Magma Genesis and Arc Evolution at the Indochina Terrane Subduction: Petrological and Geochemical Constraints From the Volcanic Rocks in Wang Nam Khiao Area, Nakhon Ratchasima, Thailand

Abstract

Volcanic rocks and associated dikes have been exposed in Wang Nam Khiao area, Nakhon Ratchasima Province, northeastern Thailand where complex tectonic setting was reported. These volcanic rocks are classified as rhyolite, dacite, and andesite whereas dikes are also characterized by andesitic composition. These dikes clearly cut into the volcanic rocks and Late Permian hornblende granite in the adjacent area. Rhyolite and dacite are composed of abundant plagioclase and quartz whereas andesite and andesitic dike contain mainly plagioclase and hornblende with minor quartz. The volcanic rocks typically show plagioclase and hornblende phenocrysts embedded in fine-grained quartz and glass groundmass whereas dike rocks contain less glass matrix with more albitic laths. P-T conditions of crystallization are estimated, on the basis of Alin-hornblende geobarometry and hornblende geothermometry, at about 4.5-5.5 kbar, 861-927 • C and 4.8-5.5 kbar, 873-890 • C for the magma intrusions that fed volcanic rocks and andesitic dikes, respectively. Whole-rock geochemistry indicates that these rock suites are related to calc-alkaline hydrous magma. The enriched large-ion lithophile elements (LILE; e.g., Rb, Sr) and depleted high-field-strength elements (HFSE; e.g., Nb, Ce, Ti), with similar rare earth element (REE) patterns indicate arc magmatism. The results of this study are comparable with the continental arc magmatism along the Loei Fold Belt (LFB) as a consequence of the Late Permian Palaeo-Tethys subducted beneath Indochina Terrane.

Geochemical and zircon U-Pb geochronological constraints on late mesozoic Paleo-Pacific subduction-related volcanism in southern Vietnam

“…Figure 12b summarizes the emplacement ages of Mesozoic volcanic rocks obtained in this study, Late Paleozoic-Early Mesozoic rocks (Fanka et al 2018;Nualkhao et al 2018;Cheng et al 2019;Hunyek et al 2020;Nong et al 2022) and Late Mesozoic rocks are compiled from the literature (Nguyen et al 2004;Zhou et al 2006;Shellnutt et al 2013;Xu et al 2016;Yan et al 2017;Cheng et al 2019;Nong et al 2021). Volcanism and plutonism along western Indochina occurred episodically from the Carboniferous to the Triassic in the Loei Fold Belt and Sukhothai arc Meffre 2007, Zaw et al 2014;Fanka et al 2018;Hunyek et al 2020).…”

“…The Loei Fold Belt and Sukhothai terranes along the western margin of Indochina are widely accepted to be magmatic arcs formed during the subduction of the Paleo-Tethys beneath Indochina (Zaw and Meffre 2007;Kamvong et al 2014;Zaw et al 2014;Nualkhao et al 2018;Nong et al 2022). The Loei Fold Belt mainly comprises Late Permian-Triassic andesitic-rhyolitic volcanic rocks and subordinate Devonian-Carboniferous and Silurian magmatic rocks which bear signatures of a subduction environment (Zaw and Meffre 2007;Hunyek et al 2020). Along the eastern Indochina margin, a number of Jurassic and Early-Mid-Cretaceous volcanic and plutonic rocks distributed throughout Sumatra, SE Borneo, Vietnam, and eastern China have been frequently linked with Paleo-Pacific subduction (Nguyen et al 2004;Clements et al 2011;Shellnutt et al 2013;Nong et al 2021).…”

Geochemistry of extrusive rocks at Khun Dan Prakan Chon Dam site, Nakhon Nayok Province, Thailand

“…These dikes clearly cut into the volcanic rocks and Late Permian hornblende granite implying that the volcanic rocks and dikes have taken place during/after Late Permian. Whole-rock geochemistry indicated that these suites are related to calc-alkaline hydrous magma, and rare earth element patterns indicated arc magmatism [10]. The aim of the present study was to identify rock types and tectonic settings of eruption of volcanic rock samples.…”

“…The mafic-to-intermediate rock samples shared the distributions of elements such as HFSE (Nb, Ti, P), Th, Zr, and Y indicating high affinity with a within plate tectonic setting, while the felsic rock samples were continental volcanic arc tectonic setting. In addition, the Khao Yai Volcanics at Khun Dan Prakarnchon Dam were correlated with the Wang Nam Khiao Volcanics [10], as rhyolite, dacite, and andesite were calc-alkaline magma resulted from continental arc subduction. Moreover, the andesitic dikes were within-plate environments taken place during/after volcanic eruption.…”

Tectonic Implication of the Permo-Triassic Khao Yai Mafic Volcanic Rocks in Nakhon Nayok Province, Thailand: Evidence from Geochemistry and Rare Earth Elements (REEs)

“…The Khao Yai volcanics may correlate with the Permo-Triassic volcanic rocks and associated plutonic complexes in the Wang Nam Khiao area, Wang Nam Khiao District, Nakhon Ratchasima Province at the eastern part of Khao Yai volcanics for the timing of eruption. Fanka et al [20,21] studied plutonic rocks in the Wang Nam Khiao area, Nakhon Ratchasima, Thailand and point out that the zircon U-Pb geochronology of the Carboniferous biotite granite, Late Permian hornblende granite and Triassic biotite-hornblende granite yielded intrusion ages of 314.6 -284.9 Ma, 253.4 Ma, and 237.8 Ma, respectively, probably indicating the arc-magmatism related to subduction of Palaeo-Tethys beneath the Indochina Terrane during the Late Carboniferous/Early Permian, Late Permian, and Middle Triassic. Hunyek et al [21] reported that the Permo-Triassic volcanic rocks in the Wang Nam Khiao area are composed of rhyolite, dacite, andesite, and andesite dikes.…”