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Indonesian Stratigraphic Lexicon: Past, Present and Future Darman, Herman; Permana, Asep; Syavitri, Dewi
Berita Sedimentologi Vol 49, No 3 (2024)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51835/bsed.2024.49.3.444

The Stratigraphic Lexicon is an important source of regional geological information. Due to the development of the science and the geological understanding, the lexicon needs to be updated. Following the first Indonesian Stratigraphic Lexicon by Marks (1957), Harahap et al. (2003) made an update to the lexicon. The latter version was later published online as a website. A GIS format of the lexicon will soon be available for geoscientists to use. This paper also provides suggestions for improving the lexicon, which includes the preparation of logs type for each section. A systematic approach to periodically ever greening the lexicon is necessary. The Geological Survey of Indonesia and the Indonesian Association of Geologists should be involved in the future improvement of the lexicon.

Short Note: Sedimentology of Bali Touristic Locations - Tanah Lot and Uluwatu Darman, Herman
Berita Sedimentologi Vol 25, No 1 (2012)
Publisher : Ikatan Ahli Geologi Indonesia

Tanah Lot and Uluwatu are famous touristic sites in the southern part of Bali, and part of the Sunda Volcanic Arc. Most visitors come to these places to enjoy the scenery and visit the temple. The uniquity of these sites, however, is the result of the specific local geological setting in which they are located.The Tanah Lot temple was built on top of Quarternary volcanic clastic deposits, and was separated from the main island because of erosional processes. Uluwatu which is well known for the temple was built on a Miocene limestone cliff. Due to the excellent exposure of the geology, both localities allow for studying the sedimentary history which has resulted in these remarkable sites.This article discusses the stratigraphy and sedimentological features seen on these two locations. Despite the excellent exposure, both locations have received very little attention and only few studies have been reported. Both sites but especially the Uluwatu cliff, provides an excellent lateral exposure, allowing to discuss the depositional in a spatial framework. The outcrops in both locations show close relationship between volcanic activity and carbonate deposition.

BOOK REVIEW: PIONEERS AND MILESTONES OF INDONESIAN GEOLOGY Purba, Junida Rejeki; Darman, Herman
Berita Sedimentologi Vol 51, No 1 (2025)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51835/bsed.2025.51.1.443

J.T. van Gorsel's four-volume series, "The Pioneers and Milestones of Indonesian Geology," provides a comprehensive exploration of the geological history of Indonesia. The books delve into the lives and contributions of 238 researchers, including geologists, paleontologists, and other scientists who have made significant advancements in understanding the region's complex geology.Through extensive research and analysis of historical documents, the author highlights the pioneering work of these individuals, many of whom were foreign-born and active during the Dutch colonial era. The books offer valuable insights into the challenges and rewards of conducting geological research in Indonesia, a region known for its diverse landscapes and complex geological processes.By preserving the legacy of these pioneers, Van Gorsel aims to inspire future generations of geoscientists and provide a solid foundation for ongoing research in Indonesian geology.

Book Review: Biodiversity, Biogeography and Nature Conservation in Wallacea and New Guinea (Volume 1) Darman, Herman
Berita Sedimentologi Vol 23, No 1 (2012)
Publisher : Ikatan Ahli Geologi Indonesia

Biodiversity, Biogeography and Nature Conservation in Wallacea and New Guinea (Volume 1)Edited byDmitry Telnov, Ph.D.Chairman of Coleopterology, The Entomological Society of Latvia Stopinunovads, Darzaiela 10, DZIDRINAS, LV-2130, Latvia / Lettland / LettonieWebsites: http://leb.daba.lv and http://www.zin.ru/Animalia/Coleoptera/eng/telnov.htm

Short Note: Well Rounded Kuta and Tanjung Aan Lombok Beach Sand Koesoemadinata, R.P.; van Gorsel, J.T.; Darman, Herman
Berita Sedimentologi Vol 25, No 1 (2012)
Publisher : Ikatan Ahli Geologi Indonesia

Coarse, well rounded carbonate sand grains are found in Kuta and Tanjung Aan beach Lombok. These kinds of sands are also common on Sanur Beach and other localities along the East coast of Bali, where many visitors believed them to be ooids (oolites). The grains are generally about 3-4 mm in diameter and well rounded. The colors of the grains are white to light-brownish white. In places they are mixed with coral remain and other small shells which are angular to sub-angular or sub-rounded to oval shape, with generally the same grain size or larger.

Paleogene paleogeographic reconstructions of the Kutai Basin: Refinement based on outcrop and subsurface data Darman, Herman
Berita Sedimentologi Vol 49, No 1 (2023)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51835/bsed.2023.49.1.397

The Kutai Basin is a Cenozoic sedimentary basin located in the eastern part of Borneo Island. Many studies were done on the eastern part of the basin, which is dominated by Neogene sediments. The west margin of the basin is outcropped onshore and to the east, the basin opens up to the Makassar Strait. Paleogene and older rocks outcrop in the west margin of Kutai Basin. The terrain and the access to the area are difficult and no significant hydrocarbon discovery was made in Paleogene sediments up to now.This study revisited the field works completed in the 1970s by a Shell team, which focused on the Paleogene section of the Kutai Basin. The result was integrated with later studies, and altogether were synthesized into a series of paleogeographic maps. A new set of paleogeographic maps is proposed in this paper, for Middle Eocene, Late Eocene, Early Oligocene, and Late Oligocene levels. The works included in this study comprised outcrop observations, biostratigraphy analysis of the samples and limited seismic in parts of the area. The results were integrated with other more recent work to build the new set of Paleogene paleogeographic maps.Outcrops data and well information show the distribution of shallow marine sediment in the Middle Eocene time with some fluvial input from the north and southwest of the basin. In the Late Eocene, some carbonates developed in the north of the basin. During Early Oligocene, the carbonate complex developed both in the south and in the north of the basin. In the Late Oligocene, the carbonate in the south became more stable. Through Paleogene time the center of Kutai Basin was dominated by the bathyal section.

Seismic Expression of Tectonic Features in the Lesser Sunda Islands, Indonesia Darman, Herman
Berita Sedimentologi Vol 25, No 1 (2012)
Publisher : Ikatan Ahli Geologi Indonesia

The Sunda Arc is a chain of islands in the southern part of Indonesia, cored by active volcanoes. The western part of the Sunda arc is dominated by the large of Sumatra and Java, and is commonly called "the Greater Sunda Islands‟. The tectonic terrain within this part is dominated by the oceanic subduction below the southeastern extension of the Asian continental plate, which is collectively known as the Sunda Shield, Sunda Plate or Sundaland. Towards the east the islands are much smaller and are called "the Lesser Sunda Islands‟. The transition from oceanic subduction to continent-island arc collision developed in this area, while further west the Banda Arc marks full continent to island arc collision between Australia and the Asian plate. The Australian lithosphere, which is interpreted as Precambrian continental crust is moving northward at a rate that currently varies from 6.7 to 7 cm/year.The Sunda Arc has long been considered as a classical accretionary margin system where the Indo-Australian oceanic plate is underthrust beneath the Asian Continent, active since the Late Oligocene. At the eastern end of the Sunda Arc the convergent system changes from oceanic subduction to continent island arc collision of the Scott Plateau, part of the Australian continent, colliding with the Banda island arc and Sumba Island in between.The Lesser Sunda Islands are also called the inner-arc islands. The formation of these islands is related to the subduction along the Java Trench in the Java Sea. The island of Bali marks the west end of the Lesser Sunda Islands and Alor Island at the east end. To the south of the inner-arc islands, an accretionary wedge formed the outer-arc ridge. The ridge is subaerially exposed in the east as Savu and Timor Island. The northwest of the Lesser Sunda Islands are underlain by a Late Cretaceous Accretionary Crust, which changes to an oceanic crust in the northeast. The Sumba Island has a unique orientation and the origin of the island is still debated.The aim of this article is to provide a broad overview about the structures of the tectonic units based on some selected seismic lines. These lines also give a better geological understanding, including recent processes that developed in the area.

Seismic Expression of the Timor-Tanimbar, Eastern Indonesia Darman, Herman
Berita Sedimentologi Vol 24, No 1 (2012)
Publisher : Ikatan Ahli Geologi Indonesia

The Timor-Tanimbar Trough is an oceanic trough, which is an eastern continuation of the Sunda Trench. It marks the boundary between Indo-Australian Plate's continental shelf and the Timor Plate in the north. The trough is located in the south of Timor Island and is called the Timor Trough with WSW to ENE orientation. Further east, the trough orientation changes to SW-NE and is called Tanimbar Trough.A number of seismic lines across Timor-Tanimbar Trough have recently been published by different authors in several publications. Five of those seismic lines which provided regional geological understanding of the southern part of Banda arc, are discussed in this paper. These seismic lines provide a better geological understanding of the area after Hamilton published regional seismic lines in 1979. In this paper, consistent stratigraphic nomenclature has been applied to these key seismic lines. This will help to understand the regional geological process in chronological order.From west to east, the coverage of the sections published in this article are as follow:Section 1: West part of Timor trough, published by Jones et al (2011);Section 2: East part of Timor trough to Australian Platform, published by Lee and Bawden (2011);Section 3: A regional older section, which provides a regional understanding of the tectonic in the area, is published by Hamilton (1979);Section 4: South of the Tanimbar trough, published by Carter at al. (2003);Section 5: A regional section across the northern part of Tanimbar trough published by Dinkelman et al. (2010), with details which is published by Roberts et al (2011).This article discusses the observations of these seismic lines, but the alternative interpretations are quite limited, for the lack of access to the original data. Seismic-to-well tie is not explained in the source of these seismic sections, and it will not be discussed in this paper.

East Java Basin Carbonate Reservoirs: Time Control on Reservoir Character Darman, Herman; Abigail, Stevany; Lamba, Lisa Christi; Wulandari, Diah Retno; Ascaria, Alit; Prasetya, Lilik
Berita Sedimentologi Vol 51, No 1 (2025)
Publisher : Ikatan Ahli Geologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51835/bsed.2025.51.1.462

The East Java Basin, a prolific back-arc basin in Indonesia, hosts significant hydrocarbon accumulations within Cenozoic carbonate reservoirs. This study explores the link between carbonate age, fossil assemblages, and reservoir characteristics. The oldest reservoir, the Ngimbang Formation, dominated by large foraminifera and interbedded shale, exhibits limited vertical growth potential. Conversely, the Oligo-Miocene Kujung Formation, rich in coral reefs, boasts the basin's highest hydrocarbon content. Pliocene Globigerina sands offer excellent reservoir quality due to both inter- and intra-granular porosity, but their distribution is restricted. This work analyzes the variations in reservoir properties (porosity and permeability) influenced by these distinct fossil assemblages across the formations. Additionally, comparisons of formation geometries and their impact on hydrocarbon trapping are addressed. By understanding these factors, the paper explores the potential for identifying hidden reservoirs within the basin for future exploration.

Dinoflagellate biostratigraphy of Eastern Indonesia stratigraphy: key of petroleum exploration success Darman, Herman
Berita Sedimentologi Vol 47, No 3 (2021)
Publisher : Ikatan Ahli Geologi Indonesia

Several major discoveries in the eastern part of Indonesia (e.g. Tangguh and Abadi) have increased more petroleum exploration interest in the area. These sizeable discoveries encountered gas in the Jurassic sandstone, which is a key reservoir target in the Northwest Shelf of Australia. The Mesozoic sandstone provenance is located in the Australian Continental Plate or also known as the Sahul Shelf. Thousands of wells were drilled in the Sahul Shelf and the stratigraphy in this area is well understood. The extension of the Mesozoic sandstone towards Indonesian territory, with much less well information, is one of the keys of success for petroleum exploration. Refinement of the stratigraphy of the eastern part of Indonesia is crucial to understand the extension.To refine the stratigraphy of Eastern Indonesia, especially for the Mesozoic interval, dinoflagellates play a significant role. Several types of this marine biota have been used by Australian stratigraphers as markers. In the case where stratigraphic tie to Northwest Shelf Australia discoveries, key wells or standard chronostratigraphy, dinoflagellate understanding is critical.Dinoflagellate markers are used to mark several subdivisions of Plover Sandstone. Norvick (2001) used W. indotata and D. caddaensis Maximum Flooding Surfaces to subdivide the reservoir target into upper, middle and lower Plover Formation. These surfaces are named after dinoflagellates. More markers were identified to mark the source rock and seal in the petroleum system. To have a detail correlation from Indonesia to the NW Shelf, understanding of dinoflagellates is crucial.

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