#TITLE_ALTERNATIVE#

• Main Author: HARDIKA C. NUGRAHA (NIM 12007074), R.
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/13779
• Institution: Institut Teknologi Bandung

The research area is located in the north-eastern tip of Mangkalihat Peninsula. Geographically, it is located at 50N, E 108000m-116000m and N 713000m-721500m, on Landas-Labuhan Pinang Area, Sub-District of Sandaran, District of Kutai Timur, East Kalimantan, with approximately 60,5 km2. Geomorphology of research area has certain patterns, such as hills, valley, ridge, and pattern of river flow which are controlled by either lithology or structure. Lineaments in the research area are controlled by joints or fractures in limestone and geological structure. Observed four geomorphology units are Karsts Highland, Anticlinal Ridge, Anticlinal Valley, and Alluvial and Beach Deposits. Stratigraphy of research area is divided into four units, from older to younger are Claystone-Sandstone Unit (Mid-Late Early Oligocene) which is deposited in tidal flat environment, Limestone Unit (Early-Late Oligocene), which was deposited in backreef-shelf environment, Limestone-Marl Unit (Early Miocene-Pliocene), which was deposited in deeper marine environment, and Alluvial and Beach Deposits. Geological structures in research area consist of thrust fault and folds and aged Plio-Pleistocene, with main stress NW-SE trend. Landas Thrust Fault, Km 6 Plunging Anticline, Km 6 Syncline, Batulobang Hills Anticline, and Batulobang Hills Syncline may occurred at the same period. Four Facies Associations in both Limestone Unit and Limestone-Marl Unit, have been identified in research area indicating different depositional environment through geological time. Facies Association Restricted Circulation and Winnowed Edge Platform (Late Eocene to Early Oligocene), deposited in lagoon and barrier bar (e.g. coastal spit, offshore bar, etc). The second Facies Association is Open Circulation Shelf (Late-Early Oligocene), deposited in carbonate shelf with favorable circulation and there was local patch reef developed in this environment. The next Facies Association is Foreslope-Toe of Slope (Early-Middle Miocene) which is consist of turbiditic deposite. The last Facies Association is Deeper Shelf (Middle Miocene-Pliocene). Changes from shallow environment of carbonate deposition to deeper environment indicated backstepping on carbonate platform from Early Oligocene until Pliocene.