--> ABSTRACT: Forming Conditions and Deposition Characteristic of Shallow-Water Deltas in Putaohua Formation of Songliao Basin, Northeast China, by Pan, Shuxin; Wang, Jiangong; Liang, Sujuan; #90135 (2011)

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Forming Conditions and Deposition Characteristic of Shallow-Water Deltas in Putaohua Formation of Songliao Basin, Northeast China

Pan, Shuxin 1; Wang, Jiangong 1; Liang, Sujuan 1
(1)PetroChina Exploration & Development Research Institute (Northwest), Lanzhou, China.

Shallow-water delta in large lacustrine depression basins is different from conventional delta in aspects of framework, microfacies, sandbody, scale and shape. Based on analysis of palaeotopography,palaeoclimate, hydrodynamic condition , high resolution sequence strata and sedimentary facies distribution, the geological settings and deposition characteristic of shallow-water delta in Putaohua Formation of Songliao basin is analyzed in this article.

Songliao Basin are characterized by stable structure, slow subsidence, flat palaeotopography, dry climate and sufficient material source during Putaohua Formation, thus formed a distinctive shallow-water delta deposition. Unlike conventional terrigenous basins, its shoreline often migrated in large scale and few deep lacustrine and semi- deep lacustrine facies developed .

The shallow-water delta can be distinguished by following characteristics:(1)The channel of shallow-water delta extended far away, up to 160km from delta plain to lake center; Divaricating and confluence were often happen in delta . Sand bodies show obvious direction and birds foot-like distribution on the isopach map.(2)Mouth bar in the front of delta was not developed as restricted by accommodation and washing action. The sandstone reservoirs were obviously controlled by fluvial system.(3)channel on the delta front were reformed to sheetlike sandstone by lake water and can be divided into three styles which include poorly sheetlike, moderately sheetlike and intensely sheetlike styles;(4)The sedimentary models of shallow-water delta differ from Gilbert delta style which have topset bed, bottomset bed and foreset bed.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.