Research articles
ScienceAsia 47S (2021): 103-111 |doi:
10.2306/scienceasia1513-1874.2021.S007
Geochemistry of extrusive rocks at Khun Dan Prakan
Chon Dam site, Nakhon Nayok Province, Thailand
Patcharin Kosuwan Jundeea,*, Warisa Hansakulcharoenchaib, Burapha Phajuya, Piyatida Sangtongb
ABSTRACT: The extrusive rock samples were collected from outcrops at Khun Dan Prakarn Chon Dam site, Nakhon
Nayok Province. They are parts of the Pre-Cretaceous Khao Yai Volcanics located at the southern end of the western LoeiPetchabun-Nakhon Nayok Volcanic Subbelt. Petrological study found that the extrusive rock samples can be classified
into four groups: felsic pyroclastic rocks, felsic volcanic lava flows, mafic pyroclastic rocks, and mafic-to-intermediate
volcanic/hypabyssal rocks. Geochemical characteristics of the extrusive rock samples, however, can be divided into
two groups which are mafic-to-intermediate extrusive rocks and felsic extrusive rocks. Although the major and some
trace element signatures of these extrusive rocks are identical to those of typical calc-alkalic magmas, the tectonic
discrimination diagrams for least-altered rocks showed that they were different in the magmatic suite and erupting
episode; and discriminant diagrams can be successfully used to identify the tectonic environments of extrusive rocks
and to evaluate the tectonic setting of a region. Incompatible trace element plot on the tectonic discrimination diagrams
for the mafic-to-intermediate extrusive rock samples indicated high affinity with a within-plate tectonic setting, while
felsic extrusive rock samples had high affinity with continental volcanic arc tectonic setting. In addition, the tectonic
setting of these mafic-to-intermediate extrusive rock samples could be correlated to the Khiao Andesite located in the
east of studied area. Dykes could be associated with multiple arc magmatism in Loei Fold Belt and resulted in the
subduction in the Late Permian.
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| a |
Department of Geological Sciences, Faculty of Science, Chiang Mai University, Chiang Mai 50200
Thailand |
| b |
Geoscience Program, Mahidol University, Kanchanaburi Campus, Kanchanaburi 71150 Thailand |
* Corresponding author, E-mail: patcharinkosuwan.j@cmu.ac.th
Received 10 Nov 2020, Accepted 16 Apr 2021
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