Collaborative Research: Quantifying Paleotopography and Paleoclimate to Test Geodynamic Models in the Peruvian Andes

合作研究：量化古地形和古气候以测试秘鲁安第斯山脉的地球动力学模型

• 批准号: 1550101
• 负责人: Christopher Poulsen
• 金额: $ 20.82万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1550101&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; Paleotopography; Paleoclimate

Although plate tectonics provides a first-order explanation of the origin of mountain belts, the tectonic processes that drive surface the uplift and exhumation of mountain belts are not well understood. Even less well understood are the interactions of between uplift, erosional processes, and climate that shape the mountain landscape. This project uses state-of-the art to examine the interaction of tectonics, erosion, and climate in the Peruvian Andes to test new and controversial ideas concerning the uplift of the Andes. The project advances desired societal outcomes through: (1) full participation of women and underrepresented minorities in STEM through support of an female researchers and students plus outreach programs to high school and undergraduate students from underrepresented minorities; (2) increased public scientific literacy and public engagement with STEM through participation of outreach programs that provide research experiences for high school and undergraduate students from underrepresented minorities ; (3) development of a diverse, globally competitive STEM workforce through undergraduate and graduate student training and support of several early career researchers; and (4) increased partnerships through international collaboration. The Division of Earth Sciences Tectonics and Geomorphology & Land Use Dynamics Programs and the NSF Office of International Science and Engineering supported this project.Earth's surface topography responds directly to mantle processes and plate tectonics, controls surface drainage and sediment transport patterns, and influences atmospheric circulation and climate. As the type example of ocean-continent subduction-generated high topography, the Central Andes are critical to evaluating geodynamic models of orogenesis. Although previous studies of the structural history, past elevations, and incision record have provided important insights on surface uplift, these studies also suggest a disparate range of uplift histories and associated tectonic drivers. Current geodynamic models for Andean orogenesis include: (1) continuous late Cenozoic crustal thickening and shortening, resulting in gradual surface uplift and canyon incision; (2) late Cenozoic delamination of South American lithosphere, resulting in rapid surface uplift and a late Miocene pulse of incision; and (3) early Cenozoic contraction-driven crustal thickening, resulting in near modern elevations in the west by late Eocene and propagating deformation eastward through the Cenozoic. To distinguish between models, this project uses: (1) stable isotope analyses of volcanic glasses and soil carbonates to provide quantitative estimates of paleoelevations over time, coupled with geochronology to constrain timing; (2) isotope-enabled general circulation modeling to determine how changing elevations affected climate and to quantitatively interpret stable isotope data, constrained by modern elevation-isotope and climate-isotope relationships; (3) data-validated fluvial erosion modeling to predict the erosional response to different models; and (4) fluvial and lacustrine sedimentology and sediment provenance to identify changes in drainage system extent and basin development. By synthesizing these data, the research team will quantify surface topography and erosion during orogenic evolution and distinguish between proposed tectonic and climatic controls.

尽管板块构造对山带的起源提供了一阶解释，但尚不清楚山带的隆起和挖掘的构造过程。隆起，侵蚀过程和塑造山区景观的气候之间的相互作用甚至不太了解。该项目使用最先进的方法来研究秘鲁安第斯山脉中构造，侵蚀和气候的相互作用，以测试有关安第斯山脉提升的新的和有争议的思想。该项目通过：（1）通过支持女性研究人员和学生的妇女和代表性不足的少数群体的全面参与所期望的社会成果，并向高中和来自代表性不足的少数群体的大学生提供外展计划； （2）通过参与外展计划，增加了公共科学素养和与STEM的公众参与，这些计划为高中和本科生的研究经验提供了研究经验； （3）通过本科生和研究生培训和支持几位早期职业研究人员的支持以及支持多样化的全球竞争性STEM劳动力； （4）通过国际合作增加了伙伴关系。地球科学构造与地貌学与土地使用动力学计划以及NSF国际科学与工程办公室支持该项目。Earth的表面地形直接响应地幔过程和板块构造，控制表面排水和沉积物的运输方式，并影响大气循环和气候。作为海洋俯冲生成的高地形的类型例子，中央安第斯山脉对于评估造山学的地球动力学模型至关重要。尽管以前对结构历史，过去的海拔和切口记录的研究为表面隆升提供了重要的见解，但这些研究也表明了不同的隆起历史和相关的构造驱动因素。当前用于安第斯造成的地球动力学模型包括：（1）连续的新生代地壳增厚和缩短，导致逐渐的表面隆起和峡谷切口； （2）南美岩石圈的新生代晚期分层，导致表面迅速隆升和中新世晚期切口； （3）早期的新生代收缩驱动的地壳增厚，从始新世晚期导致西方的现代高度接近现代海拔，并通过培育代菌向东传播变形。为了区分模型，该项目使用：（1）火山玻璃和土壤碳酸盐的稳定同位素分析，以随着时间的推移提供古含量的定量估计，并加上年代学以限制时间安排； （2）支持同位素的一般循环模型，以确定高程如何影响气候和定量解释稳定的同位素数据，受到现代高程 - 异位和气候 - 同位素关系的约束； （3）数据验证的河流侵蚀建模，以预测对不同模型的侵蚀反应； （4）河流和湖泊的沉积学和沉积物出处，以识别排水系统范围和盆地发育的变化。通过综合这些数据，研究团队将在造山学演化过程中量化表面形貌和侵蚀，并区分拟议的构造和气候控制。