Reconstruction Of The Living Environment Of Lufengpithecus Lufengensis In Yunnan Shihuiba

Global climate change and the responses from human beings and other lives have become hot research topics in the world.Assessing the current state and challenges of human development and the earth's ecosystems requires researches on the interaction between life and the environment,especially exploring the causes and processes of major environmental changes in geological history.Yunnan Plateau is located in the southeast margin of the Tibetan Plateau.Yunnan Plateau has been sensitive to the uplift of the Tibetan Plateau and climate change,and thus,is an important location to study physiognomy and environment evolution.The location also becomes a hotspot to study human origin after the discovery of Lufengpithecus lufengensis,an early member of hominids that lived about 8 million years ago.Lufengpithecus lufengensis was first found at the Lufeng Shihuiba in central Yunnan province,and has attracted global attention ever since,as this hominid is considered as an essential part of the process of human origin and evolution.The study of the relationship between the evolution of Lufengpithecus lufengensis and environmental changes can improve our understanding on the influence of environment on human origin and evolution.The outcomes of the study can be used to evaluate the coupling process and mechanism between organisms and environment during major transition periods in geological history.In this thesis,we have drilled several sedimentary cores at the fossil sites of Lufengpithecus lufengensis in Lufeng Shihuiba,and selected two of the cores(LF1805 and LF1807)as the main research objects.Both sediment cores bear stable and successive deposition.LF1805 was used to analyze the grain size and clay mineral contents;and LF1807 was used to analyze sedimentary facies and geochemical elements.The results were synthesized to reconstruct the environmental evolution process before,during and after the presence of Lufengpithecus lufengensis.Here we list the major findings of the thesis.(1)Before the presence of Lufengpithecus lufengensis: Lufeng was an intermountain basin in Yunnan.The sediment facies are lacustrine facies,with weak dynamic energy.The climate was generally warm with reduced rainfall,and had a seasonal dry-wet alternate.At later stage,the climate gradually became colder and drier and the sediment facies changed to lakeside subfacies.(2)During the presence of Lufengpithecus lufengensis: The sedimentary environment at Lufeng was changing from shallow lakes with the strong dynamic energy to the swamp with weak energy,and finally changed to a relatively stable static water environment.The regional climate was in general changing from warm and moist to cold and dry.At the early stage,the climate was alternating between warm-humid and colddry,and during this stage,Lufengpithecus lufengensis and other mammals was developing prosperously.At the later stage,the climate was stabilizing to cold-dry condition.The deteriorating climate could have reduced the food supply,forcing Lufengpithecus lufengensis to start to live on the ground,gradually gain the bipedal posture,and become the early member of hominid.(3)After the presence of Lufengpithecus lufengensis: Lufeng became a land sedimentary environment,probably resulted from a dryer and colder climate in central Yunnan due to the uplift of the Tibet Plateau and the global climate change.The loss of food and water might have led Lufengpithecus to extinction or migration.