Last Glacial to Recent in the Gulf of California: A Sediment Trapping and Long Piston Coring Program

由于其地理和海洋环境，加利福尼亚州海湾记录了海洋范围和区域海洋和气候信号的混合。极高的沉积速率和频繁的年度层片(Varive)使墨西哥湾成为从季节到千年(或更大)尺度开展高分辨率古环境变化研究的理想地点。尽管人们对海湾火山口的兴趣由来已久，但这将是第一个利用沉积物圈闭直接确定火山口形成过程的项目。这一结果将有助于更好地理解气候/海洋记录是如何保存的，这些记录将用于恢复冰期和间冰期沉积物。将检验以下假设：1)沟槽的形成是由风吹来的陆源物质的季节性输入造成的；2)海湾东西两侧形成亮片和暗片的季节时间不同，3)冰期和新仙女木时期非片层沉积物的沉积是由于太平洋中深水含氧量的增加和营养物质含量的减少；4)18-0海湾的消冰振荡是由于盐度较低的事件，可能是季风环流增加所致。

Because of its geographic and oceanographic setting, the Gulf of California records a mix of oceanwide and regional oceanographic and climatic signals. The extremely high rates of sedimentation and frequent occurrence of annual laminae (varves) make the Gulf an ideal location for carrying out high resolution studies of paleoenvironmental change on the seasonal to millenial (and greater) scale. Despite the long interest in Gulf varves, this will be the first project to use sediment traps to directly determine the process of varve formation. The results will lead to a better understanding of how the climatic/oceanographic record is preserved, which will be used in the recover glacial as well as interglacial sediments. Following hypotheses will be tested: 1) that varve formation results from the seasonal input of wind-blown terrigenous material, 2) that the seasonal timing of light and dark laminae formation differs between the eastern and western sides of the Gulf, 3) that the deposition of nonlaminated sediment during glacial and Younger Dryas time resulted from increased oxygen and decreased nutrient content of intermediate depth waters in the Pacific Ocean, and 4) that deglacial oscillations of Gulf 18-0 resulted from episodes of lower salinity, perhaps caused by increased monsoonal circulation.