Collaborative Research: EAGER: A Seismic Reflection Survey to Assess the Deep Drilling Potential of Laguna de Tota, Colombia

拟议的工作将对哥伦比亚安第斯山脉东科迪勒拉的一个大型构造湖--托塔湖进行详细的地球物理调查。这项调查将确定海底沉积层的厚度和布局，并使研究人员能够更好地了解可供以后可能的探险通过钻探岩心提取样本的材料类型。拟议的地球物理工作涉及一个由美国和哥伦比亚地球科学家组成的国际团队，他们将加强国际合作，并为美国和哥伦比亚的研究生提供培训。伯德和埃斯科瓦尔博士将通过在社区中心讲授地球物理和钻探项目，让依赖托塔水资源的当地社区参与进来。他们还将在哥伦比亚的大学发表演讲，以提高人们对安第斯水资源和气候变化的认识。这个湖的位置很重要，因为作为南美洲第三大湖，它与另外两个湖(玻利维亚和秘鲁的喀喀湖和朱宁湖)相距甚远。来自拉古纳德托塔的沉积物岩芯可能包含记录过去数十万年来温度和湖泊过程历史的气候数据，并包括几个冰川/间冰期气候信号，包括南美夏季季风的气候信号，其细节被很好地理解。使用一个小型、高分辨率的单通道气枪地震反射系统和啁啾海底剖面仪，研究小组将绘制托塔的水深测量图，确定湖泊沉积序列的厚度，定位沉积中心，并识别湖平面海侵-海退序列。2013年从托塔收集的沿海沉积物岩心表明，该湖的沉积物档案包含详细的气候信息，包括过去湖泊水位变化的证据。该团队将描述托塔的沉积物档案，并评估其开发长期古气候记录的潜力。尽管几乎可以肯定，托塔的沉积物档案至少跨越了数十万年，但之前还没有人在该湖上进行过已知的地球物理或古气候研究。因此，拟议的工作是一个独特的机会，可以调查一个具有巨大潜力的地点，其中包含北半球、南美洲更新世气候的长期、连续记录。这项工作还处于初始阶段，但有可能改变我们对热带气候变化的理解。因此，这项工作适合于急切的资助机制，该机制旨在支持早期阶段的“高风险-高回报”的探索工作。首席PI申请的资金为1/3个月的夏季，他的研究生为1个月，以及3名PI和2名美国研究生的旅费。还要求从LacCore空运取心设备，并按Tota附近地区的每日费用返还，以及租用船只和卡车。

The proposed work would conduct a detailed geophysical survey of the Laguna de Tota, a large tectonic lake in the Eastern Cordillera of the Colombian Andes. The survey would determine the thickness and layout of the bottom sediment layers, and allow the researchers to better understand the type of materials available for a possible later expedition to extract samples by drilling for cores. The proposed geophysical work involves an international team of U.S. and Colombian geoscientists, which will strengthen international collaboration and provide training for U.S. and Colombian graduate students. Drs. Bird and Escobar will engage local communities that rely on Tota's water resources by giving lectures about the geophysical and drilling project at community centers. They will also speak at Colombian universities to increase awareness about Andean water resources and climate change. The location of the lake is important, because as South America's third largest lake, it is well removed to the North from the other two (Lakes Titicaca and Junin, in Bolivia and Peru). A sediment core from the Laguna de Tota could potentially contain climate data recording temperatures and lake process history over the last several hundred thousand years, and include several glacial/inter-glacial climate signals, including that of the South American Summer Monsoon, whose details are poorly understood.Using a small, high-resolution single-channel airgun seismic reflection system and a CHIRP sub-bottom profiler the team would map Tota's bathymetry, determine the thickness of lacustrine sedimentary sequences, locate depositional centers and identify lake-level transgression-regression sequences. Littoral sediment cores collected from Tota in 2013 suggest that the lake's sediment archive contains detailed climatic information, including evidence of past lake level changes. The team would characterize Tota's sediment archive and assess its potential for developing a long-term paleoclimate record. Despite near certainty that Tota's sediment archive spans at least several hundred thousand years, no known geophysical or paleoclimate work has been conducted on the lake previously. The proposed work therefore represents a unique opportunity to investigate a site that has tremendous potential for containing a long, continuous record of Northern Hemisphere South American Pleistocene climate. This work is in its initial phases, but has potential to transform our understanding of tropical climate change. As such, this work is appropriate for the EAGER funding mechanism that is designed to support "high risk-high pay off" exploratory work in its early stages.The funding is requested for ¾ of a summer month for the lead PI, 1 month for his graduate student, as well as travel for 3 PIs and 2 U.S. graduate students. Airfreight for the coring equipment from LacCore and its return, per diem in the Tota vicinity, and boat and truck rental are also requested.