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KONDISI PAELOSALINITAS PADA MIOSEN AKHIR–PLEISTOSEN DI CEKUNGAN JAWA TIMUR UTARA, INDONESIA, BERDASARKAN PERUBAHAN POPULASI NANOPLANKTON Wahyu Dwijo Santoso; Halmi Insani; Rubiyanto Kapid
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 24, No 1 (2014)
Publisher : Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1987.875 KB) | DOI: 10.14203/risetgeotam2014.v24.77

Abstract

Abstract Quantitative biostratigraphy analysis by observing Sphenolithus abies and Helicosphaera carteri could predict paleosalinity changes at a sedimentary basin diachronically. Hyposaline conditions can be investigated from the abundance changes of Helicosphaera carteri and Calcidiscus leptoporus counts. Along this line, the increasing number of Sphenolithus abies demonstrates particular states of normal saline. Paleosalinity changes in the North East Java Basin, from Late Miocene to Pleistocene were identified from the top of Wonocolo Formation to bottom of Ledok Formation. Paleosalinity along this episode was interpreted as hyposaline condition. While at the top of Ledok Formation to Mundu Formation; paleosalinity had changed to normal saline. Furthermore, environmental conditions return to hyposaline when Selorejo Formation sediment was deposited. And during the deposition of Lidah Formation, deposition environment had returned to the normal saline.
Duboisia santeng (BOVIDAE, ARTIODACTYLA) DARI BUMIAYU Suharyogi, Ifan Yoga Pratama; Wibowo, Unggul Prasetyo; Insani, Halmi; Setiyabudi, Erick
Bulletin of Scientific Contribution Vol 17, No 1 (2019): Bulletin of Scientific Contribution GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (711.943 KB) | DOI: 10.24198/bsc.v17i1.20639

Abstract

Telah ditemukan sebuah spesimen fosil tanduk bovidae sebelah kiri pada penelitian lapangan tahun 2016 di Kali Santanaya, Cisaat (Bumiayu). Fosil tanduk tersebut disebandingkan dengan fosil Boselaphus tragocamelus, Tetracerus quadricornis, Bibos palaeosondaicus, Bibos javanicus, Bubalus palaeokerabau, Epileptobos groeniveldtii, dan Duboisia santeng berdasarkan morfologi dan ukurannya. Walaupun merupakan temuan permukaan, namun berdasarkan analisa geologinya disimpulkan berasal dari Formasi Gintung dan berdasarkan biostratigrafi fauna vertebrata dimungkinkan termasuk Unit Fauna Kedung Brubus dengan lingkungan hidup berupa lingkungan hutan yang terbuka.
Quaternary nannoplankton in the Northeast Java Basin Kapid, Rubiyanto; Santoso, Wahyu Dwijo; Insani, Halmi
Berita Sedimentologi Vol 47, No 3 (2021)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (876.714 KB) | DOI: 10.51835/bsed.2021.47.3.357

Abstract

In Indonesia, nannofosils are commonly used for age estimation on Miocene marine sediment, but they are rarely performed on Quaternary sediment. This paper introduces two nannofossil biozones, Martini (1971) and Backman et al. (2012) and the comparison between the two biozones. An uninterrupted interval of marine sediments was described and picked for quantitative nannoplankton analysis. The samples were taken from Ledok Formation to Lidah Formation in Pati Region, Northeast Java Basin. The samples were prepared by quick smear slides method and and analyzed by quantitative field of view method. Martini (1971) biozone can be used to subdivide the Late Miocene–Pleistocene sediments into 5 biozones, but Backman et al. (2012) can be used to classify the same sediments into 8 biozones. The biozone subdivision from Backman et al. (2012) is more detailed than that of Martini (1971) because an updated dating and biozone in the three new dating zone data.