湖南道县福岩洞古人类生存环境研究

Preliminary study on the living environment of hominin occupation at Fuyan cave,Daoxian County,Hunan

早期现代人起源、演化、扩散与环境背景的关系是备受关注的前沿科学问题。湖南道县福岩洞发现于20世纪80年代,近年来,该遗址因发现距今12~8万年前的东亚最早的早期现代人牙齿化石,为国际学术界广泛关注。本文对福岩洞的洞穴发育进行分析,对堆积物的粘土矿物、氧化物(主量元素)、牙齿釉质C、O稳定同位素和哺乳动物群等进行分析和测试,尝试重建该遗址古人类生存时期的环境背景。福岩洞发育于上古生界碳酸盐岩系内,属于大型管道型溶洞,洞穴发育由早期的垂直裂隙水为主演变为后期的水平状溶蚀;洞内堆积物以砂砾石层和红粘土为主。环境分析结果表明,道县福岩洞古人类遗址所在区域总体气候特点表现为温暖湿润,古植被类型属以C3为主的森林环境;古人类活动期的气候特点较洞穴发育初期略显偏凉,总体上环境较为稳定。福岩洞古人类生存环境的研究表明,相对温暖湿润和稳定的环境条件,为早期现代人在遗址的生存和繁衍提供了理想的条件,对理解和阐释华南地区晚更新世早期现代人起源、迁徙和演化及其与环境关系具有重要意义。

The origin of modern humans and associated environmental background continue to intrigue the scientific community and broader public attentions.The recent discovery and morphological analysis of the early Late Pleistocene hominin fossils from several sites of China indicate that early modern humans appear as early as 100 ka B.P.in some regions of East Asia.However,little is known about the relationship between the modern human evolution,dispersal and environmental background.This paper presents the paleoenvironmental reconstructions of a newly discovered modern human site at Fuyan Cave,Daoxian County,Hunan Province.Fuyan Cave site(25°39'02.7"N,111°28'49.2"E;232 m above sea level),which was discovered in 1984,is an important early Late Pleistocene cave which hominin teeth were discovered in China.It is located in Tangbei village,Lefutang town,Daoxian County,Hunan Province.A new investigation was conducted by a joint team from the staff of Institute of Vertebrate Paleontology and Paleoanthropology(Chinese Academy of Sciences),Institute of Cultural Relics and Archaeology of Hunan Province,and Office for Cultural Relics Administration of Daoxian County from 2011 to 2013.Forty-seven hominin teeth and a large number of mammalian fossils were unearthed.U-series dating indicate that early human occupied the site most probably took place between 120~80 ka B.P.,a period that spans Marine Isotope Stages 5.The Fuyan Cave,developed in the limestone series of Upper Paleozoic,is located in the hinterland of South China Plate,and south margin of North Subtropical Zone.The karst development of the cave belongs to the late stage of the karst developing system,which shows the peak forest karst and karst basin of the geomorphological feature in the adjacent regions.The cave,with main subject extent from north to south,belongs to large size pipeline type cave.The Fuyan Cave was formed by the vertical vadose fracture water dissolution and transferred to horizontal vadose water corrosion which became the dominant resorption pattern of the karst development.Sand gravel and red clay was developed in the cave which was rich in hominin fossil and mammalian fossils.In order to interpret the possible environmental background especially the impact on human occupation at Fuyan Cave,the systematic analysis of the mammalian fauna,stable isotopes,clay minerals,as well as oxides from sediments were carried out by the authors in the current paper.The study indicates that the climate and environment were optimal as a warm and humid to some degree which shows the area belongs to north subtropical zone.Stable carbon and oxygen isotope of fossil tooth enamel suggest that the Fuyan Cave dominated by C3 plants was in a region belong to forest but not so closed,indicating the climate was relatively mild.It should be noted that the human fossils and mammalian fossils were mainly distributed in upper part of the deposits which environment were exhibited relatively cool and dry than the lower part of the depositional profile.Overall,the relative mild and stable climate were optimal as a warm temperature with flourished of forest,as well as animals,which may lead to the intensified occupation of early hominins during later stage of formation processes of the cave.Early Late Pleistocene or MIS 5 is the important period which witnessed the evolution and dispersal of the anatomically modern humans in East Asia.Our results suggest that the relatively mild and stable climate condition in South China probably provide a suitable environmental background for the evolution and adaptation of early modern humans in East Asia.