MORPHOLOGY, PETROGRAPHY, AND MINERAL CHEMISTRY OF MIGMATITE JUNDENG, LAMPUNG

• Main Author: GALUH SAGARA (NIM: 22013003), MOHAMAD
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/28993
• Institution: Institut Teknologi Bandung

<p align="justify">This research is focused on partial melting had occurred in Migmatit Jundeng unit in Sidoluhur dan Timbulrejo area, in Bangunrejo District, Lampung <br /> Tengah Regency, Lampung Province. Based on UTM projection with datum WGS 84, -48 zone (102o E – 108o E, Southern Hemisphere), mapping area lies in between 9436000 m North - 9431500 m South and 498000 m West - 502000 m East. The geological mapping and sampling was conducted including morphological observation of migmatite. Furthermore, several chosen rock samples was observed through petrography observation followed with mineral chemistry measurement using scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS). <br /> Partial melting indication revealed on Migmatite Jundeng through petrography observation and backscatter image of mineral composition. These, complement the field observation data which is set on its morphology. The genesis, examined from the change of mineral assemblages using modal and textural data, indicate a reaction relationship of the form: Am + Pl = Cpx + Grt + Pl + leucosome (melt), implying that the migmatite forming process involved fluid-absent hydrate-breakdown partial melting of amphibolite protolith. Peak of metamorphism from mineral assemblage predicted at minimum pressure 13 kbar and temperature 1175oC. This, included with the <br /> result of semiquantitative geothermobarometry calculation using amphibole in paleosom and secondary amphibole in melanosom, used to extrapolate the P-T paths which is form counter-clockwise metamorphism path. Thermal anomaly caused by mantle underplating was proposed as the heat source.<p align="justify">