Late Miocene Molluscan Stage of Jawa Insight from New Field Studies

2nd Transdisciplinary Research on Environmental Problems in Southeast Asia

地球科学;生态环境科学

Aswan^1 ; Sufiati, Elina^2 ; Kistiani, Desty^2 ; Yudi Abdurrahman, Irman^2 ; Dwijo Santoso, Wahyu^1 ; Rudyawan, Alfend^1 ; Zin Oo, Thaw^3

Geology Department, Faculty of Earth Sciences and Technology, Institute of Technology Bandung, Jalan Ganesa 10, Bandung, Indonesia^1

Geological Museum Bandung, Jalan Diponegoro No.57, Bandung, Indonesia^2

Geology Department, East Yangon University, Yangon Division, Thanlyin Township, Myanmar^3

关键词: Early pleistocene;    Jawa;    Late Miocene;    Molluscan;    Neo genes;    Planktonic foraminifera;    Sedimentary deposits;    Sedimentary sequence;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/71/1/012031/pdf
DOI  :  10.1088/1755-1315/71/1/012031

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

Neogene stratigraphic stages of Jawa based on molluscan index fossils firstly compiled by Oostingh in 1938. This concept is widely used by palaeontologists, both for application in and outside Jawa. Based on the estimated ages of previous researchers the Neogene stages from old to young are: Rembangian stage considered equivalent to Early Miocene, Preangerian stage (Middle Miocene), Odengian stage (Upper Miocene), Cheribonian stage (Early Pliocene), Sondian stage (Late Pliocene) and Bantamian stage (Early Pleistocene). Further studies to determine a more precise age of each stage are often difficult due to lack of planktonic foraminifera fossils and other age index fossils within the sedimentary deposits that are mostly shallow marine sediments. This study focuses to re-examine the age of sediments of Preangerian and Odengian Stages on new field studies. The type locality and rock units that are correlated with these stages are part of the well-exposed Nyalindung formation around Sukabumi area. The studies were carried out in four main fosill-rich sedimentary sequences that are exposed along Cijarian, Citalahab, Ciangsana and Ciodeng rivers. More detailed ages were obtained from the sediments. The exposed sequences along the Ciangsana and Citalahab rivers are Middle Miocene (N9-N14) while the Cijarian and Ciodeng rivers sequences were deposited between Middle to early Late Miocene (N9-N16). The Nyalindung formation in the Cijarian river also contain Vicarya sp, an index fossil that marks a rise in sea level in the Miocene (12 Ma), which previously only been reported from the Ciangsana river sediments.