Taxonomy and Paleolimnology of the Bacillariophyceae (Diatoms) from Lacustrine Sequences in the Pliocene Hadar Formation, Afar Regional State, Ethiopia

摘要

A taxonomic description of three novel species and update of two previously described Bacillariophyta (Diatom) species from the Pliocene Hadar Formation, Afar Depression of Ethiopia is presented. The taxonomic description preludes a quantitative reconstruction of the environmental conditions of Paleolake Hadar, also presented herein. This thesis plays an integral role in the Hominin Sites and Paleolakes Drilling Project (HSPDP), an interdisciplinary investigation into the climate, environment, and ecological context of human and hominin evolution in East Africa. The HSPDP aims to provide a continuous record of paleo-conditions that influenced hominin evolution. This thesis focuses on the Northern Awash Werenso drill-core site from the Afar Depression, Ethiopia. This site was chosen to target the Pliocene Hadar Formation because of prominent hominin fossil finds of Australopithecus afarensis including the iconic and most complete specimen, 'Lucy'. This investigation has revealed novel species of diatoms and a highly variable climate system closely associated with the last known temporal occurrence of Australopithecus afarensis fossils.