ENVIRONMENTAL CONTROL OF NANNOPLANKTON AND FORAMINIFERA ASSEMBLAGES IN MADURA WATERS

Nannoplankton is widely used for determining age of sediments following the other microorganism foraminifera since the late 1960s; and it was started being used for marine geography study in the year of 1984. This topic interests to be done in Indonesia as one of the tropic region. The research covered a study about environment using nannoplankton and it is compared with the same study using foraminifera. Methods of the study include: (1) collecting secondary data and samples; (2) collecting field data record; (3) laboratory analyses upon sediment samples to determine the content of nannoplankton and foraminifera (micropaleontology analyses), the texture and composition of minerals (by means of grain size, petrology megascopic and microscopic analyses) (4) intergrating all of the analyses result. Madura waters can be divided into four zones, among all : (I) inner shelf (water depth less than 30 m) in Madura Strait, (II) inner shelf in open marine north of Madura, (III) outer shelf (water depth 30 to 80 m) in Madura Strait, and (IV) outer shelf in open marine north of Madura. Inner shelf in the Madura Strait (Zone I) is characterized by less than 1% sediment of nannoplankton (are made up of Gephyrocapsa oceanica); rare assemblages of benthic foraminifera only (Ammonia spp., arenaceous carbonate test taxa such as : Ammobaculites spp., Textularia agglutinans, Haplophragmoides spp., and milliolidae). Inner shelf open marine north of Madura (Zone II) yielded few nannoplankton assemblages, dominated by Gephyrocapsa oceanica with low number of Emiliania huxleyi, Helicosphaera carteri, H. pavimentum, H. walichii and Pontosphaera spp; common foraminifera assemblages consist of rare planktic Globigerinoides ruber, G. trilobus sacculiferus, G. conglobatus with one or two dominant benthic (Elphidium spp, Ammonia spp., Pseudorotalia spp., Asterorotalia spp.). Outer shelf of Madura Strait (Zone III) assigned by common nannoplankton assemblages, dominated by Gephyrocapsa oceanica and Emiliania huxleyi with few to common Helicosphaera carteri, H. pavimentum, H. wallichii, Pontosphaera spp., Calcidiscus leptoporus, Umbellosphaera irregularis and Umbilicosphaera spp.; common benthic foraminifera assemblages Elphidium spp, Ammonia spp., Cibicides spp., Pseudorotalia spp., and Asterorotalia spp. with rare planktic Globigerinoides ruber, G. trilobus sacculiferus, and G. conglobatus. In the outer shelf open marine north of Madura (Zone IV), it is recorded abundant of nannoplankton Gephyrocapsa oceanica, Emiliania huxleyi, Helicosphaera carteri, H. pavimentum, H. wallichii, Pontosphaera spp., Discoaster spp., Calcidiscus leptoporus, Umbellosphaera irregularis, Umbilicosphaera spp.; the presence of moderate divers and abundance of planktic foraminifera Globigerina calida, Pulleniatina obliquiloculata, Orbulina universa, Hastigerina aequilateralis with common abundance benthic Bolivina spp., Bulimina spp., Cibicides spp., Pseudorotalia spp., Asterorotalia spp., Lenticulina spp., Cassidulina spp., Siphonina spp., the presence of Uvigerina spp. are noted. The most significant physical environment parameter of each zone controlling appearance of marker species and abundancy of microorganism assemblages are bathymetry, salinity, temperature, pH and sediment due to fluvial supply. Keywords : nannoplankton, foraminifera, environment, marker species, Madura Waters Nannoplankton telah digunakan secara luas untuk penentuan umur sedimen di samping mikroorganisme lain, foraminifera, sejak tahun 1960-an; dan mulai digunakan untuk studi geografi laut pada tahun 1984. Kajian ini menarik untuk dilakukan di Indonesia yang termasuk daerah tropis. Studi ini mempelajari perubahan lingkungan berdasarkan analisis nannoplankton, dibandingkan dengan foraminifera yang umum dipakai untuk kegunaan sejenis. Metode penelitian mencakup : (1) pengumpulan data sekunder dan sampel; (2) pengambilan data lapangan; (3) pekerjaan laboratorium meliputi analisis mikropaleontologi dan petrologi ; serta (4) integrasi seluruh hasil analisis. Perairan Madura dapat dibedakan menjadi empat zona, yaitu: (I) Paparan dalam (kedalaman muka air laut kurang dari 30 m) di Selat Madura; (II) Paparan dalam pada laut terbuka di Perairan Utara Madura; (III) Paparan luar (kedalaman muka air laut 30 hingga 80 m) di Selat Madura; dan (IV) Paparan luar pada laut terbuka di Perairan Utara Madura. Paparan dalam di Selat Madura (Zona I) dicirikan oleh kumpulan nannoplankton kurang dari 1% total sedimen (Gephyrocapsa oceanica); foraminifera bentik jarang (Ammonia spp., cangkang gamping pasiran seperti Ammobaculites spp., Textularia agglutinans, Haplophragmoides spp., dan miliolida). Paparan dalam di laut terbuka (Zona II) dicirikan oleh nannoplankton kurang melimpah yang didominasi oleh Gephyrocapsa oceanica dengan beberapa Emiliania huxleyi, Helicosphaera carteri, H. pavimentum, H. walichii, Pontosphaera spp; foraminifera cukup melimpah dengan plankton Globigerinoides ruber, G. trilobus sacculiferus, G. conglobatus dalam jumlah jarang serta satu atau dua jenis bentik yang dominan (Elphidium spp, Ammonia spp., Pseudorotalia spp., Asterorotalia spp.). Paparan luar di Selat Madura (Zona III) dicirikan oleh nannoplankton dalam jumlah yang umum, didominasi oleh Gephyrocapsa oceanica dan Emiliania huxleyi dengan beberapa Helicosphaera carteri, H. pavimentum, H. wallichii, Pontosphaera spp., Calcidiscus leptoporus, Umbellosphaera irregularis, Umbilicosphaera spp.; foraminifera bentik jumlahnya umum seperti Elphidium spp, Ammonia spp., Cibicides spp., Pseudorotalia spp., dan Asterorotalia spp. dengan foraminifera planktik seperti Globigerinoides ruber, G. trilobus sacculiferus, dan G. conglobatus dalam jumlah jarang. Di paparan luar laut terbuka (Zona IV) teridentifikasi nannoplankton yang melimpah seperti Gephyrocapsa oceanica, Emiliania huxleyi, Helicosphaera carteri, H. pavimentum, H. wallichii, Pontosphaera spp., Discoaster spp., Calcidiscus leptoporus, Umbellosphaera irregularis, Umbilicosphaera spp.; dan beragam jenis foraminifera planktik seperti Globigerina calida, Pulleniatina obliquiloculata, Orbulina universa dan Hastigerina aequilateralis serta foraminifera bentik seperti Bolivina spp., Bulimina spp., Cibicides spp., Pseudorotalia spp., Asterorotalia spp., Lenticulina spp., Cassidulina spp., Siphonina spp. dan Uvigerina spp. dalam jumlah yang umum. Parameter lingkungan fisik yang paling berpengaruh dalam mengontrol kehadiran spesies penunjuk (indikator) dan kelimpahan kumpulan mikroorganisma adalah: batimetri, salinitas, temperatur, pH dan sedimen. Katakunci : nannoplankton, foraminifera, lingkungan, spesies penunjuk, Perairan Madur

FORAMINIFERA ASSEMBLAGES AS A MARKER OF MUD ERUPTION SOURCE IN CIUYAH, CINIRU – KUNINGAN, WEST JAVA

Mud eruptions that rise claystone to sandstone-size fragments, liquid, gas, and heat to the surface have been identified in Ciuyah, Ciniru District, Kuningan. Field observation and sampling were conducted on host rock as well as mud in Ciuyah. Forty-two planktic and forty-two benthic foraminiferal species were identified in rock samples; while 89.28% of them are recorded in mud samples. Foraminifera contained in claystone and sandstone of Pemali and Halang Formations reveals the age of Middle to Late Miocene. Based on their stratigraphic ranges, planktic foraminifera assemblages in mud represent four age-marker groups, there are: older than Zone N.10 / Middle Miocene (indicated by the appearance of Globorotalia archeomenardii), ranges of Zone N.11 – N.12 / Middle Miocene (marked by the appearance of Globorotalia fohsi lobata and Globorotalia praemenardii), ranges of Zone N.13–N.14 / Middle Miocene (Globorotalia siakensis and Globorotalia mayeri), and ranges of Zone N.15–N.17 / Late Miocene (Globorotalia acostaensis acostaensis and Neogloboquadrina dutertrei dutertrei). Benthic foraminifera can be grouped into outer neritic and bathyal typical assemblages. That several age-marker planktic foraminifera groups mixing and deep marine typical benthic occurrence in mud samples is produced by reworking process during turbidity sedimentation, as well as erosion and elution of base- and side-rock composed by Pemali and Halang Formations.Semburan lumpur yang membawa fragmen-fragmen berukuran batulempung hingga batupasir, cairan, gas dan panas ke permukaan telah teridentifikasi di Ciuyah, Kecamatan Ciniru, Kuningan. Observasi  lapangan dan pengambilan sampel dilakukan terhadap batuan induk serta lumpur di Ciuyah dan sekitarnya. Empat puluh dua spesies foraminifera planktik dan empat puluh dua spesies bentik teridentifikasi dalam sampel batuan; dengan 89,28% di antaranya terekam dalam sampel lumpur. Foraminifera yang terkandung dalam batulempung dan batupasir Formasi Pemali dan Halang menunjukkan umur Miosen Tengah hingga Akhir. Berdasarkan rentang stratigrafinya, kumpulan foraminifera planktik dalam lumpur menunjukkan empat kelompok penanda umur, yaitu: lebih tua dari Zona N.10 / Miosen Tengah (ditunjukkan oleh kehadiran Globorotalia archeomenardii), rentang Zona N.11 - N.12 / Miosen Tengah (ditandai oleh kehadiran Globorotalia fohsi lobata dan Globorotalia praemenardii), rentang Zona N.13 -N.14 / Miosen Tengah (Globorotalia siakensis dan Globorotalia mayeri), dan rentang Zona N.15 - N.17 / Miosen Akhir (Globorotalia acostaensis acostaensis dan Neogloboquadrina dutertrei dutertrei). Foraminifera bentik dapat dikelompokkan dalam kumpulan neritik luar dan batial. Beberapa kelompok penanda umur foraminifera planktik dan kehadiran bentik laut dalam pada lumpur dihasilkan oleh pengerjaan ulang selama sedimentasi turbidit, serta erosi dan elusi batuan dasar dan batuan samping yang tersusun oleh Formasi Pemali dan Halang

The Dynamics of the Developing Calcarenite Member of Pamutuan Formation In Cintaratu Area, Pangandaran, West Java

The investigated area is located in Cintaratu, Parigi District, Pangandaran Regency in the Southeastern part of Southern Mountain of West Java. The rock unit in the investigated area is described as the Calcarenite Member of the Pamutuan Formation. The present study applying detailed lithologic and paleontologic description reveals five lithologic units. Combining the field method with microscopic analysis leads to the verification of the age and environments of this carbonate rocks. The study concludes the development of reef complex in Early Mid Miocene, followed by the high energy of the dynamic environment producing the fragments of the lime clasts embedded in the packstone, indicates the deposition in the fore slope. The regression took place and moved the deposition environment to the low-energy condition at the back of the reef, producing bioclastic packstone containing larger foram. Rising seawater level amplified the dynamics of the seawater in mid-Middle Miocene. The formation of planktic packstone marked an initial transgression phase that was well-represented as regional transgressive in Southeast Asia. This phase continued until interbedded calcareous mudstone and sandstone were produced. Finally, in Late Mid Miocene the sea level regressive accumulated coarse materials of calcarenite grain size containing fragments of larger foram within shallower deposition environment. The NNW-SSE elongated distribution of five units of Calcerinite Member pointed out the configuration of Middle Miocene coastal line. In Early Middle Miocene, various carbonate rocks formation was primarily controlled by tectonic activities. Afterward, the rock deposition affected by the regional sea level rise and drop during Mid to Late Middle Miocene. The detailed description of the Calcarenite Member, therefore, contributed to the understanding of the paleogeography of Mid Miocene age and the dynamics of the environmental deposition

The geologic potentials of Riau Islands Province and its development design

Geologically Riau Islands is located in the topography of the old stadium erosion. The morphology is characterized by smooth hills with convex slopes and alluvial plain consisting of the erosion products. The morphology exhibits the remnants of peneplain that submerged at ca 13,000 BP now forming Sunda Shelf with the average depth of 120 meters. The irregular coast’s line of almost all the islands in Riau Islands characterized the submerged old morphologic stadium. The lithology consists of granites and metasediments. Granites contain various types of economic minerals. The weathered granites produce bauxite, kaolin and quartz sands. The metasediments are generally soft resulting in the formation of valleys suitable for agriculture and settlements due to the availability of surface and subsurface water. Irregular coastal line provides the bays for harbors. The geological potentials to be developed therefore consists of the provision of stable plain and resistance to landslide and earthquake, the bays suitable for various marine industries, granites for building materials, and base metals. The submarine hydrocarbon basins produce oil and gas. Geologically Riau Islands is very unique because it represents the remnants of the peneplain of Jurassic and Cretaceous age of about 63 to 181 years old now becoming the Sunda shelf which is the largest in the world. This region is very good when developed as an industrial area, trade, and marine tourism  Keywords: Riau Islands, geologic potentials, granites, submerge, marine touris

KELIMPAHAN FORAMINIFERA BENTIK RESEN PADA SEDIMEN PERMUKAAN DI PERAIRAN TELUK JAKARTA

Perairan Teluk Jakarta merupakan wilayah perairan dangkal dengan kedalaman perairan sangat bervariasi, umumnya memiliki kedalaman 30 meter meskipun di beberapa lokasi hingga 70 meter seperti di utara Pulau Pari dan di utara Pulau Semak Daun. Habitat  foraminifera terdiri dari semua kedalaman laut dari tepi pantai sampai pada laut dalam. Secara umum, spesies  bentik hidup pada kedalaman tertentu. Penelitian ini dilakukan untuk mengetahui kelimpahan dan jenis-jenis foraminifera bentik resen yang terdapat pada sedimen permukaan di perairan Teluk Jakarta. Sebanyak 25 sampel sedimen permukaan yang diambil dari  25 buah core milik Pusat Penelitian dan Pengembangan Geologi Kelautan yang berada di dalam cold storage di Cirebon. Sampel yang diperoleh dianalisis jenis sedimennya dan kandungan foraminifera bentik resen didalamnya. Jumlah yang ditemukan 85  spesies yang termasuk dalam 42 genus. Spesies yang banyak melimpah ditemukan di perairan iniOperculina ammonoides (Gronovlus), Elphidium indicum (Cushman),Planulina  floridana (Cushman) dan Asterorotalia trispinosa (Thalmann). Jenis sedimen yang mendominasi perairan Teluk Jakarta adalah lempung ( 21 stasiun) dan lanau  (4 stasiun)