辽宁本溪庙后山遗址的铀系年代研究

【作者】 张丽；

【导师】 沈冠军；

【作者基本信息】 南京师范大学 ， 自然地理学， 2008， 硕士

【摘要】 现代人起源的时间、地点和环境背景是当今古人类学研究的前沿课题之一。二种主要假说“非洲起源”和“多地区连续演化”已激烈争论了近二十年。东亚直立人（Homo erectus）和早期智人（archaic Homo sapiens）在演化系统上的联系与此直接相关。依原有人类化石地点年代系列,一般认为中国直立人和早期智人的交替发生在约200 ka前,远晚于同一事件在非洲发生的～600 ka。这一格局应有利于东亚直立人演化较慢和当地早期智人外来的假说。位于辽宁省本溪县的庙后山地点,是我国东北地区的重要中更新世人类遗址,其年代位置的确立对相关学科的研究有着重要意义。本文报道该地点出土人类化石的第5、6堆积层次生碳酸盐岩和骨化石样的铀系测年结果。夹生于第6堆积层三个钙板的年龄分别为276_-38⁺⁶⁰、＞535、346_-61⁺¹⁶⁰ka,其下第5层中的钙板为526±31 ka,据此堆积层无地层倒序现象,第6层顶部应至少为200 ka,第5层中部应大于500 ka。本文结果远大于该地点原基于骨化石铀系测年的年代框架,支持中国直立人和早期智人交替比原认为约200 ka早得多的观点。主要基于次生碳酸盐岩铀系年代这一时标,已有研究的安徽巢湖银山、周口店第1、4、15地点的测年结果亦如此。这些地点新的年代数据是我国中更新世人类遗址年代框架被整体压缩的有力证据。我国直立人和早期智人的交替,很可能与非洲同一事件无重要的时间距离,倘被进一步证实。本文结果对东亚人类演化模式的研究将有重要意义。更多还原

【Abstract】 For about 20 years,there has been an intense debate over the origin of anatomically modern Homo sapiens between exponents of two competing hypotheses,"multiregional origins" and "recent out of Africa".The phylogenetic relationship between Homo erectus and archaic Homo sapiens in East Asia impacts directly on the hotly debated issues.According to the previously accepted chronology,the erectus-sapiens interface in China occurred somewhere around 200 ka, far too late compared with the same transition event in Africa which is believed to take place ca. 600 ka.The Miaohoushan site,with the recovery of 3 hominid fossils,76 stone artifacts and a faunal assemblage of 72 mammalian species,is known for marking the northernmost human presence in Middle Pleistocene China.This paper presents ²³⁰Th/²³⁴U dates on four calcite and two fossil samples from the hominid fossil-bearing 5^thand 6^thdepositional layers of the site.The flowstone intercalated in 5^thlayer yields an age of 526±30 ka,while three speleothem horizons of the 6^th layer give ages of 276_-38⁺⁶⁰,＞535 and 346_-61⁺¹⁶⁰ka respectively.Based on these results we propose that the topmost section of the 6^thlayer should be no less than 200 ka,and the middle pan of the 5^thlayer older than 500 ka.The results here presented,much older than the previous temporal frame based on the U-series dates on fossil bones,are in support of the proposition for a much earlier Homo erectus-archaic Homo sapiens interface in China.The conclusion is consistent with the chronology of several hominid sites,including Zhoukoudian Localities 1、4 and 15 and Chaoxian hominid site that has been studied with the U-series dating intercalated speleothem formations,being in line with the observation that the existing chronological framework for Chinese Middle sites may have been compressed as a whole. The erectus-sapiens interface in China may be not far from that the same event took place in Africa.If being proved further,our results would impact profoundly on the models of human evolution in East Asia.更多还原