PEMBENTUKAN UNDAK BATUGAMPING DAN HUBUNGANNYA DENGAN STRUKTUR DIAPIR DI PERAIRAN TANJUNG AWAR-AWAR PACIRAN JAWA TIMUR

Batuan yang mendominasi di daerah penyelidikan adalah batugamping koral Formasi Paciran zona Rembang. Batugamping koral inilah membentuk undak pantai di Tanjung Awar-awar dan di pantai Tuban dan sekitarnya. Terdapatnya undak batugamping ini, menandakan adanya pengangkatan secara vertikal pada satuan batuan ini. Batimetri daerah penyelidikan secara umum merupakan dataran dimana bagian yang dangkal terdapat di bagian baratdaya (ke arah pantai) dengan kedalaman 2 meter dan terdalam ke arah timurlaut dengan kedalaman 9 meter. Sebanyak 7 lintasan seismik berarah timurlaut-baratdaya dan 15 lintasan berarah barat laut â€“ tenggara telah dilakukan dan beberapa titik bor untuk memperkuat penafsiran jenis batuan di setiap lapisan penampang seismik. Struktur geologi yang ditafsirkan dari seismik pantul ini adalah adanya suatu blok batuan yang seperti tersesarkan dan terdorong ke atas sebagai struktur diapir. Struktur diapir ini berkembang sangat baik di penampang seismik ke arah barat daya atau ke arah daratan dimana di sekitar pantainya batugamping ini membentuk undak batugamping. Munculnya struktur diapir ini kemungkinannya dikarenakan bagian selatan dari zona Rembang ini terdapat suatu zona yang mempunyai anomali gaya berat negatif dan karena batugampingnya banyak terpatahkan sehingga sangat mudah diintrusi oleh sedimen yang mempunyai berat jenis kecil. Kata kunci : undak pantai, batugamping koral, struktur diapir, Tanjung Awar-Awar Jawa Timur The study area is dominated by coral reef limestone of Paciran Formation of Rembang Zone. This coral reef limestone is responsible to form the beach terraces along the Tanjung Awar-Awar and Tuban beach and its surrounded. The formation of this coral reef limestone terraces closely related to vertical movement of these rocks units. The study area is bathymetrically flat where the shallow part is on southwest (towards the beach) with 2 meters depth and the deeper part is to northeast part with 9 meters depth. There are 7 seismic reflection lines of NE-SW and 15 lines of NW-SE have been done and some rocks drilling to emphasize the seismic sequences. The interpretation of geological structure from seismic reflection shows a feature of rocks unit was faulted and intruded as diapiric structures. These features are well developed towards the beach where the terrace of coral reef limestone can be found on the beaches. The formation of these diapiric structures are interpreted where on southward of the Rembang Zone there is a gravity negative anomalies and also due to the limestone were faulted and it seems to be easy intruded by a sediment with low density. Keywords : beach terraces, coral reef limestone, diapiric structure, Tanjung Awar- Awar East Java

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Formation of diapiric structure in the deformation zone, central Indian Ocean: A model from gravity and seismic reflection data

Journal of Earth System Science ◽

10.1007/bf02702219 ◽

2002 ◽

Vol 111 (1) ◽

pp. 17-28 ◽

Cited By ~ 1

Author(s):

K. S. Krishna ◽

D. Gopala Rao ◽

Yu. P. Neprochnov

Keyword(s):

Indian Ocean ◽

Seismic Reflection ◽

Deformation Zone ◽

Seismic Reflection Data ◽

Reflection Data ◽

Central Indian Ocean ◽

Diapiric Structure

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Biodegradation of Polyethylene Microplastic using Culturable Coral-Associated Bacteria Isolated from Corals of Karimunjawa National Park

ILMU KELAUTAN Indonesian Journal of Marine Sciences ◽

10.14710/ik.ijms.26.4.237-246 ◽

2021 ◽

Vol 26 (4) ◽

pp. 237-246

Author(s):

Prastyo Abi Widyananto ◽

Sakti Imam Muchlissin ◽

Agus Sabdono ◽

Bambang Yulianto ◽

Fauziah Shahul Hamid ◽

...

Keyword(s):

Coral Reef ◽

National Park ◽

Plastic Material ◽

Low Density Polyethylene ◽

Phase Identification ◽

Low Density ◽

Bacterial Isolates ◽

Plastic Pollution ◽

Bacterial Gene ◽

Associated Bacteria

Polyethylene is a plastic material that was globally produced and is well known as a non-degradable pollutant product. Plastic pollution, primarily microplastics, have been distributed to coral reef ecosystems, where these areas are ecosystems with high productivity. Karimunjawa National Park in Indonesia is one of the protected areas for coral reef ecosystem habitat in Central Java, threatened by microplastic contamination. Recent studies have shown that coral-associated bacteria have an adequate ability to degrade marine pollutant materials. No one has reported that the use of indigenous coral-associated bacteria has the potential for microplastic biodegradation, especially low-density polyethylene microplastic materials. Hence, the objective of this study was to find the potential of microplastic biodegradation agents derived from coral-associated bacteria in Karimunjawa National Park area. Various coral life-forms were isolated in July 2020 from conservation areas and areas with anthropogenic influences. Bacterial isolates were screened using tributyrin and polycaprolactone as substrates to reveal potential microplastic degradation enzymes. The total isolation results obtained 92 bacterial isolates, and then from the result of enzyme screening, there were 7 active bacteria and only 1 bacteria that potential to degrade polyethylene. LBC 1 showed that strain could degrade by 2.25±0.0684 % low-density polyethylene microplastic pellet by incubating bacterial growth until the stationary phase. Identification of LBC 1 strain was carried out by extracting DNA and bacterial 16S rRNA sequences. Bacterial gene identification refers to Bacillus paramycoides with a similarity level in the National Center Biotechnology Information database of 99.44%. These results prove that hard coral association bacteria can degrade low-density polyethylene microplastics.

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Full-scale load testing of two large-diameter drilled shafts in coral-reef limestone formations

Bulletin of Engineering Geology and the Environment ◽

10.1007/s10064-017-1206-1 ◽

2017 ◽

Vol 77 (3) ◽

pp. 1127-1143 ◽

Cited By ~ 6

Author(s):

Zhihui Wan ◽

Guoliang Dai ◽

Weiming Gong

Keyword(s):

Coral Reef ◽

Large Diameter ◽

Full Scale ◽

Drilled Shafts ◽

Load Testing ◽

Reef Limestone

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From Proterozoic strata to a synthesized seismic reflection trace: implications for regional seismic reflection patterns in northwestern Canada

Canadian Journal of Earth Sciences ◽

10.1139/e06-040 ◽

2006 ◽

Vol 43 (11) ◽

pp. 1639-1651 ◽

Cited By ~ 2

Author(s):

Frederick A Cook ◽

Samantha M Siegel

Keyword(s):

British Columbia ◽

Seismic Reflection ◽

Sedimentary Rocks ◽

P Wave ◽

Low Density ◽

Seismic Profiles ◽

Deep Basin ◽

Middle Crust ◽

Wave Velocities ◽

Regional Gravity

Calculation of a synthetic seismic reflection trace from detailed descriptions of exposed Proterozoic strata in northwestern Canada permits correlation of reflections on regional seismic profiles to surface outcrop. Approximately 5.4 km (composite thickness) of Paleo- and Mesoproterozoic strata are exposed in the Muskwa anticlinorium that is located within the foreland of the Cordillera in northeastern British Columbia. The Tuchodi anticline is the easternmost structure of the Muskwa anticlinorium and has the deepest levels of Proterozoic strata exposed. At this location, prominent seismic reflection layering rises toward the surface and is easily correlated to the deeper formations of the Muskwa assemblage stratigraphy. These layers are followed westward into the middle crust, where they are overlain by dramatically thickened (by about five times) strata, primarily of the Tuchodi Formation. Along the same line of section, the Muskwa assemblage reflections overlie additional subparallel layered reflections at depth whose lithology and origin are unknown. However, coupled with other observations, including regional refraction results that indicate the crustal layers have both low seismic p-wave velocities and low ratios of p- and s-velocities, regional gravity observations that indicate the layers are low density, and correlation to similar layers on other seismic profiles that exhibit characteristic seismic stratigraphic features, the subparallel layers that are present beneath the known Muskwa assemblage are most easily interpreted as layered Proterozoic (meta-) sedimentary rocks. These results provide the basis for interpreting the Muskwa anticlinorium as a crustal-scale structure that formed when a deep basin of Proterozoic strata was inverted and thrust over an ~20 km high footwall ramp during Cordilleran orogenesis.

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