Collaborative Research: A multi-proxy approach to Early Miocene community, landscape, and climate reconstruction, Ethiopian Plateau

合作研究：埃塞俄比亚高原早中新世群落、景观和气候重建的多代理方法

• 批准号: 1053549
• 负责人: Bonnie Jacobs
• 金额: $ 17.4万
• 依托单位: Southern Methodist University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1053549&HistoricalAwards=false
• 关键词: Collaborative; Research; multi; proxy; approach

Project Abstract Collaborative Research: A multi-proxy approach to Early Miocene community, landscape, and climate reconstruction, Ethiopian PlateauTechnical Description: The Cenozoic rock record contains a rich and critically important history of varied climates and biotic communities, and these serve as aids to understanding current and future climatic and biotic change. While the scales are different, the deep geologic past provides test cases against which climate models can be compared or from which they can be created. However, spatial coverage by paleoclimate proxies is best for middle latitudes, and quite limited for the tropics and subtropics, especially in the terrestrial realm. This project will investigate a new extraordinary Early Miocene (22 Ma) site where carbonaceous shales and tuffaceous sediments preserve lagerstätten-quality fossils including abundant compressed leaves, fruits and seeds with exquisite cuticular features, complete frogs with both skeletal and soft body parts, fish and large mammal bones. These enable reconstruction of paleoclimate, pCO2, paleoecology, and significant biogeographic data for African flora, and perhaps fauna. The objectives of this project are to:1. compare Early Miocene and Late Oligocene paleoclimate, paleoecology, and biogeography using multiple independent proxies.2. provide pCO2 estimates from pedogenic goethite and stomatal indices.3. provide Early Miocene paleoecological and paleoclimatological context for faunal evolution during an otherwise poorly known, but significant time interval for Africa. 4. address plant biogeographic questions, e.g. a decline in palm richness and importance5. test methods by (a) comparing δD isotopes from aquatic and terrestrial lipids to test for enrichment of D due to evapotranspiration, (b) comparing goethite and stomatal index pCO2 data (c) evaluating the consistency of paleotemperature and precipitation reconstructions using methods based upon leaf physiognomy, overlapping ranges of plant taxa, qualitative and quantitative paleosol analyses, and multiple isotope geochemical proxies. Non-technical Description and Broader Significance: This grant funds a multidisciplinary team of scientists who will sample rocks and fossils from the Ethiopian Plateau northeast of Addis Ababa to reconstruct past climate, vegetation, atmospheric CO2 concentration (pCO2), and the physical landscape 22 million years ago in an integrated and collaborative way. Team members, who have collaborated before on rocks from the Plateau that are 27 million years old, have expertise in the study of plant fossil identification, insect damage to fossil leaves, the reconstruction of past climate and ecology, the geochemistry of ancient soils and organic plant compounds, and geology. The locality preserves extraordinary plant fossils having cellular detail, smaller vertebrates including frogs with soft tissue preservation, and large mammal bones. The scientific significance of our work is that it will resolve currently conflicting data regarding global temperature and pCO2 between 27 million and 22 million years ago. Marine records show a significant rise in global temperature between these times, but some records of pCO2 show a decline and others a rise. Resolution of this conflict by acquisition of temperature and pCO2 data from one region using multiple independent sources will tell us if our understanding of CO2, in relation to global temperature is correct. Furthermore, the modern land connection between Africa and Eurasia was established about 24 million years ago, so we will be able to compare the younger plant and animal fossils with those from a time prior to contact with Eurasia. Africa?s flora and fauna was in a period of transition at this time, and its documentation is important for understanding the origins of modern biomes. Educational outreach includes distance learning for thousands of K-12 students. This team has a history of blogs, currently hosted by the SMU Public Affairs office on the main website, and recently through the NY Times Scientist at Work pages. Students will be an integral part of this project ? this team has regularly taken students into the field and will continue to do so. We also plan to host an Ethiopian graduate student for training in the U.S.

项目摘要：合作研究：埃塞俄比亚高原早中新世群落、景观和气候重建的多代理方法技术描述：新生代岩石记录包含了丰富而至关重要的气候和生物群落历史，这些记录有助于理解当前和未来的气候和生物变化。虽然尺度不同，但深层地质历史提供了可以比较或创建气候模型的测试案例。然而，古气候代用物的空间覆盖在中纬度地区是最好的，而在热带和亚热带地区，特别是在陆地领域，其覆盖范围相当有限。该项目将调查一个新的非凡的早中新世（22 Ma）遗址，在那里碳质页岩和凝灰质沉积物保存了lagerstätten-quality化石，包括大量压缩的叶子，具有精致表皮特征的水果和种子，完整的青蛙骨骼和柔软的身体部分，鱼类和大型哺乳动物的骨头。这些可以重建古气候、二氧化碳分压、古生态和重要的生物地理数据，用于非洲的植物群，也许还有动物群。这个项目的目标是：1。使用多个独立的代理比较早中新世和晚渐新世的古气候、古生态和生物地理。根据成土针铁矿和气孔指数估算pCO2。提供早中新世的古生态和古气候背景，以了解非洲在其他方面知之甚少但重要的时间间隔内的动物进化。解决植物生物地理问题，例如棕榈丰富度和重要性的下降。试验方法(a)比较&amp；#948；(b)比较针岩和气孔指数pCO2数据(c)利用基于叶片地貌、植物类群重叠范围、定性和定量古土壤分析以及多种同位素地球化学代理的方法，评估古温度和降水重建结果的一致性。非技术描述和更广泛的意义：这项资助资助了一个多学科科学家团队，他们将从亚的斯亚贝巴东北部的埃塞俄比亚高原采集岩石和化石样本，以综合和协作的方式重建过去的气候、植被、大气二氧化碳浓度（pCO2）和2200万年前的自然景观。团队成员之前曾合作研究过2700万年前青藏高原的岩石，他们在植物化石鉴定、昆虫对化石叶子的破坏、重建过去的气候和生态、古代土壤和有机植物化合物的地球化学以及地质学等方面拥有专业知识。该地区保存着具有细胞细节的非凡植物化石，保存着软组织的小型脊椎动物，包括青蛙，以及大型哺乳动物的骨头。我们这项工作的科学意义在于，它将解决目前有关2700万至2200万年前全球温度和二氧化碳分压的相互矛盾的数据。海洋记录显示，在这段时间里，全球温度显著上升，但二氧化碳分压的一些记录显示下降，而另一些记录显示上升。通过使用多个独立来源从一个地区获取温度和二氧化碳分压数据来解决这一冲突，将告诉我们我们对二氧化碳与全球温度关系的理解是否正确。此外，非洲和欧亚大陆之间的现代陆地连接是在大约2400万年前建立的，因此我们将能够将较年轻的动植物化石与与欧亚大陆接触之前的化石进行比较。非洲?这一时期美国的动植物群正处于过渡时期，其文献资料对理解现代生物群系的起源具有重要意义。教育拓展包括为数千名K-12学生提供远程教育。这个团队有博客的历史，目前由新大公共事务办公室在主网站上托管，最近通过纽约时报科学家在工作页面。学生将是这个项目不可分割的一部分？该小组定期带学生到实地考察，并将继续这样做。我们还计划接待一名埃塞俄比亚研究生到美国接受培训