Publications

The research area is located in the Cilograng area, Lebak District, Banten, about 10 km NW of Pelabuhan Ratu. There are six lithologic units present (from old to young): Tuff-Sandstone, Limestone, Tuff-Sandstone Intercalated with Breccias, Polymict Breccias, Monomict Breccias, Andesite Intrusion and Alluvial. Geological structures developed in this area are E-W trend syncline and anticline, a NNE-WSW trend strike slip fault and an inferred NNE-WSW trend normal fault. The objectives of this research are to identify facies development of the Citarate carbonate rocks and to determine their depositional environments. Field observation, stratigraphic column reconstruction and petrographic analysis were conducted in order to accomplish the research objectives. Microfacies identified in the Citarate carbonate rocks from bottom to top are 1) algae packstone, 2) packstone-grainstone, 3) coral-algae packstone, and 4) foraminifer wackestone-packstone. Algae packstones are dominated by red algae, Lepidocyclina sp. and Spiroclypeus sp. are common, whereas planktonic foraminifers are rare. Packstones-grainstones are dominated by planktonic foraminifers such as Globigerina sp., Globorotalia sp., and Globigerinoides sp. Few benthonic foraminifers (Bulimina sp., and Lenticulina sp.) are also present. Red algae and coral, and subordinate large foraminifers (Miogypisna sp. and Lepidocyclina sp.) are the dominant fragments in coral-algae packstones. Foraminifer wackestonespackstones are dominated by large foraminifers (Lepidocyclina sp., Spiroclypeus sp., and Miogypsina sp.) and rare milliolide. Terrigenous fragments (quartz, plagioclase, andesite lithic) are commonly present in all the four microfacies. Based on textural and faunal assemblages, algae packstone, coral-algae packstone, and foraminifer wackestone-packstone microfacies (first group) are interpreted to be deposited in an open platform back reef, whereas packstone-grainstone microfacies and lower part of foraminifer wackestone-packstone (second group) are in fore reef (toe of slope and open sea shelf) with episodic supply of materials from upper slope (foreslope). The development of packstone-grainstone microfacies suggests at least two possible short drowning periods during the deposition of the Citarate carbonate rocks.