Analysis Diagenesis and Porosity Values of Carbonate Rocks of the Wonosari Formation in Krakitan Village, Bayat

Abstract

Diagenesis is a process that are common in sedimentary rocks especially in carbonates. The process may cause an increase or decrease in the porosity of rocks depending on their types. The types of diagenesis varies, depends on the environment of where they happened. This variation of the environment will affecting the type of the diagenesis that will affecting the pore types and certain diagenesis characteristics of the rocks. The purpose of this research is to understand the type and the role of diagenesis to the porosity of rocks from Wonosari Formation. The study site is located at 458119 South, 9143867 West, at the northern part of Jiwo Barat hills in Bayat, Central Java. We implement field investigation methods by conducting a measured stratigraphy of the rock layers, describe the rock layers in hand specimen, and also laboratory analysis including petrographic analysis to estimate the porosity value of the samples. In general, samples taken at Wonosari Formation of Jiwo Barat experienced intensive leaching diagenesis processes and calcite cementation. The type of porosity observed in the samples are channel and vuggy. The porosity value is increase in the samples with leaching diagenesis and decrease in the samples with cementation diagenesis.