Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1130/GES00595.1 |
A reassessment of Mojavia and a new Cheyenne Belt alignment in the eastern Great Basin | |
Nelson, Stephen T.1; Hart, Garret L.2; Frost, Carol D.3 | |
通讯作者 | Nelson, Stephen T. |
来源期刊 | GEOSPHERE |
ISSN | 1553-040X |
出版年 | 2011 |
卷号 | 7期号:2页码:513-527 |
英文摘要 | A separate basement terrane, Mojavia or the Mojave province with characteristic 2.0-2.3 Ga model ages, has been proposed to underlie much of the western U. S. Its existence, posited on patterns of Pb and Nd isotope data, has been propagated in the literature for more than two decades. New and compiled U/Pb geochronology shows there is no direct evidence of > 2.0 Ga juvenile basement rocks exposed within Mojavia of the eastern Great Basin. Pb and Nd model ages, by contrast, vary from Archean to Neoproterozoic with large variations exhibited, commonly within small regions. Archean ages are concentrated northward, suggesting the influence of sediment shed southward from the Wyoming province onto Paleoproterozoic basement terranes. In places, including the Farmington Canyon complex, sediment has been tectonically reprocessed and now is preserved as high-grade metamorphic rock in accretionary melanges. There is no strong evidence that Mojavian basement exists outside of the Mojave Desert region proper. A statistical evaluation of common Pb and Sr isotopes in Phanerozoic igneous rocks shows distinct differences north and south of one proposed boundary between Mojavia and the Yavapai province. However, close examination suggests that variation in these parameters could be produced by the influence of Archean material shed from the Wyoming province rather than representing a distinct difference in the age and isotopic character of the basement. Statistical discrimination of candidate terranes and terrane boundaries may be valuable for their recognition, but such differences alone do not prove their existence. The northern boundary of Mojavia with the Wyoming province in the eastern Great Basin has been given the same name, the Cheyenne Belt, as the exposed suture be tween Paleoproterozoic and Archean basement in southern Wyoming. We re assess the location of this boundary in the Great Basin. New age controls on key basement outcrops in the Uinta Mountains and Farmington Canyon complex that were previously considered Archean indicate that these rocks are Paleoproterozoic in age (similar to 1.7 Ga). Thus, the Cheyenne Belt has traditionally been placed too far south; it must lie in a poorly defined location north of these localities. |
类型 | Article |
语种 | 英语 |
国家 | USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000288993400013 |
WOS关键词 | WESTERN UNITED-STATES ; MESOZOIC CRUSTAL STRUCTURE ; METAMORPHIC CORE COMPLEX ; GEOCHEMICAL CLASSIFICATION ; NORTHWESTERN ARIZONA ; PROTEROZOIC SUTURE ; TERTIARY GRANITE ; ROCKY-MOUNTAINS ; UINTA MOUNTAIN ; HUMBOLDT RANGE |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/168312 |
作者单位 | 1.Brigham Young Univ, Dept Geol Sci, Provo, UT 84602 USA; 2.Washington State Univ, Sch Earth & Environm Sci, Pullman, WA 99164 USA; 3.Univ Wyoming, Dept Geol & Geophys, Dept 3006, Laramie, WY 82071 USA |
推荐引用方式 GB/T 7714 | Nelson, Stephen T.,Hart, Garret L.,Frost, Carol D.. A reassessment of Mojavia and a new Cheyenne Belt alignment in the eastern Great Basin[J],2011,7(2):513-527. |
APA | Nelson, Stephen T.,Hart, Garret L.,&Frost, Carol D..(2011).A reassessment of Mojavia and a new Cheyenne Belt alignment in the eastern Great Basin.GEOSPHERE,7(2),513-527. |
MLA | Nelson, Stephen T.,et al."A reassessment of Mojavia and a new Cheyenne Belt alignment in the eastern Great Basin".GEOSPHERE 7.2(2011):513-527. |
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