气候变化领域集成服务门户(CCPortal): Early arc development recorded in Permian-Triassic plutons of the northern Mojave Desert region, California, USA

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DOI	10.1130/B31963.1
	Early arc development recorded in Permian-Triassic plutons of the northern Mojave Desert region, California, USA
	Cecil M.R.; Ferrer M.A.; Riggs N.R.; Marsaglia K.; Kylander-Clark A.; Ducea M.N.; Stone P.
发表日期	2019
ISSN	167606
起始页码	749
结束页码	765
卷号	131 期号:2021-05-06
英文摘要	Permian-Middle Triassic plutons in the northern Mojave Desert, USA, are emplaced into the cryptic El Paso terrane, which is characterized by a northwest-striking belt of deep marine eugeoclinal strata juxtaposed against Proterozoic basement and its miogeoclinal cover. Fourteen new zircon U-Pb ages from the El Paso Mountains and Lane Mountain region of the Mojave Desert record nearly continuous magmatism occurring between ca. 275 and 240 Ma. These ages, which are taken to record the onset of subduction-related magmatism along the southwestern Laurentian margin, are older than the earliest arc plutons documented in the southern Sierra Nevada region to the north and in the Transverse Ranges to the south. They overlap, however, with Permian arc plutons documented in Sonora, Mexico. Dated plutons are compositionally variable, but can be characterized as intermediate to felsic, calcic to calc-alkalic, and having chemistries consistent with generation in an arc setting. Whole rock Sr-Nd isotopic compositions vary widely from relatively primitive (Sri = 0.7035, initial εNd = +3, initial εHf in zircon = +13) to moderately evolved (Sri = 0.708, initial εNd = -5, initial εHf in zircon = -3). Isotopic signatures differ considerably from partially coeval Triassic suites of the Transverse Ranges and central Mojave, which are more evolved and consistent with emplacement in Proterozoic continental crust of the Mojave province. They also differ considerably from those typical of intermediate plutons generated in intra-oceanic arcs, which are overall much more mantlelike. This suggests that the underpinnings of the El Paso terrane may be at least partly composed of continental crust and that magmas emplaced into the terrane may have been variably contaminated by crustal components. This is supported by the presence of Precambrian and early Paleozoic zircon inheritance recorded in some plutons. In all isotopic systems, values are the most evolved in the oldest plutons (ca. 275-270 Ma), becoming more juvenile in the Middle Triassic. These temporal trends, together with pluton fabrics and new estimates of Permian plate vectors, are interpreted to reflect generation of the earliest arc in a contractional setting that may have driven crustal thickening and a greater involvement of crustal materials in Permian magmas. This result supports a model of forced subduction initiation, which is favored by a change in plate motions along a previously weak margin, and predicts an initial compressive state in the upper plate. The uniformly primitive signatures of Triassic melts are taken to indicate a change to a transtensional upper-plate stress regime that promoted the development of more voluminous, primarily mantle-derived melts. Regional pluton age patterns suggest that arc magmatism initiated in restricted areas of the southwestern Laurentian margin (northern Mojave, Sonora) and then migrated north and south ultimately becoming a continuous arc by Jurassic time. © 2018 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184920
作者单位	Department of Geological Sciences, California State University-Northridge, Northridge, CA 91130, United States; School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011, United States; Department of Earth Science, University of California at Santa Barbara, Santa Barbara, CA 93106, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Faculty of Geology and Geophysics, University of Bucharest, Bucharest, 010041, Romania; U.S. Geological Survey, Menlo Park, CA 94025, United States
推荐引用方式 GB/T 7714	Cecil M.R.,Ferrer M.A.,Riggs N.R.,et al. Early arc development recorded in Permian-Triassic plutons of the northern Mojave Desert region, California, USA[J],2019,131(2021-05-06).
APA	Cecil M.R..,Ferrer M.A..,Riggs N.R..,Marsaglia K..,Kylander-Clark A..,...&Stone P..(2019).Early arc development recorded in Permian-Triassic plutons of the northern Mojave Desert region, California, USA.Bulletin of the Geological Society of America,131(2021-05-06).
MLA	Cecil M.R.,et al."Early arc development recorded in Permian-Triassic plutons of the northern Mojave Desert region, California, USA".Bulletin of the Geological Society of America 131.2021-05-06(2019).