%0 Journal Article
%T MAJOR ELEMENT RECORDS FROM THE QINGHAI LAKE BASIN-GONGHE BASIN SEDIMENTS INDICATING THE NANSHAN (QINGHAI) UPLIFT EVENT<br>青海南山隆起的盆地沉积物常量元素记录
%A Chang Hong
%A An Zhisheng
%A Wu Feng
%A <br>常宏
%A 安芷生
%A 吴枫
%J 第四纪研究
%D 2008
%I 
%X The Nanshan(Nan Mountain)uplift process is very important in understanding structural evolution of the Qinghai Lake Basin-Gonghe Basin in Qinghai Province.Late Cenozoic sediments are rarely found in natural profile from the east to the west in the Qinghai Lake Basin along Nanshan,but they are common in the Gonghe Basin,especially in its northwestern and northeastern part.The basement of the Gonghe Basin is composed of flysch formation and granite which is assigned to Triassic,upon which the Late Cenozoic sediments are deposited.An angular unconformity was found in the Pliocene stratum during a field exploration in the Xiaoshuiqiao section in northwestern part of the Gonghe Basin and abrupt changes in detrital minerals were detected from its overlying and underlying sediments.The composition of the clast ofthe overlying sediments,with 10%± of limestone and marly limestone,is similar to that of the outcropping along the Nanshan.But clast of limestone and marly limestone does not exist in the underlying sediments,indicating the change of source material.To test this hypothesis,sediment samples were taken for experiments in element content.The average CaO content of the underlying stratum is 3.74%,which is obviously lower than the UCC(4.20%),showing no carbonate in its source material.However,the average CaO content of the overlying stratum is more than 2 times than the UCC,thus carbonate should be occurred in the source material.Moreover,the element ratio result reveals that both relatively immobile elements(Ti,Si)and high mobile element(Ca)were "enriched" in the sediments of the overlying stratum,which also suggests that the carbonate should be occurred.Additionally,the adding of Ca is more than its loss in the overlying stratum.In summary,the change of minerals of clast between the overlying and underlying strata has been confirmed not only by major element content,element ration,but also by inter-element relationship and chemical classification of sedimentary rock.Carbonate occurs in rocks of Nanshan,which is also the source material of sediments of the modern basin.We thus believe that the Nanshan offered source material for the overlying stratum but did not for the underlying stratum.Although gradual uplift and denudation can also be used to interpret the abrupt changes of the clasts and geochemical characters of the sediments,considering the existence of the angular unconformity,an reliable evidence for a tectonic movement,as well as the regional geological documents,we suggest that the uplift of the Nanshan tilted the stratum in the southward range-front and changed the geomorphology of the paleo-basin.After the unconformity,the Nanshan started to serve as the new source of the Qinghai Lake Basin and the Gonghe Basin.
%K Qinghai Nanshan
%K angular unconformity
%K major elements
%K element ratio
%K chemical classification of sedimentary rock
%K provenance of the sediment<br>青海南山
%K 角度不整合面
%K 常量元素
%K 元素比值
%K 岩石化学分类
%K 沉积物源区
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=EA07051745CDC8D89D5F01A3A4CFE6A9&aid=82B9CC994D9B2AD49231560A8D59A13B&yid=67289AFF6305E306&vid=D3E34374A0D77D7F&iid=94C357A881DFC066&sid=F7C11D7E3E8C5D3F&eid=CE16DE2ABCD4D365&journal_id=1001-7410&journal_name=第四纪研究&referenced_num=0&reference_num=42