COLLABORATIVE RESEARCH: Revised Stratigraphy: Geochemical Fingerprinting, Paleomagnetism and 40Ar/39Ar Dating, Olduvai Gorge, Tanzania

9905383SwisherOlduvai峡谷切开了坦桑尼亚北部的塞伦盖蒂平原，为东非的上新世-更新世大陆记录打开了一扇长达25公里的窗口。暴露的连续200万年的古环境历史包含了广泛的脊椎动物记录（包括原始人）和丰富的文化记录，对人类进化的研究至关重要。通过野外地层测量结合凝灰岩地球化学“指纹”来约束辐射测年和古地磁测年，可以解决近年来在峡谷工作中发现的重要对比问题。从理论上讲，一次火山喷发的产物具有独特的化学特征，并提供了一个等时标志。每个凝灰岩都可以使用矿物学进行“地球化学指纹”，并使用单个玻璃碎片的主、次和微量元素丰度数据，然后使用富钾长石晶体确定40Ar/39Ar的年代。古地磁记录将为我们的相关性提供独立的验证。合并后的数据集将为解释当地记录以及与全球环境、古人类和古地磁记录相关联提供关键的时间框架。

9905383SwisherOlduvai Gorge incises the Serengeti Plain of northern Tanzania and exposes a 25 kilometer-long window into the Plio-Pleistocene continental record of east Africa. The exposed continuous two million year paleoenvironmental history contains an extensive vertebrate record (including hominids) and a rich cultural record of central importance in the study of human evolution. Important correlation problems discovered during recent work in the Gorge can be resolved by using field stratigraphic measurements combined with geochemical "fingerprinting" of tuffs to constrain radiometric and paleomagnetic dating. The product of a single volcanic eruption, in theory, has unique chemical characteristics and provides an isochronous marker. Each tuff can be "geochemically fingerprinted" using mineralogy, and major, minor, and trace element abundances data for individual glass shards and then 40Ar/39Ar dated using potassium-rich individual feldspar crystals. The paleomagnetic record will provide an independent verification of our correlations. The combined data set will provide the crucial chronological framework for interpreting the local record and correlating with global environmental, paleoanthropolgical and paleomagnetic records.