Highest Pluvial-Lake Shorelines and Pleistocene Climate of the Western Great Basin
Highest Pluvial-Lake Shorelines and Pleistocene Climate of the Western Great Basin
复制标题
西部大盆地最高的雨湖海岸线和更新世气候
DOI：
10.1006/qres.1999.2064
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发表时间：
1999
影响因子：
2.3
通讯作者：
M. Reheis
中科院分区：
文献类型：
--
作者：
M. Reheis
北美洲西部大盆地的几个雨成湖的湖岸海拔记录了从更新世早期到晚期湖泊依次变小的情况。湖泊面积的这种减小表明该地区气候存在长期的干旱趋势，这在全球海洋氧同位素记录中未有所体现。在比其更新世晚期湖岸线高70米处，中更新世早期的拉洪坦湖淹没了一些先前被认为是孤立的盆地。其他已知包含高于更新世晚期水位的更古老雨成湖记录的盆地包括哥伦布 - 菲什湖（哥伦布 - 伦尼湖）、科比 - 戴蒙德（乔纳森湖和戴蒙德湖）、纽瓦克、朗（哈布斯湖）和克洛弗。其中一些湖泊的高水位可能引发了先前内部排水盆地的溢流，从而增加了拉洪坦湖的面积。基于湖泊面积差异的简单计算表明，这些雨成湖的最高水位要求该地区的有效湿度相对于更新世晚期的雨成量增加1.2到3倍（假设有效湿度与水文指数，即湖泊面积/支流流域面积成正比）。这些先前未知的湖泊水位反映了气候、构造和（或）流域配置的重大变化，并且可能促进了大盆地水生生物的迁徙。
Shoreline altitudes of several pluvial lakes in the western Great Basin of North America record successively smaller lakes from the early to the late Pleistocene. This decrease in lake size indicates a long-term drying trend in the regional climate that is not seen in global marine oxygen-isotope records. At +70 m above its late Pleistocene shoreline, Lake Lahontan in the early middle Pleistocene submerged some basins previously thought to have been isolated. Other basins known to contain records of older pluvial lakes that exceeded late Pleistocene levels include Columbus-Fish Lake (Lake Columbus-Rennie), Kobeh-Diamond (Lakes Jonathan and Diamond), Newark, Long (Lake Hubbs), and Clover. Very high stands of some of these lakes probably triggered overflows of previously internally drained basins, adding to the size of Lake Lahontan. Simple calculations based on differences in lake area suggest that the highest levels of these pluvial lakes required a regional increase in effective moisture by a factor of 1.2 to 3 relative to late Pleistocene pluvial amounts (assuming that effective moisture is directly proportional to the hydrologic index, or lake area/tributary basin area). These previously unknown lake levels reflect significant changes in climate, tectonics, and (or) drainage-basin configurations, and could have facilitated migration of aquatic species in the Great Basin.