Geologi laut pak yusuf surachman kuliah geologi kelautan-1

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KULIAH GEOLOGI KELAUTAN JURUSAN GEOLOGI FAKULTAS TEKNOLOGI MINERAL UNIVERSITAS TRISAKTI SEMESTER II, 2002 DOSEN : IR YUSUF SURACHMAN DJAJADIHARDJA MSC

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  • 1. KULIAH GEOLOGI KELAUTAN JURUSAN GEOLOGI FAKULTAS TEKNOLOGI MINERAL UNIVERSITAS TRISAKTI SEMESTER II, 2002 DOSEN : IR YUSUF SURACHMAN DJAJADIHARDJA MSC

2. SILABUS 1. PEMAHAMAN MENGENAI GEOLOGIKELAUTAN 2. STRUKTUR DAN FORMASI BUMI 3. BENTUK DAN CEKUNGAN SAMUDERA 4. EVOLUSI CEKUNGAN SAMUDERA 5. TEKTONIK 6. STRATIGRAFI 3. II STRUKTUR DAN FORMASI BUMI 4. Vp = + 2 Vs = / Koefisien Lame Modulus rigidity Density 5. Ray path concept (seismic method) to determine physical properties 6. B bT = B + b bB medan magnet bumi (B) menginduksi partikel magnetik dalam batuan (b) dan menghasilkan komponen total (T) 7. Interior could be estimate based on seismic waves propagation 8. lintasan gelombang seismik jika bumi tidak homogen akibat adanya struktur perlapisan bumi 9. lintasan gelombang seismik jika kecepatan gelombang seismik meningkat thd. kedalaman 10. proses internal di dalam inti bumi menyebabkan bumi memiliki medan magnet Geomagnetik Sosialisasi HAGI-UI, HG-2007 11. Gravity Method Sosialisasi HAGI-UI, HG-2007 12. gg11 gg22 gg33 jarakjarak gg Anomali gravitasi hasil pengukuran menggambarkan anomali rapat massa bawah- permukaan Sosialisasi HAGI-UI, HG-2007 13. BENTUK CEKUNGAN SAMUDERA Kerak samudera terus berubah terhadap waktu karena dua hal; 1. Gerakan lempeng - Samudera Atlantik terus melebar tetapi tidak ada zona subduksi - Samudera Pacific menyempit karena subduksi lebih menonjol dibanding pemekaran. 2. Bathimetri berubah karena; - kontraksi akibat masa batuan mendingin - pengendapan sedimen dari benua - erosi dan formasi ngarai (canyon) bawah laut akibat pengaruh arus - penyesuaian isostatik 14. Pinggiran benua Dua tipe pinggiran benua; Tipe Atlantik ; aseismik Tipe Pacific ; pinggiran aktif 15. Sedimen 1. Pelagic sedimen ialah sedimen yang diendapkan di dasar laut dimana sumbernya berasal dari lautan 2. Terrigenous sedimen adalah sedimen yang diendapkan didasar laut dimana sumbernya berasal dari daratan (continen) 3. Hemipelagic sedimen adalah sedimen yang diendapkan di dasar laut dimana sumbernya berasal dari daratan dan lautan. 16. Multi Channel Seismic Reflection, Gravity, Magnetic, and Multibeam Gravity, Magnetic, and Multibeam 17. SO98-27 18. Tectonic Evolution of the Celebes Sea Eocene Middle Miocene Reconstruction About 87.7 m unit IV composed mainly of Dark grayish brown to reddish brown claystone including volcanic Indicating an open oceanic environment (Rangin, Silver, von Breymann et al., 1990) 19. Isopach map of sediment unit IIIC and IV (contour interval in second) Grey shadows are topographic high of the oceanic basement 20. Oligocene Reconstruction Spreading of the South China Sea Started at 32 m.y (Taylor & Hayes, 1983, Holloway, 1982) 21. Satyana et al., 1999 Middle Miocene Late Miocene Reconstruction - South China Sea was still spreading, - In the North Borneo, extended South China margin thrusted beneath Borneo - In early Miocene central Borneo was eroded shed sediment into the Kutai, Tarakan and Sandakan basin - In Tarakan basin progradation of deltaic environment was deposited during Eocene Late Miocene Satyana et al., 1999 22. New Isopach map of Unit IIIB (middle Miocene turbidite) in seconds (TWT) 23. Sediment unit IIIA continue deposited up to late Miocene, probably same source environ ment as sub unit IIIB (major delta complex) Subunit IIIA consists of Hemipelagic claystone Interbedded claystone/silty claystone turbidite and Minor carbonate claystone Rate of accumulation of unit IIIA about 33 m/m.y. 24. Late Miocene-Holocene Reconstruction Nichols et al., 1999 25. During late Miocene to Holocene was dominantly by the terrigenous turbidite and Hemipelagic sediment. Within sediment unit II, hemipelagic sediment gradually coarsens upward to clayey silt, Silt size consisting of volcanic ash. 26. Subunit I mostly contain volcanogenic clayey. Most of volcanogenic materials depo sited during late Miocene to Holocene were deposited from volcanic arc around Celebes Sea (e.g. Sulu ridge, Mindanao, Sangihe, and North Sulawesi arc) Sediment accumulation rate of subunit IIIA, II, and I range from 33 60 m/m.y. 27. Sea Level Change 1.Global Warming (Es di Kutub mencair) 2.Subside & Accretion of the Basin (Penurunan atau naiknya dasar Samudera ) 3.Weighting of the Earths crust by local ice sheet Is the sea level changing, or is it the land that is moving?