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Turbidite Facies of the Halang Formation in Ajibarang Area, Central Java
Full text linkDOI: 10.17014/ijog.v6i1.112An understanding of deepwater turbidite sediments is very important mainly dealing with the determination of a reservoir geometry. The problem arising in the turbidite sediment geometry is very complex and varied, and its existence depends on how, when, and type of its environment. In Central Java, the broad turbidite sediment distribution of the Halang Formation is needed to be observed its facies association. This paper will discuss the turbidite facies of Halang Formation in the Ajibarang area. The method used to analyze the turbidite facies is by measuring stratigraphic sections and observing the lithofacies characteristics to reconstruct its depositional environment. The Halang Formation outcrop in the Ajibarang area is dominantly composed of alternating sandstone and claystone or marl. Based on the observation, the turbidite facies of Halang Formation, in the Ajibarang area, was deposited on a submarine fan system at the middle fan of suprafan lobes. Compiling with the previous studies, the source of the Halang Formation is indicated to be derived from the south southwest.</p
SEDIMEN SEBAGAI ARSIP PERUBAHAN LINGKUNGAN
Full text linkPerubahan lingkungan di wilayah pesisir teluk Jakarta akan berpengaruh pada kualitas lingkungan perairan di Teluk Jakarta. Hal tersebut akan terekam oleh inti bor sediment yang terdapat di Teluk Jakarta. Penelitian ini merupakan penelitian pendahuluan yang bertujuan untuk meneliti perubahan pola sedimentologi dari conto inti bor sedimen dari teluk Jakarta. Dalam studi pendahuluan ini dilakukan analisis LOI untuk mengetahui kadar material organik dan juga analisis mikropaleontologi
Hasil analisis pada Bor GC 21 menunjukkan adanya korelasi yang baik antara peningkatan kadar material organic dan penurunan kadar karbonat dengan perubahan kandungan fosil. Meningkatnya kandungan foraminifera plankton pada kedalaman 13-14 cm diikuti menghilangnya ostracoda pada kedalaman 12-13 cm kemungkinan berkaitan dengan letusan Krakatau 1883.
Kata Kunci : sedimen, inti bor, lingkungan, Teluk Jakarta.
The environtmental changes around Jakarta coastal area will influence the environmental quality of Jakarta bay waters. Marine sediment core in the Jakarta bay will records these changes. This preliminary research will study the sedimentology pattern of marine sediment located at Jakarta bay. In this study LOI sediment core will be analysed for LOI and micropaleontology. The result from core GC 21 shows that increasing material organic content coincide with decreasing the content of carbonate and microfossil. Increasing foraminifera plankton at 13-14 cm depth coincide with disappearance of ostracode at 12-13 depth, this suppose that related to the Krakatau eruption on 1883. However the further research is still required to convince the result.
Keywords : sediment, core bor, environment, Jakarta Ba
STRATIGRAFI DAN SEDIMENTASI ENDAPAN KUARTER DAERAH PURING DAN SEKITARNYA. GOMBONG SELATAN
Full text linkPenelitian lapangan dan laboratorium telah dilakukan untuk mempelajari stratigrafi dan sedimentasi endapan Kuarter di daerah Puring, Gombong Selatan. Penelitian lapangan dilakukan dengan pemboran inti, sedangkan laboratorium terdiri dari paleontologi dan granulometri.Hasil analisa stratigrafi menunjukkan bahwa sedimen Kuarter diendapkan diatas endapan Tersier Formasi Halang yang dapat dibedakan menjadi 4 satuan litologi dari bawah keatas yaitu satuan pasir- lempung, satuan pasir I, satuan lempung dan satuan pasir II.Hasil analisis granulometri menunjukkan bahwa satuan pasir I dan II diperkirakan sebagai pematang pantai, yang diendapkan pada lingkungan pantai yang dipengaruhi oleh sungai. Berdasarkan analisa paleontologi satuan pasir lempung dan satuan lempung diendapkan pada lingkungan laut dangkal
Carbonate Facies and Sedimentation of the Klapanunggal Formation in Cibinong, West Java
Full text linkDOI:10.17014/ijog.v1i3.196The limestone of Klapanunggal Formation is well exposed in the area of Cibinong and its surrounding,West Java. Detailed Observation of carbonate rock has been conducted in this area and aims to studythe carbonate facies and its growth environment. The method used in the field is the detailedinvestigation, while mikropaleontology and petrogaphic analysis conducted in the laboratory. Theresult of this study indicate that the carbonate rocks in the study area consists of four facies. namely:(1) boundstone facies, (2) packstone facies, (3) rudstone facies, and (4) limestone breccia facies. Basedon these data be interpreted that the boundstone facies was deposited in the reef front to reef crestenvironment, packstone facies developed on the lower slope, upper slope, and back-reef lagoonenvironment. Rudstone facies formed on the reef front, and breccia limestone facies were formed inthe lower slope. Geographically, the position of the carbonate body environment that is at the reeffront, upper slope and lower slope is expected to be in the North – North East while the reef crest andback reef lagoon is on the South – Southwest.</p
Studi Potensi Batuan Induk pada Sub Cekungan Banyumas dan Serayu Utara
Full text linkKajian yang dilakukan di daerah Banjarnegara, Wonosobo dan Kebumen bertujuan untuk memperoleh data permukaan endapan klastik berbutir halus serta karakteristik litofasiesnya yang diduga berpotensi sebagai batuan induk. Sebanyak 9 conto dianalisa kandungan material organik karbonnya (TOC). Hasil analisa tersebut memperlihatkan bahwa nilai TOCnya berkisar antara 0,08 % dan 1,42 %. Berdasarkan hasil tersebut, didapatkan 2 conto berpotensi baik dan 3 conto berpotensi sedang untuk dapat membentuk hidrokarbon, sedangkan 4 conto lainnya tidak berpotensi untuk membentuk hidrokarbon. Pyrolisis rock-eval dilakukan terhadap 5 conto yang berpotensi membentuk hidrokarbon, dan mempunyai nilai HI berkisar antara 26 dan 95 mgHC/gTOC. Berdasarkan nilai parameter evaluasi batuan induk HI (Waples, 1985), conto tersebut berada dalam fasies organik CD dan D. Batuan induk tersebut dapat menghasilkan gas dalam kuantitas kecil. Hasil sementara dari pengamatan singkapan menunjukkan bahwa batuan klastik berbutir halus di daerah Banjarnegara diduga diendapkan dalam lingkungan dysaero
POTENSI DAN KARAKTERISTIK BATUAN SUMBER HIDROKARBON DARI CONTO PERMUKAAN DI DAERAH KARAWANG, JAWA BARAT
Full text linkABSTRAK Penelitian batuan sumber hidrokarbon yang dilakukan di daerah Karawang bertujuan untuk memperoleh data permukaan endapan klastik berbutir halus serta karakteristik litofasies yang diduga sebagai batuan induk hidrokarbon. Metode yang dipakai adalah penelitian lapangan dan laboratorium. Penelitian lapangan meliputi pengamatan stratigrafi detil dan pengambilan conto batuan. Analisa laboratorium terdiri dari analisa kandungan TOC dan pirolisis Rock Eval. Hasil analisa TOC terhadap 17 conto batulempung yang diambil dari Formasi Jatiluhur menunjukkan nilai berkisar antara sebesar 0,53-2,02%. Tmax delapan conto sebesar 422o-432oC menunjukkan tingkat kematangan thermal yang belum matang. Delapan conto lainnya masuk dalam kategori matang dengan nilai Tmax sebesar 436o-462oC, sedang satu conto dengan nilai Tmax 467oC menunjukkan kategori pasca matang. Nilai HI berkisar antara 33-143 mg HC/TOC, dan termasuk dalam Fasies D, CD dan C. Berdasarkan nilai tersebut, batuan sumber di daerah penelitian dapat menghasilkan gas dengan kuantitas kecil. Potensi hidrokarbon di daerah penelitian menunjukkan kategori kekayaan material organik rendah hingga menengah, dengan kerogen yang termasuk type II dan III. Kualitas batuan sumber berdasarkan nilai HI termasuk dalam kategori gas prone
Depositional Environment of the Batuasih Formation on the Basis of Foraminifera Content: A Case Study in Sukabumi Region, West Java Province, Indonesia
Full text linkDOI: 10.17014/ijog.v7i2.139The research was carried out on the sediments of the Batuasih Formation cropping out at Batuasih Village, Cibatu River, Padaarang Sukabumi. Data obtained from field observation, as well as foraminifera and sedimentology analyses conducted in the laboratory, were used to interpret its depositional environment. The investigation was focused on planktonic and benthic foraminiferal assemblages for depositional environment interpretation that might not be used by previous researchers. The Batuasih Formation is composed of black shaly claystone, where the lower part is rich in clay ball, and limestone intercalations in the upper part of the formation. In Cibatu Section, no clay balls is recognized in the lower part, but intercalations of limestone still occur. However, a contrast difference is found in Padaarang section, where green claystone interbeds with fine-grained sandstone. The Batuasih Formation conformably overlies the Walat Formation containing conglomerate. Foraminifera fossil found in the Batuasih Formation consists of bad preserved black benthic and planktonic foraminifera, more abundant towards the lower part of formation. Based on foraminifera assemblage comprising genus Uvigerina, Cibicides, Elphidium, Operculina, Bulimina, Bolivina, Eponides, and Neoconorbina, supported by sedimentology data, the Batuasih Formation was deposited in a shallow to deep marine environtment, during Early Oligocene (P19) time. Upwards to be the Rajamandala Formation, the depositional environment tends to be shallower gradually.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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