“ 许家窑人”埋藏地层与时代探讨
王法岗1，李 锋2, 3
1. 河北省文物考古研究院，石家庄 050031；2. 中国科学院脊椎动物演化与人类起源重点实验室，中国科学院古脊椎动物与古人类研究所，北京 100044；3. 中国科学院生物演化与环境卓越创新中心，北京 100044
摘要：“许家窑人”化石发现于河北省阳原县泥河湾盆地西端的侯家窑遗址。该遗址20世纪70年代历经数次发掘，发现古人类化石20件、石制品数万件以及大量的哺乳动物化石。虽然已有大量关于遗址的研究成果发表，但人类化石和考古遗物的出土地层仍有些模糊，文化层时代也存在较大争议；年代数据在20 kaBP到500 kaBP的大范围间变化，影响学者们对“许家窑人”及其文化遗存演化位置的认识。鉴于此，河北省文物研究所（现河北省文物考古研究院）在2007~2012年对该遗址开展了持续的考古调查及发掘，重要目的之一在于廓清遗址埋藏的地貌部位和文化层的分布状况等基本信息。侯家窑遗址的地层包含上、下两个文化层；下文化层以下2~3 m（距地表约14.5 m）处确认了不整合接触面，其下为泥河湾层堆积，之上为河流阶地堆积。综合对20世纪70年代发掘的地层描述、新发掘地层以及人类化石保存状态的认识，“许家窑人”化石应出自遗址地层沉积序列的上文化层中，而非湖相的泥河湾层中。通过对目前遗址已有测年数据的重新梳理，我们认为，上文化层即“许家窑人”化石的时代为200~160 kaBP，主要对应深海氧同位素6阶段早期；下文化层的准确年代仍需验证，目前光释光年龄为198±15 kaBP，26Al/10Be埋藏年代为240±50 kaBP。
关键词：许家窑人；侯家窑遗址；河流沉积；泥河湾层；年代
Discussions on stratigraphy and age of the Xujiayao hominin
WANG Fagang1, LI Feng2, 3
1. Hebei Provincial Institute of Cultural Relics and Archaeology, Shijiazhuang 050031; 2. Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044; 3. CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044
Abstract: The Xujiayao hominin fossils discovered at the Houjiayao site in Yangyuan County Hebei Province in the western Nihewan Basin have been well-known and intensively studied in North China. However, the stratigraphy and age of the human fossils have been hotly debated for many years. The site was firstly excavated in the late 1970s, and twenty pieces of hominin fossils have been discovered along with thousands of stone artifacts and mammalian fossils. From 2007 to 2012, a new excavation by Hebei Provincial Institute of Cultural Relics was conducted from which new stratigraphic information has been obtained besides the newly discovered archaeological remains. An uncomformity of the depositional sequence was identified in the 2007~2012 excavation about four to five metres under the lower archaeological horizons which sheds new light on understanding the dates and stratigraphic association of hominin fossils and archaeological material at the site. The hominin fossils, stone artifacts and mammalian fossils once considered to be buried in the Nihewan formation were actually yielded in the fluvial deposit above the uncomformity which might belong to the third terrace of the Liyigou River. Many independent dating projects have been conducted at the sites since its discovery applying U-series, Radiocarbon, Paleomagnetic, OSL, and ESR, and a range of 200 to 500 kaBP was suggested for the estimated age of the archaeological layers. In this paper, we evaluate various dating results together with the new stratigraphic information obtained during the new excavations. We suggest that dating results yielded from OSL and 26Al/10Be methods are the best representatives of the age of the site. We propose that the Xujiayao hominin from the upper archaeological horizon lived in the late Middle Pleistocene, around 200~160 kaBP; the age of lower archaeological horizon requires more work, and currently the OSL result suggests an age of 198±15 kaBP and the 26Al/10Be results suggest an average age of 240±50 kaBP.
Key words: Xujiayao hominin; Houjiayao site; Fluvial deposit; Nihewan formation; Chronology
