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the strata because they would still be buried, and modern strata would continue to be deposited on top of them. The earth's surface has been far too dynamic to allow that to occur anywhere. No area has been in such a static condition throughout the earth's long history. Areas that have had sediment deposited on them at one time are later uplifted and eroded. In some places this has occurred many times. There is ample evidence to prove such a sequence of events.
94:. The eonothem is not to be confused with the eon itself, which is a corresponding division of geologic time spanning a specific number of (hundreds of millions of) years, during which rocks were formed that are classified within the eonothem. Eonothems have the same names as their corresponding eons, which means during the
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Technically, a complete geologic record doesn't occur anywhere. For such a record to develop would require the area to have been receiving sedimentary deposits continually ever since the origin of the earth. Nowhere is such a situation known to exist. If it did exist, we could not effectively look at
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Eonothems are not often used in practice as expert dating estimates can be and usually are specified into the more refined timelines of smaller chronostratigraphic units, which can be subdivided in turn down to the many defined
114:. A rock stratum, fossil or feature present in the "upper Phanerozoic" eonothem would therefore have originated within the "later Phanerozoic" eon. In practice, the rock column is discontinuous:
127:), can be compared to others where the rock record is more complete and, by correlation of points of correspondence, be fixed appropriately within the eon. They are therefore useful as broad
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and improved methods of fossil dating is used to define such boundaries. In contrast to GSSAs, GSSPs are based on important events and transitions within a particular
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Oxfordian (Upper
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and their sub-fields, and a whole system of cross-disciplinary classification by strata is in place with oversight by the
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or well preserved sections to identify the key events necessary for a GSSP so GSSAs are defined based on fixed dates.
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units, specifying approximate age within the timelines within the rock column.
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Totality of rock strata laid down during a certain eon of the geologic timescale
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Geotime chart displaying geologic time periods compared to the fossil record.
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Rocky Roads from
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Chart of The Global
Boundary Stratotype Sections and Points (GSSP)
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only four eonothems were formed. Oldest to newest these are the
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Eonothems, despite discontinuities (locally missing strata or
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The Global
Boundary Stratotype Section and Point (GSSP)
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subdivision of an age, not used by the ICS timescale
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519:Cohen, K.M.; Finney, S.; Gibbard, P.L. (2015),
338:22 defined, tens to ~one hundred million years
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192:(GSSP), largely based on research progress in
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200:. In older sections, there is insufficient
190:Global Boundary Stratotype Section and Point
466:: CS1 maint: numeric names: authors list (
528:, International Commission on Stratigraphy
323:10 defined, several hundred million years
59:; dominant cycle is the 200000 year-cycle.
555:International Commission on Stratigraphy
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175:International Commission on Stratigraphy
148:International Commission on Stratigraphy
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522:International Chronostratigraphic Chart
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269:Units in geochronology and stratigraphy
23:Horseshoe Canyon Formations exposed in
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353:34 defined, tens of millions of years
308:4 total, half a billion years or more
160:see the hierarchy of comparative units
138:and their smaller subdivisions within
547:, New York, John Wiley and Sons, 1976
448:"An Overview of the Geologic Record"
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586:Math Words - An alphabetical index
171:Global Standard Stratigraphic Ages
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551:International Stratigraphic Chart
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368:99 defined, millions of years
134:Eonothems are subdivided into
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442:Richard Burky, ©1990 by the
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577:Web Geological Time Machine
565:Washington State University
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188:For more recent periods, a
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86:deposited during a certain
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263:Multidiscipline comparison
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560:USA National Park Service
543:Hedberg, H.D., (editor),
223:transliteration from the
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444:Worldwide Church of God
293:geochronological units
481:Sissingh, Wim (2012).
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198:stratigraphic section
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640:Geologic time scales
407:Related other topics
96:history of the Earth
645:Geology terminology
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240:) from the archaic
129:chronostratigraphic
75:is the totality of
625:Chronostratigraphy
570:2011-07-26 at the
391:Chronostratigraphy
281:chronostratigraphy
275:Segments of rock (
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92:geologic timescale
90:of the continuous
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494:978-90-6266-305-7
396:Lithostratigraphy
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144:paleobiology
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65:stratigraphy
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582:Eon or Aeon
225:koine Greek
219:, “age”, a
112:Phanerozoic
108:Proterozoic
77:rock strata
619:Categories
600:: overview
538:References
505:2017-11-17
453:2008-06-21
374:Chronozone
194:geobiology
29:Drumheller
553:from the
413:Body form
208:Etymology
49:competent
45:limestone
568:Archived
462:cite web
299:Eonothem
291:Notes to
258:See also
213:Eonothem
185:exists.
136:erathems
73:eonothem
606:: chart
314:Erathem
250:), and
238:ho aion
140:geology
104:Archean
69:geology
33:Alberta
491:
344:Series
334:Period
329:System
277:strata
156:stages
110:, and
100:Hadean
84:record
51:) and
526:(PDF)
429:Notes
379:Chron
359:Stage
349:Epoch
279:) in
252:thema
248:aiwon
243:αἰϝών
227:word
221:Latin
71:, an
27:near
489:ISBN
468:link
232:αἰών
142:and
67:and
57:clay
53:marl
364:Age
319:Era
304:Eon
217:eon
179:mya
88:eon
63:In
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460:{{
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230:ὁ
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