拉密达地猿的地质、同位素、植物、无脊椎动物及低等脊椎动物环境。

The geological, isotopic, botanical, invertebrate, and lower vertebrate surroundings of Ardipithecus ramidus.

作者信息

WoldeGabriel Giday, Ambrose Stanley H, Barboni Doris, Bonnefille Raymonde, Bremond Laurent, Currie Brian, DeGusta David, Hart William K, Murray Alison M, Renne Paul R, Jolly-Saad M C, Stewart Kathlyn M, White Tim D

机构信息

Earth Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

出版信息

Science. 2009 Oct 2;326(5949):65e1-5. doi: 10.1126/science.1175817.

DOI:10.1126/science.1175817

PMID:19810191

Abstract

Sediments containing Ardipithecus ramidus were deposited 4.4 million years ago on an alluvial floodplain in Ethiopia's western Afar rift. The Lower Aramis Member hominid-bearing unit, now exposed across a > 9-kilometer structural arc, is sandwiched between two volcanic tuffs that have nearly identical 40Ar/39Ar ages. Geological data presented here, along with floral, invertebrate, and vertebrate paleontological and taphonomic evidence associated with the hominids, suggest that they occupied a wooded biotope over the western three-fourths of the paleotransect. Phytoliths and oxygen and carbon stable isotopes of pedogenic carbonates provide evidence of humid cool woodlands with a grassy substrate.

摘要

含有拉密达地猿化石的沉积物于440万年前沉积在埃塞俄比亚西部阿法尔裂谷的冲积洪泛平原上。现在暴露在一条超过9公里长的构造弧上的阿拉米斯组下部含人科动物单元夹在两层火山凝灰岩之间，这两层火山凝灰岩的40Ar/39Ar年龄几乎相同。这里呈现的地质数据，以及与这些人科动物相关的植物、无脊椎动物、脊椎动物古生物学和埋藏学证据表明，它们在古断面西部四分之三的区域占据了一片树木繁茂的生物群落。植物硅酸体以及土壤成因碳酸盐的氧和碳稳定同位素提供了有草地基质的湿润凉爽林地的证据。