鄂西高坪龙骨洞地层形成环境的研究

鄂西龙骨洞保存有早更新世早期的地层,并产早期人类化石和巨猿化石以及石器。通过对这套地层的形成环境的研究表明:沉积物形成于水动力条件较弱的暗河环境,期间发生过几次水体干涸事件,形成钙板层。根据沉积环境的特点,龙骨洞的地层可划分为4部分:第一部分是剖面的底部,在洞穴沉积物的形成初期,沉积物粒度较粗,形成水动力较强的暗河环境;第二部分是钙板层或强钙质胶结层的形成,表明洞穴处于干涸或水很少的环境;第三部分是地层的主体部分,以粘土和亚粘土为主,形成于弱水流的暗河环境,化石主要产自这部分;第四部分是剖面的顶部,为钙板层,洞穴干涸。洞中的化石和石器部分是被水流带入洞中沉积形成的,部分为人类和巨猿在洞中生存时留下的。

STUDY ON THE SEDIMENTS OF THE LONGGU CAVE WITH GIGANTOPITHECUS AT GAOPING,WESTERN HUBEI, CHINA

The Longgu Cave, located at Gaoping in Jianshi County, western Hubei is almost fully filled with the early Early Pleistocene sediments.The authors collected early human and Gigantopithecus fossils and stone artifacts from the cave sediments. The research on the sediments in sedimentary facies shows that the sediments in the Longgu Cave were deposited under the underground river that water flowed slowly, and sometimes the cave was lack of a flow of water. During the period of no flow, the calcareous beds were formed in the cave. According to the calcareous beds and sedimentary environment, the sediments of the cave are subdivided into four parts from bottom to top. The first part, the bottom of the sections, consists of sand layers and pebble layers, and was formed under stronger hydrodynamic underground river; The second part is calcareous layers and was formed in the no flow cave; The third part is a main segment of the sections and consists of clay layers and silt clay layers, and at that time the cave was of the slow flow and became the underground river; The fourth part is the top of the sections and is calcareous layers, so the cave was dry at that time. During the period of the dry cave, the early human and giant ape maybe live in this cave. Based on the study on the fossils and stone artifacts in morphology,it is suggested the great majority of the early human fossils, Gigantopithecus fossils and stone artifacts were brought into the cave by flow water and deposited, but the minority may be left by the early human and giant ape living in the cave.