Study on origins of man and living apes in East Africa

正如我们项目的标题所示，主要目标是弄清原始人的起源和现代非洲猿类的起源。最初，我们计划在肯尼亚和扎伊尔进行实地调查。前者是发现原始人的化石，后者是发现黑猩猩和大猩猩的祖先。然而，自1991年春末以来，扎伊尔的政治局势一直在恶化。因此，我们停止了在扎伊尔的实地调查。肯尼亚研究的地区是Samburu丘陵和Nachola地区，根据地层学的基础，该地区的新近系按升序划分为以下7个组：Nachola F.(19-15 Ma)，又名Aiteputh F.(15-10 Ma)，Namurungule F.(10-7 Ma)，Nanyangten-Kongia F.(7-5 Ma)，Tirr-Tirr F.(4 Ma)。根据地质和年代学资料，纳木伦古勒组和南阳屯组之间存在着非常显著的构造裂隙，表明纳丘拉、艾特普特和纳穆伦古勒组断裂较多，而南阳屯组上部断裂较少。下部三个组的断裂指示了9~8 Ma裂谷系的一次大的构造运动。在纳穆隆古勒组中发现了大量的等长和球形遗迹。这些分类群指示开阔的林地到稀树草原环境。Namurungule动物群似乎可能是稀树大草原和林地环境中现代撒哈拉以南动物群的先驱。在地层中发现了一种大型古人类--桑布鲁-古人类。类人猿可能是陆栖的指关节步行者或两足动物。对于原始人起源的讨论，预计会有更多的类人猿发现。

As shown in the title of our project, the major objectives have been to make clear the origin of hominids and origin of modern African apes. Originally, we had planned to conduct field surveys in Kenya and Zaire. The former was to discover fossils of proto-hominids, and the latter was to discover ancestors of chimpanzees and gorillas. A political situation of Zaire, however, has been worse since late spring of 1991. Therefore, we stopped having the field survey in Zaire. The areas studied in Kenya are Samburu Hills and Nachola area.On the basis of stratigraphy, the Neogene System in the areas is divided into following seven formations in ascending order : Nachola F. (19-15Ma), Aka Aiteputh F. (15-10Ma), Namurungule F. (10-7Ma), Nanyangaten-Kongia F. (7-5Ma), and Tirr-Tirr F. (4Ma). From the geological and geochronological data, an extremely marked structural gap is recognized between the Namurungule and Nanyangaten formations indicating many faults in Nachola, Aka Aiteputh and Namurungule formations but few in the upper formations from Nanyangaten Formation. The faults in the lower three formations is indicating a major tectonic movement of rift system in age from 9 to 8 Ma.The numerous equid and bovid remains have been found from the Namurungule Formation. These taxa indicates the open woodland to savanna environments. It seems that the Namurungule Fauna might have been the forerunner of the modern Sub-Saharan fauna in savanna and woodland environments. A large hominoid, Samburu-hominoid, was discovered from the formation. The hominoid might have been terrestrial knuckle-walkers or bipeds. Additional discoveries of the hominoids are strongly expected for a discussion of the origin of hominids.