Abstract- Two fossil wood were discovered from Sindangsari Village, Sajira District, Lebak Regency, Banten Province, Indonesia. They were preserved within tuffaceous rocks of the Genteng Formation in Early Pliocene age in littoral to terrestrial environment deposition. To identify mineral composition of the silicified wood, XRD analyser method was applied. Result of XRD analyses shows that both of fossil wood are Dryobalanoxylon sp. consist of quartz mineral with d value is 3.358 Å and 3.350 Å Keywords : Dryobalanoxylon, Early Pliocene, Genteng Formation, Quartz
Previous geologists showed that Sentolo Formation was interfingering with Jonggrangan Formation and both of them laid unconformably on Old Andesite Formation. The aim of this study is a deeper understanding of the sedimentation dynamics of Sentolo Formation in order to know its stratigraphic relationship to Old Andesite Formation. Petrographic analysis was used to describe the microfacies. Paleontological analysis was used to know the age and sedimentation environment. Stratigraphic measurement of Sentolo Formation in the section of Niten Stream traverse showed that Sentolo Formation was sedimented on the basin environment (SMF3/FZ1; SMF2/FZ1), deep shelf margin (SMF3/FZ3) to foreslope (SMF4/FZ4). The paleontological data indicate that these sedimentary rocks was depositing during Early Miocene until the beginning of Middle Miocene (N6-N9). Sedimentary rock succession is generally dominated by layered limestone with tuff sandstones that develop well in the lower-middle layer. It indicates that the dynamic of basin sedimentation which formed during that period was influenced by volcanic activity that gradually weakened and caused the basin relatively quiet, producing thick limestone.
The research area is located in the Muara Teweh, North Barito, Central Kalimantan. The cocking coal deposits are well known as they were produced from this area. Upper part of Tanjung Formation is target coal production. The study objectives are to analyze paleoenvironment and to determine the relative age of coal deposits based on palynological data. Preparing palinological analysis used standard procedure by hydrofluoric acid method.Palynomorphs data grouped into six types of ecology, and the sequence is as follows ; fresh water and lowland (41,75 %), brackish water swamp (30,10%), Peat and freshwater swamp (17,96%), marine element (7,77 %), back mangrove (1,46%) and upland element (0,97). Palmae pollen is very dominant, especially from freshwater and peat swamp that grow around coastal area i.e. Dicolcopollis, Proxapertites cursus, Proxapertites operculatus, Longapertites and Palmaepollenites kutchensis. Although marine fossil found, but the frequency less than one percent, that was the evidence of influence sea water to swamp area. The palynomorphs indicate the coal sedimented at upper delta plain. Fossil index of relative age consist of Proxapertites cursus, Proxapertites operculatus, Magnastriatites howardi Verrucatosporites usmensis, Retistephanocolpites , and Ixonantes type which refer to Late Eocene.
Bayah is located in Lebak Regency, Banten Province. This location is chosen due to its abundant mollusk fossils which exposed along the outcrops. The aim of this research is to determine depositional environmental changes using mollusk fossil assemblages. Data obtained from a measured stratigraphic section of Cimanceuri Formation. It is dominated by very fine-fine sandstones with claystone intercalation. A total thickness of measured stratigraphic section is 4.2 meters. There are at least seventeen mollusk associations (bottom-top) consisting of 1) Ringicula arctatoides - Olivella tomlini were obtained. 2) Ringicula arctatoides - Marginella (Cryptospira) ventricosa sangiranensis. 3) Olivella tomlini, 4) Ringicula arctatoides - Olivella tomlini, 5) Ringicula arctatoides, 6) Turritella (Turritella) bantamensis - Scapharca (Scapharca) gedinganensis, 7) Polinices aurantius - Marginella (Cryptospira) ventricosa sangiranensis, 8) Scapharca (Scapharca) gedinganensis, 9) Scapharca (Scapharca) multiformis - Timoclea bataviana, 10) Turritella (Turritella) bantamensis tjicumpaiensis - Ringicula arctatoides, 11) Turritella (Turritella) bantamensis - Ringicula arctatoides, 12) Turritella (Turritella) bantamensis tjicumpaiensis - Turritella (Turritella) bantamensis, 13) Turritella (Turritella) bantamensis tjicumpaiensis - Ringicula arctatoides, 14) Turritella (Turritella) bantamensis - Architectonica sp., 15) Turritella (Turritella) bantamensis tjicumpaiensis, 16) Turritella (Turritella) bantamensis – Turritella (Turritella) bantamensis tjicumpaiensis, and 17) Turritella (Turritella) bantamensis. The condition with the most stable ecosystem is the association of Turritella (Turritella) bantamensis tjicumpaiensis - Turritella (Turritella) bantamensis (Association 12). At least there are seven depositional environmental changes that occur in this research area with two shallowing – deepening cycles : 1) open shallow marine, 2) subtidal – open shallow marine, 3) open shallow marine, 4) open shallow marine – subtidal, 5) subtidal, 6) subtidal – open shallow marine, and 7) open shallow marine.
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