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

大盆地南部是北美最干旱的地区之一。它几乎没有一年生的溪流，但确实有1000个泉水。这些泉水是栖息在沙漠海洋中的水生岛屿。值得注意的是，许多这些孤立的泉水包含不同的水生生态系统，甚至特有的鱼类、泉螺和其他水生生物。许多只能在水中生存的水生物种的存在证明，泉水是常年排水系统的残留物，而特有物种的存在需要在百万年范围内进行遗传分化，这证明至少其中一些泉水在地质时间尺度上从未干涸。这是一个项目，目的是扩大已经很大的区域生物地理数据库，并使用新的和先前存在的数据相结合的数据来检验南方大盆地的构造和古水文演化模型。PI指数将集中在两个时间尺度上：晚中新世至今该地区的伸展解体时间和冰川/间冰期气候旋回的时间尺度。为了了解该地区的伸展历史，人们已经做了大量的工作来了解该地区的伸展历史，该伸展历史始于研究区东部约14 Ma，并在板块边界动力学的驱动下向西迁移到内华达前山。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一演化过程，该模型将沿断层的运动、质量分布、岩浆作用、均衡补偿和挠曲变形与包括侵蚀和沉积在内的水文和地表地貌过程完全耦合。将研究水文系统的扩展破碎，而地下水流动将是区域构造-地貌-水文模型的组成部分。模拟的古水文历史将与生物数据(水生生物群名录、微生物和大型动物DNA以及遗传分化时间)进行岛屿生物地理学理论的检验。PI将测试水文破碎年代学与特有物种的关系，以及根据地下水年龄和气候驱动的建模所推断的生态系统多样性与泉水弹性的关系。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。

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.