Stratigraphy and sedimentology of South American foreland basin lakes: Keys to deciphering climatic and tectonic controls on lacustrine deposition in ancient foreland basins

南美前陆盆地湖泊的地层学和沉积学：破译古代前陆盆地湖泊沉积的气候和构造控制的关键

• 批准号: 0542993
• 负责人: Andrew Cohen
• 金额: $ 3万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0542993&HistoricalAwards=false
• 关键词: Stratigraphy; sedimentology; South; American; foreland

AbstractResearch would produce an understanding of topographic closure, lake/wetland evolution, and lacustrine stratigraphic architecture associated with foreland basins. Results would include the first comprehensive models of modern foreland basin lakes and test the hypotheses of related basin evolution. 3D modeling would be used to test interpretations of other ancient foreland basins providing a means to transport results to other projects. Prior results exemplify a very capable team.Broader impact:Two Ph.D.s and several undergrads. International linkage with sister programs, collaborators, and students in Argentina and Brazil. Results also disseminated to public and paleoclimatology community and biologists studying speciation in foreland basin watersheds.Strengths:Studies of modern and ancient lakes have become common as geologists recognize them as recorders of climate and non-marine life. However, few scientists have focused on understanding the tectonic influence on lake system evolution. This is a much-needed study! Excellent team and collaborators including expertise in paleolimnology, tectonics, geophysics, stratigraphic modeling, and local expertise. Excellent review and plan. Prior experience in handling a synthesis project on lake deposits is evident. Good use of GIS synthesis and SRTM imagery for high resolution geomorphic characterization. Excellent sedimentologic and stratigraphic approach, including utilization of hierarchical sequence stratigraphy that is closely linked to process and grid/stratified sampling design for sedimentologic and facies studies.Work is exciting and addresses an important, fundamental problem. Study provides an integrated approach to better understand topographic closure, lake and wetland evolution, and lacustrine stratigraphic architecture in association with foreland basin, in a similar level of detail as their successful studies of rift valley lacustrine settings. Model input includes multiscaled sampling, coring, and seismic. 3D stratigraphic simulation is quite robust, handling input of 3D structural flexure, erosion and deposition, bed aggradation and degradation, all solved simultaneously. This is an excellent use for computer simulation to extend results of this work to other areas and for use in the classroom.Weaknesses:Panel asks what role the chemical sediments in these lakes play in this study. Recent studies on the saline lakes in the Andean region shows that individual lakes can change greatly both physically and chemically over various short time periods. Evaporites can accumulate quickly and, just as easily dissolve quickly, so their accumulation rates cannot be directly related to time. In addition, these hypersaline lakes change greatly on seasonal and decadal scales. One visit to one of these lakes does not allow a good characterization of it. Will the PIs consult with someone who has studied these hypersaline Andean lakes in detail? Such publications were not cited.Panel expressed concern about the quantification of organic burial rates to be integrated with sediment accumulate rates, which are being measured on very different scales. The 75 carbon analyses currently requested are only one days lab work. Panel suggests the budget be increased for this analytical work. Also, panel requests that PIs ensure that results are not overgeneralized, realizing that the sampling regime must be placed in the context of the dynamic conditions of these lakes. The panel would also encourage the PIs to include one very small lake to be included in their study so that their work is not biased towards medium - large lakes.In general, the proposal is quite ambitious. The panel is concerned that the PIs will not be able to study each lake in enough detail to best understand it.Outcome of this work could have a high impact for a little known depositional system.

AbstractResearch将产生对地形闭合、湖泊/湿地演化和与前陆盆地相关的湖泊地层结构的理解。结果将包括现代前陆盆地湖泊的第一个综合模型，并测试相关盆地演化的假设。3D建模将用于测试其他古代前陆盆地的解释，为将结果传输到其他项目提供一种手段。之前的结果体现了一支非常有能力的团队。更广泛的影响：两名博士和几名本科生。与阿根廷和巴西的姐妹项目，合作者和学生的国际联系。研究结果也传播给公众和古气候学社区和生物学家研究物种在前陆盆地watersheds.Strengths：现代和古代湖泊的研究已经成为共同的地质学家认识到他们作为气候和非海洋生物的记录。然而，很少有科学家关注构造对湖泊系统演化的影响。这是一项非常需要的研究！优秀的团队和合作者，包括古湖沼学、构造学、地球物理学、地层建模方面的专业知识和当地专业知识。优秀的回顾和计划。在处理湖泊沉积物综合项目方面的经验是显而易见的。良好地利用地理信息系统综合和卫星遥感TM图像，以确定高分辨率地貌特征。优秀的沉积学和地层学方法，包括利用与沉积学和相研究的过程和网格/分层取样设计密切相关的分层层序地层学。工作令人兴奋，并解决了一个重要的基本问题。研究提供了一个综合的方法，以更好地了解地形封闭，湖泊和湿地的演变，湖泊地层结构与前陆盆地，在类似的详细程度，他们的裂谷湖泊环境的成功研究。模型输入包括多尺度采样、取芯和地震。三维地层模拟是相当强大的，处理输入的三维结构弯曲，侵蚀和沉积，床加积和退化，所有同时解决。这是计算机模拟的一个很好的用途，可以将这项工作的结果扩展到其他领域，并用于课堂。缺点：小组询问这些湖泊中的化学沉积物在这项研究中起什么作用。最近对安第斯地区盐湖的研究表明，单个湖泊在不同的短时间内可能会发生巨大的物理和化学变化。蒸发物可以迅速积累，也可以迅速溶解，因此它们的积累速度与时间没有直接关系。此外，这些高盐度湖泊的季节和年代际尺度变化很大。对这些湖泊的一次访问并不能很好地描述它的特征。PI是否会咨询那些详细研究过这些高盐安第斯湖的人？专家小组对将有机埋藏率与沉积物积累率结合起来加以量化表示关切，因为这两种速率是在非常不同的尺度上测量的。目前要求的75项碳分析仅需一天的实验室工作。专家组建议增加这项分析工作的预算。此外，专家组要求项目研究者确保结果不被过度概括，认识到采样制度必须放在这些湖泊的动态条件的背景下。专家小组还将鼓励项目执行人在其研究中纳入一个非常小的湖泊，以便其工作不偏向于中型湖泊。专家组担心，专业研究人员将无法对每个湖泊进行足够详细的研究，以最好地了解它。这项工作的结果可能对一个鲜为人知的沉积体系产生很大影响。