60:
20:
119:, forming a ring dike. These dikes can form as a direct result of collapse caldera formation, or through many injections around the ring fault over time. The magma of a ring dike is typically composed of acidic or intermediate composition due to the less dense melt that exists at the top of the magma chamber.
127:
It has been hypothesized that ring dikes may form when inclined sheets are captured within a ring fault system, which cause them to act as feeder dikes. The deflection of the sheets may be caused by the difference in material properties between and within the
87:. The geometry of the top of the magma chamber dictates the location and magnitude of the tension fractures. In addition, it was found that the higher the radius to depth ratio of the magma chamber, the higher the probability of forming a collapse
46:
body that is circular, oval or arcuate in plan and has steep contacts. While the widths of ring dikes differ, they can be up to several thousand meters. The most commonly accepted method of ring dike formation is directly related to collapse
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body forms an oval and its diameter can be measured at roughly 5.8 km by 8.5 km. The width of the dike varies throughout the profile, with a maximum width of approximately 300 meters. The composition varies from
94:
Once a tension threshold is approached, the roof of the magma chamber collapses in on itself, and is known as cauldron subsidence. Tension fractures extend deeper in the profile and shear fractures or
282:
Johnson, Scott E., S. R. Paterson, and M. C. Tate. "Structure and emplacement history of a multiple-center, cone-sheet–bearing ring complex: The Zarza
Intrusive Complex, Baja California, Mexico."
83:
away from the chamber are both mechanisms that can empty a magma chamber. As pressure in the magma chamber changes, an increase in tensile stresses create tension fractures at the surface of the
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Whether or not a caldera ring fault dips inward or outward from the center of subsidence is a highly contentious issue. Ring faults near the surface are subject to
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subsidence appears to be the mechanism leading to the formation of some of the ring dikes, but not all of them. The composition ranges from
586:
148:, changing the morphology of the caldera walls and making it difficult to tell the dip of the fault at formation.
337:
429:"Lateral versus vertical emplacement in shallow-level intrusions? The Slieve Gullion Ring-complex revisited"
517:"Caldera faults capture and deflect inclined sheets : An alternative mechanism of ring-dike formation"
481:
Gudmundsson, Agust, Joan Marti, and
Elisenda Turon. "Stress fields generating ring faults in volcanoes."
622:
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314:"Cyclic caldera collapse: Piston or piecemeal subsidence? Field and experimental evidence"
8:
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Billings, Marland P. "Section of
Geology and Mineralogy: Ring-dikes and Their Origin."
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Emeleus, C. Henry; Troll, Valentin R.; Chew, David M.; Meade, Fiona C. (March 2012).
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Questa
Caldera ring dike, exposed in the valley of the Red River, New Mexico, US
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Modell, David. "Ring-Dike
Complex of the Belknap Mountains. New Hampshire."
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71:. Effusive eruptions that take place on the flanks of the associated
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201:, serves as a classic example of a well formed ring dike. This
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form in a circular pattern around the caldera and are known as
374:"Formation of caldera periphery faults: an experimental study"
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223:
80:
312:
Troll, V. R.; Walter, T. R.; Schmincke, H.-U. (2002-02-01).
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10.1130/0091-7613(2002)030<0135:CCCPOP>2.0.CO;2
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faults. When they are inward dipping, they are known as
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Gudmundsson, Agust. "Formation of collapse calderas."
426:
372:
Walter, Thomas R.; Troll, Valentin R. (2001-06-01).
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and when they are outward dipping they are known as
115:. Ring faults then allow magma to rise through the
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579:Mind Over Magma: The Story of Igneous Petrology,
360:Petrology: igneous, sedimentary, and metamorphic
271:Transactions of the New York Academy of Sciences
103:. Ring faults can be either vertical or steeply
67:Collapse calderas form due to the emptying of a
581:Princeton University Press, 2003, pp. 341–42,
358:Blatt, Harvey, Robert Tracy, and Brent Owens.
156:
371:
161:About 36 ring dikes have been found in the
597:Lockwood, John P. and Richard W. Hazlett,
515:Browning J. & Gudmundsson A. (2015).
123:Another mechanism of ring dike formation
58:
55:Caldera collapse and ring dike formation
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566:Geological Society of American Bulletin
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494:O'keefe, John A., Paul D. Lowman, and
284:Geological Society of America Bulletin
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498:. "Lunar Ring Dikes from Orbiter I."
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433:Journal of the Geological Society
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27:Ring Dike Complex in South Africa
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599:Volcanoes:Global Perspectives,
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16:Type of intrusive igneous body
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483:Geophysical Research Letters
273:5.6 Series II (1943): 131–44
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544:10.1007/s00445-014-0889-4
453:10.1144/0016-76492011-044
157:Ossipee ring-dike complex
568:47.12 (1936): 1885–1932.
193:ring dike, found on the
601:Wiley-Blackwell (2010).
524:Bulletin of Volcanology
502:155.3758 (1967): 77–79.
378:Bulletin of Volcanology
286:111.4 (1999): 607–19).
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485:24.13 (1997): 1559–62
398:10.1007/s004450100135
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362:. Macmillan, 2006.
302:16.9 (1988): 808–10.
536:2015BVol...77....4B
496:Winifred S. Cameron
445:2012JGSoc.169..157E
390:2001BVol...63..191W
330:2002Geo....30..135T
152:Well known examples
79:system that direct
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623:Igneous petrology
577:Young, Davis A.,
185:Loch Bà ring dike
163:Ossipee Mountains
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146:mass wasting
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136:Implications
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618:Volcanology
216:phenocrysts
101:ring faults
25:Pilanesberg
628:Ring dikes
612:Categories
384:(2): 191.
257:References
241:Cone sheet
226:minerals.
177:to quartz
469:130108022
461:0016-7649
406:1432-0819
346:0091-7613
251:Laccolith
236:Batholith
203:intrusive
175:monzonite
117:fractures
41:intrusive
37:ring dyke
33:ring dike
552:54022484
530:(4): 4.
414:59140680
230:See also
208:rhyolite
199:Scotland
49:calderas
532:Bibcode
500:Science
441:Bibcode
386:Bibcode
326:Bibcode
318:Geology
300:Geology
214:, with
212:felsite
191:Loch Bà
179:syenite
171:Caldera
142:erosion
105:dipping
89:caldera
85:volcano
77:fissure
73:volcano
44:igneous
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132:zone.
75:and a
39:is an
548:S2CID
520:(PDF)
465:S2CID
410:S2CID
224:mafic
130:fault
81:magma
583:ISBN
457:ISSN
402:ISSN
342:ISSN
222:and
189:The
144:and
23:The
540:doi
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