| 项目编号: | 1347433
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| 项目名称: | Thermal Structure of a Long-lived Ultrahigh-pressure Terrane, North Qaidam, Northwest China |
| 作者: | Chris Mattinson
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| 承担单位: | Central Washington University
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| 批准年: | 2013
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| 开始日期: | 2014-04-01
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| 结束日期: | 2018-03-31
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| 资助金额: | USD235294
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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: | rock
; continental collision
; north qaidam uhp terrane
; result
; pacific northwest
; thermal structure
; project
; other well-documented uhp terrane
; pressure
; western china
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| 英文摘要: | The growth, evolution, and destruction of continental crust during continental collision are fundamental processes that form great mountain belts such as the Himalaya, alter regional and global climate, and impact the transfer of mass between the Earth's surface and deep interior. Deeply buried rocks that have returned to the Earth's surface record these processes in their textures, chemistry, and isotopic composition, so analyzing such samples allows reconstruction of the continental collision processes, analogous to using a flight data recorder to reconstruct the events leading to a plane crash. Rocks buried to >100 km are termed ultrahigh-pressure (UHP) rocks, and are particularly useful for testing models of continental collision. Study of UHP rocks also aids understanding of the physical conditions relevant to the fluid-releasing mineral reactions that are linked to the deep earthquakes and melting that occur beneath volcanic chains such as the Cascade Range of the Pacific Northwest and the Aleutian Islands of Alaska.
This project focuses on the processes responsible for the deep (>100 km) burial and exhumation of continental crust, as recorded in rocks of the North Qaidam UHP terrane, western China, where UHP rocks and a long-lived (>30 Myr) collisional history are well documented. Ultrahigh-pressure metamorphism is now recognized as an integral component of continental collision for at least the past 600 Myr, but a growing data set indicates that some of the largest terranes remained at UHP conditions for an unexpectedly long time, challenging the commonly invoked interpretation that the complete burial + exhumation cycle must be brief (<5-10 Myr).
Models developed to explain long UHP durations predict distinct spatial and temporal trends in temperature and pressure, but current data lack the necessary spatial distribution and temperature resolution to test the applicability of these models. This project will determine the thermal structure (spatial and time evolution of temperature, as well as pressure) of the southeastern segment of the North Qaidam UHP terrane by combining (1) recently developed trace element thermometers, forward thermodynamic modeling, and conventional approaches to improve the accuracy and precision of temperature estimates, and (2) systematic U-Pb geochronology, tied to pressure and temperature constraints using trace elements and inclusions, to place these results in a time context. The planned research will involve education and training of graduate and undergraduate students in fundamental analytical techniques as well as international collaborative research. Results of the project will provide the fundamental constraints necessary to evaluate processes leading to long UHP duration, to test existing model predictions as well as develop new models, and to make meaningful comparisons with other well-documented UHP terranes. These results should significantly advance our knowledge of general UHP formation/exhumation processes in ancient and modern collisional mountain belts. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/97219
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Chris Mattinson. Thermal Structure of a Long-lived Ultrahigh-pressure Terrane, North Qaidam, Northwest China. 2013-01-01.
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