This study is a preliminary assessment of an extremely diverse Tortonian (late Miocene) mollusk assemblage from a coral carpet environment preserved at Bontang (East Kalimantan, Indonesia). Even though coral-associated aragonitic faunas are rarely well preserved, the composition of the assemblage described here can be used to address the following questions: (1) How do the mollusk assemblages in coral habitats differ from other habitats, and (2) What is the effect of sampling on estimates of taxon richness? The mollusk assemblage is dominated by predatory snails and includes typical modern coralassociated taxa such as the gastropod Coralliophila and the bivalve Tridacna. Our investigation implies that adequate documentation of Cenozoic mollusk diversity in the Indo-Pacific is even more challenging than previously expected as very large samples are required to capture species richness. Further assessments of fossil faunas from coral-dominated habitats will be required to provide insight to development of Indo-Pacific biodiversity through time.

-The Triassic rocks of the (West) Timor Basin mainly deposited in the marine environment have been identified. The fine-grained clastic and carbonate rocks of this Triassic marine facies are considered to be the most promising source rocks potential in this basin. Geochemical and petrographic data from outcrop samples of the Triassic carbonate of Aitutu Formation are presented in this paper, in terms of the organic maturation, kerogen type, and the origin of the organic matter. Some representative selected samples were subjected to Rock-Eval Pyrolysis, vitrinite reflectance measurement, and thermal alteration index determination as well as bitumen extraction. The extracts were then analyzed by the GC-MS (Gas Chromatography-Mass Spectrometry). The samples were collected from a marine deposit of the Triassic sequence. The TOC (Total Organic Carbon) values of the analyzed samples range between fair and rich level (0.51% -9.16%, wt.%, TOC), whilst the kerogen is dominated by Type II with minor Type III. The organic matter was considered to be predominantly oil/gas prone with lesser gas prone potential. The thermal maturity assessed from T max, TAI, and vitrinite reflectance shows an immature to early peak mature stage. The biomarkers indicate mainly that the organic matter was derived from mixed source rocks facies containing alga debris and higher plant terrestrial origin.

Batuan silisiklastik berumur Trias yaitu Formasi Kanikeh, tersebar di Pulau Seram hingga Pulau Kesui dan Teor dari Maluku hingga Maluku Tenggara. Formasi Kanikeh telah lama dikenal memiliki karakteristik batuan induk yang baik. Pemahaman tentang Formasi Kanikeh masih minim, interpretasi lingkungan pengendapan dan korelasi stratigrafi masih ada perbedaan. Tujuan penelitian ini adalah mendapatkan hasil interpretasi lingkungan pengendapan berdasarkan data terbaru. Metode yang digunakan dalam penelitian ini adalah pengukuran penampang stratigrafi pada empat lintasan pengamatan di daerah Seram Bagian Timur dengan menggunakan pendekatan analisis litofasies dan asosiasi fasies. Hasil dari penelitian ini menunjukkan adanya 9 litofasies, yaitu: Litofasies Batupasir Konglomeratan (Sg); Litofasies Batupasir Lapisan Silangsiur Mangkok (Sp); Litofasies Batupasir Bioturbasi (Sb); Litofasies Batupasir Karbonan (Sc); Litofasies Batupasir Bergelombang (Sw); Litofasies Batupasir Flasser (Sf); Litofasies Batupasir Laminasi Sejajar (Sh); Litofasies Batulumpur Lenticular (Fl); Litofasies Batulumpur Berlapis (Fsc). Deskripsi litofasies tersebut termasuk ke dalam suatu sistem pengendapan pasang-surut (intertidal) yaitu tidal channel, tidal sand flat, tidal sand-mud mixed flat, dan tidal mudflat. Formasi Kanikeh terendapkan dengan sistem pengendapan batuan silisiklastik yang dipengaruhi oleh arus pasang-surut pada lingkungan pengendapan transisi. ABSTRACT - Facies and depositional environment of Kanikeh Formation, Bula Basin, Maluku. The Triassic siliciclastic rocks, Kanikeh Formation are spread across Seram, Kesui, and Teor Island from Molucca to Southeast Molucca. The Kanikeh formation has been known as an excellent source rock. However, its interpretation of the depositional environment and stratigraphic correlation are still poorly understood. This study aims to give a better understanding of the depositional environment. This study consists of Lithofacies descriptions and facies associations of four stratigraphy measuring sections in Eastern Seram Island. The results of this study indicate that there are 9 lithofacies, including conglomeratic sandstone (Sc); Through cross bed sandstone (Sp); Bioturbated sandstone (Sb); Carboniferous sandstone (Sc); Wavy Sandstone (Sw); Flasser Sandstone (Sf); parallel laminated sandstone (Sh); lenticular mudstone (Fl); dan laminated mudstone (Fsc). The lithofacies description is included in four facies associations which are included in a tidal deposition system (intertidal) there are tidal channels, tidal sand flat, tidal sand-mud mixed flat, dan tidal mudflat. Based on the results Kanikeh Formation is deposited with a siliciclastic deposition system influenced by tidal currents within transition deposition environments.

The Triassic aged sandstone from Kanikeh Formation, are spread across Seram, Kesui and Teor Island. The Kanikeh formation has been known as excellent source rock, however, reservoir characteristics of this formation are unknown. This paper aimed at the diagenetic influence on reservoir characteristics was investigated for the Carnian-Norian sandstone sequence in the Eastern Seram. This study comprises two methods which are petrographic analysis and Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS). The petrographic analysis shows the sandstones of the Carnian sequence in the Eastern Seram are lithic wacke, litharenite, arkose. SEM-EDS observations showed that the minerals belong to the silica group derived from the silica minerals, feldspar, clay, and mica minerals. The silica mineral is a quartz grain. The observed feldspar mineral is K-Feldspar in the form of granules. The most dominant clay minerals are smectite, illite, chlorite, kaolinite, halloysite. The observed mica group is muscovite. Diagenetic identified in these sandstones include compaction, cementation by calcite, quartz, clay minerals, iron oxides, dissolution, and alteration of unstable clastic grains, tectonically induced grain fracturing. Unstable clastic grains like feldspars suffered considerable alteration to clay minerals. Based on characteristics of the Diagenetic, the Carnian-Norian sandstones in the study area have a negligible reservoir characteristic.

Batupasir Formasi Kanikeh yang berumur Carnian-Norian, tersebar dari Maluku hingga Maluku Tenggara. Formasi Kanikeh terendapkan pada lingkungan transisi dan karakter reservoir pada formasi ini masih belum banyak diungkap. Studi ini fokus terhadap pengaruh diagenesis terhadap karakteristik reservoir pada sikuen batupasir berumur Carnian-Norian di Daerah Seram Bagian Timur, Maluku. Metode yang digunakan adalah pengamatan petrografi dan Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS). Hasil pengamatan petrografi menunjukkan batupasir pada Seram Bagian Timur ini didominasi oleh lithic wacke, litharenite, dan arkose. Dari pengamatan SEM-EDS, mineral yang teramati termasuk dalam grup silika yang berasal dari kelompok mineral silika, feldspar, mineral lempung, dan mineral mika. Kelompok silika berupa butiran kuarsa. Kelompok feldspar yang teramati adalah K-feldspar yang berupa butiran. Kelompok mineral lempung paling dominan muncul di antaranya smektit, illit, kaolinit, halloisit. Kelompok mika yang teramati adalah muskovit. Diagenesis yang terjadi pada batupasir ini termasuk kompaksi; sementasi kalsit, kuarsa, mineral lempung, dan oksida besi; pelarutan; dan rekahan pada butiran karena tektonik. Butiran klastik yang tidak stabil, seperti feldspar mengalami alterasi menjadi mineral lempung. Berdasarkan karakteristik diagenesis tersebut, batupasir Formasi Kanikeh pada daerah ini memiliki karakter reservoir yang dapat diabaikan.Katakunci: Diagenesis, Kanikeh, reservoir, Seram.