The Mechanism and Controlling Factor of Paleogene Rift Basin in the Western Indonesia

Sapiie, Benyamin; Hadiana, Meli
Geology, Institut Teknologi Bandung, Bandung, Indonesia.

During Paleogene time, Western part of Indonesia as part of the Sundaland margin was characterized by the development of widespread rift basin. The Paleogene rifting event is very important for controlling the hydrocarbon distributions in the western part of Sundaland margin for example the most prolific basin such as Sumatra, Java and Kalimantan (Borneo). Understanding tectonics of the rifting phase during Paleogene has been an interesting research subject for many years. For fact, rift-related sediment is the most important elements in petroleum system because they contain the critical lacustrine source rocks and often the reservoir. Therefore, understanding the mechanism and distribution of rift-related sediment is the key for searching future exploration target. However, visualizing and simulating the mechanism of rifting are difficult due to poor geologic information particularly concerning pre-existing basement structure. The main objectives of this paper is present the results of analogue sandbox modeling technique to solve rifting mechanism particularly concerning basement geometries, timing and fault styles with special case of the Central and South Sumatra Basin.

Analogue sandbox modeling has proven to be an effective and relatively inexpensive tool for investigating tectonic processes. Series of sandbox experiments have been run using numerous deformation settings for evaluating rifting mechanism. Three modeling variables affected the results; these are stratigraphic and pre-existing basement fault orientation as well as their geometry (i.e. planar vs. listrict). Lithologic variation affected the total number of faults development. The result strongly show that pre-existing basement fault orientation strongly influenced the fault pattern and distribution. Modeling results concluded that most of the Paleogene rifting was formed as a result of simultaneous extension along pre-existing basement structures with listrict geometry controlled by regional movement of dextral strike-slip fault system.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012