Collaborative Research: Integrating tectonics, climate, and mammal diversity

合作研究：整合构造、气候和哺乳动物多样性

• 批准号: 1813844
• 负责人: Lucy Flesch
• 金额: $ 23.54万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1813844&HistoricalAwards=false
• 关键词: Collaborative; Research; Integrating; tectonics; climate

The researchers seek to understand how movement of tectonic plates, which produced major mountain barriers and influenced regional climate, controlled the evolution and geographic distribution of mammals in western North America. The EarthScope Transportable Array, a network of seismic stations, has produced data that allow an unprecedented view of the Earth's structure in the western United States, providing a unique starting point from which to consider how it came to have the 3-D structure that is imaged by seismic methods. This, combined with a rich published record of structures that record changes in plate tectonics and deformation history over the past 36 Ma, allows us to estimate crustal thickness and topography throughout the western US over this important interval in mammal evolution. The researchers propose to use 3D models to understand the collapse of topography in the western US, which led to marked changes in mammal diversification that coincide with changes in the strain rates recorded in the fault movement record. The research will be accomplished through collaboration of teams that will 1) Improve dating of the sedimentary record that contains the mammalian record, as well as focused sampling of fossils from under-represented areas and time intervals, 2) produce 3D models for lithosphere modification that account for changes in heat flux and boundary conditions, 3) model regional climate that builds on topographic constraints, 4) analyze mammal speciation and diversification and its links over time with topography and climatic gradients, and 5) synthesize all of the results into a 4D model for change through the past 36 Ma. The ultimate goal is to produce a more fundamental understanding of the factors responsible for crustal and topographic changes and how these influence mammal speciation and diversification. The quantitative analysis of crust and mantle dynamics provides an important framework for advancing knowledge in fields linked to the economic geology (mineral belts) of the southwestern US. The research will provide valuable technical training to high school, undergraduate, graduate and post-doctoral researchers. The collaborative team will develop several outreach products, including an informational video for the general public, materials for museum presentations and exhibits at the University of Michigan Museum of Natural History, the departmental Museum Display at Stony Brook, and materials for talks and presentations to the public.The integrated topography model shows a Nevadaplano of ~4.36 +/- 0.4 km (1-sigma) average elevation in central, eastern, and southern Nevada, western Utah, parts of easternmost California, and central portions of westernmost Arizona at 36 Ma. Our model shows that highlands of the Nevadaplano connected to a continuous mountain chain through southeastern Arizona and into northern Mexico. This topography results from the long history of crustal shortening from Sevier - Laramide orogenies. The topography of this massive range collapsed from 36 Ma to the present, leading to as much as 200% extension, the present-day Basin and Range, and exhumation of metamorphic core complexes along the belt of thickened crust. Distributions of lithospheric body forces continue to drive this collapse today. Differences in gravitational potential energy are known to drive extensional deformation, particularly in regions of extreme topography. Yet the reasons for the timing of the collapse, along with the magnitudes and distributions of deviatoric stresses responsible for the collapse, remain enigmatic. The changing topography associated with extensional collapse dramatically altered the climate and mammal diversity dynamics of the western Cordillera. Our research targets three topics within the Integrated Earth System: (1) The topography, distribution, and 3-D deviatoric stresses responsible for the collapse history, (2) The climatic response to the collapse and generation of climate gradients, and (3) The response of mammal lineages and faunas to changing topographic and climate gradients and removal of topographic barriers. No previous study of climate gradients and their impact on mammal diversity has ever been integrated with quantitative kinematic and dynamic reconstructions of continental deformation. The intellectual merit of this study involves the power of combining these fields, while incorporating formal uncertainties in models at all stages of analysis.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.

研究人员试图了解构造板块的运动如何控制北美西部哺乳动物的进化和地理分布，板块运动产生了主要的山脉屏障并影响了区域气候。 EarthScope 可移动阵列是一个地震台网络，它产生的数据可以让我们对美国西部的地球结构进行前所未有的观察，提供了一个独特的起点，让我们可以思考地球是如何形成 3D 结构的。通过地震方法成像。这与记录了过去 36 Ma 期间板块构造和变形历史变化的丰富已发表的结构记录相结合，使我们能够估计哺乳动物进化中这一重要时期整个美国西部的地壳厚度和地形。研究人员建议使用 3D 模型来了解美国西部地形的塌陷，这种塌陷导致哺乳动物多样化发生显着变化，这与断层运动记录中记录的应变率的变化相一致。该研究将通过团队合作完成，这些团队将 1) 改进包含哺乳动物记录的沉积记录的年代测定，以及对来自代表性不足的区域和时间间隔的化石进行集中采样，2) 生成用于岩石圈修改的 3D 模型，考虑热通量和边界条件的变化，3) 基于地形限制的区域气候模型，4) 分析哺乳动物的物种形成和多样化及其随时间与地形和气候梯度的联系，以及 5)将所有结果综合到 4D 模型中，以了解过去 36 Ma 的变化。最终目标是对导致地壳和地形变化的因素以及这些因素如何影响哺乳动物的物种形成和多样化有更基本的了解。地壳和地幔动力学的定量分析为推进美国西南部经济地质（矿带）相关领域的知识提供了重要框架。该研究将为高中、本科生、研究生和博士后研究人员提供宝贵的技术培训。合作团队将开发多种外展产品，包括面向公众的信息视频、密歇根大学自然历史博物馆的博物馆演示和展览材料、石溪博物馆展示材料以及向综合地形模型显示，内华达州中部、东部和南部、犹他州西部、加利福尼亚州最东部部分地区和中部地区的内华达普拉诺平均海拔约为 4.36 +/- 0.4 公里（1 西格玛） 36 Ma 亚利桑那州最西端部分地区。我们的模型显示，内华达普拉诺高地与一条连续的山脉相连，穿过亚利桑那州东南部并进入墨西哥北部。这种地形是由塞维尔-拉拉米德造山运动造成的地壳缩短的悠久历史造成的。这个巨大山脉的地形从 36 Ma 至今塌陷，导致了多达 200% 的延伸，形成了今天的盆地和山脉，并沿着增厚的地壳带折返了变质核杂岩。今天，岩石圈体力的分布继续推动着这次崩塌。众所周知，重力势能的差异会驱动拉伸变形，特别是在极端地形的区域。然而，塌陷时间的原因以及导致塌陷的偏应力的大小和分布仍然是个谜。与伸展塌陷相关的地形变化极大地改变了西部科迪勒拉山脉的气候和哺乳动物多样性动态。我们的研究针对综合地球系统内的三个主题：(1) 地形、分布和导致塌陷历史的 3-D 偏应力，(2) 对塌陷的气候响应和气候梯度的产生，以及 (3)哺乳动物谱系和动物区系对地形和气候梯度变化以及地形障碍消除的反应。先前对气候梯度及其对哺乳动物多样性影响的研究从未与大陆变形的定量运动学和动态重建相结合。这项研究的智力价值涉及结合这些领域的力量，同时在所有分析阶段将形式不确定性纳入模型中。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持标准。