THE APPLICATION OF QUANTITATIVE BIOSTRATIGRAPHY WITH RANKING AND SCALING METHOD,AT THE ROKAN BLOCK, CENTRAL SUMATERA BASIN

• Main Author: FIRDAUS , MUFDI
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/8674
• Institution: Institut Teknologi Bandung

The application of quantitative biostratigraphy with ranking and scaling method was applied in the study area of Rokan Block, Central Sumatra Basin. This probabilistic analysis has the following aims: to compile an optimal and detail biostratigraphic zonation and to assess the reliability of optimum events/taxon for more precise and detailed correlation (based on quantitative biostratigraphic zones) within this study area. Data used in this application based on the composition and distribution of microfossil assemblages or the range of taxon that determined using semi quantitative or quantitative analysis (faunal chart). This distribution data obtained from 10 (ten) selected wells or sections (Well A through Well J). Objectivity of this study is stratigraphic range of the last occurrence (LO) from all the taxon within the well or section. This research applies software of RASC and CASC version 20 (2007). Based on scaled optimum sequences is obtained 8 (eight) quantitative biostratigraphic zones which is characterized by the average last occurrence of optimum events. The eight successive zones are Zone I, Zone II, Zone III, Zone IV, Zone V, Zone VI, Zone VII, and Zone VIII. There are 284 microfossil events of foraminifer and nannoplankton, whereas only 43 events are revealed as being reliable for biozonation and correlation in this study. In the 43 optimum events, there are 6 (six) unique events which can be used as marker of relative age. On the Well A, Well B, Well G are obtained nine quantitative biostratigraphic zones. Well C, Well D, Well F, Well I and Well J have eight quantitative biozonation schemes, while Well H has six zones. Biozonation of the Well E can be divided into six zones and one range zone. In general, eight applicable quantitative biozonation schemes can be applied within north-south correlation section in this study area. This result shows an optimal and high-resolution correlation without contradiction of stratigraphic range between optimum events. The quantitative correlation is more precise and accurate than the conventional zonation. These optimum events are marker zonation boundary of quantitative biostratigraphy on the wells or sections of this study area.