Continued Paleoanthropological Investigations at the Hadar Hominid Site, Ethiopia

继续对埃塞俄比亚哈达尔原始人类遗址进行古人类学调查

• 批准号: 0080378
• 负责人: William Kimbel
• 金额: $ 21.05万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0080378&HistoricalAwards=false
• 关键词: Continued; Paleoanthropological; Investigations; Hadar; Hominid

Scientific understanding of human evolution in the period between 3.0 and 4.0 million years ago is based chiefly on information derived from the Ethiopian site of Hadar. Since the early 1970s paleoanthropologists now with the Institute of Human Origins (IHO) at Arizona State University have conducted nine seasons of field work at the Hadar site. This research has yielded nearly 350 hominid specimens, the great majority of which fall within the 3.0-3.4 Myr time period and are attributed to the species Australopithecus afarensis. Included in the Hadar hominid sample are "Lucy," the fragmentary remains of at least 13 individuals at A.L. 333, and the first fairly complete skull of the species (A.L. 444-2). One of the persistent data gaps in the hominid fossil record lies within the period between 3.0 and 2.0 myr, a period that witnessed the diversification of the specialized, megadont "robust" Australopithecus lineage and the rise of our own, Homo. Sediments representing this interval are exposed along Awash River tributaries in both the eastern and western sectors of the Hadar site. 2.5-Myr Oldowan stone tools were excavated at localities on the edge of the Gona tributary in 1976 by H. Roche and J. Harris and in 1992-1993 by S. Semaw. In 1994 the IHO team conducted field work in young sediments exposed along the Kada Hadar tributary and recovered a hominid upper jaw of Homo aff. H. habilis (A.L. 666-1) and stone tools on the surface of 2.33 Myr sediments. A small trial excavation uncovered in situ tools and fragmentary faunal remains. Geological and faunal studies infer a significant shift toward drier, more open conditions at Hadar after 2.95 Myr, represented in sediments stratigraphically situated above a significant erosional event (so-called Major Disconformity Surface, or MDS).The ulitmate goal the two year research plan is to increase the documentary evidence at Hadar concerning this relatively poorly known period in the human fossil record. Excavation of additional localities where stone tools and bones co-occur will be accompanied by volcanic tephra correlation studies and paleomagnetic sampling to achieve a more finely resolved temporal framework for the post-MDS sequence. In addition, this research plan includes further excavations at the unique A.L. 333 A. afarensis locality, which, 20 years after its discovery, continues to yield hominid fossils. Finally, reconnaissance survey of outlying areas that were visited briefly in the early 1970s may be undertaken. These areas are known to be fossilferous and appear to lie within the critical 2.0-3.0 Myr range.

对300万至400万年前人类进化的科学认识主要基于埃塞俄比亚哈达尔遗址的信息。 自20世纪70年代初以来，亚利桑那州立大学人类起源研究所的古人类学家已经在哈达尔遗址进行了九个季节的实地考察。 这项研究已经获得了近350个人科动物标本，其中绝大多数属于3.0-3.4百万年的时间段，并被认为是南方古猿阿法种。 在哈达尔人科样本中包括“露西”，在A.L.333至少有13个个体的碎片遗骸，以及该物种的第一个相当完整的头骨（A.L.444 -2）。原始人类化石记录中持续存在的数据空白之一是在300万年到200万年之间，这一时期见证了特化的巨型“强壮”南方古猿谱系的多样化和我们自己的人属的兴起。 代表这一区间的沉积物在哈达尔场址的东部和西部沿沿着阿瓦什河支流出露。 2.5-Myr Oldowan石器是1976年由H. Roche和J. Harris以及S.奶奶 1994年，国际水文学组织的研究小组在卡达哈达尔支流沿着暴露的年轻沉积物中进行了实地考察，发现了一个原始人的上颌。H. habilis（A.L. 666-1）和石器。 一次小规模的试掘发现了现场工具和动物群的碎片。 地质和动物群研究推断，29.5万年后，哈达尔地区的环境发生了显著的变化，变得更加干燥和开放，这表现在沉积物的地层学上位于一个重要的侵蚀事件（所谓的主要不整合面，或MDS）之上。两年研究计划的最终目标是增加哈达尔地区关于人类化石记录中这个相对鲜为人知的时期的文献证据。 对石器和骨骼共存的其他地点的挖掘将伴随着火山熔岩对比研究和古地磁采样，以获得更精细的时间框架后MDS序列。 此外，这项研究计划还包括在独特的A.L. 333 A进行进一步的挖掘。阿法西斯地区，在发现20年后，继续产出原始人类化石。 最后，可以对1970年代初短暂访问过的外围地区进行侦察调查。 已知这些地区含有化石，似乎位于2.0-3.0百万年的临界范围内。