Publications

Four (4) facies associations can be identified based on core data of three shallow wells in the Cikamuning area supported by outcrop observations. From older to younger they are: coral bindstone to rudstone facies association, prograding rudstone to packstone facies association, well bedded turbiditic packstone to grainstone facies association, and thick bedded to massive rudstone to grainstone facies association.The coral bindstone to rudstone facies association is massive to thick bedded, dominated by platy corals that are typically 0.5cm to 1cm thick, embedded within packstone to grainstone matrix. This facies association is interpreted as a reef margin carbonate platform. The prograding rudstone to packstone facies association is generally thick bedded to massive, clast supported, generally coral fragments ranging in size from 1 cm to approximately 5 cm, embedded in packstone to grainstone matrix. The prograding rudstone to packstone facies association is interpreted as reef slope deposit. Field observations indicate that prograding rudstone to packstone facies association onlaps to coral bindstone to rudstone facies association. The well bedded turbiditic packstone to grainstone facies association is characterized by interbedded grainstone and marl, with gradded bedding, parallel lamination, and convolute sediment structures indicative of turbiditic deposits in complete Bouma classic turbidite sequence. Thick bedded to massive rudstone to grainstone facies association is characterized by thick, massive bedded rudstone, with erosional truncation at the base and marl intercalations. Paleontology data indicate that this facies was deposited in deeper water environment (upper bathyal), with debris flow mechanism.Facies reconstruction of coral bindstone to rudstone facies association, prograding rudstone to packstone facies association, and well bedded turbiditic packstone to grainstone facies association indicate that the reef body located on the south-west area progrades northeast. This conclusion is different from previous general view that carbonate deposition system in Rajamandala area was controlled by regional high trending northeastsouthwest, and deepening to the northwest.The forth facies association is characterized by thick bedded to massive rudstone to grainstone facies association, with thin bedded marl or calcareous claystone intercalations. Field observations show that this facies truncates the turbiditic facies indicating higher energy system, however, paleontological data for this interval suggest a deeper water setting.