The Petrology and Volcano-Stratigraphy of The Muria-Peninsula High-K Volcanic Rocks, Central Java, Indonesia

The Muria-Peninsula is a Quaternary volcano located in the northern Sunda arc. Its activity was controlled under high potassic and very magma series resulting leucite-rich trachyte pyroxene-rich basaltic-andesite. It strato-type that composed of lava, breccia, tuff layers, some dikes have volcanic craters maars varying age composition. study area covering volcanoes Muria, Genuk, Patiayam. This paper aims to describe petrology, mineralogy, volcano-stratigraphy different materials. data materials were sourced from primary secondary data. methods are field mapping, stratigraphy measurements, collecting samples, thin section analyses, major element geochemistry using X-Ray fluorescence (XRF). results two groups rocks consisting andesitic-basaltic trachytic Augite presents andesitic basalt together with small grains olivine few anorthite foid minerals. Aegirine (Na-Pyroxene) present often associated biotite hornblende. Na-Ca Plagioclase such as labradorite-andesine basaltic-trachy-andesite usually rarely leucite. elements show high-K % K2O 4-5.9% (with between 6-8.24%) low-K contain 2-3,9%. There silicic-rich (~57-64% SiO2) low-silicic (~46-50%). TAS diagram identifies tephrite, phonolite, trachyte. Stratigraphic calcareous sediments Bulu Formation basement Muria trachyandesite. Beds pumice-rich breccia Ujungwatu basanite-tephrite Genuk Volcano, also exposed basanite-tephritic-phonolite Patiayam Volcano. leucite-like feldspars common andesite lava compose crater Muria. Most leucite, while pyroclastic flows basaltic lava. elemental analysis indicate rock tends be medium K affinity (~2% K2O). older tephrite-phonolite. periods magmatic developed magmatism Kalk-alkaline magmatism.