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{{Short description|Geological process that leaves marks altering the marks of an earlier process}} |
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{{references}} |
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[[image:Orthogneiss Geopark.jpg|thumb|In this [[orthogneiss]] from the [[Czech Republic]] the original [[igneous rock|igneous]] [[rock texture]] has been overprinted by [[foliation (geology)|foliation]] associated with [[metamorphism]].]] |
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In [[geology]] the '''overprinting''' refers to ac[[geological process]] that leave marks altering the marks of another earlier geological process. Examples include various phases of [[deformation]] of rocks in such way the initial [[rock structure|structure]]s are modified –sometimes even beyond recognition. |
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'''Overprinting''' is a [[geology|geological]] process that superimposes a set of characteristics on rock that partially obscure earlier characteristics. Examples include '''metamorphic overprinting''' ('''superimposed metamorphism'''<ref>{{cite book |last1=Yardley |first1=Bruce W. D. |title = An Introduction to Metamorphic Petrology |date=1989 |publisher=Longman Scientific & Technical |location=Harlow, Essex, England |series = Longman Earth Science Series | isbn=0-582-30096-7 |url = https://archive.org/details/introductiontome0000yard/mode/2up?view=theater | url-access = registration| page=246}}</ref>), in which new structure,<ref>{{cite book |editor1-last=Jackson |editor1-first=Julia A. |title=Glossary of geology. |date=1997 |publisher=American Geological Institute |location=Alexandria, Virginia |isbn=0922152349 |edition=Fourth |chapter=metamorphic overprint}}</ref> texture, or mineral composition is imposed on existing rock.{{sfn|Yardley|1989|pp=211, 214}}<ref>{{cite journal |last1=Zhao |first1=Lei |last2=Zhai |first2=Ming-Guo |last3=Nutman |first3=Allen P. |last4=Oh |first4=Chang-Whan |last5=Bennett |first5=Vickie C. |last6=Zhang |first6=Yanbin |title=Archean basement components and metamorphic overprints of the Rangnim Massif in the northern part of the Korean Peninsula and tectonic implications for the Sino-Korean Craton |journal=Precambrian Research |date=July 2020 |volume=344 |pages=105735 |doi=10.1016/j.precamres.2020.105735|s2cid=218819425 }}</ref> For example, the [[Tauern window]] of [[Alps]] contains beds that were originally metamorphosed to [[eclogite]] but have since been overprinted to the [[blueschist]] and then the [[greenschist]] [[Metamorphic facies|facies]].{{sfn|Yardley|1989|p=211}} Likewise, deformation associated with the [[Mazatzal orogeny]] in [[Arizona]] and [[New Mexico]], US, was subsequently overprinted by deformation associated with the [[Picuris orogeny]].<ref>{{cite journal |last1=Mako |first1=Calvin A. |last2=Williams |first2=Michael L. |last3=Karlstrom |first3=Karl E. |last4=Doe |first4=Michael F. |last5=Powicki |first5=David |last6=Holland |first6=Mark E. |last7=Gehrels |first7=George |last8=Pecha |first8=Mark |title=Polyphase Proterozoic deformation in the Four Peaks area, central Arizona, and relevance for the Mazatzal orogeny |journal=Geosphere |date=December 2015 |volume=11 |issue=6 |pages=1975–1995 |doi=10.1130/GES01196.1|doi-access=free }}</ref> |
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[[Geochemistry|Geochemical]] signatures can also be overprinted when the geochemistry of a geological body is changed by eliminating or modifying the earlier geochemical signature. |
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[[Geochemistry|Geochemical]] signatures can also be overprinted when the geochemistry of a geological body is changed by eliminating or modifying the earlier geochemical signature.{{sfn|Jackson|1997|loc="overprint [geochron]"}}<ref>{{cite journal |last1=Brewer |first1=Timothy S. |last2=Menuge |first2=Julian F. |title=Metamorphic overprinting of SmNd isotopic systems in volcanic rocks: the Telemark supergroup, southern Norway |journal=Chemical Geology |date=March 1998 |volume=145 |issue=1–2 |pages=1–16 |doi=10.1016/S0009-2541(97)00114-9}}</ref> |
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[[Category:Geology]] |
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==References== |
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{{reflist}} |
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[[Category:Geological processes]] |
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Latest revision as of 17:56, 30 July 2023
Overprinting is a geological process that superimposes a set of characteristics on rock that partially obscure earlier characteristics. Examples include metamorphic overprinting (superimposed metamorphism[1]), in which new structure,[2] texture, or mineral composition is imposed on existing rock.[3][4] For example, the Tauern window of Alps contains beds that were originally metamorphosed to eclogite but have since been overprinted to the blueschist and then the greenschist facies.[5] Likewise, deformation associated with the Mazatzal orogeny in Arizona and New Mexico, US, was subsequently overprinted by deformation associated with the Picuris orogeny.[6]
Geochemical signatures can also be overprinted when the geochemistry of a geological body is changed by eliminating or modifying the earlier geochemical signature.[7][8]
References
[edit]- ^ Yardley, Bruce W. D. (1989). An Introduction to Metamorphic Petrology. Longman Earth Science Series. Harlow, Essex, England: Longman Scientific & Technical. p. 246. ISBN 0-582-30096-7.
- ^ Jackson, Julia A., ed. (1997). "metamorphic overprint". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN 0922152349.
- ^ Yardley 1989, pp. 211, 214.
- ^ Zhao, Lei; Zhai, Ming-Guo; Nutman, Allen P.; Oh, Chang-Whan; Bennett, Vickie C.; Zhang, Yanbin (July 2020). "Archean basement components and metamorphic overprints of the Rangnim Massif in the northern part of the Korean Peninsula and tectonic implications for the Sino-Korean Craton". Precambrian Research. 344: 105735. doi:10.1016/j.precamres.2020.105735. S2CID 218819425.
- ^ Yardley 1989, p. 211.
- ^ Mako, Calvin A.; Williams, Michael L.; Karlstrom, Karl E.; Doe, Michael F.; Powicki, David; Holland, Mark E.; Gehrels, George; Pecha, Mark (December 2015). "Polyphase Proterozoic deformation in the Four Peaks area, central Arizona, and relevance for the Mazatzal orogeny". Geosphere. 11 (6): 1975–1995. doi:10.1130/GES01196.1.
- ^ Jackson 1997, "overprint [geochron]".
- ^ Brewer, Timothy S.; Menuge, Julian F. (March 1998). "Metamorphic overprinting of SmNd isotopic systems in volcanic rocks: the Telemark supergroup, southern Norway". Chemical Geology. 145 (1–2): 1–16. doi:10.1016/S0009-2541(97)00114-9.