东北亚已知最早的现代人化石产地-萨拉乌苏遗址的层位、年代与生态环境研究

The study of strata in the Salawusu River Valley of Mu Us Desert suggests that Ordos Man is modern human with some characteristics of Neanderthal, and is also known as the earliest modern human in Northeast Asia. However, whether the age of Salawuau site where the Ordos Man fossils were contained is of MIS3-4 or MIS 5 still remains controversial, and the ecological environment of Salawusu remains unknown. This research will be carried out as follows: 1. to investigate the strata of 3 sections of Salawusu sites in the Salawusu River and determine their ages; 2. to figure out the lithology and sedimentary facies of the layers with Salawusu site, as well as the horizontal distribution and their contrast; 3. to date OSL and ESR ages; 4. to understand the ecological environment of Ordos Man revealed by the geological information such as fossil vertebrates, molluscs and pollen and other kinds of climate proxies in the Salawusu sites; 5. the ecological environment of Ordos Man period and how to respond to the global climate changes and the East Asian monsoon. The research is of great scientific significance to understand the regional ecological survival environment of the earliest modern human in Northeast Asia, and the response to the evolution of the East Asian monsoon and global climate variations in the Late Quaternary.

对分布于毛乌素沙漠萨拉乌苏河沿岸地层中的研究表明，"河套人"是"兼具少量尼安德特人的特征"的现代人类，也是东北亚已知的最早的现代人。然而，对河套人活动的萨拉乌苏遗址的时代属于"MIS3-4"还是"MIS5"，迄今仍然存在很大分歧，而对河套人时期的生态环境几乎无人问津。为此，本项目拟开展：1. 萨拉乌苏河沿岸3个含萨拉乌苏遗址剖面的地层调查与时代划分；2. 遗址层位的岩性、沉积相特征，其层位在水平方向的分布与对比；3. 遗址的OSL和铀系法年代；4.遗址地质信息（具有指示生态环境的脊椎动物、软体动物和孢粉化石及各类气候代用指标）指示的河套人时期的生态环境；5.河套人时期生态环境及其对过去全球变化、东亚季风演化的响应。本项目工作成果对于深入理解东北亚最早的现代人类生存的区域生态环境及其对晚第四纪全球变化-东亚季风环境演化的响应具有重要的科学意义。

摘要：河套人是我国乃至东北亚已知的最早的现代人，但长期以来对河套人活动的萨拉乌苏/河套人遗址的时代属于“MIS3—4”还是“MIS5”存在很大分歧，而对河套人时期的生态环境几乎无人问津。为此，本项目重点选择萨拉乌苏河谷范家沟湾的萨拉乌苏遗址进行了地层层位、年代与生态环境的探讨。本项研究获得了以下重要结果：.1.萨拉乌苏遗址的OSL年代起止时间为115.10~92.50 ka BP，大致相当于MIS5c~MIS5d。其中，含石器的萨拉乌苏遗址的年代为97.00~93.00 ka BP。2.根据对气候代用指标—主量化学元素的分析结果，提出河套人生活时期—MIS5c+d东亚冬夏季风经历了17个旋回的高分辨率的千年尺度气候波动（平均约为1350a/季风旋回）。3.对含石器的萨拉乌苏遗址的孢粉分析与研究，揭示了97.00~93.00 ka BP的河套人生活时期经历了5个极温暖草原、2个温暖草原、7个温暖荒漠草原、1个温凉荒漠草原和1个温凉荒漠的自然阶段的生态环境变化，且主要表现为温暖极温暖草原带与温暖荒漠草原带交替演变。4.确定了河套人最早在萨拉乌苏河谷出现的时间是150ka BP，其延续的时间——150~75 ka BP。这一结果，将近年确定的我国现代人类最早出现的年代（道县人和许昌人）向前延续了25 ka。据此提出，萨拉乌苏河谷是中国乃至东亚现代人类的发源地。本项目研究结果，对于深入理解河套人在现代人类进化的位置、生存的区域生态环境及其对全球变化—东亚季风环境演化的响应具有重要的科学意义。.