ANALISIS PALEOEKOLOGI BERDASARKAN FOSIL FORAMINIFERA BENTONIK PADA FORMASI KEREK DI DAERAH WONOSEGORO, DAN SEKITARNYA, KECAMATAN WONOSEGORO, KABUPATEN BOYOLALI, PROVINSI JAWA TENGAH

Abstract

The Kerek Formation at the research site is generally composed of two rock units, interbedded carbonate sandstone and carbonate mudstone Kerek (a) and interbedded carbonate sandstone and carbonate siltstone (b) indicating that the location of the deposition is a marine environment, so it is an ideal location for paleoecological analysis. Benthonic foraminifera is a type of foraminifera that lives by mooring itself using vagile or sesile and lives on the seabed at a certain depth. Paleoecology is an ancient ecological constance or a description of ecological conditions (sedimentary environment, salinity and temperature) in the past. The location of data collection was carried out at five points (Observation Locations) located in the Wonosegoro. The research site consists, interbedded carbonate sandstone and carbonate mudstone Kerek (LP 32, LP 52, LP 71) and interbedded carbonate sandstone and carbonate siltstone (LP 15 and LP 143) which represent the top-middle and battom areas of the two rock units that make up the Kerek Formation. In the paleobatimetry analysis, it was obtained that at the five points of the research location there was a bathymetric zone in the form of an inner bathyal (Tipsword, et al. 1966). Paleosalinity based on classification according to Boltovskoy (1991) and Murray (1989; 1991) is in a salinity condition that changes five times, starting from high salinity / hypersaline (>40%) and ending with medium salinity (32-40%). Meanwhile, the paleotemperature condition based on the temperature characteristic genus according to Ujetz (1996), there are 6 temperature changes with the initial phase of medium temperature (10 – 20 C), in the middle phase there is a change to cold (<10) and closed with the final phase of medium temperature.