Depositional Environment of Sediments in Tonle Sap Sedimentary Basin, Western Part of Cambodia: Insights from Field and Geochemical Studies  

作　　者：Sopheap Pech Chandoeun Eng Chanmoly Or Afikah Binti Rahim Ratha Heng Chitra Buth Sreymean Sio Sopheap Pech;Chandoeun Eng;Chanmoly Or;Afikah Binti Rahim;Ratha Heng;Chitra Buth;Sreymean Sio(Research and Innovation Center, Institute of Technology of Cambodia, Phnom Penh, Cambodia;Faculty of Geo-Resources and Geotechnical Engineering, Institute of Technology of Cambodia, Phnom Penh, Cambodia;Faculty of Engineering, Universiti Teknologi Malaysia, Johor, Malaysia;Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand)

机构地区：[1]Research and Innovation Center, Institute of Technology of Cambodia, Phnom Penh, Cambodia [2]Faculty of Geo-Resources and Geotechnical Engineering, Institute of Technology of Cambodia, Phnom Penh, Cambodia [3]Faculty of Engineering, Universiti Teknologi Malaysia, Johor, Malaysia [4]Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand

出　　处：《Open Journal of Geology》2023年第7期651-666,共16页地质学期刊（英文）

摘　　要：Tonle Sap sedimentary basin was considered a favorable geological condition for hydrocarbon accumulation in the onshore Cambodia. Two exposure outcrops in Battambang province, called Somlout and Takream, were selected to represent sediments in this basin. The sedimentology and geochemistry studies provide insights into the depositional environment of sediments using field investigation, lithological, sedimentological, paleontological, and geochemical analysis. The redox condition, water column, and depositional setting were analyzed by plotting the ratio of V vs. Cr, Uauthigenic vs. V/Cr, Sr vs. Ba, Ca vs. (Fe + Ca), and Fe₂O₃/TiO₂ vs. Al₂O₃/(Al₂O₃ + Fe₂O₃) diagram. Moreover, these diagrams can be used to predict depositional conditions as well. Based on the results, Somlout and Takream comprise calcareous shale and limestone facies. The geochemical analysis showed that Somlout calcareous shale samples were deposited in the dysoxic freshwater of the lake setting during the regression, while Somlout limestones and Takream were deposited in high salinity seawater, oxic condition of shallow-marine water. In addition, Somlout limestones consist of fragmental fusulinid foraminifera, bivalve shelve, and bryozoan, which suggest a barrier environment. Meanwhile, Teakream consists of fine-grained calcareous shale, and lime-mudstone, which are presented to form in the quiet marine setting of the lagoon environment. Therefore, the Tonle Sap basin sediments were deposited in the Somlout area’s barrier and lake environment, and the lagoon environment for Takream.Tonle Sap sedimentary basin was considered a favorable geological condition for hydrocarbon accumulation in the onshore Cambodia. Two exposure outcrops in Battambang province, called Somlout and Takream, were selected to represent sediments in this basin. The sedimentology and geochemistry studies provide insights into the depositional environment of sediments using field investigation, lithological, sedimentological, paleontological, and geochemical analysis. The redox condition, water column, and depositional setting were analyzed by plotting the ratio of V vs. Cr, Uauthigenic vs. V/Cr, Sr vs. Ba, Ca vs. (Fe + Ca), and Fe₂O₃/TiO₂ vs. Al₂O₃/(Al₂O₃ + Fe₂O₃) diagram. Moreover, these diagrams can be used to predict depositional conditions as well. Based on the results, Somlout and Takream comprise calcareous shale and limestone facies. The geochemical analysis showed that Somlout calcareous shale samples were deposited in the dysoxic freshwater of the lake setting during the regression, while Somlout limestones and Takream were deposited in high salinity seawater, oxic condition of shallow-marine water. In addition, Somlout limestones consist of fragmental fusulinid foraminifera, bivalve shelve, and bryozoan, which suggest a barrier environment. Meanwhile, Teakream consists of fine-grained calcareous shale, and lime-mudstone, which are presented to form in the quiet marine setting of the lagoon environment. Therefore, the Tonle Sap basin sediments were deposited in the Somlout area’s barrier and lake environment, and the lagoon environment for Takream.

关 键 词：Depositional Environment Sedimentary Basin GEOCHEMISTRY PALEONTOLOGY Tonle Sap 

分 类 号：F42[经济管理—产业经济]