泥河湾盆地麻地沟E5旧石器地点的遗址成因与石器技术

Site formation processes and lithic technology at the MDG-E5 Paleolithic site in the Nihewan Basin

麻地沟E5旧石器地点位于泥河湾盆地东端岑家湾台地古人类活动集中区,埋藏于泥河湾层灰白色-灰黄色细砂和粉砂层内。遗址发现于2007年,中国科学院古脊椎动物与古人类研究所于2014年对其进行考古发掘,揭露面积22m^2,出土143件石制品、8件动物碎骨和235件砾石。遗址成因(标本分布状况、原料与个体大小、风化磨蚀状况和标本空间聚集特征等)分析表明,遗址形成受到明显的水流搬运和改造。石制品原料均来自遗址周围1km^2范围内,岩性以硅质白云岩、燧石和火山岩为主;锤击法剥片和修理石器,剥片和修理随意,石制品形态无定型,显示旧石器时代早期奥杜威(Oldowan)工业特点。初步古地磁年代测定显示古人类在该遗址活动的时间大致为1.20 Ma。该遗址的发掘对研究泥河湾盆地早更新世遗址成因与古人类的生存方式具有重要意义。

The Madigou （MDG） site provides a new archaeological sequence for the Early Pleistocene in the Nihewan basin, North China. This paper reports on the archaeological sequence, which is attributed to an Oldowan-like （Mode 1） industry. Emphasis is placed on analysis of site formation processes and lithic technology at the MDG-E5 Paleolithic site withinthe MDG site complex The Madigou site complex is located in the key area of Early Pleistocene human occupation at the Cenjiawan Platform in the eastern part of the Nihewan basin. The MDG-E5 site was discovered in 2007 and was excavated by staff from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences in 2014. A total of 22 mE was exposed and 143 stone artifacts, eight mammalian fossil fragments, and 235 cobbles were unearthed from the site. The stratigraphic profile, 8 m in thickness, is comprised of grey-yellow, grey, and grey green fine sands, silts, and clays. The archaeological materials were located in grey-grey yellow fine sands and silts. The site is characterized by the concentrated distribution of gravels （roughly 4-8cm diameter） in which small numbers of stone artifacts are contained relative to dozens of cobbles and pebbles that are varied but size-sorted by hydraulic action. The current study thus indicates that MDG-E5 has been preserved in a secondary context in a lakeshore environment. Multiple lines of evidence include the distribution patterns of archaeological and natural lithic materials, size sorting, artifact abrasion, and spatial patterning. The MDG-E5 archaeological deposits most probably were buried in lake margins deposits of fine sands and silts that were moderately transported and disturbed by relatively moderate energy hydraulic forces. This indicates that the MDG-E5 artifacts have been buried and re-worked by natural agencies and are not in primary context. Technologically, lithic raw materials were procured from an adjacent area ca lkm2 in size, in which silicious dolomite, chert, and volcanic lava dominate the rock types. The flaking technique is direct hard hammer percussion without core preparation, and modified pieces casually retouched by direct hammer percussion. The flaking strategies morphology of the stone artifacts were simple, producing a Mode 1 assemblage which most resembles the Oldowan industry of Africa. Preliminary paleo-magnetic dating indicates that early humans colonized the site most probably at 1.20 Ma. Excavation of the MDG-E5 site is particularly significant for study of site formation processes, which helps us to interpret the adaptive behaviors of hominins in the Nihewan basin during the Early Pleistocene.