Collaborative Research: 100 million Years of Biotic and Tectonic Evolution in the Western Branch of the East African Rift System

合作研究：东非裂谷系西支一亿年的生物和构造演化

• 批准号: 1349592
• 负责人: William Clyde
• 金额: $ 1.91万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1349592&HistoricalAwards=false
• 关键词: Collaborative; Research; 100; million; Years

The fossil record of sub-Saharan Africa holds keys for testing a range of paleobiogeographic hypotheses that assess how large-scale landform dynamics have influenced biotic evolution over the past 100 million years. Annual expeditions since 2002 to the Rukwa Rift Basin in southwestern Tanzania have revealed a remarkable diversity of new Cretaceous and Cenozoic terrestrial and freshwater vertebrates. Moreover, the discovery and characterization of novel tectono-sedimentary relationships within the Western Branch of the East African Rift System (EARS) have firmly established the importance of this region for examining the interplay between tectonic events and macroevolutionary patterns, encompassing the origin, diversification, paleobiogeography, and extinction of major terrestrial vertebrate clades on continental Africa from the Mesozoic well into the Cenozoic Era. This research group aims to explore the relationship between landform evolution and biotic response in deep time at both local and regional levels, sampling time-distinct geological units to document faunal and floral dynamics at key points in eastern Africa.New Cretaceous discoveries from this project represent all major vertebrate groups, including novel mammals, dinosaurs, and crocodyliforms. The team has concurrently identified the only late Oligocene terrestrial and freshwater assemblage south of the equator, preserving a novel and diverse fauna characterized by spectacularly preserved examples of fishes, snakes, turtles, crocodylians, birds, and a diversity of mammals. Their field area is unique in encompassing both sides of the K/Pg boundary within a restricted geographic area. Multi-modal geochronologic approaches have been applied to reveal that Cenozoic activation of the Western Branch of the EARS initiated at least 14 million years earlier than previously estimated, penecontemporaneously with the better characterized Eastern Branch. Taken together, these results underscore the significance of this region for testing paleobiogeographic hypotheses regarding the origin and distribution of Gondwanan vertebrates during the geologically and biologically dynamic period from the Cretaceous into the Cenozoic. To date the team has explored only a fraction of the deposits within the RRB, and has recently initiated exploratory surveys into adjacent basins (e.g., the Malawi Rift Basin). The goals of this proposal are: 1) to provide explicit stratigraphic, sedimentologic, and depositional context for strata in the RRB and hitherto unexplored adjacent sub-basins, together with precise age constraint for fossil-bearing intervals; 2) to further characterize the interplay between tectonic activity and sub-basin development/drainage patterns that resulted in these rare terrestrial/freshwater assemblages from sub-equatorial Africa; and 3) to conduct detailed anatomical and phylogenetic studies on fossils recovered from the field, using these data to assess competing macroevolutionary hypotheses related to the origin, diversification, paleobiogeographic distribution, and extinction patterns of late Mesozoic and Cenozoic vertebrate groups. Understanding how organisms respond to environmental change is of critical importance, particularly considering that today?s ecosystems are undergoing an unprecedented rate of change. Information from the fossil record plays an essential role for providing a deeper perspective on how environmental changes influence animal and plant species over time. This project provides important new data from an interval spanning 100 million years of Earth's history, through geological and paleontological exploration of a critically undersampled region on the African continent. Large portions of the large East African Rift System, particularly in southwestern Tanzania, have received relatively little scientific attention, yet they record dramatic changes in landform (e.g., rifting, uplift topography, surface water flow), climate change, and the impact of these events through time for the region?s resident animals and plants. This project examines three distinct time intervals within the rift system, integrating geological data with paleontological data to assemble a precisely dated picture of fossil organisms within the environmental settings that entombed them. Field teams consisting of students and faculty from several US institutions will conduct expeditions in the study area to collect paleontological data (fossils) and geological samples (for age-dating of rock units and sedimentary rock analyses that document environmental setting). These data will provide important new information on environmental change and the evolution of past life on the planet. This research will (1) provide new paleobiological data from eastern Africa at three key points in geologic time; (2) utilize new and more precise laboratory approaches to constrain the age and environmental conditions of the geological settings; (3) offer numerous opportunities for US researchers (students and faculty) to participate as part of an international, interdisciplinary research group focused on integrating field and laboratory approaches for characterizing biodiversity and environmental conditions in deep time, and (5) disseminate results to scientific and public audiences via conference presentations, websites, and museum venues in the US and internationally. This research will impact our understanding of animal and plant distributions (biogeography), ecological conditions of past environments (paleoecology), and provide fundamental insights into key topics in evolutionary biology (e.g., adaptation, extinction). It will also contribute baseline data for use by other disciplines, including geophysics/tectonics, climate studies, computer modeling, conservation, and STEM education in biological and Earth sciences.This program of work is jointly funded by the Sedimentary Geology & Paleobiology Program of the Geosciences Directorate, and by the International Science & Engineering Program of the Office of International & Integrative Activities.

撒哈拉以南非洲的化石记录是测试一系列古生物地理假设的钥匙，这些假设评估了大规模的地表地面动态在过去1亿年中影响了生物进化。自2002年以来，坦桑尼亚西南部的Rukwa Rift盆地以来的年度探险表明，新的白垩纪和新生代陆地和淡水脊椎动物的多样性。此外，东非裂谷系统（EARS）内部新型构造统治关系的发现和表征牢固确定了该地区的重要性，以检查构造事件与宏观进化模式之间的相互作用，并涵盖了起源，多元化，古生物地理位置，以及近地层次的多样化，范围内的多元化层次，并散发出了非洲层次的层次。新生代时代。 This research group aims to explore the relationship between landform evolution and biotic response in deep time at both local and regional levels, sampling time-distinct geological units to document faunal and floral dynamics at key points in eastern Africa.New Cretaceous discoveries from this project represent all major vertebrate groups, including novel mammals, dinosaurs, and crocodyliforms.该小组同时确定了赤道以南唯一的晚期渐新世陆地和淡水组合，保留了一种新颖而多样的动物，其特征是壮观的鱼类，蛇，乌龟，鳄鱼，鳄鱼，鸟类，鸟类和多样性的哺乳动物。 它们的野外区域在限制了受限地理区域内K/PG边界的两侧是独一无二的。多模式的测量方法已应用于揭示耳朵的西部分支的新生代激活至少比以前估计的1400万年，比起先前的conectanemante，其特征性的东部分支更好。综上所述，这些结果强调了该区域对在地质和生物学动态时期内从白垩纪到新生代的地质和生物动态时期期间关于贡旺丹脊椎动物的起源和分布的古生物地理假设的重要性。迄今为止，该团队仅探索了RRB内的一小部分沉积物，最近对邻近盆地（例如，马拉维裂谷盆地）进行了探索性调查。该提案的目标是：1）为RRB和迄今未探索的邻近子碱提供明确的地层，沉积和沉积环境，以及对化石间隔的精确年龄限制； 2）进一步描述了构造活动与亚碱发育/排水模式之间的相互作用，从而导致了来自非洲亚赤道非洲的这些罕见的陆地/淡水组合； 3）使用这些数据对从现场回收的化石进行详细的解剖学和系统发育研究，以评估与起源，多样化，古生物地理分布以及晚期中生物学和碳酸脊椎动物的灭绝模式有关的竞争宏观进化假设。了解生物对环境变化的反应是至关重要的，特别是考虑到当今的生态系统正在经历前所未有的变化速度。从化石记录中的信息提供了对环境变化如何随着时间影响动物和植物物种的更深入的观点的重要作用。该项目通过对非洲大陆的急剧采样区域的地质和古生物学探索，从1亿年的地球历史范围内提供了重要的新数据。大型东非裂谷系统的大部分地区，尤其是在坦桑尼亚西南部，受到了相对较少的科学关注，但它们记录了地面的巨大变化（例如，裂谷，隆升地形，地表水流，气候变化），气候变化以及这些事件的影响，这些事件对该地区的居民动物和植物的影响。该项目研究了裂谷系统中的三个不同的时间间隔，将地质数据与古生物学数据集成在一起，以在诱使它们的环境环境中精确的化石生物的精确描绘。由来自美国几个机构的学生和教职员工组成的野外团队将在研究区域进行探险，以收集古生物学数据（化石）和地质样本（用于记录环境环境的岩石单位和沉积岩石分析的年龄）。这些数据将提供有关环境变化和地球上终身演变的重要新信息。这项研究（1）将在地质时期的三个关键点提供来自东非的古生物学数据； （2）利用新的，更精确的实验室方法来限制地质环境的年龄和环境条件； （3）为美国研究人员（学生和教师）提供了许多机会，可以作为一个专注于在深度时间内表征生物多样性和环境条件的领域和实验室方法的国际跨学科研究小组的一部分，（5）通过会议演示，网站，网站以及我们和实习的博物馆将结果传播到科学和公众的情况下。这项研究将影响我们对动物和植物分布（生物地理），过去环境的生态条件（古生物学）的理解，并为进化生物学的关键主题（例如适应性，灭绝）提供基本见解。它还将为其他学科的使用提供基线数据，包括地球物理/构造学，气候研究，计算机建模，保护和STEM教育，并在生物和地球科学中进行。这项工作由地理科学局的沉积地质和古生物学计划共同资助，由地球科学局以及国际科学和工程学的国际科学和工程计划。