| Penulis/Author |
Dr.Eng. Ir. Akmaluddin, S.T., M.T., IPM. (1) ; M VIRGIAWAN AGUSTIN (2); Ir. Nugroho Imam Setiawan, S.T., M.T., D.Sc., IPM. (3); Ir. Moch. Indra Novian, S.T., M.Eng. (4); Dr.Eng. Ir. Didit Hadi Barianto, S.T., M.Si., IPM. (5); Ir. Esti Handini, S.T., M.Eng., D.Sc., IPM (6); Bani Tiopan Tampubolon (7) |
| Abstrak/Abstract |
The Barito Basin is a Tertiary basin that located along the southeastern edge of the stable Sundaland continent. This study conducted on Bongkang-2 well, that located in Tanjung Area. The Pre-Tertiary sedimentary rocks begin to be found at interval between 3090 m to 3200 m (TD). In previous study, this interval is considered as granodiorite basement rock, the presence of granodiorite fragments in the cutting sample. But based on the result of this study, indicate that the granodiorite fragments that found are not abundant and are thought to be only a rock fragment that embedded in the sedimentary rock matrix. In addition, the presence of fossil content also supports that this interval is sedimentary rock.
Based on petrography and micropaleontology analysis, indicate that the sedimentary basement rock in this well can be divided to three lithofacies. The lower part is composed of lithology in the form of deformed calcareous lithic wacke, which rock was deformed and no fossils found. The middle part is composed of lithology in the form of sandy allochemic limestone, which contains large benthic foraminifera fossils such as Orbitoides sp. and planktonic foraminifera such as Globotruncana cf. arca that indicate Late Cretaceous age. Based on the content of benthic foraminifera fossil, this lithology was form in inner to middle neritic environment or forereef shelf. Last, the upper part is composed of lithology in the form of lithic wacke, which no fossils of large benthic foraminifera found but contains planktonic foraminifera such as Hedbergella cf. holmdelensis and benthic foraminifera fossil, indicated this lithology was form in inner to middle neritic environment. Based on the rock fragment content, it is indicated that these pre-tertiary sedimentary rocks receive sediment supply from the Meratus Mountains. |
