Research articles
ScienceAsia 47 (2021):ID 609-617 |doi:
10.2306/scienceasia1513-1874.2021.066
Petrology and geochemistry of granitic rocks in Dan
Chang area, Suphan Buri Province, Central Thailand:
Implication for petrogenesis
Thirawat Tukphoa, Alongkot Fankab,*
ABSTRACT: Triassic granitic rocks exposed in Dan Chang area are northern and southern granitic units. These granites intruded Silurian-Devonian clastic sedimentary rocks of Bo Phloi Formation and Ordovician limestones of Thung Song Group. Fifteen representative samples were collected for petrography, whole-rock geochemistry, and mineral chemistry studies. These granites show porphyritic texture and comprise quartz, K-felspar, plagioclase, biotite, and muscovite as the major compositions, with the minor compositions of ilmenite, zircon, and apatite. Moreover, aplite and pegmatite are associated with the southern granite as dikes. Aplite and pegmatite are composed of mainly K-feldspar, quartz, tourmaline, and plagioclase. Based on the whole-rock geochemistry, these rocks can be classified as peraluminous S-type granite to granodiorite, originating from high-K calc-alkaline and derived from an upper crustal source. The geotectonic discrimination diagrams show that these granitic rocks are significantly related to syn-collision to late-orogenic. The mineral chemistry of the granites shows a close relationship of their compositions and magma genesis, which can imply that aplite might be the last stage of the granitic crystallization. Moreover, the crystallization Pressure-Temperature (P-T) conditions of the northern and the southern granites are 3.4–3.7 kbar, 571–630 °C and 3.3–3.8 kbar, 624–656 °C, with calculated intrusion depths of 12–13 km and 12–14 km, respectively. These granitic rocks are comparable to the S-type granite of the Central Belt Granite of Thailand, resulted from syn-collisional crustal thickening and subsequent post-collision after the closure of the Paleotethyan during the Late Triassic.
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Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330 Thailand |
| b |
Applied Mineral and Petrology Special Task Force for Activating Research (AMP STAR), Department of
Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330 Thailand |
* Corresponding author, E-mail: alongkot.f@chula.ac.th
Received 4 Feb 2021, Accepted 6 Jun 2021
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