High-Resolution Lacustrine Stratigraphy: Application to Hydrologic-Climatic Reconstruction in Southwestern United States

高分辨率湖泊地层学：在美国西南部水文气候重建中的应用

• 批准号: 9019134
• 负责人: Roger Anderson
• 金额: $ 5.51万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-02-15 至 1993-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9019134&HistoricalAwards=false
• 关键词: Resolution; Lacustrine; Stratigraphy; Application; Hydrologic

Laminations of gypsum sand and silt, eolian and lacustrine clay, and organic-rich material occur on a scale of millimeters in late Pleistocene/Holocene lake sediments in the Estancia Basin in central New Mexico. A feasibility study has established the seasonal character of the laminae and their potential for reconstructing a high-resolution chronostratigraphy. The vertical and lateral continuity of the laminations provides a basis for reconstructing a stratigraphic sequence on a decimeter scale and a time-series with a temporal resolution ranging from decimeter decades to centuries. Changes in the proportion of eolian, lacustrine, and biogenic components reflect changes in water depth and volume, wind intensity, and in the hydrologic balance of the closed lake system. Reconstruction of a high-resolution stratigraphy will eventually permit the measurement of the hydrologic response to climatic forcing and quantitative estimates of changes in climatic variables. Methods applied elsewhere to the reconstruction of varve time- series will be adapted to reconstruct a time-series based on accumulated thickness and composition of bedding and laminations. These parameters will be measured in closely spaced samples, indexed to an age model for the reconstructed time-series, and expressed as sediment flux. The radiocarbon chronostratigraphy will be refined with additional analyses. The high-resolution stratigraphy in the central area of the basin will be correlated with shoreline deposits to connect the stratigraphic record to an improved hydrologic/climatic model for the Estancia Basin. In addition, the investigation will compile a record of eolian influx and will help develop methodologies for reconstructing high- resolution stratigraphic records in other lacustrine basins.

在新墨西哥州中部埃斯坦西亚盆地的晚更新世/全新世湖泊沉积中，石膏砂和粉砂、风成和湖泊粘土以及富含有机质的纹层以毫米级的规模出现。一项可行性研究已经确定了纹层的季节特征及其重建高分辨率年代地层学的潜力。层理的纵向和横向连续性为重建分米尺度的地层层序和时间分辨率从分米几十年到几个世纪的时间序列提供了基础。风成、湖泊和生物成分比例的变化反映了闭合湖泊系统的水深和水量、风力强度以及水文平衡的变化。重建高分辨率地层学最终将能够测量对气候强迫的水文响应，并对气候变量的变化进行定量估计。其他地方用于重建VVE时间序列的方法将被采用，以基于累积厚度和层理和层片的组成来重建时间序列。这些参数将在紧密间隔的样本中测量，与重建的时间序列的年龄模型索引，并表示为沉积物通量。放射性碳年代地层学将通过更多的分析加以完善。盆地中心地区的高分辨率地层学将与海岸线沉积相关联，以将地层记录与埃斯坦西亚盆地改进的水文/气候模型联系起来。此外，这项调查将汇编风成流入的记录，并将有助于开发重建其他湖盆高分辨率地层记录的方法。