Sandy debris flow of middle Banna Formation in Lizhou area of Baise, Guangxi province
A set of thick turbidite was found in the Middle Triassic in Baise area of Guangxi Province, where incoordinate massive sandstone which has not been aroused concern is also partially developed. Therefore, the origin of the massive sandstone is still unclear. Based on the observation of several field geological sections and integrated with the precious research, we put emphasis on the detailed description and sample analysis of the strata which outcrops well in Lizhou area. According to the lithology characteristics, the middle part of Banna Formation in Lizhou area includes four lithofacies: sliping collapse conglomerate(lithofacies 1), thin to medium siltstone interbedded and thin to medium mudstone interbed(lithofacies 2), medium to thick fine sandstone intercalated with thin bedded mudstone(lithofacies 3) and massive fine sandstone intercalated with thin bedded mudstone (lithofacies 4). These lithofacies may represent that the middle part of Banna Formation formed in the continental slope environment and it is proximal channel deposition. According to the rock textures, sedimentary structures and sedimentary sequence features, the lithofacies 4 is supposed to be sandy debris flow deposition which occurred as lenses in the channel, superimposing with the migration of the channel. Then, through the research above, a sandy debris flow depositional model of the middle part of Banna Formation in the study area has been built up, which reflects the evolution of the channel including erosion, migration and abandonment.
WANG Yingchao , WANG Qiang , SUN Zuoxing . Sandy debris flow of middle Banna Formation in Lizhou area of Baise, Guangxi province[J]. Lithologic Reservoirs, 2014 , 26(3) : 93 -100 . DOI: 10.3969/j.issn.1673-8926.2014.03.016
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