Planning: CDP: High-Resolution Seismic Reflection Site Survey Supporting Lake Victoria Scientific Drilling

2231128scholz该奖项将支持从东非维多利亚湖获取高分辨率地震反射数据。为了对盆地湖泊沉积物的地下结构和地层格架进行成像，在两年的时间内提出了几条地震线（2000公里）。目的是确定湖泊的最佳钻探区域，作为未来计划的一部分，钻探湖泊沉积物并恢复长而连续的沉积记录，以促进区域更新世/全新世古气候学，古环境，以及该地区和湖泊生物的生物历史研究。CHIRP地震反射仪器将由一艘合同船只拖曳。收集的数据将被处理、分析和解释，使用旧技术收集的1980年代和90年代的遗留地震反射数据将被重新处理，数据集将被整合并最终存档在Lamont Doherty地球观测站的海洋地球科学数据系统（MGDS）中。规划活动和拟议的地震调查需要制定未来的竞争性建议，以便在维多利亚湖进行科学的湖泊钻探活动。pi是国际科学家团队的一部分，该团队已经得到了国际大陆科学钻探计划的支持，将于2022年夏季在坦桑尼亚举办一次规划研讨会。拟议的工作将成为锡拉丘兹大学一名坦桑尼亚国民即将入学的研究生的论文工作的基础，这项工作将与坦桑尼亚各机构，包括渔业部、地质勘查部和达累斯萨拉姆大学合作进行。维多利亚湖是非洲最大的湖泊，是白尼罗河的源头，是数百种特有生物的家园，支持着地球上最大的湖泊渔业，并包含了热带大陆第四纪气候变化的重要记录。由于其浅，宽的形态和大的表面积与集水率，湖对水文气候的变化极为敏感。湖泊水位的波动是湖泊动植物（如鲷鱼）以及更广泛的流域范围扩大、缩小、破碎、适应和多样化的重要驱动因素，并促进了早期智人种群在非洲各地的分散。先前对湖泊沉积物岩心和地震反射数据的研究表明，该湖泊在更新世晚期几乎完全干涸，湖泊流域内的陆地露头和湖泊内部的地震数据表明，该湖泊可能在其大约40万年（~400 kyr）的历史中多次干涸和重新填充。未来的钻探计划将支持一系列主题的研究，包括1)湖盆的形成和发展，2)多个冰期-间冰期的热带气候和环境变化，3)气候与湖泊干燥事件的联系，4)水生动物的多样化和进化对湖泊动态和气候变化的响应，5)与湖泊范围相关的气候和环境压力驱动早期人类种群的分散。稀树草原生态系统的变化及其生物地理意义。然而，从湖泊获得的遗留地震反射数据不适合从盆地中定位科学钻探岩心，该建议将获得现代，高分辨率的“海洋型”CHIRP地震反射数据，这些数据将通过整个盆地中存在的详细记录的晚更新世不整合进行成像。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

2231128ScholzThis award will support acquisition of high-resolution seismic reflection data from Lake Victoria in East Africa. Several seismic lines are proposed (2000 km) over a two-year period in order to image the subsurface structure and stratigraphic framework of basinal lake sediments. The intent is to determine the best areas of the lake to drill as part of a future planned proposal to drill into lake sediment and recover long and continuous sedimentary records to facilitate studies of regional Pleistocene/Holocene paleoclimatology, paleoenvironments, and biologic history of the region and lake organisms. A CHIRP seismic reflection instrument would be towed by a contracted vessel. The data collected would be processed, analyzed, and interpreted and legacy seismic reflection data collected in the 1980 and 90s using older technology would be reprocessed, the data sets integrated and ultimately archived within the Marine Geoscience Data System (MGDS) at Lamont Doherty Earth Observatory. Planning activities and proposed seismic surveys are required to develop a future competitive proposal to conduct a scientific lake drilling campaign on Lake Victoria. The PIs are part of an international team of scientists who have already been supported by the International Continental Scientific Drilling Program to host a planning workshop in Tanzania in summer 2022. The proposed work would form the basis for the thesis work of an incoming Syracuse University graduate student who is a Tanzanian national and the work would be conducted in collaboration with Tanzanian institutions, including the Department of Fisheries, the Geological Survey Department, and the University of Dar es Salaam. Lake Victoria is the largest lake in Africa, is the source of the White Nile, is home to hundreds of endemic organisms, supports the largest lake fishery on Earth and contains important records of Quaternary climate variability in the continental tropics. Given its shallow, broad morphometry and large surface area- to- catchment ratio, the lake is extremely sensitive to changes in hydroclimate. Fluctuations in the water levels of the lake are important drivers for range expansion, contraction, fragmentation, adaptation, and diversification for flora and fauna in the lake (e.g., cichlid fish), as well as the broader watershed, and have contributed to the dispersal of early populations of Homo sapiens across Africa. Prior studies of lake sediment cores and seismic reflection data document the virtually complete desiccation of the lake at the terminal Pleistocene, and terrestrial outcrops within the lake’s watershed and seismic data from within the lake suggest the lake has likely desiccated and refilled multiple times in its approximately 400,000- year (~400 kyr) history. A future drilling program would support research on an array of topics, including 1) lacustrine basin formation and development, 2) tropical climate and environmental change over multiple glacial-interglacial cycles, 3) climate linkages to lake desiccation events, 4) diversification and evolution of aquatic fauna responding to lake dynamics and climate change, 5) climate and environmental pressures associated with lake extent driving dispersal of early human populations, and 6) savanna ecosystem changes and their biogeographic implications. The legacy seismic reflection data available from the lake are not suitable however for siting scientific drill cores from the basin, and this proposal will acquire modern, high- resolution ‘marine-type’ CHIRP seismic reflection data, which will image through the well-documented late Pleistocene unconformity present across the basin.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.