Sebanyak 25 sampel sedimen dasar laut dari Teluk Bone bagian utara, Sulawesi Selatan telah digunakan untuk analisis foraminifera dalam kaitannya dengan jenis sedimen dan kedalaman. Hasil analisis diperoleh 97 spesies foraminifera bentik dan beberapa genera diantaranya mendominasi titik lokasi tertentu, seperti Amphistegina, Operculina, Heterolepa, Brizalina, Elphidium dan Quinqueloculina.Setiap genus mempunyai distribusi spasial tertentu sesuai habitatnya dengan beberapa anomali. Kisaran kedalaman daerah penelitian antara 23 dan 85 m dicirikan oleh kehadiran Amphistegina, Cibicides, Rotalia, Cavarotalia. Dalam kaitannya dengan kedalaman, sebaran foraminifera cenderung terakumulasi di sebelah timur daerah penelitian. Setiap satuan sedimen dicirikan oleh genus foraminifera tertentu. Kata kunci: foraminifera, distribusi spasial, kedalaman laut, jenis sedimen, Teluk Bone, Sulawesi Selatan A total of twenty five surface sediment samples from the northern part of Bone Bay, South Sulawesi were selected for foraminiferal study. The purpose of this study is to recognize spatial distribution foraminifera in relation with water depth and sediment types. There are 97 identified species, some ot them are dominant at certain sites, such as Amphistegina, Operculina, Heterolepa, Brizalina, Elphidium and Quinqueloculina. Each genus has certain spatial distribution as its habitat with some anomalies. The range of water depth is between 23 and 85 m that characterized by Amphistegina, Cibicides, Rotalia, Cavarotalia. In relation to water depth, the distribution of foraminifera tends to accumulate in the eastern part of the study area. Sediment unit is characterized by certain foraminifera genus. Keywords : Foraminifera, spatial distribution, water depth, sediment type, Bone Bay, South Sulawesi.
Karimata Strait is a part of Sunda Shelf connected South China Sea with Malacca Strait, Indian Ocean and Java Sea. This shelf was a large Sunda Land that has been detected by many evidences as records of various paleo-environments. The purpose of this study is to recognize the characteristic community of ostracoda related to the environmental history of this shelf. Three selected cores sediments represented east (A), middle (B) and west (C) parts of Karimata Strait were used for Ostracoda based on standard method on micropaleontology. Additional method was applied of SEM-EDX analysis to abnormal specimens. The result shows that there are 43 species of ostracoda belonging to 34 genera identified in the study area. The highest number of ostracoda is found in Core B, in the middle part of the strait, and the lowest value belongs to the Core A that close to the land of Kalimantan. Several genera of Ostracoda were documented in all cores: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere and Xestoleberis. Vertically, ostracoda are mostly found in the upper part of the cores and decrease or disappear in the lower part of Cores A and C where dominated by black organic materials. It may relate to a wide swampy area before the last sea level rise as part of the history of the SundaShelf about 15,000 years ago. Some major elements (C, CaO, Al2O4, FeO, SiO2, MgOdan SO3 covered or filled abnormal specimens that can provide additional information about environmental changes in the study area, such as Carbon may relate to charcoal from land of Kalimatan and Sumatera Keywords: Ostracoda, subsurface sediment, EDX, environmental changes, Karimata Strait Selat Karimata merupakan bagian dari Paparan Sunda menghubungkan Laut China Selatan dengan Selat Malaka, Samudera Hindia, dan Laut Jawa. Paparan ini merupakan sebuah Dataran Sunda yang luas yang terdeteksi dari bukti-bukti sebagai rekaman berbagai lingkungan purba.Tujuan dari studi ini adalah untuk mengetahui karakteristik komunitas ostracoda berkaitan dengan sejarah lingkungan paparan ini. Terpilih tiga sedimen pemercontoh inti mewakili bagian timur (A), tengah (B) dan barat (C) Selat Karimata digunakan untuk studi Ostracoda berdasarkan metoda standar pada mikropaleontologi. Metoda tambahan adalah aplikasi SEM-EDX terhadap spesimen abnormal. Hasil menunjukkan bahwa di daerah penelitian teridentifikasi 43 spesies ostracoda termasuk dalam 34 genera. Jumlah ostracoda tertinggi ditemukan di Core B dari bagian tengah selat dan terendah di Core A yang berdekatan dengan daratan Kalimantan. Beberapa genera ostracoda ditemukan di semua sampel: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere dan Xestoleberis. Secara vertikal, ostracoda umumnya ditemukan di bagian atas dari core dan menurun atau menghilang di bagian bawah Core A dan C yang di dominasi oleh material organik berwarna hitam. Hal ini kemungkinan berkaitan dengan daerah rawa yang luas dan sebelum muka laut naik terakhir pada sejarah Paparan Sunda sekitar 15.000 tahun yang lalu. Beberapa zat kimia (C, CaO, Al2O3, FeO, SiO2, MgO dan SO3) menutupi atau mengisi spesimen abnormal dapat memberi informasi tambahan tentang perubahan lingkungan di daerah penelitian, seperti karbon mungkin berkaitan dengan arang dari daratan Kalimantan dan Sumatera. Kata kunci: Ostracoda, sedimen bawah dasar laut, EDX, perubahan lingkungan, Selat Karimat
ABSTRAK Sejumlah 14 sampel sedimen dari Teluk Tomini telah digunakan untuk studi foraminifera sebagai komponen sedimen. Sampel diambil menggunakan pemercontoh jatuh bebas pada kedalaman antara 600 dan 1400 m. Studi ini merupakan bagian dari kegiatan pemetaan geologi dan geofisika saat pelayaran perdana kapal riset Geomarin III pada Tahun 2010. Kegiatan ini bertujuan untuk mengetahui geologi bawah dasar laut dalam kaitannya dengan potensi sumber daya mineral dan energi. Bagian atas sampel dari sedimen dicuci dalam ayakan dengan ukuran bukaan 0,063 mm dan kemudian dikeringkan dalam sebuah oven. Sekitar 300 spesimen foraminifera dipisahkan dari pertikel sedimen lainnya menggunakan kuas, air dan mikroskop binokuler. Hasilnya menunjukkan bahwa sebagian besar sampel mengandung foraminifera yang didominasi oleh foraminifera plangtonik (>90%), seperti Globorotalia menardii, Orbulina universa, Globigerinoides ruber dan lain-lain sebagai penciri sedimen laut dalam. Di sisi lain, foraminifera bentik ditemukan dalam jumlah sedikit (<10%) yang diwakili oleh Cibicidoides wuellerstorfi, Ceratobulimina pacifica, Pyrgo sp., Bolivinita quadralatera, Uvigerina peregrina. Karakteristik komunitas foraminifera laut dalam dari Teluk Tomini ini kemungkinan dapat digunakan untuk menginterpretasi lingkungan pengendapan di daerah sekitarnya yang bermanfaat bagi eksplorasi perminyakan.Kata kunci: foraminifera, laut dalam, Teluk Tomini, Sulawesi.
Pollen analysis has been conducted on a 90 cm gravity core taken from the Karimata Strait to reveal pollen facies in marine sediment and Late Holocene environmental changes in the central Sunda Shelf region. The core site is at 32 m water depth and located about 170 km northwest of Bangka Island, Indonesia. Ten samples were collected at 10 cm intervals through the core. The total number of pollen grains counted in the samples varies between very low (<50 grains) to abundant (>200 grains). High frequencies (50-70%) of mangrove pollen are found at 90 to 40 cm indicating that pollen facies in offshore marine sediment may be comparable with those in mangrove forest floor sediment. The core site has been in a neritic environment since its early deposition ca. 1,800 yr B.P. (~150 A.D.) when mangroves vastly grew on the tidal flats of the surrounding islands and they persisted to ca. 700 yr B.P. (~1,250 A.D.). In the middle of this period, a catastrophic event speculatively due to the 535 A.D. Krakatau eruption might have responsible for the decrease of mangroves and the disappearance of benthic foraminifers. The deposition of silicious materials (tephra) due to this eruption might have provided an opportunity for benthic foraminifers to increase their population subsequently. From ca. 700 yr B.P. (~1,250 A.D.) mangroves declined, as indicated by lower frequencies of pollen grain in samples from 30 cm deep upward. It occurred simultaneously with the deposition of coarser sediment and the increase of benthic foraminifer abundance. Interplay of anthropogenic activities, strengthening ENSO cycle, and lowering erosion base level might have been responsible for these environmental changes.
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