秦岭南麓汉中盆地更新世黄土堆积与旧石器年代研究

Hanzhong Basin is located to southern margin of Qinling Mountains in Shannxi Province, central China. Loess sediment, with thicknesses ranging from 1 m to 25 m, was deposited on the Hanshui River terraces and many small tablelands in the Hanzhong Basin. Since the 1950s, more than 1000 artifacts, including hand-axes have been collected and excavated by archaeologists. Since 2009, we have conducted several times new field investigation in the Hanzhong Basin near the Liangshan Mountain area, and fortunately, several artifact layers were found in situ at the loess section. Unfortunately, the ages of loess sediment and the ages of these artifacts are still unknown. In this project we will take intensive samples in 2 natural loess sections and 5-6 loess-covered Paleolithic localities from the first to the forth terrace. We will use TT-OSL dating, paleomagnetism, and also stratigraphic correlation method. We will reconstruct the ages of the loess-paleosol sequence, the stages of hominins activities, and the sequence of the Paleolithic industry in Hanzhong Basin.

汉中盆地位于秦岭南麓，汉江贯穿其中。上世纪50年代以来，考古学家们在汉中盆地发现了大量脱层旧石器。从2009年开始，我们经过多次野外调查，在汉中盆地及汉江两岸阶地的黄土堆积中发现了多个原生层位保存的旧石器层。 但是，迄今为止，这里的黄土堆积年代和旧石器埋藏年代并不清楚。本项目拟对盆地内梁山地区汉江第一到第四级阶地上保存较好的、厚达25米的两个自然黄土剖面和5-6个有旧石器产出的黄土剖面进行系统采样，通过高密度回授光释光测年，结合古地磁测试,并对比黄土高原标准黄土序列，建立汉中盆地黄土堆积的年代序列，揭示汉中盆地的旧石器文化序列和演化特征。

在汉江流域的汉中盆地我们发现多个黄土覆盖的旧石器地点。通过OSL、TT-OSL、古地磁、以及与洛川标准黄土-古土壤地层序列对比等多种方法，我们建立了研究区的黄土地层序列和年代序列。我们发现在汉江流域的汉中盆地，早在大约1.20 Ma年前黄土就开始堆积，总体而言黄土在汉中盆地是连续堆积的。我们更发现了秦岭地区古人类活动明显的几个重要时期： ~0.6 Ma 的刘湾地点（洛南盆地）, 乔家窑地点（卢氏盆地）,窑厂湾地点（汉中盆地）；~0.3 Ma 的龙牙洞地点（洛南盆地）和大荔人地点（渭南盆地）；~0.1 Ma的何家梁地点（汉中盆地）, 滴水岩地点（郧县盆地）, 后房地点（郧县盆地）。所以通过对大量旧石器地点的测年研究和旧石器特征分析，我们认为秦岭周边地区各个水系是古人类穿行秦岭的主要路线，而秦岭地区则是冰期-间冰期大环境影响下古人类在中国南北迁移的重要通道。