Paleozoic-Mesozoic volcanic evidence based on petrographic analysis in Mengkarang area, Jambi Province, Indonesia (original) (raw)

Mengkarang area is part of Merangin National Geopark, Jambi Province, Indonesia. The area is mainly consisted of Permian and Jurassic rocks and known for its well-preserved fossils, where the occurrence of this fossils could demonstrate the massive extinction of Permian Age. Despite numerous studies on fossils of Mengkarang area have been published, only a few petrographical studies conducted on Mengkarang area. Such study is important in the future to better determine the petrotectonic setting of the Mengkarang area. We collected several igneous, volcaniclastic, and sedimentary rock samples from various rock formations in the study area. By combining the field observation and petrographic analyses, we made several assumptions that can link Mengkarang rocks to the Paleozoic-Mesozoic volcanic activity and deformation. The vitric tuff displays flow banding and welded features. Some of the petrographic samples show low-moderate argillic to intense propylitic alteration that related to volcanic activity, with several deformation evidence. Other samples show biotite minerals that altered to chlorite and deformed by the formational compaction. Furthermore, the rocks in the southern part of the Mengkarang area generally experienced stronger deformation compared to another part of the study area.