|
Petrography and geochemistry of volcanic rocks in the Khao Sam Sip, Sa Kaeo, Eastern Thailand |
|---|---|
| รหัสดีโอไอ | |
| Creator | Maythira Sriwichai |
| Title | Petrography and geochemistry of volcanic rocks in the Khao Sam Sip, Sa Kaeo, Eastern Thailand |
| Contributor | Abhisit Salam, Takayuki Manaka |
| Publisher | Department of Geology, Chulalongkorn University |
| Publication Year | 2564 |
| Journal Title | Bulletin of Earth Sciences of Thailand (BEST) |
| Journal Vol. | 13 |
| Journal No. | 1 |
| Page no. | 18-Jan |
| Keyword | Volcanic Rock, Alkaline, Sa Kaeo, Loei-Petchabun-Sa Kaeo Volcanic Belt, Petrography, Geochemistry, Copper veins/veinlets |
| URL Website | https://www.bestjournal.org/ |
| Website title | Bulletin of Earth Sciences of Thailand |
| ISSN | 1906-280X |
| Abstract | The volcanic rocks at Khao Sam Sip, Sa Kaeo province is a part of the Loei-Phetchabun-Sa Kaeo Volcanic Belt. Based on field observation, petrographic and geochemical studies, the rocks in the study area can be divided into four rock units namely, 1) Coherent volcanic unit, 2) Intermediate-mafic breccia unit, 3) Volcanogenic-sedimentary unit, 4) Sedimentary unit. Unit 1 is the lowest unit in the sequence consisting of olivine-pyroxene-plagioclase basalt, pyroxene-phyric basalt, hornblende-plagioclase andesite, and plagioclase-phyric andesite. Unit 2 consists of polymictic andesitic breccia and polymictic andesitic sandstone. Unit 3 involves volcanogenic sedimentary rocks comprising of crystal-lithic sandstone and polymictic conglomerate. Unit 4 is a sedimentary unit that includes fine-grained clastic rock and limestone. In the geochemical study, representative rock types mainly from the coherent volcanic unit were selected for geochemical analyzes including major, trace, and rare earth elements. They are ranged in compositions of trachyandesite and alkali basalt with few rhyodacite, andesite and basanite and classified dominantly as alkaline affinity. Based on the results of trace elements and REE abundances, the rocks can be subdivided into four groups. All of the four groups have similar chemical characters of enrichment in HFSE and light rare earth elements (LREE) with distinct negative Eu anomalies, and this may suggest that the rocks were formed from Early Triassic fractionated magma of volcanic arc system as a part of Loei Fold Belt. Copper-rich veins/veinlets are hosted in coherent volcanic rocks and they may represent either skarn or epithermal style mineralization. |
