|The rocks in the research area generally range from basaltic andesite to basalt as Argopuro volcano products. The rocks are found in Rabunan and Krucil (north and west of Mount Iyang Argopuro).
The rocks found in the Rabunan (along the river) towards the hot springs other than the Argopuro volcanic rocks are also found in the holocrystalline textured gabbro (SRBN-1B, and SRBN-2A), the plagioclase minerals are partially converted to sericite and calcite, pyroxene, oxidized olivine, opaque mineral, based on the similarity of the physical features of this gabro microstructure when referring to Suharsono, et al., 1992, can be included as a member of the Kuusin quarter-old intrusive rock unit, and bypass volcanic rocks of Argopuro volcano products.
Argopuro volcanic rocks obtained in the form of lava consisting of porphyry basalt (SRBN-6) have vesicular structures partially filled with zeolite / natrolite, and chlorite, the main composition of labradorite, volcanic glass, and pyroxic, opaque, chlorite change epidotes.
There is also a porphyritic andesitic lesite (SRBN-7), an amygdaloid structure filled with calcite, the main composition of labradorite and andesine, volcanic glass, epidotes, calcite, opaque minerals.
Upstream upstream of the Rabunan River is close to the hot springs found lava, breccias and rocks that are teralterasi intensive-total.
The rocks are the olivine basalt (SRBN-2B), which shows the porphyritic glomero texture, the composition of plagioclase (labradorite) as phenocryl and mass, volcanic glass, augit and hyphenoric hypersten and then overprinted by calcite, olivine truncated by calcite veinlet, xenocryst hornblende has oxidized edges, opaque minerals.
Besides, it is obtained basalt trachy (SRBN-4.2B), showing the texture ofitik formed by feldspar and pyroxene.
composition: felspar / alkali feldspar twinning karlsbad, others as andesin as phenochris and masadasar, pyroxene of augite and hypersten species oxidized and converted to chlorite and epidote, other minerals olivine, opaque minerals.
On it is a lava bridge (SRBN-4c), consisting of fragments and matrices. The fragment is a teralterated volcanic rock (2-4 mm), andesine is generally converted into sericite minerals, altered chlorite from fine-sized mafic minerals, and the matrix of chlorized volcanic glass, opaque minerals.
In addition, volcanic rock samples were collected around the magnetoteluric measurement sites, which were conducted at Tiris, Tambak Ukir, Renteng, Pakuniran, Paiton.