| Popis: |
Waturanda Fm, a member of Old Andesite Formation-first breccias, consist of Oligo-miocene volcanic clastic rock. It could be found in South Serayu zone, part of Karangsambung complex, Central Java. It formed by Neogene Compressional Wrenching tectonic phase which caused volcanic belt in southern Java island. This formation consist of many foreign fragments. The provenan of these fragments is approximately pre-tersier age which equivalent to tectonic melange rocks karangsambung. Petrology and formation tectonic study were based on paleogeography investigation from structure analysis and petrographic thin section. Based on petrographical analysis, northern waturanda fm consist of crystalline rock fragments such as filit, quartz, slate, and deep marine sedimentary rock-chert associated with red limestone. Based on early hypothesis from petrographic analysis, foreign fragments associated with mud > 55% showed that this formation experienced depth changes which caused by west-east structure pattern, Oligo-micene tectonic phase and reactivation of north-south structure pattern known as sunda pattern. Waturanda fm assumed to be affected by basin subsidence which caused by normal fault contact. The change of morphology between Tectonic melange and olisosrtom melange to fore arc basin is caused by the normal fault contact. Sediment from both melange products deposited in the local basin. |
