Collaborative Research: Tectonic and climatic forcing of hydrological systems in the southern Great Basin: Implications for ancient and future aquatic system resilience

合作研究：大盆地南部水文系统的构造和气候强迫：对古代和未来水生系统恢复能力的影响

• 批准号: 1516698
• 负责人: Laura Rademacher
• 金额: $ 30.46万
• 依托单位: University of the Pacific
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1516698&HistoricalAwards=false
• 关键词: Collaborative; Research; Tectonic; climatic; forcing

The southern Great Basin is among the most arid regions in North America. It has almost noperennial streams, but does have 1,000 springs. These springs are islands of aquatic habitatin an ocean of desert. Remarkably, many of these isolated springs contain diverse aquaticecosystems and even endemic species of fish, spring snails, and other aquatic organisms. Thepresence of many aquatic species that can only survive in water is evidence that the springsare remnants of a perennial drainage system, and the presence of endemic species requiringintervals in the million-year range for genetic divergence are evidence that at least someof these springs have never desiccated over the geological time scale. Aquatic biogeographicalpatterns thus inform the geological and hydrological history of the region.This is a project to expand the already-large regional biogeographical database and to use the combinednew and preexisting data to test models of tectonic and paleohydrological evolution of thesouthern Great Basin. The PIs will focus on two timescales: that of the extensional breakup ofthe region from the late Miocene to the present and that of glacial/interglacial climate cycles.Extensive work has been done to understand the extensional history of the region, which startedin the eastern portion of the study area at ~14 Ma and migrated westward to the Sierra Nevadafront, driven by plate-boundary dynamics. They will simulate this evolution using a regionalquasi-3D kinematic/tectonic-geomorphic-hydrologic coupled model that fully couples movementalong faults, mass distribution, magmatism, isostatic compensation and flexural deformationwith hydrology and surface geomorphic processes, including erosion and deposition. The extensionalfragmentation of the hydrological system will be studied and groundwater flow, necessary tosimulate the resulting development of springs, will be an integral part of the regional tectonic-geomorphic-hydrologic model..Modeled paleohydrologic histories will be tested against biotic data (aquatic biota inventories,microbial and macrofaunal DNA, and genetic divergence times) with island biogeography theory.The PIs will test for relations of hydrologic fragmentation chronology with endemic species andfor ecosystem diversity with spring resilience, as inferred from groundwater ages and climaticallydriven modeling. They will use these results to assess and improve their tectonic/paleohydrologic models.

大盆地南部是北美最干旱的地区之一。它几乎没有常年溪流，但有 1,000 个泉水。这些泉水是沙漠海洋中的水生栖息地岛屿。值得注意的是，许多孤立的泉水都含有多样化的水生生态系统，甚至还有鱼类、泉螺和其他水生生物的特有物种。许多只能在水中生存的水生物种的存在证明了这些泉水是常年排水系统的残余物，而需要数百万年范围内的遗传分化间隔的特有物种的存在证明了至少其中一些泉水从未干涸在地质时间尺度上。因此，水生生物地理模式揭示了该地区的地质和水文历史。该项目旨在扩展已经庞大的区域生物地理数据库，并利用新数据和现有数据来测试南部大盆地的构造和古水文演化模型。 PI将重点关注两个时间尺度：从中新世晚期至今的该地区的伸展分裂时间和冰期/间冰期气候循环的时间尺度。为了了解该地区从东部开始的伸展历史，已经开展了大量的工作大约 14 Ma 时，研究区域发生了迁移，并在板块边界动力学的驱动下向西迁移至内华达山脉。他们将使用区域准3D运动学/构造-地貌-水文耦合模型来模拟这种演化，该模型将沿断层的运动、质量分布、岩浆作用、均衡补偿和弯曲变形与水文和地表地貌过程（包括侵蚀和沉积）完全耦合起来。将研究水文系统的伸展破碎化，并且模拟由此产生的泉水发育所必需的地下水流将成为区域构造-地貌-水文模型的组成部分。模拟的古水文历史将根据生物数据（水生生物群清单）进行测试、微生物和大型动物 DNA 以及遗传分化时间）与岛屿生物地理学理论。PI 将测试水文破碎的关系根据地下水年龄和气候驱动的模型推断，特有物种的年代学和具有春季恢复力的生态系统多样性。他们将利用这些结果来评估和改进他们的构造/古水文模型。