High-Resolution Paleoenvironmental Study of the Cariaco Basin, Venezuela: Late Quaternary to Present

高堆积率、缺乏生物扰动、丰富的独特纹层(可能是各种纹层)以及硅质和钙质微化石的保存，使卡里亚科盆地的缺氧沉积物成为构建高分辨率古气候变化记录的最佳选择。在现场计划期间，将收集这些层状沉积物的活塞、重力和箱形岩芯样本。AMS放射性碳时间控制和多个古环境指标将用于重点研究最后一次冰川终止、全新世和小冰期期间热带北大西洋西部地区信风强度和水文平衡的变化。对现有数据的初步分析表明，这种变化很大，与全球气候变化有关。在测试了沉积物纹层的年性之后，将直接根据观测的水文和气候数据，对来自沉积物的替代数据进行校准。将利用天气分析和气候模式实验来了解在全球变化背景下重建的低纬变率模式，并检验这种变率的假设原因。

High accumulation rates, the lack of bioturbation, an abundance of distinct laminae (probably varves), and the preservation of both siliceous and calcareous microfossils, make the anoxic sediments of the Cariaco Basin optimal for use in constructing high-resolution records of paleoclimatic change. During the field program, piston, gravity, and box core samples of these laminated sediments will be collected. AMS radiocarbon time control and multiple paleoenvironmental proxies will be used to focus on changes in trade wind strength and hydrologic balance over the western tropical North Atlantic region during the last glacial termination, the Holocene, and the Little Ice Age. Preliminary analysis of existing data suggests that this change was large and related to global climatic change. After testing the annual nature of the sediment laminae, calibration time series of proxy data from the sediment directly against observed hydrographic and climatic data will be made. Synoptic analysis and climate model experiments will be used to understand reconstructed patterns of low latitude variability in the context of global change and to test hypothesized causes of this variability.