J. H. Cipar, A. J. Smye, J. M. Garber, J. R. Reimink, A. R. C. Kylander-Clark
{"title":"锆石岩石年代学所记录的拉里酰胺大陆下壳的减薄和加热过程","authors":"J. H. Cipar, A. J. Smye, J. M. Garber, J. R. Reimink, A. R. C. Kylander-Clark","doi":"10.1029/2023GC011177","DOIUrl":null,"url":null,"abstract":"<p>Zircon grains from the metasedimentary lower crust of the Rio Grande Rift, New Mexico, preserve a metamorphic record of the transition from Laramide compression to Eocene extension. Zircon U-Pb isotopes and trace-element concentrations from five two-pyroxene metaigneous granulite xenoliths define discrete populations: older zircon cores (∼15–50 Ma) that are depleted in heavy rare-earth elements (HREE) but Ti-rich, and younger zircon rims (∼3–15 Ma) with elevated HREE and lower Ti concentrations. Coupled phase equilibria and garnet-melt-zircon trace-element partitioning calculations show that the older zircon cores equilibrated in thick (>40 km), hot (800–900°C), garnet-bearing lower crust during the cessation of compression at the end of the Laramide orogeny. Zircon rim domains equilibrated at lower pressures, consistent with >9 km of thinning of the lower crust. Thermal-kinematic calculations show that these pressure-temperature-time constraints require thinning of the lithospheric mantle prior to and during regional Cenozoic extension. Convective erosion of the mantle lithosphere over tens of millions of years, possibly facilitated by dynamics of the Farallon slab, provides a mechanism to facilitate lower crustal heating and extension.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 7","pages":""},"PeriodicalIF":2.9000,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011177","citationCount":"0","resultStr":"{\"title\":\"Thinning and Heating of Laramide Continental Lower Crust Recorded by Zircon Petrochronology\",\"authors\":\"J. H. Cipar, A. J. Smye, J. M. Garber, J. R. Reimink, A. R. C. Kylander-Clark\",\"doi\":\"10.1029/2023GC011177\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Zircon grains from the metasedimentary lower crust of the Rio Grande Rift, New Mexico, preserve a metamorphic record of the transition from Laramide compression to Eocene extension. Zircon U-Pb isotopes and trace-element concentrations from five two-pyroxene metaigneous granulite xenoliths define discrete populations: older zircon cores (∼15–50 Ma) that are depleted in heavy rare-earth elements (HREE) but Ti-rich, and younger zircon rims (∼3–15 Ma) with elevated HREE and lower Ti concentrations. Coupled phase equilibria and garnet-melt-zircon trace-element partitioning calculations show that the older zircon cores equilibrated in thick (>40 km), hot (800–900°C), garnet-bearing lower crust during the cessation of compression at the end of the Laramide orogeny. Zircon rim domains equilibrated at lower pressures, consistent with >9 km of thinning of the lower crust. Thermal-kinematic calculations show that these pressure-temperature-time constraints require thinning of the lithospheric mantle prior to and during regional Cenozoic extension. Convective erosion of the mantle lithosphere over tens of millions of years, possibly facilitated by dynamics of the Farallon slab, provides a mechanism to facilitate lower crustal heating and extension.</p>\",\"PeriodicalId\":50422,\"journal\":{\"name\":\"Geochemistry Geophysics Geosystems\",\"volume\":\"25 7\",\"pages\":\"\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-07-20\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011177\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geochemistry Geophysics Geosystems\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1029/2023GC011177\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geochemistry Geophysics Geosystems","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2023GC011177","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Thinning and Heating of Laramide Continental Lower Crust Recorded by Zircon Petrochronology
Zircon grains from the metasedimentary lower crust of the Rio Grande Rift, New Mexico, preserve a metamorphic record of the transition from Laramide compression to Eocene extension. Zircon U-Pb isotopes and trace-element concentrations from five two-pyroxene metaigneous granulite xenoliths define discrete populations: older zircon cores (∼15–50 Ma) that are depleted in heavy rare-earth elements (HREE) but Ti-rich, and younger zircon rims (∼3–15 Ma) with elevated HREE and lower Ti concentrations. Coupled phase equilibria and garnet-melt-zircon trace-element partitioning calculations show that the older zircon cores equilibrated in thick (>40 km), hot (800–900°C), garnet-bearing lower crust during the cessation of compression at the end of the Laramide orogeny. Zircon rim domains equilibrated at lower pressures, consistent with >9 km of thinning of the lower crust. Thermal-kinematic calculations show that these pressure-temperature-time constraints require thinning of the lithospheric mantle prior to and during regional Cenozoic extension. Convective erosion of the mantle lithosphere over tens of millions of years, possibly facilitated by dynamics of the Farallon slab, provides a mechanism to facilitate lower crustal heating and extension.
期刊介绍:
Geochemistry, Geophysics, Geosystems (G3) publishes research papers on Earth and planetary processes with a focus on understanding the Earth as a system. Observational, experimental, and theoretical investigations of the solid Earth, hydrosphere, atmosphere, biosphere, and solar system at all spatial and temporal scales are welcome. Articles should be of broad interest, and interdisciplinary approaches are encouraged.
Areas of interest for this peer-reviewed journal include, but are not limited to:
The physics and chemistry of the Earth, including its structure, composition, physical properties, dynamics, and evolution
Principles and applications of geochemical proxies to studies of Earth history
The physical properties, composition, and temporal evolution of the Earth''s major reservoirs and the coupling between them
The dynamics of geochemical and biogeochemical cycles at all spatial and temporal scales
Physical and cosmochemical constraints on the composition, origin, and evolution of the Earth and other terrestrial planets
The chemistry and physics of solar system materials that are relevant to the formation, evolution, and current state of the Earth and the planets
Advances in modeling, observation, and experimentation that are of widespread interest in the geosciences.