泥河湾盆地距今约130万年湖相沉积埋藏石铺地面的性质与成因

At Zhaopo and Putaoyuan Paleolithic sites in the eastern Nihewan Basin, possible evidence of artificial building structures (that is, stone pavement at Zhaopo and stone wall at Putaoyuan), which are buried within lacustrine clays and silts, were discovered by Yuan Baoyin and Tong Haowen in 2010. Subsequently, Yuan Baoyin, Deng Chenglong, Huang Weiwen, and Zhang Jiafu conducted geologic investigation during 2011-2012. Stratigraphic correlation indicates that the Zhaopo and Putaoyuan Paleolithic sites are of the same age as the Xiaochangliang Paleolithic site, which was estimated to be 1.36 Ma by paleomagnetic dating. Very preliminary excavation yields archeological evidence, most possibly suggesting that early humans in the Nihewan Basin were building artificial structures during the early Pleistocene. Therefore, the Zhaopo and Putaoyuan Paleolithic sites may yield the earliest evidence of artificial building structures. Detailed and systematic investigations through methods of paleoanthropology, Paleolithic archeology, megnetochronology, stratigraphy, sedimentology and paleoenvironments are required in order to probe into their significance in early human evolution.

2010-2012年袁宝印、同号文在泥河湾从事第四纪地层调查期间，在照坡遗址和葡萄园发现埋藏于湖相黏土地层中的砾石地面和砾石墙。2012年，袁宝印、邓成龙等再次考察并进行小范围挖掘探查，发现它们是埋藏的早期人类活动地面和垒砌的砾石墙。其地层层位与小长梁遗址相同，地质年龄约1.36Ma。在砾石地面上和砾石墙内侧发现旧石器、人工打击石块、动物骨片化石等，根据砾石地面和砾石墙上覆及下伏地层沉积物特征，初步判断它们是古人类有意识的建筑物。这是东亚发现最早的古人类建筑物，在“人类起源与演化”、“全球气候环境变化与人类生存” 以及早期人类生活方式、智力水平等研究中具有重要意义。目前急需开展必要后续研究，以取得足够的地质、古环境、年代学数据和考古学资料，论证它们是早期人类的人工建筑物。该项研究将增强我国学者在“人类起源与演化”领域参与国际学术竞争的实力。

泥河湾盆地小长梁一带石铺地面遗址的考古发掘、野外调查和实验室测试工作，对石铺地面的成因与性质获得如下认识：1. 石铺地面主要由20—50cm直徑的单层砾石构成。砾石接触紧密，砾石间充填黄色亚粘土，其中发现较多动物肢骨碎片化石和人工打击石块和旧石器。 2. 石铺地面的下伏地层为湖滨相亚粘土。 3. 石铺地面砾石间的亚粘土无沉积结构，属人工充填物。 4. 石铺地面遗址所在地点，上新世古地理为残留古近纪夷平面形成的基岩台地边缘的山坡上部，台地有浅冲沟流入盆地中心，冲沟沉积的灰色砾石层和泥石流堆积，岩性特征与石铺地面有明显差别。5. 早更新世泥河湾古湖快速扩张，湖水淹没基岩台地前缘山坡，沉积湖滨相亚粘土。大约距今1.36 Ma，湖泊经历短暂收缩期，湖滨出现大面积湖滩，古人类在此活动并铺砌了石铺地面。以上证据说明石铺地面不可能在该区地质、地貌条件下自然堆积而成，应是古人类有意识铺设而成。