:
5327:
5322:
5317:
5312:
5307:
5302:
5297:
5291:
5289:
5279:
5278:
5276:
5275:
5270:
5265:
5260:
5259:Whiteface Peak
5257:
5254:
5252:Waldo Mountain
5249:
5244:
5239:
5234:
5229:
5224:
5219:
5214:
5209:
5204:
5202:Three Trappers
5199:
5181:
5176:
5173:
5170:
5165:
5162:
5157:
5152:
5149:
5146:
5141:
5138:
5133:
5128:
5123:
5118:
5113:
5108:
5103:
5098:
5096:Royce Mountain
5093:
5088:
5085:
5084:Robinson Butte
5082:
5077:
5072:
5067:
5064:
5061:
5058:
5053:
5052:Pinhead Buttes
5050:
5045:
5040:
5037:
5032:
5027:
5022:
5019:
5016:
5011:
5008:
5003:
5001:Mount Thielsen
4998:
4993:
4990:
4984:
4979:
4974:
4969:
4964:
4962:Mount Harriman
4959:
4954:
4949:
4947:Mount Bachelor
4944:
4939:
4934:
4929:
4926:
4924:Maklaks Crater
4921:
4916:
4911:
4906:
4901:
4896:
4891:
4886:
4883:
4878:
4876:Little Brother
4873:
4871:Little Belknap
4868:
4863:
4858:
4853:
4850:
4847:
4842:
4837:
4836:Irish Mountain
4834:
4829:
4824:
4819:
4814:
4809:
4804:
4799:
4794:
4789:
4786:
4783:
4780:
4778:Forgotten Cone
4775:
4770:
4765:
4760:
4755:
4750:
4748:Davis Mountain
4745:
4740:
4735:
4732:
4727:
4722:
4717:
4712:
4707:
4704:
4699:
4697:Cache Mountain
4694:
4693:Buckskin Butte
4691:
4686:
4681:
4676:
4674:Belknap Crater
4671:
4666:
4663:
4658:
4653:
4648:
4646:Applegate Peak
4642:
4640:
4634:
4633:
4622:
4621:
4614:
4607:
4599:
4593:
4592:
4585:
4584:External links
4582:
4579:
4578:
4572:
4555:
4528:
4485:
4476:
4433:
4396:
4390:
4380:(3 ed.).
4373:
4340:
4305:
4266:
4227:
4194:
4153:
4118:
4069:
4022:
3981:
3942:
3913:
3907:
3881:
3868:
3855:
3830:
3797:
3769:
3735:
3714:
3681:
3641:
3640:
3638:
3635:
3633:
3632:
3620:
3583:
3565:OregonLive.com
3547:
3545:, p. 260.
3532:
3520:
3508:
3496:
3481:
3469:
3433:
3397:
3367:
3342:NGS Data Sheet
3329:
3299:
3263:
3238:NGS Data Sheet
3225:
3200:NGS Data Sheet
3196:"Powell Butte"
3187:
3185:, p. 151.
3170:
3168:, p. 150.
3121:
3119:, p. 153.
3106:
3104:, p. 151.
3091:
3079:
3077:, p. 149.
3062:
3047:
3035:
3033:, p. 257.
3014:
3002:
3000:, p. 256.
2990:
2951:
2949:, p. 147.
2936:
2924:
2909:
2897:
2895:, p. 112.
2885:
2883:, p. 142.
2868:
2866:, p. 111.
2853:
2841:
2826:
2814:
2799:
2787:
2775:
2773:, p. 149.
2763:
2751:
2749:, p. 259.
2739:
2696:
2684:
2669:
2667:, p. 310.
2657:
2645:
2633:
2618:
2606:
2591:
2579:
2577:, p. 156.
2567:
2552:
2537:
2525:
2508:
2496:
2455:
2430:
2405:
2393:
2355:
2343:
2341:, p. 107.
2331:
2291:
2279:
2267:
2255:
2243:
2228:
2211:
2196:
2184:
2172:
2155:
2140:
2123:
2111:
2092:
2080:
2063:
2046:
2029:
2017:
2002:
2000:, p. 255.
1985:
1942:
1940:, p. 356.
1930:
1918:
1906:
1894:
1892:, p. 145.
1875:
1863:
1861:, p. 101.
1848:
1825:
1806:
1794:
1792:, p. 258.
1771:
1712:
1688:NGS Data Sheet
1672:
1656:
1654:
1651:
1650:
1649:
1638:
1631:
1622:
1619:
1601:, Mount Hood,
1593:
1590:
1568:
1565:
1513:
1510:
1502:
1501:
1494:
1493:
1492:
1489:
1488:
1486:
1483:
1479:
1478:
1476:
1473:
1469:
1468:
1466:
1463:
1459:
1458:
1456:
1453:
1449:
1448:
1446:
1443:
1442:Nichol's Hill
1439:
1438:
1436:
1433:
1429:
1428:
1426:
1423:
1419:
1418:
1416:
1413:
1409:
1408:
1406:
1403:
1399:
1398:
1395:
1392:
1388:
1387:
1385:
1382:
1378:
1377:
1375:
1372:
1368:
1367:
1365:
1362:
1358:
1357:
1355:
1352:
1346:
1345:
1342:
1339:
1326:
1323:
1320:
1319:
1317:
1314:
1310:
1309:
1307:
1304:
1300:
1299:
1297:
1294:
1288:
1287:
1285:
1282:
1276:
1275:
1273:
1270:
1268:Mount Sylvania
1264:
1263:
1257:
1254:
1248:
1247:
1245:
1242:
1238:
1237:
1235:
1232:
1231:Ross Mountain
1228:
1227:
1225:
1222:
1216:
1215:
1213:
1210:
1204:
1203:
1201:
1198:
1196:Larch Mountain
1192:
1191:
1189:
1186:
1180:
1179:
1177:
1174:
1170:
1169:
1167:
1164:
1160:
1159:
1157:
1154:
1150:
1149:
1146:
1143:
1130:
1127:
1077:
1074:
896:
893:
827:Mount Bachelor
814:
811:
757:
754:
683:A Day Called X
655:prisoner labor
583:Chinook people
578:
575:
503:water howellia
479:whitetop aster
468:riparian zones
331:
328:
257:Columbia River
248:
245:
232:Larch Mountain
192:
189:
185:intrusive rock
170:Larch Mountain
149:Boring, Oregon
121:volcanic field
104:
103:
100:
94:
93:
89:Larch Mountain
86:
83:
79:
78:
73:
67:
66:
53:
49:
48:
45:
37:
36:
33:Volcanic field
31:
28:
27:
24:
15:
9:
6:
4:
3:
2:
6166:
6155:
6152:
6150:
6147:
6145:
6142:
6140:
6137:
6135:
6132:
6130:
6127:
6125:
6122:
6120:
6117:
6115:
6112:
6110:
6107:
6105:
6102:
6101:
6099:
6084:
6081:
6079:
6076:
6074:
6071:
6069:
6066:
6064:
6061:
6059:
6056:
6054:
6051:
6050:
6048:
6046:
6042:
6041:Pacific Coast
6038:
6032:
6029:
6027:
6026:Steens Basalt
6024:
6022:
6019:
6017:
6014:
6012:
6009:
6007:
6004:
6002:
6001:Imnaha Basalt
5999:
5997:
5994:
5992:
5989:
5987:
5984:
5982:
5979:
5978:
5976:
5974:
5970:
5964:
5961:
5959:
5956:
5954:
5951:
5949:
5946:
5944:
5941:
5939:
5936:
5934:
5931:
5929:
5926:
5923:
5920:
5917:
5915:
5912:
5910:
5909:Modoc Plateau
5907:
5905:
5904:Malheur Butte
5902:
5900:
5897:
5894:
5892:Lambert Rocks
5891:
5889:
5886:
5884:
5881:
5879:
5878:Jackies Butte
5876:
5874:
5871:
5869:
5866:
5864:
5861:
5859:
5856:
5854:
5851:
5849:
5846:
5844:
5841:
5839:
5836:
5834:
5831:
5829:
5828:Doherty Slide
5826:
5824:
5821:
5818:
5816:
5813:
5811:
5808:
5805:
5802:
5800:
5797:
5795:
5792:
5791:
5789:
5787:
5783:
5779:
5773:
5770:
5767:
5765:
5762:
5760:
5757:
5755:
5752:
5749:
5747:
5744:
5742:
5739:
5737:
5734:
5732:
5731:Powell Buttes
5729:
5727:
5726:Pine Mountain
5724:
5722:
5719:
5717:
5714:
5712:
5709:
5707:
5704:
5702:
5699:
5697:
5694:
5692:
5689:
5687:
5684:
5682:
5679:
5677:
5674:
5672:
5669:
5667:
5664:
5662:
5659:
5657:
5654:
5652:
5649:
5647:
5644:
5641:
5639:
5636:
5634:
5631:
5629:
5628:Bald Mountain
5626:
5625:
5623:
5621:
5617:
5611:
5608:
5606:
5603:
5601:
5598:
5596:
5593:
5591:
5588:
5586:
5583:
5581:
5578:
5576:Sunshine Rock
5575:
5573:
5572:Spencer Butte
5570:
5568:
5565:
5563:
5560:
5558:
5555:
5553:
5550:
5548:
5545:
5543:
5542:Roxy Ann Peak
5540:
5538:
5537:Ross Mountain
5535:
5533:
5530:
5528:
5525:
5523:
5520:
5518:
5515:
5513:
5510:
5508:
5505:
5503:
5500:
5498:
5495:
5493:
5492:Nesmith Point
5490:
5488:
5487:Mount Talbert
5485:
5483:
5480:
5478:
5475:
5473:
5470:
5468:
5465:
5463:
5460:
5458:
5455:
5453:
5452:Mount Ashland
5450:
5448:
5445:
5442:
5440:
5439:Lookout Point
5437:
5434:
5432:
5429:
5427:
5426:Lenhart Butte
5424:
5422:
5419:
5417:
5414:
5412:
5409:
5407:
5406:Iron Mountain
5404:
5401:
5399:
5396:
5394:
5391:
5389:
5386:
5384:
5381:
5379:
5376:
5374:
5371:
5369:
5366:
5364:
5361:
5359:French's Dome
5358:
5356:
5353:
5351:
5348:
5346:
5343:
5341:
5338:
5336:
5335:Clatsop Butte
5333:
5331:
5328:
5326:
5323:
5321:
5318:
5316:
5315:Bone Mountain
5313:
5311:
5308:
5306:
5303:
5301:
5298:
5296:
5293:
5292:
5290:
5288:
5284:
5280:
5274:
5271:
5269:
5268:Wizard Island
5266:
5264:
5261:
5258:
5255:
5253:
5250:
5248:
5245:
5243:
5240:
5238:
5235:
5233:
5230:
5228:
5227:Triangle Peak
5225:
5223:
5222:Triangle Hill
5220:
5218:
5215:
5213:
5210:
5208:
5207:Timber Crater
5205:
5203:
5200:
5197:
5193:
5192:Middle Sister
5189:
5185:
5184:Three Sisters
5182:
5180:
5177:
5174:
5171:
5169:
5166:
5163:
5161:
5160:Teardrop Pool
5158:
5156:
5155:Talapus Butte
5153:
5150:
5147:
5145:
5144:South Belknap
5142:
5139:
5137:
5134:
5132:
5129:
5127:
5124:
5122:
5121:Sentinel Rock
5119:
5117:
5114:
5112:
5109:
5107:
5106:Sand Mountain
5104:
5102:
5099:
5097:
5094:
5092:
5089:
5086:
5083:
5081:
5078:
5076:
5073:
5071:
5068:
5065:
5062:
5060:Pothole Butte
5059:
5057:
5054:
5051:
5049:
5046:
5044:
5043:Pelican Butte
5041:
5038:
5036:
5035:Olallie Butte
5033:
5031:
5028:
5026:
5023:
5020:
5017:
5015:
5012:
5009:
5007:
5004:
5002:
4999:
4997:
4994:
4991:
4989:(unconfirmed)
4988:
4985:
4983:
4980:
4978:
4975:
4973:
4970:
4968:
4965:
4963:
4960:
4958:
4957:Mount Carmine
4955:
4953:
4950:
4948:
4945:
4943:
4942:Merriam Point
4940:
4938:
4935:
4933:
4930:
4927:
4925:
4922:
4920:
4917:
4915:
4912:
4910:
4907:
4905:
4904:Lookout Butte
4902:
4900:
4897:
4895:
4892:
4890:
4887:
4884:
4882:
4879:
4877:
4874:
4872:
4869:
4867:
4864:
4862:
4859:
4857:
4854:
4851:
4848:
4846:
4843:
4841:
4838:
4835:
4833:
4830:
4828:
4825:
4823:
4820:
4818:
4815:
4813:
4812:Hayrick Butte
4810:
4808:
4805:
4803:
4800:
4798:
4795:
4793:
4792:Garfield Peak
4790:
4788:Fuji Mountain
4787:
4784:
4781:
4779:
4776:
4774:
4771:
4769:
4766:
4764:
4761:
4759:
4756:
4754:
4751:
4749:
4746:
4744:
4741:
4739:
4736:
4733:
4731:
4728:
4726:
4723:
4721:
4718:
4716:
4713:
4711:
4708:
4705:
4703:
4700:
4698:
4695:
4692:
4690:
4687:
4685:
4682:
4680:
4677:
4675:
4672:
4670:
4667:
4664:
4662:
4659:
4657:
4654:
4652:
4649:
4647:
4644:
4643:
4641:
4639:
4638:High Cascades
4635:
4631:
4627:
4620:
4615:
4613:
4608:
4606:
4601:
4600:
4597:
4591:
4588:
4587:
4575:
4569:
4565:
4561:
4556:
4544:
4540:
4536:
4535:
4529:
4517:
4513:
4509:
4504:
4503:10.3133/b1119
4499:
4495:
4491:
4486:
4482:
4477:
4465:
4461:
4457:
4452:
4447:
4443:
4439:
4434:
4422:
4417:
4412:
4408:
4404:
4403:
4397:
4393:
4387:
4383:
4379:
4374:
4362:
4358:
4354:
4350:
4346:
4341:
4326:
4322:
4318:
4311:
4306:
4291:
4287:
4283:
4279:
4272:
4267:
4252:
4248:
4244:
4240:
4233:
4228:
4224:
4220:
4216:
4212:
4208:
4204:
4200:
4195:
4190:
4185:
4181:
4177:
4173:
4169:
4165:
4164:
4159:
4154:
4150:
4146:
4142:
4138:
4134:
4130:
4126:
4125:
4119:
4104:
4100:
4096:
4091:
4086:
4082:
4075:
4070:
4055:
4051:
4047:
4043:
4039:
4035:
4028:
4023:
4018:
4013:
4009:
4005:
4001:
3997:
3993:
3992:
3987:
3982:
3977:
3972:
3968:
3964:
3961:: 1283–1314.
3960:
3956:
3952:
3948:
3943:
3931:
3927:
3923:
3919:
3914:
3910:
3904:
3900:
3896:
3892:
3888:
3882:
3878:
3874:
3869:
3865:
3861:
3860:Isochron/West
3856:
3852:
3848:
3844:
3840:
3836:
3831:
3827:
3823:
3819:
3815:
3812:: 1324–1338.
3811:
3807:
3803:
3798:
3786:
3782:
3778:
3774:
3770:
3766:
3762:
3758:
3754:
3751:: 1051–1062.
3750:
3746:
3742:
3736:
3724:
3720:
3715:
3703:
3699:
3695:
3691:
3687:
3682:
3667:
3663:
3659:
3655:
3648:
3643:
3642:
3630:, p. 97.
3629:
3624:
3608:
3604:
3600:
3599:
3594:
3587:
3571:
3567:
3566:
3561:
3554:
3552:
3544:
3539:
3537:
3530:, p. 38.
3529:
3524:
3517:
3512:
3506:, p. 69.
3505:
3500:
3493:
3488:
3486:
3478:
3473:
3457:
3453:
3449:
3448:
3443:
3437:
3421:
3417:
3413:
3412:
3407:
3401:
3385:
3381:
3377:
3371:
3355:
3351:
3347:
3343:
3339:
3333:
3317:
3313:
3309:
3303:
3287:
3283:
3279:
3278:
3273:
3272:"Mount Scott"
3267:
3251:
3247:
3243:
3239:
3235:
3229:
3213:
3209:
3205:
3201:
3197:
3191:
3184:
3179:
3177:
3175:
3167:
3162:
3160:
3158:
3156:
3154:
3152:
3150:
3148:
3146:
3144:
3142:
3140:
3138:
3136:
3134:
3132:
3130:
3128:
3126:
3118:
3113:
3111:
3103:
3098:
3096:
3088:
3083:
3076:
3071:
3069:
3067:
3060:, p. 84.
3059:
3054:
3052:
3044:
3039:
3032:
3027:
3025:
3023:
3021:
3019:
3011:
3006:
2999:
2994:
2983:September 27,
2978:
2974:
2970:
2969:
2964:
2958:
2956:
2948:
2943:
2941:
2933:
2928:
2922:, p. 37.
2921:
2916:
2914:
2907:, p. 10.
2906:
2901:
2894:
2889:
2882:
2877:
2875:
2873:
2865:
2860:
2858:
2851:, p. 31.
2850:
2845:
2839:, p. 17.
2838:
2833:
2831:
2824:, p. 34.
2823:
2818:
2812:, p. 86.
2811:
2806:
2804:
2796:
2791:
2784:
2779:
2772:
2767:
2761:, p. 14.
2760:
2755:
2748:
2743:
2732:September 27,
2727:
2723:
2719:
2718:
2713:
2707:
2705:
2703:
2701:
2694:, p. 42.
2693:
2688:
2682:, p. 12.
2681:
2676:
2674:
2666:
2661:
2655:, p. 75.
2654:
2649:
2642:
2637:
2630:
2625:
2623:
2615:
2610:
2603:
2598:
2596:
2589:, p. 74.
2588:
2583:
2576:
2571:
2565:, p. 43.
2564:
2559:
2557:
2549:
2544:
2542:
2534:
2533:Hildreth 2007
2529:
2523:, p. 76.
2522:
2517:
2515:
2513:
2505:
2500:
2484:
2481:
2477:
2476:
2471:
2464:
2462:
2460:
2448:September 27,
2443:
2437:
2435:
2423:September 27,
2418:
2412:
2410:
2403:, p. 88.
2402:
2397:
2381:
2377:
2373:
2369:
2362:
2360:
2353:, p. 29.
2352:
2347:
2340:
2335:
2324:September 27,
2319:
2315:
2311:
2310:
2305:
2298:
2296:
2288:
2283:
2276:
2275:Anderson 2009
2271:
2264:
2263:Anderson 2009
2259:
2252:
2251:Anderson 2009
2247:
2240:
2239:Anderson 2009
2235:
2233:
2225:
2224:Anderson 2009
2220:
2218:
2216:
2209:, p. 13.
2208:
2203:
2201:
2194:, p. 11.
2193:
2188:
2181:
2176:
2169:
2164:
2162:
2160:
2152:
2147:
2145:
2137:
2132:
2130:
2128:
2120:
2115:
2109:, p. 28.
2108:
2103:
2101:
2099:
2097:
2090:, p. 25.
2089:
2084:
2078:, p. 14.
2077:
2072:
2070:
2068:
2061:, p. 73.
2060:
2055:
2053:
2051:
2043:
2038:
2036:
2034:
2026:
2021:
2014:
2009:
2007:
1999:
1994:
1992:
1990:
1978:September 27,
1973:
1969:
1965:
1964:
1959:
1958:"Boring Lava"
1953:
1951:
1949:
1947:
1939:
1934:
1928:, p. 11.
1927:
1922:
1915:
1910:
1903:
1898:
1891:
1886:
1884:
1882:
1880:
1873:, p. 16.
1872:
1867:
1860:
1855:
1853:
1846:, p. 13.
1845:
1840:
1838:
1836:
1834:
1832:
1830:
1823:, p. 36.
1822:
1817:
1815:
1813:
1811:
1804:, p. 10.
1803:
1802:Treacher 1942
1798:
1791:
1786:
1784:
1782:
1780:
1778:
1776:
1764:September 26,
1759:
1755:
1751:
1750:
1745:
1739:
1737:
1735:
1733:
1731:
1729:
1727:
1725:
1723:
1721:
1719:
1717:
1701:
1697:
1693:
1689:
1685:
1684:"Larch Reset"
1679:
1677:
1669:
1664:
1662:
1657:
1647:
1642:
1639:
1635:
1632:
1628:
1625:
1624:
1618:
1614:
1612:
1608:
1604:
1603:Mount Rainier
1600:
1589:
1585:
1581:
1579:
1575:
1574:volcanic plug
1564:
1562:
1558:
1553:
1550:
1536:
1531:
1526:
1518:
1504:
1498:
1487:
1484:
1480:
1477:
1474:
1470:
1467:
1464:
1460:
1457:
1454:
1450:
1447:
1444:
1440:
1437:
1434:
1430:
1427:
1424:
1420:
1417:
1414:
1412:Mount Norway
1410:
1407:
1404:
1400:
1396:
1393:
1391:Brunner Hill
1389:
1386:
1383:
1379:
1376:
1373:
1369:
1366:
1363:
1359:
1356:
1353:
1351:
1347:
1336:
1330:
1318:
1315:
1311:
1308:
1305:
1301:
1298:
1295:
1293:
1292:Mount Talbert
1289:
1286:
1283:
1281:
1277:
1274:
1271:
1269:
1265:
1262:
1258:
1255:
1253:
1249:
1246:
1243:
1239:
1236:
1233:
1229:
1226:
1223:
1221:
1217:
1214:
1211:
1209:
1205:
1202:
1199:
1197:
1193:
1190:
1187:
1185:
1181:
1178:
1175:
1171:
1168:
1165:
1163:Cook's Butte
1161:
1158:
1155:
1151:
1140:
1134:
1126:
1118:
1114:
1109:
1103:
1099:
1093:
1091:
1082:
1073:
1071:
1066:
1064:
1063:hydrogeologic
1059:
1055:
1051:
1047:
1043:
1039:
1035:
1031:
1027:
1023:
1015:
1009:
1007:
1003:
999:
995:
991:
987:
983:
979:
975:
971:
967:
963:
959:
955:
951:
947:
942:
940:
936:
932:
931:calc-alkaline
928:
924:
920:
916:
912:
909:
906:
902:
892:
890:
886:
882:
872:
868:
864:
860:
856:
850:
848:
844:
840:
836:
832:
828:
824:
823:Indian Heaven
820:
819:Cascade Range
810:
808:
804:
800:
796:
791:
787:
783:
775:
771:
767:
762:
753:
751:
747:
743:
739:
734:
732:
726:
724:
715:
711:
707:
702:
698:
690:
685:
684:
680:
674:
672:
668:
664:
660:
656:
652:
647:
639:
634:
630:
626:
624:
620:
616:
612:
608:
605:
604:William Clark
601:
597:
596:the Clackamas
593:
592:the Multnomah
588:
584:
574:
572:
568:
564:
560:
556:
552:
548:
547:Yuma myotises
544:
540:
536:
532:
528:
524:
520:
516:
512:
508:
504:
500:
496:
492:
491:pale larkspur
488:
484:
480:
476:
471:
469:
461:
455:
453:
449:
446:
442:
438:
437:western hazel
434:
430:
426:
422:
418:
414:
410:
406:
402:
401:bigleaf maple
398:
394:
390:
386:
382:
378:
374:
370:
366:
362:
358:
354:
350:
346:
336:
327:
324:
318:
316:
312:
308:
304:
301:
297:
293:
288:
286:
282:
278:
274:
270:
266:
262:
258:
254:
244:
237:
233:
229:
225:
220:
218:
214:
210:
206:
197:
188:
186:
182:
178:
173:
171:
165:
163:
154:
150:
146:
142:
138:
134:
130:
126:
122:
119:
115:
111:
101:
99:
95:
90:
84:
80:
77:
74:
72:
68:
65:
61:
57:
54:
50:
43:
38:
34:
29:
22:
19:
6083:Yaquina Head
6068:Devils Elbow
5933:Saddle Butte
5863:Harney Basin
5853:Glass Buttes
5806:Clarks Butte
5768:Yainax Ridge
5764:Yainax Butte
5716:Paulina Peak
5651:Cline Buttes
5642:Bly Mountain
5638:Barnes Butte
5604:
5594:
5579:
5551:
5536:
5522:Powell Butte
5511:
5506:
5467:Mount Pisgah
5438:
5425:
5397:
5393:High Prairie
5387:
5378:Grizzly Peak
5362:
5350:Devil's Rest
5349:
5340:Cook's Butte
5339:
5329:
5325:Cascade Head
5319:
5294:
5242:Twin Craters
5217:Tot Mountain
5196:South Sister
5188:North Sister
5168:The Pinnacle
5151:Summit Butte
5101:Rustler Peak
5048:Phantom Ship
5021:North Wilson
5010:Mount Wilson
4977:Mount Mazama
4952:Mount Bailey
4937:Merriam Cone
4932:Melvin Butte
4914:Lumrum Butte
4849:Lemiti Butte
4840:Katsuk Butte
4827:Hoodoo Butte
4817:Hillman Peak
4807:Hamner Butte
4768:Dutton Cliff
4758:Diamond Peak
4730:Cryder Butte
4684:Black Crater
4665:Barlow Butte
4559:
4547:. Retrieved
4533:
4520:. Retrieved
4468:. Retrieved
4425:. Retrieved
4401:
4377:
4365:. Retrieved
4352:
4348:
4332:. Retrieved
4297:. Retrieved
4258:. Retrieved
4242:
4238:
4202:
4199:GSA Bulletin
4198:
4167:
4161:
4128:
4122:
4110:. Retrieved
4061:. Retrieved
3995:
3989:
3954:
3950:
3934:. Retrieved
3921:
3886:
3872:
3859:
3838:
3834:
3805:
3802:GSA Bulletin
3801:
3789:. Retrieved
3744:
3740:
3727:. Retrieved
3706:. Retrieved
3693:
3689:
3673:. Retrieved
3657:
3653:
3623:
3611:. Retrieved
3596:
3586:
3574:. Retrieved
3563:
3528:Trimble 1963
3523:
3518:, p. 1.
3516:Trimble 1963
3511:
3499:
3479:, p. 3.
3472:
3460:. Retrieved
3445:
3436:
3424:. Retrieved
3409:
3400:
3388:. Retrieved
3370:
3358:. Retrieved
3341:
3332:
3320:. Retrieved
3302:
3290:. Retrieved
3275:
3266:
3254:. Retrieved
3237:
3228:
3216:. Retrieved
3199:
3190:
3082:
3038:
3005:
2993:
2981:. Retrieved
2977:the original
2966:
2932:Trimble 1963
2927:
2920:Trimble 1963
2900:
2888:
2849:Trimble 1963
2844:
2822:Trimble 1963
2817:
2797:, p. 5.
2790:
2778:
2766:
2754:
2742:
2730:. Retrieved
2726:the original
2715:
2692:Trimble 1963
2687:
2660:
2648:
2636:
2609:
2582:
2570:
2563:Swanson 1986
2535:, p. 2.
2528:
2499:
2487:. Retrieved
2473:
2446:. Retrieved
2421:. Retrieved
2396:
2384:. Retrieved
2371:
2346:
2339:Trimble 1963
2334:
2322:. Retrieved
2307:
2289:, p. 9.
2287:Trimble 1963
2282:
2277:, p. 8.
2270:
2265:, p. 6.
2258:
2253:, p. 5.
2246:
2241:, p. 7.
2226:, p. 4.
2187:
2182:, p. 6.
2175:
2170:, p. 8.
2153:, p. 5.
2138:, p. 8.
2136:Trimble 1963
2121:, p. 7.
2119:Trimble 1963
2114:
2083:
2076:Dougall 2007
2044:, p. 6.
2042:Trimble 1963
2025:Trimble 1963
2020:
2015:, p. 5.
2013:Trimble 1963
1976:. Retrieved
1961:
1933:
1921:
1916:, p. 8.
1909:
1897:
1866:
1821:Trimble 1963
1797:
1762:. Retrieved
1747:
1705:November 18,
1703:. Retrieved
1687:
1646:vaporization
1641:
1634:
1627:
1615:
1595:
1586:
1582:
1570:
1554:
1527:
1523:
1452:Pohl's Hill
1328:
1313:Walker Peak
1208:Powell Butte
1132:
1129:Oregon vents
1111:A series of
1110:
1094:
1090:petrographic
1086:
1067:
1044:and dropped
1010:
1006:aeromagnetic
970:Clark County
943:
898:
889:mantle wedge
851:
816:
779:
735:
730:
727:
703:
699:
681:
675:
667:rock gardens
644:In 1893 the
643:
627:
580:
487:tall bugbane
472:
456:
425:Devil's club
347:, featuring
341:
319:
289:
285:Sandy Rivers
250:
221:
202:
174:
166:
125:cinder cones
113:
109:
107:
18:
6139:Lava fields
6078:Heceta Head
5963:Warner Peak
5810:Clarno Unit
5803:Chalk Basin
5799:Black Hills
5736:Round Butte
5721:Pilot Butte
5671:Horse Ridge
5605:Walker Peak
5532:Rogers Peak
5527:Rocky Butte
5507:Palmer Peak
5482:Mount Tabor
5411:Kelly Butte
5355:East Buttes
5300:Armet Creek
5295:Angels Rest
5164:The Husband
5080:Ringo Butte
5025:Odell Butte
5014:Nash Crater
4919:Maiden Peak
4894:Lolah Butte
4845:Kwolh Butte
4802:Grouse Hill
4753:Desert Cone
4725:Crater Peak
4715:Crater Lake
4679:Black Butte
4656:Bald Crater
4651:Aspen Butte
4549:October 10,
4522:October 16,
4470:October 16,
4427:October 10,
4367:October 10,
4239:The Ore Bin
4112:October 10,
4063:October 10,
4002:: 101–115.
3791:October 11,
3690:The Ore Bin
3675:October 10,
3654:The Ore Bin
3598:The Outlook
3462:October 11,
3426:October 11,
3390:October 11,
3360:October 11,
3292:October 11,
3256:October 11,
3218:October 11,
3058:Madin 2009a
2893:Werner 1991
2881:Werner 1991
2864:Werner 1991
2810:Madin 2009a
2795:Madin 2009b
2653:Madin 2009a
2587:Madin 2009a
2521:Madin 2009a
2480:Tegna, Inc.
2401:Madin 2009a
2059:Madin 2009a
1914:Madin 2009b
1599:Mount Adams
1432:Mount Zion
1280:Mount Tabor
1252:Mount Scott
1241:Swede Hill
1220:Rocky Butte
1184:Kelly Butte
1076:Subfeatures
1038:deformation
1002:plagioclase
978:labradorite
948:basalt and
929:to high-K,
905:Pleistocene
881:slab window
807:slack water
782:cinder cone
731:Tabor Times
671:scoriaceous
571:coho salmon
563:bald eagles
433:Indian plum
385:Douglas fir
375:trees like
353:huckleberry
315:groundwater
309:into local
236:monogenetic
6098:Categories
5833:Drake Peak
5741:Smith Rock
5696:Monkeyface
5681:Gray Butte
5580:Swede Hill
5552:Scout Camp
5517:Pilot Rock
5462:Mount Hebo
5447:Marys Peak
5247:Union Peak
5140:Sisi Butte
5136:Siah Butte
5126:Sharp Peak
5116:Scout Hill
5087:Rock Butte
5075:Red Crater
4967:Mount Hood
4782:Fort Butte
4738:Danger Bay
4689:Broken Top
4669:Bear Butte
4661:Ball Butte
4537:(Thesis).
4492:(Report).
4440:(Report).
4405:(Thesis).
4334:October 5,
4299:October 4,
4276:(Report).
4260:October 1,
4135:: 96–114.
4079:(Report).
4042:B0001030NS
4032:(Report).
3936:October 9,
3889:(Report).
3875:(Thesis).
3729:January 7,
3708:August 24,
3613:October 3,
3576:October 2,
3183:Allen 1975
3166:Allen 1975
3117:Allen 1974
3102:Allen 1974
3087:Allen 1974
3075:Allen 1974
2947:Allen 1975
2771:Allen 1975
2575:Allen 1975
2489:October 2,
2386:October 3,
1890:Allen 1975
1653:References
1611:picnicking
1592:Recreation
1341:Elevation
1259:Named for
1145:Elevation
1113:lava tubes
1022:weathering
990:Mount Hood
982:iddingsite
964:and platy
939:refractory
927:tholeiitic
911:lava flows
837:under the
831:subduction
786:lava domes
772:under the
766:subduction
723:Quaternary
607:documented
587:indigenous
448:sword fern
445:herbaceous
405:Oregon ash
381:vine maple
369:blackberry
361:poison oak
307:intrusions
261:Willamette
145:Washington
133:lava flows
60:Washington
5981:Boat Rock
5838:Fort Rock
5646:China Hat
5562:Snow Peak
5363:Elk Point
5310:Battle Ax
5172:The Twins
5091:Rock Mesa
4992:Mount Ray
4861:Llao Rock
4822:Hogg Rock
4773:Egan Cone
4763:Dry Butte
4710:Cleetwood
4626:Volcanoes
4512:793416650
4460:974647668
4286:502019232
4249:: 73–92.
4174:: 69–79.
4099:182746810
3951:Geosphere
3781:702299177
1050:landslide
1034:xenoliths
1030:quartzite
871:anticline
679:docudrama
640:platform.
441:snowberry
409:red alder
373:deciduous
317:locally.
303:sandstone
300:Troutdale
281:Washougal
277:Clackamas
228:elevation
217:lithology
191:Geography
5996:Hat Rock
5794:Big Hole
5175:The Wife
5070:Red Cone
5063:Redcloud
4856:Llao Bay
4543:Archived
4516:Archived
4464:Archived
4421:Archived
4361:Archived
4325:Archived
4321:74466975
4290:Archived
4251:Archived
4209:: 1–24.
4133:Elsevier
4103:Archived
4054:Archived
4050:31507910
4000:Elsevier
3930:Archived
3785:Archived
3723:Archived
3702:Archived
3666:Archived
3607:Archived
3570:Archived
3384:Archived
3316:Archived
2483:Archived
2380:Archived
2318:Archived
1972:Archived
1970:. 2013.
1758:Archived
1561:effusive
1397:2 vents
1303:TV Hill
1042:uplifted
1032:-pebble
1014:hummocky
962:columnar
919:Tertiary
915:breccias
901:Pliocene
615:Tualatin
273:Tualatin
253:terraces
209:Portland
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