小柯机器人

科学家发现直立人10万年前最后的踪迹
2019-12-19 16:08

美国爱荷华大学Russell L. Ciochon、麦考瑞大学Kira E. Westaway等研究人员合作发现,117000至108000年前,直立人最后一次出现在爪哇的Ngandong地区。2019年12月18日,国际知名学术期刊《自然》在线发表了这一成果。

研究人员表示,直立人是东南亚岛屿上最早的人种,并在150万年前到达爪哇(印度尼西亚)。在1931年至1933年间,在Ngandong(中爪哇省)梭罗河上方约20米的骨床上发现了十二个直立人的颅盖颅骨和两个胫骨(小腿骨),这是直立人最年轻、最先进的形式。尽管这些Ngandong化石很重要,但化石、阶地充填与年龄之间的关系一直受到激烈争论。

为了解决Ngandong证据的年龄,研究人员使用52个辐射年龄估计值的贝叶斯模型建立了第一个区域、山谷和地方尺度的可靠年表。研究人员使用了闪石的铀系列测年来限制区域景观的演变;发光、40氩/39氩(40Ar/39Ar)和铀系列测年限制了阶地演化的顺序;并在非人类化石上应用了铀系列和铀系列-电子自旋共振(US-ESR),直接追溯了研究人员对Ngandong的重新发掘。研究人员表明,至少在50万年前(ka),梭罗河被分流到肯登山丘,它形成了316和31 ka之间的Solo阶地序列以及大约140和92 ka之间的Ngandong阶地。在Ngandong的重新发掘过程中发现的非人类化石的日期为109至106 ka(最小铀系列),以及134至118 ka(US–ESR),此外对于直立人骨床(洪水时堆积而来)的模拟年龄为117至108千年(kyr)。这些结果否定了该地点提议的极端年龄,并确定Ngandong为该物种的最后一个已知踪迹。

附:英文原文

Title: Last appearance of Homo erectus at Ngandong, Java, 117,000–108,000 years ago

Author: Yan Rizal, Kira E. Westaway, Yahdi Zaim, Gerrit D. van den Bergh, E. Arthur Bettis, Michael J. Morwood, O. Frank Huffman

Issue&Volume: 2019-12-18

Abstract: Homo erectus is the founding early hominin species of Island Southeast Asia, and reached Java (Indonesia) more than 1.5 million years ago1,2. Twelve H. erectus calvaria (skull caps) and two tibiae (lower leg bones) were discovered from a bone bed located about 20 m above the Solo River at Ngandong (Central Java) between 1931 and 19333,4, and are of the youngest, most-advanced form of H. erectus58. Despite the importance of the Ngandong fossils, the relationship between the fossils, terrace fill and ages have been heavily debated914. Here, to resolve the age of the Ngandong evidence, we use Bayesian modelling of 52 radiometric age estimates to establishto our knowledgethe first robust chronology at regional, valley and local scales. We used uranium-series dating of speleothems to constrain regional landscape evolution; luminescence, 40argon/39argon (40Ar/39Ar) and uranium-series dating to constrain the sequence of terrace evolution; and applied uranium-series and uranium serieselectron-spin resonance (USESR) dating to non-human fossils to directly date our re-excavation of Ngandong5,15. We show that at least by 500 thousand years ago (ka) the Solo River was diverted into the Kendeng Hills, and that it formed the Solo terrace sequence between 316 and 31 ka and the Ngandong terrace between about 140 and 92 ka. Non-human fossils recovered during the re-excavation of Ngandong date to between 109 and 106 ka (uranium-series minimum)16 and 134 and 118 ka (USESR), with modelled ages of 117 to 108 thousand years (kyr) for the H. erectus bone bed, which accumulated during flood conditions3,17. These results negate the extreme ages that have been proposed for the site and solidify Ngandong as the last known occurrence of this long-lived species. Bayesian modelling of radiometric age estimates provides a robust chronology for Homo erectus at Ngandong (Java), confirming that this site currently represents the last known occurrence of this species.

DOI: 10.1038/s41586-019-1863-2

Source:https://www.nature.com/articles/s41586-019-1863-2

 

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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