| 项目编号: | 1524785
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| 项目名称: | Collaborative Research: The Record of Early Cretaceous Growth of the Nevadaplano From Syn-orogenic Deposits of the Sevier Hinterland |
| 作者: | Kathryn Snell
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| 承担单位: | University of Colorado at Boulder
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| 批准年: | 2016
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| 开始日期: | 2016-01-01
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| 结束日期: | 2018-12-31
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| 资助金额: | 140965
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| 资助来源: | US-NSF
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| 项目类别: | Continuing grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | surface elevation
; study
; surface uplift
; mountain belt
; sevier orogeny
; geochemical record
; hinterland paleoelevation
; research infrastructure
; early career researcher
; result
; subduction
; response
; time
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| 英文摘要: | Researchers have long been interested in mountain belts and the processes that create them. The Cordillera of the western United States has long been interpreted as a mountain belt that developed in response to subduction of oceanic crust beneath continental crust. Despite being a "type" mountain belt, however, questions remain about the timing and magnitude of surface uplift during much of the prolonged duration of subduction off of the west coast of North America during the Mesozoic. Intensive study of the South American Andes has led some to suggest that surface uplift lags behind the shortening that occurs in response to subduction; this runs counter to the conventional wisdom that surface uplift and shortening should occur in tandem with each other. This study aims to provide an estimate of surface elevation relatively early in the Cordilleran mountain building event, during which a large amount of shortening took place. This estimate, combined with existing surface elevation estimates from the end of the Cordilleran event and at greatest levels of crustal thickening, should enable us to determine whether surface uplift occurred after or in tandem with shortening during the Mesozoic. These results have the potential to teach us a great deal about the response of the lithosphere to subduction in different types of mountain belts, which has broad implications for seismic activity and hazards. In addition, because we use ancient climate data to estimate ancient elevations, this project will provide valuable insight into ancient climate conditions during a relatively warm period in Earth's history, and also how animals and plants respond to both climate and elevation change through time. Museum displays at the Las Vegas Natural History Museum and Sierra College (Rocklin, CA), will inform visitors about the new findings related to mountain development, as well as Mesozoic plants and animals which once inhabited the area. Other important societal outcomes include providing support for three early career researchers; broadening of participation in an important STEM (science, technology, engineering, and mathematics) discipline; and development of research infrastructure. Results of the research will be presented in the peer-reviewed scientific literature and at professional science meetings; analytical data will be made available via publically accessible community data repositories.
To determine surface elevation in central Nevada during the Early Cretaceous, the project team will use conventional and "clumped" stable isotope geochemistry to estimate ancient temperature and stable isotope composition of water. These data will then be compared to similar datasets from the time-equivalent Cedar Mountain Formation in Utah (a study in progress) in order to estimate hinterland paleoelevation. These data will be integrated with sedimentology, paleontology, palynology, geologic mapping and tuff geochronology to provide critical context about the ancient environment of the region that will bolster the interpretations of the geochemical records and improve the resulting paleoelevation estimates. When placed in the existing framework of the timing and magnitude of crustal shortening that occurred during the Sevier orogeny, the paleoelevation estimates will be used to distinguish between three surface elevation scenarios, each with distinct geodynamic implications. Surface elevations of 1-2 kilometers are predicted directly from the shortening history, assuming that isostatic compensation accompanied crustal thickening throughout the duration of shortening. Elevations lower than this would imply that crustal thickening coincided with generation of dense lower lithosphere, and elevations higher than this would suggest that removal of dense lithosphere operated early during orogenesis. The results of this study will provide valuable insight into the range of lithospheric processes that operate during subduction-related orogenesis as well as provide valuable ancient climate data for the western United States. In addition, this study will push paleoaltimetry farther back in time than existing datasets, so modifications we make to typical approaches used in paleoaltimetry to determine these very ancient paleoelevations will be valuable for pushing paleoaltimetry estimates in other orogenic systems further back in time. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92961
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Kathryn Snell. Collaborative Research: The Record of Early Cretaceous Growth of the Nevadaplano From Syn-orogenic Deposits of the Sevier Hinterland. 2016-01-01.
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