Open AccessThe Geophysics evidence for fault in Tertiary, Pre-Tertiary deposits rock of Lok Ulo central Java, revealed by Gravity data
Author(s) -
Agus Laesanpura,
Eko Januari Wahyudi,
Wahyudi W. Parnadi,
Welnaldo Abdi Gunawan
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1949/1/012008
Subject(s) - geology , fault (geology) , anticline , sedimentary rock , basement , block (permutation group theory) , seismology , weathering , fault block , geochemistry , paleontology , tectonics , archaeology , geometry , history , mathematics
Lok Ulo is a mayor river extended from north to South Kebumen. Area is famous pre-tertiary basement rock exposed to the surface. The evidence of fault directly is difficult due to in part by thick weathering surface, and second it could be hidden beneath the river. The gravity instrument of micro Gal precision is running to overcome the problem across the area where anticline valley is very subtle. Geology reconstruction is doing, but the geophysics evidence is giving another solution. The anomalous of 2.5 mGal is because of 1.5 km downthrown block. The reconciliation finally deducted, hence the fault is separating two block. Therefore, the thickness of sedimentary rock is becoming into two parts, the west and east. The throw of fault shows significant separating the mélange complex from the others. The gravity data is estimating the fault take deep seated origin. The thickness claystone of tertiary sedimentary is covering the mélange (the older one) and separating each other. By consequence, the sediments formation in east part is thicker than the west.