COLLABORATIVE: EAGER: Seismic Survey of Lake Junin, Peru in Preparation for Deep Drilling

这笔赠款将为计划中的朱宁湖（秘鲁）深层钻探提供关键的现场勘测信息。该小组将对朱宁湖进行气枪地震勘测，以估计沉积厚度，并提供选择最佳深钻地点所需的空间分辨率。这项工作将在一个很短的（约两周）现场季节完成，结果提供给国际大陆钻探计划（ICDP）钻井讲习班。湖朱宁包含一个沉积物记录，可能跨越多个冰川循环？也许覆盖了几十万年，它含有碳酸盐，可以提供湖泊水文和区域气候的同位素记录，分辨率低于十年。许多教师和学生跨越四十年作出了贡献，对湖泊及其流域的广泛数据库。然而，朱宁湖的最深沉积区从未取过芯，也从未用能够穿透湖中心下厚沉积层的机械取芯器取过芯。ICDP的科学咨询小组认为，朱宁湖确实值得进行深钻工作，并已资助高达40美元，2000美元用于举办一个国内讲习班，为一个深钻项目建立一个科学小组。这次研讨会将在秘鲁举行，将汇集来自美国的20多名科学家，加拿大、德国和其他ICDP国家。尽管ICDP科学咨询小组对可能在朱宁湖进行深层钻探表示了热情，但他们也指出，改进对朱宁湖盆地的地震成像是批准ICDP钻探的先决条件，预期成果包括更全面地了解朱宁湖盆地湖相沉积物和夹层冰川沉积物的厚度和分布，这将为选择适当的取芯设备和钻探地点提供必要的指导，并将使估计的沉积物芯的长度，将需要处理的任何未来的深钻项目。拟议的工作的智力价值是基于这样一个事实，即一个改进的地震对朱宁湖的调查是进行深层钻探的先决条件，而深层钻探又将产生沉积物岩心，从而解决第四纪晚期热带气候变化方面的几个基本问题。其中包括：（1）热带地区最后几次冰期旋回与两半球高纬度地区冰期旋回的同步程度;（2）间冰期和冰间期水文气候的稳定程度;（3）间冰期ENSO的长期演变;和4）温度和降水在控制热带安第斯山脉冰川物质平衡中的相对作用，拟议研究的更广泛意义将取决于朱宁湖深钻项目的成功开发。这样一个项目将为培训众多本科生和研究生以及促进我们秘鲁同事的气候变化研究提供一个理想的平台。

This grant will generate critical site survey information for planned deep drilling of Lake Junin (Peru). The team will carry out an airgun seismic survey of Lake Junin in order to estimate the sediment thickness, and to provide the spatial resolution needed for selection of the best deep drilling sites. The work would be completed in a short (~two week) field season, with results made available for an International Continental Drilling Program (ICDP) drilling workshop.Lake Junin contains a sediment record that likely spans multiple glacial cycles?perhaps covering many hundreds of thousands of years, and it contains carbonates that can provide isotopic records of lake hydrology and regional climate with sub-decadal resolution. Numerous faculty and students spanning four decades have contributed to an extensive database on the lake and its watershed. However, Lake Junin has never been cored in its most deep sedimented areas, and has never been cored with a mechanical corer capable of penetrating the thick sedimentary sequences that lie under the center of the lake.The Scientific Advisory Group of the ICDP has agreed that Lake Junin is indeed worthy of a deep drilling effort, and has funded up to US $40,000 for an in-country workshop to develop a science team for a deep drilling project. This workshop, which will be held in Peru, will bring together about two dozen scientists from the U.S., Canada, Germany and other ICDP countries. Although the Scientific Advisory Group of ICDP has expressed their enthusiasm for potential deep drilling of Lake Junin, they have also noted that improved seismic imaging of the Lake Junin basin is a prerequisite for ICDP drilling approval.Expected results include a more complete understanding of the thickness and distribution of lacustrine sediment and intercalated glaciogenic sediment in the Junin basin, which will provide essential guidance for selection of appropriate coring equipment and drilling sites, and will enable estimates to be made of the length of sediment core that will need to be processed for any future deep drilling project.The intellectual merit of the proposed work is grounded in the fact that an improved seismic survey of Lake Junin is a prerequisite for deep drilling, which, in turn, will yield sediment cores that can address several fundamental issues regarding tropical climate change during the late Quaternary. These include: 1) the degree of synchrony between the last several glacial cycles in the tropics and those in higher latitude regions of both hemispheres, 2) the degree of hydroclimatic stability that prevailed during interglacial and interstadial intervals, 3) the long-term evolution of ENSO during interglacial intervals, and 4) the relative roles of temperature and precipitation in governing glacier mass balances in the tropical Andes over multiple glacial, deglacial, and interglacial intervals.The broader significance of the proposed research will depend on the successful development of a deep drilling project on Lake Junin. Such a project would provide an ideal platform for training numerous undergraduate and graduate students, and for promoting climate change research by our Peruvian colleagues.