摘要
根据黄土高原古地理及气候演变、黄土地层年代学和侵蚀期与堆积期的资料分析，得出黄土高原出现之前为红土高原，气候以温暖半湿润弱波动为特征，２５０×１０４ ａ 来的黄土高原可分３ 个阶段。第一阶段出现在２５０×１０４～１４０×１０４ ａ之间，为高原内部弱侵蚀循环期，气候冷暖振动幅度较小。第二阶段出现在１４０×１０４～０．４×１０４ ａ之间，侵蚀动力加强，为高原自然侵蚀加强时期，气候冷暖振动幅度较大；第三阶段出现在４ ０００ ａ 以来，为高原异常加速侵蚀外流期。未来２００ ａ 黄土高原有向冷干发展的表现，这对黄土高原的治理是不利的，但不会发生大的自然变化。通过人类活动的积极作用，黄土高原的加速侵蚀向自然侵蚀或小于自然侵蚀的变化将会发生。可以预测，未来２００ ａ的黄土高原仍是适于人类生存的好地方。
Loess Plateau has experienced pre plateau of loess, initial plateau where eroded loess was transported only within the plateau, middle plateau where loess erosion strengthened naturally and eroded loess was transported away partly from the plateau, recent plateau where loess erosion is quickened unnaturally, and future plateau that will be harnessed fast. \;The pre plateau of loess was consisted of red clay that developed during late Tertiary, when the prevailed climate was warm and semi humid and changed frequently within narrow range. \;The initial loess plateau developed during 2 5~1 4 Ma B.P., when main rivers did not occur and river erosion did not take place, erosion processes was weak and eroded loess substance did not transport away from the area and moved only from a place to another place within the area. During the period, loess did not deposit beyond the Liupan mountain westward and Wucheng loess covered the eastern area to Liupan mountain; lakes developed, and there was Sangmen large lake in the south of Loess Plateau and some lakes in the middle of Loess Plateau. The climate was more cold and arid than that in pre plateau and it changed with about 100 ka period. Through this period the climate change contained more than 20 stages composing about 10 cycles. The middle loess plateau occured between 1 4 and 0 004 Ma B.P., when lakes became small or disappeared and main rivers appeared. River flow eroded strongly loess and carried loess substance away from the area through Sanmen gorge that was dissected by Yellow River at about 15 ka B.P.. Loess erosion was strengthened in the period, but the process was still much less than deposition process. Loess began to deposit in the areas beyond Liupan mountain westward and all loess strata developed well in the eastern area to Liupan mountain. The change range of climate became greater gradually and reached the greatest in the late period. During the period climate change included about 30 stages composing 15 cycles and the changing period in early stages was 0 04 Ma and 1 0 Ma in late stages.\;The recent loess plateau has been developed since 4 ka B.P., when the erosion process was sped up. The modern fast erosion of Loess Plateau is not caused naturally by climate change, vegetation change, tectonic uplift and geomorphology development but caused by human being destroying vegetation and this can be tackled by planting trees, conservating vegetation and taking engineering measures, therefore Loess Plateau in the future 200 years will still be a good place for human being living.
出处
《中国沙漠》
CSCD
北大核心
1999年第4期333-337,共5页
Journal of Desert Research
基金
国土资源部九五项目!(9501104)
关键词
黄土高原
古地理
侵蚀历史
阶段划分
古气候
Loess Plateau
evolution of paleogeography
erosion history
stage division
future development
