U-Pb dating for zircons from granitic rocks in southwestern Cambodia

Etsuo Uchida; Shinya Nagano; Sota Niki; Ko Yonezu; Takumi Yokokura; Rathborith Cheng; Takafumi Hirata

doi:10.1016/j.heliyon.2023.e19734

U-Pb dating for zircons from granitic rocks in southwestern Cambodia

Heliyon. 2023 Sep 2;9(9):e19734. doi: 10.1016/j.heliyon.2023.e19734. eCollection 2023 Sep.

Authors

Etsuo Uchida¹, Shinya Nagano¹, Sota Niki², Ko Yonezu¹, Takumi Yokokura¹, Rathborith Cheng³, Takafumi Hirata²

Affiliations

¹ Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo, 169-8555, Japan.
² Geochemical Research Center, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo, 113-0064, Japan.
³ Department of Geology, Ministry of Mines and Energy, #79-80, St. 51, Sankat Phsar Thmey III, Khan Daun Penh, Phnom Penh, 12210, Cambodia.

Abstract

U-Pb dating was conducted for zircons from a total of 14 samples from 13 granite bodies in southwestern Cambodia using LA-ICP-MS. The granitic rock samples were collected from southwestern Cambodia, southwest of the Mae Ping Fault extending from northwest Cambodia via Tonle Sap Lake to southern Vietnam. The studied rock bodies belong to the ilmenite-series, except for three granitic rock bodies. They were identified as I-or A-type. The analysis yielded three distinct age ranges: 295-309, 191-232, and 75-98 Ma. The 295-309 Ma ages are associated with the Paleo-Tethys Sea subduction beneath the Indochina Block. The ages of 191-232 Ma may correspond to the amalgamation period of the Sibumasu and Indochina Blocks during the Indosinian Orogeny. Granitic rocks with ages of 75-98 Ma occur near the southeastern Cambodia-southern Vietnam border. Formation of these granitic rocks was associated with the Paleo-Pacific Ocean Plate (the Izanagi Plate) subduction beneath the Indochina Block. The region in which these granitic rocks occur is part of the Dalat-Kratie Zone.

Keywords: Granite; Indosinian Orogeny; Mae Ping Fault; Southwestern Cambodia; U–Pb dating; Zircon.