Geochemical Characteristics,Sedimentary Environment and Tectonic Setting of Huangqikou Formation,Ordos Basin
Song Lijun
Liu Chiyang
Zhao Hongge
Wang Jianqiang
Zhang Xiaolong
Abstract：A set of ultra-thick Middle Proterozoic clastic sedimentary rocks deposited in and around southwestern Ordos basin, with the Huangqikou Formation(HKF)as the most typical one,has great potential for oil and gas exploration.However,our understanding of HKF needs to be enhanced.Thus,by means of main-trace,rare elements and detrital component method,we probed into the sedimentary environment and tectonic setting of the HKF.The sedimentary environment discrimination dia-grams of both main and trace elements show that the HKF was deposited wholly under a dry environment with fresh water oxi-dized,or an oxygen-enriched environment,with an average paleoseawater temperature of 32 ℃.The tectonic environment dis-crimination diagrams of clastic composition,and main and trace elements all show similarity to those of the East African rift ba-sin,and gradual increasing of the quartz sandstone content from the lower to the upper parts,suggesting that HKF deposited under an intracontinental rift tectonic-sedimentary setting,which may have been caused by the counterclockwise rotation of North China Craton.It is concluded that the HKF was deposited in an intracontinental rift basin in the fresh water,and the tectonic setting became more stable from early to late stage,which was intra-continental rift in the early stage and post-rift depression in the late one.
Keywords：Huangqikou Formation (HKF)geochemistrysedimentary environmenttectonic settingOrdos basin
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 1295-1308,1321 )