Collaborative Research: RUI: Plio-Quaternary History of Basin Evolution, Climate Change, and Fold Growth in the Qaidam Basin-Investigating Wind-enhanced Climate-Tectonic Feedback

合作研究：RUI：柴达木盆地盆地演化、气候变化和褶皱生长的普里奥-第四纪历史——研究风增强的气候构造反馈

• 批准号: 1348075
• 负责人: Richard Heermance
• 金额: $ 18.76万
• 依托单位: The University Corporation, Northridge
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1348075&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Plio; Quaternary

The project aims to document acceleration in fold-growth due to increased wind erosion within the hyperarid western Qaidam Basin, China, and thus would provide the first example of wind-enhanced tectonics on Earth. In addition to understanding climate-tectonic feedbacks, this project will yield multiple high-resolution records of environmental change in the western Qaidam Basin across the late Pliocene climate crash and onset of Northern Hemisphere glaciations. This integrated, basin-scale dataset will provide evidence for desertification rates resulting from this climate shift, and may be useful as an analogue for comparable climate changes observed today. Moreover, the resultant new stratigraphic and structural datasets will be incorporated into a geoscience lab and made freely available via the Science Education Resource Center for educators across the country to use as a teaching tool. The project develops STEM workforce by training of graduate and undergraduate and the international collaboration provides an opportunity for international research experiences for those students. The project is supported by the Tectonics Program (Division of Earth Sciences) and International Science and Engineering (Office of International and Integrative Activities).Global climate changed to cooler, more arid conditions near the Plio-Pleistocene transition (3.6 to 2.6 Ma), causing environmental changes worldwide. In many regions, concurrent tectonic activity during this time period has evoked hypotheses of climate-tectonic feedbacks, but a causal relationship between observed depositional changes and local tectonics is difficult to quantify. One possible mechanism for climate-enhanced tectonics includes focused erosion across fold crests, or decreased overburden due to lake-level drop, both of which would enhance the isostatic response of uplift. This project, in collaboration with scientists from Lanzhou University (China) and Universite de Rennes (France), will test the hypothesis that climate change (manifested by enhanced aridity in central Asia) at about 3 Ma initiated episodic and spatially non-uniform wind erosion in the western Qaidam Basin in China, which in turn led to an acceleration and enhancement of fold growth. This research focuses on 8 stratigraphic sections spaced evenly throughout the Qaidam Basin and located on the flanks of active anticlines and involves: measurement of detailed sections; magnetostratigraphy; measurements of magnetic susceptibility, O and C stable isotopes; mapping of lithofacies, bed thickness, growth strata, and intraformational unconformities; and construction of 3-D structural models and palinspastic kinematic restorations of the folds. Data from each fold will be synthesized to test hypotheses that lake desiccation resulting from global climate aridification at about 3.0 Ma facilitated wind-erosion that enhanced fold growth on the basin floor; and that the western Qaidam Basin underwent alternating episodes of lake-level lowstands (and wind deflation) and lake-level highstands during Plio-Quaternary glacial and interglacial periods, respectively, in phase with the loess-paleosol successions of the Loess Plateau located to the east. The research project will provide basin-scale data on the relationship between aridification and deformation, allowing a test of whether wind erosion led to accelerated fold-growth.

该项目旨在记录中国柴达木盆地西部极度干旱地区由于风蚀加剧而导致的褶皱生长加速，从而提供地球上风增强构造的第一个例子。除了了解气候构造反馈之外，该项目还将产生上新世晚期气候崩溃和北半球冰川爆发期间柴达木盆地西部环境变化的多个高分辨率记录。这个综合的、流域规模的数据集将为这种气候变化导致的荒漠化率提供证据，并且可以作为当今观察到的可比气候变化的类比。此外，由此产生的新地层和结构数据集将被纳入地球科学实验室，并通过科学教育资源中心免费提供给全国各地的教育工作者作为教学工具。该项目通过培训研究生和本科生来培养 STEM 劳动力，国际合作为这些学生提供了获得国际研究经验的机会。该项目得到了构造计划（地球科学部）和国际科学与工程（国际和综合活动办公室）的支持。在上里奥-更新世过渡期（3.6 至 2.6 Ma），全球气候变得更凉爽、更干旱，造成全球环境变化。在许多地区，这一时期同时发生的构造活动引发了气候构造反馈的假设，但观测到的沉积变化与当地构造之间的因果关系很难量化。气候增强构造的一种可能机制包括褶皱顶部的集中侵蚀，或由于湖面下降而减少的覆盖层，这两者都会增强隆起的均衡响应。该项目与兰州大学（中国）和雷恩大学（法国）的科学家合作，将检验以下假设：约 3 Ma 的气候变化（表现为中亚干旱加剧）引发了偶发性和空间不均匀的风蚀在中国柴达木盆地西部，这反过来又导致褶皱生长的加速和增强。本研究重点关注柴达木盆地分布均匀、位于活动背斜侧翼的 8 个地层剖面，包括： 详细剖面测量；磁性地层学；磁化率、O 和 C 稳定同位素的测量；岩相、地层厚度、生长地层和地层内不整合面绘图；以及 3D 结构模型的构建和褶皱的回弹运动学恢复。来自每个褶皱的数据将被综合起来，以检验这样的假设：约 3.0 Ma 的全球气候干旱导致的湖泊干燥促进了风蚀，从而增强了盆地底部褶皱的生长；柴达木盆地西部在普里奥-第四纪冰川期和间冰期分别经历了湖位低位（和风塌）和湖位高位的交替，与位于黄土高原的黄土-古土壤序列同步。东方。该研究项目将提供有关干旱化和变形之间关系的流域规模数据，从而可以测试风蚀是否导致褶皱加速生长。