Bulletin of the Geological Society of Malaysia, Volume 19, April 1986, pp. 349 – 367
*Dept. of Geology, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung, Indonesia
**Geological Research & Development Centre, Jalan Diponegoro No 57, Bandung, Indonesia
Abstract: The southern granitoid complex in this study refers to granitoid exposures in the areas of Menumbing-Tempilang along the southern coast and Pelangas-Kelapa further north, south of Kelabat intrusive complex. Petrographically the rocks consist of medium to coarse grained porphyritic monzogranite, syenogranite and monzonite. The main minerals are quartz, K-feldspar, plagioclase and biotite.
In a southerly direction from Pelangas-Kelapa to Menumbing-Tempilang complex, the following changes have been observed, viz. disappearance of hornblende, increase of myrmekitic, granophyric and micrographic textures, development of replacement-type microperthite, increase of Rb/Sr, Nb, F, Sn, normative corumdum, and decrease of CaO/MgO and Ba.
Nearly all granitoids plot in the S-type field; generally they show low magnetic susceptibility suggesting Ilmenite Series. Tin mineralization in the granitoid and country rocks took place mostly along west northwest, north northeast and nearly north-south directions, and they seem to be more related to Late Triassic deformation.