This study focuses on the analysis of sedimentary facies and ichnogenus variations to determine the palaeogeographic setting of turbidite deposits that are clearly exposed in the surroundings of Majalengka area, West Java, Indonesia. Lithofacies variation in turbidite deposits, identified from detailed stratigraphic sections, were visually presented as a composite log and indicated a thickening and coarsening pattern due to a regressive event. Trace fossils exposed in all stratigraphic levels consist of Thalassinoides, Chondrites, Cruziana and Planolites. They are commonly found in a series of thin to medium bedded fine grained turbiditic sandstones intercalated with shales. Hereinafter, the integration analysis in between sedimentology and ichnology data, the sediment shed into the basin in the submarine channelized related to slope system. Such findings cast no doubt as to whether integrated sedimentary facies and ichnofacies analysis can be viewed as precise methods for sedimentary basin interpretation, in which external parameter, for example magmatic processes, also are considered to play a role.

The research was carried out on the sediment of Middle Bandung Basin. Samples were taken from a depth of 20 meters to 10 meters, each meter a taken sample for analysis. The characteristics of the sample are greenish grey clay deposits with remnant plant material. Research aims to identify climate change based on palynological data from the Pleistocene-Holocene Boundary. The resulting of radiocarbon dating (14C), shows that age of the sample from the 18 m depth around 11820 years BP. Separation of pollen from sediment used an acetolysis method. Palynomorphs are grouped according to their habitat that related to vegetation zone, i.e., lowland forest zone, submontane forest zone, lower montane forest zone, riparian/open herbaceous swamp vegetation, freshwater algae, and Aquatic plant. The composition of pollen shows a succession of vegetation that reflection of climate changes. From Pleistocene-Holocene boundary at least has been recorded seven times of the shift vegetation zone that is evidence of climate change. The oldest sample at 20 m depth is the coldest temperature occurred in zone one at a depth of 20-19 meters that was dominated by lower montane forest vegetation; the event was around Late Pleistocene. The opposite condition occurred in zone seven at 10 meters depth; temperature becomes warmer that indicated by disappears of pollen submontane forest and dominated by lowland forest pollen similar to the current condition. Climate change is also reflected by fluctuations the quantity pollen of open herbaceous swamp vegetation.

AbstrakAlga merupakan mikroorganisme fotosintesis yang tidak memiliki tubuh sejati dengan distribusi lingkungan yang sangat luas dan memiliki banyak fungsi, salah satunya sebagai indikator perubahan lingkungan. Wilayah Cekungan Bandung telah dilakukan penelitian dari beberapa aspek. Akan tetapi, penelitian terutama dari aspek alga yang memperlihatkan perubahan lingkungan belum dilakukan pada daerah tersebut. Penelitian ini dilakukan untuk melihat bagaimana perubahan lingkungan dari endapan sag pond bekas Danau Bandung pada wilayah Cekungan Bandung menggunakan keberagaman alga dan ukuran butir sedimen. Metode asam dilakukan untuk memisahkan alga dari endapan, serta deskripsi batuan dilakukan untuk melihat ukuran butir endapan pada lokasi penelitian. Analisis data dan pemodelan dilakukan dengan mengelompokkan alga sesuai dengan kondisi habitatnya yang terbagi menjadi kelompok Pinnularia, Euglena, Acrinastrum dan Dinobryon. Hasil penelitian menunjukkan bahwa lokasi penelitian mengalami empat kali perubahan lingkungan yang dibagi kedalam zona-zona dan subzona. Setiap zona tersebut diawali dengan kondisi air tercemar yang ditandai oleh peningkatan kelompok Euglena dan ukuran butir halus dari sedimen. Sedangkan pada bagian akhir, perairan memperlihatkan kondisi air normal yang ditunjukkan dengan peningkatan kelompok Pinnularia dan ukuran butir sedimen yang menjadi lebih kasar.AbstractAlgae is known as a photosynthetic microorganism that don’t have a true body with very broad distributions of the environment. Algae have a lot of functions, one of which is an indicator of environmental change. The Bandung Basin area has been researched from several aspects. However, research especially from the algae aspect that shows environmental changes, has not been carried out in this area. This research was conducted to see how the environmental changes of Lake Bandung sag pond deposits in the Bandung Basin by using algae diversity and grain size deposits. The acetolysis method is carried out to see algae content in the sediment, and rock description is carried out to see the grain size of the sediment in the study area. Furthermore, data analysis and modeling were conducted by grouping algae according to environmental conditions which are divided into Pinnularia group, Euglena group, and other groups. The result showed that the study area occurred four times in environmental changes which were divided into zones and subzones. Each zone initially had polluted water conditions characterized by an increase in Euglena groups and the fine grain size of sediment. While in the end, the waters showed normal water conditions characterized by an increase in Pinnularia group and the grain size of the sediment became coarser.

ABSTRAK Formasi Jatiluhur di sekitar Sungai Cileungsi merupakan lingkungan laut dangkal (zona neritik) berdasarkan dominasi foraminifera yang dikandungnya. Namun beberapa penelitian terdahulu menyatakan umur Formasi Jatiluhur yang bervariasi. Penelitian paleobatimetri berdasarkan kumpulan foraminifera kecil diharapkan dapat melengkapi kajian detil yang terkait dengan evolusi daerah ini selama Miosen. Pengambilan 30 sampel sedimen dilakukan secara sistematik pada satu lintasan di sepanjang Sungai Cileungsi. Hasil preparasi sampel sedimen dengan metode hidrogen peroksida menghasilkan 57301 individu foraminifera kecil yang terdiri dari 23276 individu foraminifera plangtonik dan 34025 foraminifera bentonik. Untuk mengetahui paleobatimetri, digunakan rasio foraminifera plangtonik dan foraminifera bentonik kecil. Hasil Rasio P/B berkisar antara 4,4 % -74,0 % menunjukkan paleobatimetri Formasi Jatiluhur berkisar antara zona neritik dalamzona batial atas.

The central role of Mahakam River in the construction of Mahakam Delta is to supply sediment from terrestrial to the river mouth. The river upstream comes from Mount Camaru and the downstream part terminate at Makasar Strait. The surrounding area of the river is overgrown by wet tropical flora that produces pollen. The existence pollen in river sediments as an indicator that sediment came from terrestrial, and foraminifera as an indicator that sediment came from marine. The ratio changes of pollen to foraminifera show that there were differences of sediment source supply. The study was conducted at the river mouth. A shallow core, 200 cm depth, composed of sand and mud and sandy mud, from it taken vertically 11 samples to be analyzed pollen and foraminifera. Sample preparation was using standard methods acetolysis. Meanwhile, sample preparation of foraminifera using Hydrogen Peroxide method. Pollen found in all samples, but foraminifera only found in 8 samples. The data indicating that sedimentation process in the mouth of a river not only gets sediment supplies from terrestrial but also from marine. The quantity of pollen and foraminifera varies vertically. The frequency of pollen much higher than foraminifera that indicates of source sediments dominance came from terrestrial which carried by Mahakam river current. Sonneratia caseolaris pollen continuously found in all samples. Stictogongylus vandiemensis is species foraminifera the most common that followed by Ramulina confossa, both of them come from the sea particularly from the shallow sea.