#TITLE_ALTERNATIVE#

• Main Author: YUSUF ABDUL MADJID (NIM: 12009014); Pembimbing: Ir. Benyamin Sapiie, Ph D., MUHAMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/18962
• Institution: Institut Teknologi Bandung

East Java Basin is one of many prolific basins in Indonesia. Surface <br /> <br /> <br /> <br /> <br /> <br /> geological mapping in Bulu and surroundings area, Rembang and Blora District is <br /> <br /> <br /> <br /> <br /> <br /> highly expected can give some additional geological data of that basin. A purpose <br /> <br /> <br /> <br /> <br /> <br /> of this research is to understand geological setting and sandstone facies of <br /> <br /> <br /> <br /> <br /> <br /> Ngrayong Member, Tawun Formation in research area. <br /> <br /> <br /> <br /> <br /> <br /> Research area is divided to 4 geomorphological units, there are <br /> <br /> <br /> <br /> <br /> <br /> Kedungrejo Anticlinal Hills, Tlogo Homoclinal Ridge, Pasedan Homoclinal <br /> <br /> <br /> <br /> <br /> <br /> Valley, and Sumbermulyo-Kalijeper Flood Plain which have mature geomorphic <br /> <br /> <br /> <br /> <br /> <br /> stage. <br /> <br /> <br /> <br /> <br /> <br /> Stratigraphy of research area is divided to 5 lithostratigraphy units which <br /> <br /> <br /> <br /> <br /> <br /> are deposited in shallow marine environment, and Aluvial Unit. At Early <br /> <br /> <br /> <br /> <br /> <br /> Miocene, Limestone-Claystone Unit was deposited in inner neritic-middle neritic <br /> <br /> <br /> <br /> <br /> <br /> environment, regression phase was occured at lower part of Middle Miocene <br /> <br /> <br /> <br /> <br /> <br /> when Sandstone Unit is deposited conformably in transition-inner neritic <br /> <br /> <br /> <br /> <br /> <br /> environment. Transgession phase began at upper part of Middle Miocene when <br /> <br /> <br /> <br /> <br /> <br /> Limestone unit is deposited conformably above Sandstone Unit in middle neritic <br /> <br /> <br /> <br /> <br /> <br /> environment. Transgression continuous untill Late Miocene when Marl Unit is <br /> <br /> <br /> <br /> <br /> <br /> deposited in middle neritic - outter neritic. Then, regression phase was occured at <br /> <br /> <br /> <br /> <br /> <br /> Late Miocene – Early Pliocene when Sandstone-Limestone Unit is deposited in <br /> <br /> <br /> <br /> <br /> <br /> inner neritic-middle neritic. <br /> <br /> <br /> <br /> <br /> <br /> Deformation during Plio-Pleistocene form reverse faults as main <br /> <br /> <br /> <br /> <br /> <br /> structures with additional structures are anticline and strike slip faults. Main stress <br /> <br /> <br /> <br /> <br /> <br /> trend is north-south with pure shear mechanism. Geomorphic processes after <br /> <br /> <br /> <br /> <br /> <br /> deformation untill now form the present morphology and deposit the Aluvial Unit <br /> <br /> <br /> <br /> <br /> <br /> unconformably above the older lithostratigraphy units. <br /> <br /> <br /> <br /> <br /> <br /> Based on granulometry and lithofacies analyses, facies association of <br /> <br /> <br /> <br /> <br /> <br /> Ngrayong Member sandstone, Tawun Formation can be divided into 2 sand types, <br /> <br /> <br /> <br /> <br /> <br /> there are beach sand, and wave-zone sand influenced by Wave-Tide Dominated <br /> <br /> <br /> <br /> <br /> <br /> Shallow Marine depositional system.