Author(s)

Sopheap Pech^1,2*, Chandoeun Eng¹, Chanmoly Or², Afikah Binti Rahim³, Ratha Heng^1,2, Chitra Buth⁴, Sreymean Sio¹

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

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.

Depositional Environment, Sedimentary Basin, Geochemistry, Paleontology, Tonle Sap

Pech, S. , Eng, C. , Or, C. , Rahim, A. , Heng, R. , Buth, C. and Sio, S. (2023) Depositional Environment of Sediments in Tonle Sap Sedimentary Basin, Western Part of Cambodia: Insights from Field and Geochemical Studies. Open Journal of Geology, 13, 651-666. doi: 10.4236/ojg.2023.137028.