Quaternary Paleohydrology of the Western Great Basin Province, USA: The Radiogenic Isotope Record of Lacustrine Sediments of the Owens River System

9814943该奖项支持一项放射性同位素研究，该研究保存在大盆地加州东南部的一系列普拉湖中，记录了独特的大陆风化和气候变化记录。这一周期性相互关联的湖泊链被称为欧文斯河水系，是过去数百万年来从内华达山脉东部从莫诺湖以南到加洛克断层的几乎所有碎屑和化学沉积物的储存库。尽管对欧文斯河水系进行了大量工作，但对这些大盆地湖盆中阳离子和碎屑沉积物来源的研究相对较少。锶和钕同位素是阳离子输入的潜在敏感示踪剂，无论是以溶解形式还是以悬浮沉积物的形式都是如此。初步数据表明，这些同位素示踪剂可成功地用于欧文斯河水系监测：(1)化学风化和沉积物来源位置的变化(从而影响降水模式)；(2)高山环境中化学风化与机械风化的关系；(3)湖泊之间的水文连通性，这些湖泊在丰水期共享共同供水，但在枯水期成为封闭、孤立的盆地。将拟议研究的结果与欧文斯河水系以前和正在进行的工作结合起来，将对盆地和山脉省第四纪气候变化提供强有力的制约，而这些变化反过来又与北大西洋和全球气候波动有关。

9814943StewartThis award supports a radiogenic isotope study of a unique continental record of weathering and climate change preserved in a series of playa lakes in the southeastern California section of the Great Basin. This chain of periodically interconnected lakes, referred to as the Owens River System, is the repository for essentially all of the clastic and chemical sediments shed over the past several million years from the eastern Sierra Nevada from just south of Mono Lake to the Garlock Fault. Despite the large amount of work that has been carried out on the Owens Rivers System, there have been relatively few studies examining the sources of cations and clastic sediments in these Great Basin lacustrine basins. Strontium (Sr) and neodymium (Nd) isotopes are potentially sensitive tracers of cation inputs, both in the dissolved form and as suspended sediments. Preliminary data suggest that these isotope tracers can be successfully used in the Owens River System to monitor (1) changes in location of chemical weathering and sediment sources (therefore of precipitation patterns); (2) the relationship of chemical to mechanical weathering in the alpine environment; and (3) hydrologic connectivity between lakes that share a common water supply during wet periods but that become closed, isolated basins during dry periods. Integration of the results from the proposed study with previous and ongoing work in the Owens River System will provide powerful constraints on Quaternary climate shifts in the Basin and Range Province, which have in turn been linked to North Atlantic and global climate fluctuations.