Middle Miocene Grasslands of Kenya

肯尼亚中中新世草原

• 批准号: 9513175
• 负责人: Gregory Retallack
• 金额: $ 8.95万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 1998-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9513175&HistoricalAwards=false
• 关键词: Middle; Miocene; Grasslands; Kenya

This is a proposal to study fossil soils and grasses as evidence for Middle Miocene grasslands in East Africa and their role in the evolution of apelike ancestors of humans. The role of grasslands in human evolution has been debated since Charles Darwin's day, and the existence of Middle Miocene (14 Ma) grasslands in Kenya has continued to be controversial. Several lines of evidence now converge to indicate Middle Miocene grasslands in Kenya: (1) isotopic study of carbonate in fossil soils and apatite of mammalian teeth indicating tropical grassy vegetation, (2) fossil soils similar to those of modern grasslands (Mollisols), (3) grazing muzzle and tooth scratching on antelope fossils, and (4) fossil grasses with the abundant opal (phytoliths) and scarce pores (stomates) of open country grasses. These findings are in some cases based on only preliminary studies and now need to be extended to more sites of Middle Miocene age (13-16 Ma) scattered through southwestern Kenya: Ombo, Majiwa, Maboko, Nyakach, Fort Ternan, Serek and Kapsibor. Fossil soils at each site will be described and sampled for laboratory analysis. Fossil grasses will also be collected and returned to the laboratory for the microscopic examination needed to identify them using a computer database. Also planned are isotopic studies of the grasses and fossil soils to determine the kinds of grasses and vegetation present (C3 or C4 grasses). This project builds on the highlights of a previously successful program to provide a detailed view of the physiology, nature, botanical composition and extent of the earliest East African grasslands.

这是一个研究化石土壤和草的建议，作为东非中中新世草原的证据，以及它们在人类类人猿祖先进化中的作用。自查尔斯达尔文时代以来，草原在人类进化中的作用一直存在争议，肯尼亚中新世中期（14 Ma）草原的存在一直存在争议。现在有几条证据表明肯尼亚的中中新世草原：（1）化石土壤中碳酸盐的同位素研究和哺乳动物牙齿的磷灰石指示热带草原植被，（2）化石土壤类似于现代草原（软土），（3）羚羊化石上的放牧口吻和牙齿划痕，（4）具有大量蛋白石（植硅体）和稀疏气孔（气孔）的化石草。这些发现在某些情况下仅基于初步研究，现在需要扩展到分布在肯尼亚西南部的中中新世（13-16 Ma）的更多地点：Ombo，Majiwa，Maboko，Nyakach，Fort Ternan，Serek和Kapsibor。将描述每个地点的化石土壤，并取样进行实验室分析。化石草也将被收集并返回实验室进行显微镜检查，以使用计算机数据库识别它们。还计划对草和化石土壤进行同位素研究，以确定草和植被的种类（C3或C4草）。该项目建立在以前成功的项目的亮点之上，提供了最早的东非草原的生理学，自然，植物组成和范围的详细视图。