Semiquantitative and Quantitative Biostratigraphy for Correlation and Depositional Environment Analysis Case Study Kedinding Hill Area, Blora, Central Java

Abstract

Biostratigraphy has a significant role in petroleum exploration, especially for correlation and depositional environment analysis. This research located in Kedinding Hill Area, Blora, Central Java, Indonesia. We uses semiquantitative graphic correlation method and quantitative constrained cluster analysis with data taken from measuring section of Kedinding River Track (Section-1) and Kalen River Track (Section-2). Both sections generate crossover in biostratigraphic event sequence that trouble the biozonation determination which resolved by Graphic Correlation Method and generate FAD Neogloboquadrina humerosa – LAD Globorotalia merotumida – LAD Globigerina venezuelana as regional biostratigraphic event sequence. Constrained Cluster Analysis method generate five cluster for depositional environment in both Section-1 and Section-2. Depositional environment of each cluster in Section-1 are: Cluster 1 (unpredictable), Cluster 2 (deep middle – outer shelf), Cluster 3 (outer shelf), Cluster 4 (outer shelf), Cluster 5 (outer shelf – upper slope), meanwhile in Section-2: Cluster 1 (inner shelf), Cluster 2 (deep middle – outer shelf), Cluster 3 (deep middle shelf), Cluster 4 (deep middle shelf), Cluster 5 (outer shelf – upper slope).