云南禄丰古猿生活时期的古气候初步研究

本文通过对云南禄丰古猿化石地点的沉积物进行综合分析,提出古猿生活时期的气候变迁。即石灰坝组一段为干燥而凉爽气候;二段为温暖较湿润的气候;三段为湿热的南亚热带—热带气候;四段为古猿生活时期,已转变成干湿相间的南亚热带—热带季风气候。庙山坡组(五段),初期气候—度变得相当干燥而炎热、到后期又逐渐为干温气候。

ON THE PALEOCLIMATE DURING THE PERIOD OF RAMAPITHECUS IN LUFENG COUNTY, YUNNAN PROVINCE

This paper deals with the reeostruetion of the late Miocene paleoelimate by meaus of sedimentary analyses of the stratum containing Ramapithecus fossils. The analyses include: differential thermal analysis, X-ray diffraction, heavy mineral content, pH value, organic substances, sporo-pollens and identification of aquatie plant maero-fossils.
The paleoclimate of the late Miocene gradually changed along with the uplifting of the highlands of Qinghai-Xizang (Tibet) and the Hengduan mountains. The geological section containing Ramapithecus fossils can be divided into five different depositional stages, from bottom to top:
The first stage— (the First Member of Shihuiba Formayion) The climate in this stage is drier and cooler than in the second one.
The second stage- (the Second Member of Shihuiba Formation) The climate is charaterized by a warm and wet perind.
The third stage—includes the early deposits of deep lacustrine and lacustrine-swamp environments in the basin. It indicates a hot, wet elimatic character, typical of the South Asian tropical zone.
The fourth stage—repersents the later lacustrine-swamp deposits of the middle and upper parts of the basin. The climate during this stage is different from that of the first—It indicates a climate that alternates between wet and dry and hot and wet. It demonstrates the periodie return of wet and dry eonditions, and is similar to that of the Sino-India tropical monsoon climate of South Asia. This climatic change is pro- bobly related to the uplifting of the Qinghai-Xizang (Tibet) plateau and the orogeny which produced the Himalayas and the Hengduan mountains.
The fifth stage includes the deposits of shallow lakes or rivers above the erosional surface in the geological section bearing Ranapithecus fossils. Here, substantial climatic change is indieated. Following the uplifting of the Qinghai-Xizang (Tibet) plateau, the Lufeng lacustrine-swamp environment faded away, and a very dry elimate is suggested. Finally one withesses the return of a rather warm and wet sub-tropical climate.