High-resolution Stratigraphy: Application to Hydrologic- climatic Reconstruction in Southwestern U.S.

在新墨西哥州中部的埃斯坦西亚湖盆中，发现了一个长的、几乎是变色的晚更新世-全新世纹层和层理序列。层理和层理具有显著的垂向连续性，为重建十年、百年和千年分辨率的地层时间序列提供了基础。最初应用于各种沉积物的方法将被调整，以重建基于层理和层片累积厚度的时间序列，并与放射性碳测年“调整”。浅湖水量和扩张收缩的变化反映在粘土、碳酸钙的堆积速率和石膏砂的风沙流入速率上。这些参数将在紧密间隔的样本中测量，与重建的时间序列索引，并表示为沉积物通量。高水位岸线沉积与盆地中心地层的对比将导致先进的水文-气候模型的发展。该项目将确定在半干旱湖泊环境中重建高分辨率地层记录的可行性，同时评估一个潜在重要地点和沉积物记录的水文气候敏感性。

A long, almost varved sequence of late Pleistocene-Holocene laminations and bedding have been identified in the Estancia lake basin in central New Mexico. Remarkable vertical continutity of laminations and bedding provide a basis for reconstructing a stratigraphic time-series with decadel, centennial and millenial resolution. Methods originally applied to varved sediments will be adapted to reconstruct a time-series based on accumulated thickness of bedding and laminations and "tuned" with radiocarbon dates. Changes in water volume and expansion and contraction of the shallow lake are reflected in the rate of accumulation of clay, calcium carbonate, and eolean influx of gypsum sand. These parameters will be measured in closely spaced samples, indexed to the reconstructed time-series, and expressed as sediment flux. Correlation of high-stand shoreline deposits with basin-center strata will lead to the development of an advanced hydrologic- climatic model. The project will determine the feasibility of reconstructing high-resolution stratigraphic records in semi-arid lacustrine environments and at the same time evaluate the hydrologic- climatic sensitivity of a potentially important site and sediment record.