Pak Rovicky,
Delta Sepinggan memang delta di pinggir Delta Mahakam, bukan terpinggirkan,
pada masanya (middle Miocene, atau N13-N15 menurut van de Weerd dan Armin,
1992, AAPG Bull.) ia delta yang aktif bersama delta tua lainnya (Maruat,
Yakin). Meskipun tidak lagi menjadi pusat perhatian sebesar Mahakam, Delta
Sepinggan punya andil kepada reservoir, sources, dan seals untuk beberapa
lapangan di selatan Cekungan Kutei offshore, dan ia merupakan delta paling
prolific di selatan Kutei Basin offshore.
Kalau yang dipublikasi memang tak banyak, ada dari Charlie Stuart dan Leveq
tahun 1996 (AAPG Bull, 1996, abstract only) saat mereka masih aktif di Unocal,
tetapi hanya abstrak. Stuart pun pernah mempresentasikan Sepinggan di Simposium
Seq Strat IPA 1996. Yang mungkin berhubungan dari Bu Etty Nuay (IPA, 1985),
meskipun itu untuk wilayah onshore Delta Sepinggan. Keterangan yang
sedikit-sedikit itu, diambil dari sana-sini bisa dipakai sebagai awal berangkat.
Pak Rovicky bisa cek artikel/paper2 ini :
Nuay et al., (1985) : EARLY MIDDLE MIOCENE DELTAIC PROGRADATION IN THE SOUTHERN
KUTAI BASIN, IPA Proceedings, p. 63-81 -paper ini menunjukkan onshore part
Sepinggan Delta.
van de Weerd and Armin (1992) : Origin and Evolution of HC-Bearing Basins of
Kalimantan (Borneo), Indonesia, AAPG Bull, Nov. 1992 - paper ini menunjukkan
bagaimana delta2 di Kutei dari yang paling tua ke yang paling muda
berprogradasi.
Stuart & Leveq (1996) : Evolution of Miocene Pre-Mahakam Delta, East
Kalimantan, Indonesia: ABSTRACT AAPG Bulletin Volume 80 (1996) - hanya abstrak,
tetapi lebih detail membahas progradasi delta2 tua di selatan Kutei (Maruat to
Yakin to Sepinggan)
Stuart et al. (1996) : SEQUENCE STRATIGRAPHIC STUDIES IN THE LOWER KUTEI BASIN,
EAST KALIMANTAN, INDONESIA, hanya Proceedings IPA Seq Strat Symposium -
seperti presentasinya di AAPG di atas, Charlie Stuart di sini membahasanya dari
segi seq strat, lumayan ada pembahasannya tentang Sepinggan, meskipun tak
banyak, full paper.
Studi lebih detail tentu berasal dari in house study Unocal (Chevron sekarang),
mungkin juga Total yang sekarang sedang mengeksplorasi lebih aktif wilayah
selatannya. Tetapi itu bukan barang yang bisa diakses.
salam,
Awang
Paper2 di atas mudah diakses, beberapa saya muatkan abstraknya.
Evolution of Miocene Pre-Mahakam Delta, East Kalimantan, Indonesia: ABSTRACT
Charles J. Stuart, Richard A. Leveq
AAPG Bulletin
Volume 80 (1996)
Sequence stratigraphy played a prominent role in two Unocal regional studies of
late Paleogene and Neogene strata in the eastern (offshore) Kutei basin, East
Kalimantan, Indonesia. A chronostratigraphic framework was applied to regional
correlation, facies analysis, organic geochemistry, and 2-D basin modeling.
Sedimentation at the southern basin margin was significantly affected by the
stable Paternoster platform and reactivation of faults associated with the
Paleogene Adang fault zone. Three major delta systems are recognized, in
addition to late middle Miocene Mahakam deltaics: the early Miocene Maruat
system, and middle Miocene Yakin and Sepinggan systems. The depocenters of
these delta systems appear to have shifted progressively to the east- northeast
where they bec ome fixed in the late middle Miocene (Mahakam delta). Maruat
deltaic sedimentation ended abruptly at the Maruat Limestone, which was
deposited during a widespread, possibly
global-eustatic, flooding event. Variations in limestone thickness may be due
to irregular paleobathymetry caused by early movement of normal faults within
the reactivated Adang zone. Normal fault movement accelerated during deposition
of overlying Yakin Formation deltaics. The Yakin thickens abruptly across
faults in the Adang fault zone demonstrating syndepositional fault movements.
Yakin deltaics are sharply overlain by a thick, aggradational succession of
coaly deltaic sediments that comprise the Sepinggan Deltaics. These strata
grade upward into distal deltaics and reefal(?) limestones that are the
southerly equiv lents to the Mahakam delta system.
EARLY MIDDLE MIOCENE DELTAIC PROGRADATION IN THE SOUTHERN KUTAI BASIN
PROCEEDINGS INDONESIAN PETROLEUM ASSOCIATION Fourteenth Annual Convention,
October 1985, p. 63-81
Synthesis of geology, paleontology and seismic strati-
graphy ina 1200square km areamrrounding Balikpapan Bay,
East Kalimantan, has led to the recognition of an eastward
prograding delta system, active during Middle Miocene time.
.Facies interpretation based on well cuttings and side wall
cores fiom 9 wells combined with approximately 4000
shothole samples from seismic time equivalent rock units
in outcrop, provided the frame-work for this synthesis.
Subsurface delineation of the 3 main depostional en-
vironments was achieved by means of seismic stratigraphy.
It is inferred that this progradationand observed eastward
shift of paleoenvironments in thi's delta and shore complex
are the result of uplift during Early Middle Miocene times.
The source for these fairly pure, well-sorted and rounded
quartzose sediments are probably sandstones of an earlier
progradational cycle that was derived directly from the
highly granitic Sunda shield.
--- Pada Sel, 2/2/10, Rovicky Dwi Putrohari <rovi...@gmail.com> menulis:
Dari: Rovicky Dwi Putrohari <rovi...@gmail.com>
Judul: [iagi-net-l] Delta Sepinggan yang "terpinggirkan" - Need info
Kepada: "IAGI" <iagi-net@iagi.or.id>, "Forum HAGI" <fo...@hagi.or.id>,
geologi...@googlegroups.com
Tanggal: Selasa, 2 Februari, 2010, 7:49 AM
Ada yang tahu keberadaan artikel atau paper tentang delta sepinggan ?
Sepinggan Delta bukan merupakan delta yang aktif saat ini. Karena ukurannya
jauh lebih kecil dari Delta Mahakam disebelah utaranya. Delta ini menjadi
delta yang "terpinggirkan". Saya juga kesulitan mencari tulisan atau artikel
tentang Delta Sepinggan ini.
Adakah yang mengetahui adanya artikel atau paper yang memiliki bahasan
khusus Delta Sepinggan ini ?
RDP
Lebih bergaul dan terhubung dengan lebih baik. Tambah lebih banyak teman
ke Yahoo! Messenger sekarang! http://id.messenger.yahoo.com/invite/
