Late Quaternary History of the Walker River: The Tale of a River with a Split Personality

步行者河的第四纪晚期历史：一条人格分裂的河流的故事。内华达州里诺市亚当斯沙漠研究所摘要步行者河是流入内华达州西北部和邻近加州东北部的拉洪坦盆地的五条主要河流之一。自更新世晚期以来，这条河的行为是相当不寻常的，因为它不是像今天一样流入步行者湖，而是在全新世期间有时改道流入卡森水槽。当这种情况发生时，步行者湖成为一个相对干燥的干盐湖，而卡森水槽获得了一个重要的新水源。当河流改道回到步行者湖时，普拉亚被洪水淹没，卡森水槽中的湖泊大概缩小了。因此，基于两个流域湖泊的行为和状态的古气候重建必须考虑步行者河的改道历史。PI项目将对自拉洪坦湖最后一次高位以来步行者河的行为及其对步行者湖和卡森水槽的古水文学影响进行综合研究。这项研究对大盆地过去、现在和未来的研究工作具有重要意义。首先，这项研究的结果将有助于测试的假设，快速均衡反弹后，最后一个主要的湖泊周期造成的步行者河改变其路线。其次，步行者湖流域的湖平面波动可能是河流改道的一个功能，而不是气候波动。第三，卡森水槽中的大型短命湖泊在全新世晚期将人、动物和植被转移到水槽的外围，这也可能是由于河流改道而不是气候波动。第四，本研究的结果将作为均衡回弹建模工作的修正输入参数。第五，受威胁的拉洪坦割喉鳟鱼的历史和生存将被置于一个新的视角，这可能有助于恢复工作。这项研究是重建拉洪坦地区过去30万年的古气候和反弹历史的长期努力的一部分。认识到，快速均衡反弹可能会引起大规模的地貌和水文影响的基础上完善的均衡反弹模型的拉洪坦湖盆地和记录这些影响的古环境历史的地区的重要性。拟议研究的结果将导致更完整的古气候记录从盆地，也将记录气候变化，地球深部过程和表面过程之间的相互关系。

Late Quaternary history of the Walker River: The tale of a river with a split personalityKenneth D. AdamsDesert Research InstituteReno, NevadaAbstractThe Walker River is one of five major streams that flow into the Lahontan basin of northwestern Nevada and adjacent northeastern California. The behavior of this river since the late Pleistocene is quite unusual because instead of flowing into Walker Lake as it does today, at times during the Holocene it diverted to flow into the Carson Sink. When this happened, Walker Lake became a relatively dry playa whereas the Carson Sink gained a significant new water source. When the river diverted back to Walker Lake, the playa was flooded and lakes in the Carson Sink presumably shrank in size. Paleoclimatic reconstructions based on the behavior and status of lakes in both basins must therefore consider the diversion history of the Walker River.The project-PI will perform an integrated study of the behavior of the Walker River since the last highstand of Lake Lahontan and its effects on the paleohydrology of Walker Lake and the Carson Sink. This research is significant to a host of past, present, and future research efforts in the Great Basin. First, the results of this research will serve to test the hypothesis that rapid isostatic rebound after the last major lake cycle caused the Walker River to change its course. Second, fluctuations of lake levels in the Walker Lake basin may be a function of river diversion, not climatic fluctuations. Third, large short-lived lakes in the Carson Sink that displaced people, animals, and vegetation to the periphery of the Sink in the late Holocene may also be due to river diversion and not climatic fluctuations. Fourth, the results of this research will serve as revised input parameters for isostatic rebound modeling efforts. And fifth, the history and survival of the threatened Lahontan Cutthroat Trout will be placed into a new perspective that may assist recovery efforts.The research is part of a longer-term effort to reconstruct the paleoclimatic and rebound history of the Lahontan region over the last 30 ka. Recognition that rapid isostatic rebound may have invoked large-scale geomorphic and hydrographic effects underlies the importance of refining the isostatic rebound model for the Lake Lahontan basin and documenting these effects on the paleoenvironmental history of the region. The results of the proposed research will lead to a more complete paleoclimatic record from the basin and will also document the interrelationships between climate change, deep Earth processes, and surface processes.