The Late Cambrian to Neogene Evolution of the Khanom Core Complex (Peninsular Thailand)

Author(s)
Urs S. Klötzli, Bernhard Neugschwentner, Jolanta Burda, Pitsanupong Kanjanapayont, Qiu Li Li, Yu Liu, Patrik Konečný, Punya Charusiri
Abstract

The Khanom Core Complex in Peninsular Thailand is a part of the crystalline basement of Sundaland and plays a key role in our understanding of the evolution of Thailand and SE Asia. The complex comprises ortho- and paragneisses, schists, meta-volcanics, subordinate calcsilicate rocks, and postkinematic granitoids. New petrochronological data reveal that the sedimentation and metamorphism of the paragneiss precursors (Haad Nai Phlao complex, Khao Yoi paragneisses) occurred in the Late Cambrian at the latest. A syn- to postsedimentary andesitic intrusion/extrusion in the Haad Nai Phlao complex at 495 ± 10 Ma defines a minimum age for the former event(s). In the Early Ordovician (477 ± 7 Ma), the Haad Nai Phlao complex and the Khao Yoi paragneisses were intruded by the Khao Dat Fa granite. During the Indosinian orogenic events, the Laem Thong Yang (211 ± 2 Ma) and Haad Nai Phlao (210 ± 2 Ma) granitoid plutons were intruded. Immediately afterward (ca. 208-205 Ma), the first metamorphic overprinting of the Laem Thong Yang granite and the Haad Nai Phlao complex including the Khao Dat Fa granite occurred. A second metamorphic overprinting of all lithological units and the contemporaneous intrusion of the Khao Pret granite followed in the Late Cretaceous and Early Paleogene (ca. 80-68 Ma). The tectonic formation of the core complex took place in the Eocene (<42 Ma), followed by exhumation and regional cooling below ca. 450°C and the latest cooling to ca. 120°C in the Miocene (ca. 20 Ma). The evolutionary data show that the Khanom Core Complex is part of Sibumasu, and its Late Cretaceous-Neogene cooling pattern and exhumation history can be directly related to the northward drift of India.

Organisation(s)
Department of Lithospheric Research, Department of Geology
External organisation(s)
University of Silesia in Katowice, Chulalongkorn University, Chinese Academy of Sciences (CAS), State Geological Institute of Dionyz Stur
Journal
Lithosphere
Volume
2024
ISSN
1941-8264
DOI
https://doi.org/10.2113/2024/LITHOSPHERE_2023_272
Publication date
2024
Peer reviewed
Yes
Austrian Fields of Science 2012
105127 Geochronology, 105120 Petrology, 105101 General geology
ASJC Scopus subject areas
Geology
Portal url
https://ucrisportal.univie.ac.at/en/publications/033f8800-434a-4b14-b6dc-a9bf687def25