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  • 1Geologi Struktur(Aplikasi Struktur Geologi : Mineralasasi-Migas)

    Oleh :Irvani

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Referensi : Van Der Pluijm, B. A. and Marshak, S. 2004. Earth Structure. 2nd Edition. W. W. Norton &

    Company, Inc., USA. Rowland, S.M., Duebendorfer, E.M. and Schiefelbein, I.M. 2007. Structural Analysis and

    Synthesis : A Laboratory Course in Structural Geology. 3th Edition. Blacwell Publishing Ltd. Voctoria, Australia.

    Bates, R.L. and Jackson, J.A., 1987. Glossary Geology. 3th Edition. American Geological Institute Elexandria, Virginia.

    Davis, G.H. 1984. Structural Geology of Rocks and Regions. John Wiley & Sons, New York. Ragan, D.M. 2009. Structural Geology : An Introduction to Geometrical Techniques. 4th Edition.

    Cambridge University Press, New York. Twiss R.J. And Moores, E.M. 2007. Structural Geology. 2nd Edition. W.H. Freeman and

    Company, USA. Ramsey J. and Huber, M. 1983. The Techniques of Modern Structural Geology : Strain Analysis.

    Vol. 1. Academic Press, Inc., London. Ramsey J. and Huber, M. 1987. The Techniques of Modern Structural Geology : Fold and

    Fractures. Vol. 2. Academic Press, Inc., London. Ramsey J. and Huber, M. 2000. The Techniques of Modern Structural Geology : Applications of

    Continuum Mechanics in Structural Geology. Vol. 3. Elsevier Academic Press, Inc., California. Cox, A. and Hart, R.B. 1986. Plate Tectonics : How It Works. Blacwell Scienific Publications, Inc.,

    California. Trouw, R.A.J. and Passchier, C.W. 1996. Microtectonics. Springer Verlag Berlin Heidelberg,

    Germany. Moon, C.J., Whateley, M.K.G. And Evans A.M., 2006. Introduction to Mineral Exploration. 2nd

    Edition. Blacwell Publishing, USA. Reichard, J.S. 2011. Environmental Geology, McGraw-Hill, New York. Montgomery, C.W. 2003. Environmental Geology, 6th Edition, McGraw-Hill, New York. DLL.

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 2Pokok Bahasan :I Pendahuluan (P.1)

    II Tektonika & Orogenesa (P.2-3)a. Tektonik lempengb. Orogenesa

    III Gaya, Tegangan, Strain & Deformasi (P.4-5)

    a. Gaya & Teganganb. Strain & Deformasi

    IV Struktur Geologi (P.6-9)a. Unsur strukturb. Lipatan c. Kekar d. Sesar/Patahan

    V Identifikasi Struk. Geologi (P.10-11)a. Pengukuran dan analisis

    struktur geologib. Analisis geofisika struktur

    geologi

    VI Aplikasi Struk. Geologi (P.12-13)a. Mineralisasi b. Migasc. Kebencanaan geologi

    VII Geologi Struk. Indonesia (P.14)a. Umumb. Sumatra&Jawa c. Bangka Belitung

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Hydrothermal

    Hydrothermal ore deposits form in various ways. (A) Ore deposition in veins around a magma chamber. Less-concentrated ore is disseminated through the rock as fluids seep outward from magma. (B) Sulfides can also be deposited by hydrothermal circulation around a spreading ridge. Photographs (C and D) by W. R. Normark, USGS Photo Library, Denver, CO. Montgomery (2008)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    I Mineralisasi

  • 3Hydrothermal DepositsNaturally, the intense heat from the magma body raises the temperature of any groundwater that is present in the country rocks. The combination of these waters results in hot, mineral-rich fluids that transport ions and chemically react with rocks in a zone around an igneous intrusion. Minerals that crystallize from these highly enriched fluids form what are referred to as hydrothermal deposits.

    Vein and disseminated ore deposits result from hot, mineral-rich fluids that chemically react with minerals in an igneous intrusion and surrounding rocks, and then transfer elements within a zone around theigneous intrusion. The photo shows a vein deposit containing valuable tungsten and tin minerals in aPortuguese mine.

    Reichard (2011)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Massive sulfide deposits (A) form when hydrothermal fluids discharge from mid-oceanic ridges and then mix with cool seawater. Here metallic ions bond withsulfur, forming sulfide minerals that eventually accumulate on the seafloor. Note how heat convection pulls cold seawater into the ridge, where it reacts chemically with basalt to form hydrothermal fluids. Photo (B) shows sulfide minerals precipitating as hydrothermal fluids escape from vents on the seafloor. Reichard (2011)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 4The hot, mineral-laden water streams out into the ocean at blacksmoker chimneys (C). (D) Hydrothermal sulfides permeate this basaltic rock. The most visible are pyrite (brassy gold crystals).Photographs (C and D) by W. R. Normark, USGS Photo Library, Denver, CO.

    Montgomery (2008)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Lutgens et al. (2012)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 5Illustration of the relationship between a parent igneous bodyand the associated pegmatite and hydrothermal deposits. Inset photo shows light-colored vein deposits emplaced along a series of fractures in dark-colored metamorphic rock. (Photo by James E. Patterson) Lutgens et al. (2012)

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    High grade gold ore from a mine in Ghana, West Africa. (Photo by Greenshoots Communications/Alamy)

    Lutgens et al. (2012)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 6Tabular orebodies

    Vein occupying a normal fault and exhibiting pinch-and-swell structure, giving rise to ribbon ore shoots. The development of a flat beneath impervious cover is shown also.

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Irregular replacement deposits

    Skarn deposit at Iron Springs, Utah. (After Gilluly et al. 1959.)

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 7Concordant orebodies

    Cross-section through the ore zone, Sullivan Mine, British Columbia. (After Sangster & Scott 1976.)

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Distribution of pay streaks (gold orebodies) in the Main Leader Reef in the East Rand Basin of the Witwatersrand Goldfield of South Africa. The arrows indicate the direction of dip at the outcrop orsuboutcrop. (After Du Toit 1954.)

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 8Generalized diagram of an unconformity associateduranium deposit. (After Clark et al. 1982.)

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Sketch map of the geology in the vicinity of the Trinity silver deposit, Nevada. (After Ashleman 1988.)

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 9Carlin-type depositsThese deposits areresponsible for the majorityof gold production in Nevada, 261 t in 2001.Typically the gold occurs as micron meter-sizedgrains which are invisible to the naked eye(noseeum gold), within impure limestones orcalcareous silstones.

    Diagram for the formation of Carlin style deposits. (After Sawkins 1984.) Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Moon et al. (2006)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 10

    Underground Mining

    Underground mining involves blasting shafts and horizontal tunnels to access mineral deposits. Although safety has greatly improved, surface mining is generally preferred over underground mining as it presents fewer hazards and lower operating costs.

    Reichard (2011)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    PetroleumPetroleum is a general term geologists use to describe both oil and natural gas. Oil and gas are composed of similar types of organic molecules and are commonly found together in the subsurface under similar geologic conditions.

    Reichard (2011)

    II Migas

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  • 11

    Hydrocarbon molecules form when organic-rich source rocks are buried to the point where temperatures reach the oil and gas windows. The molecules rise until encountering a permeable reservoir rock, then flow laterally with the groundwater until reaching a trap where the lighter hydrocarbons accumulate on top of the water. Aerial photo shows the characteristic pattern that a dome trap makes at the surface. Note the individual wells that are extracting petroleum trapped in the rocks below. Reichard (2011)

    Genetic

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    Types of petroleum traps. (A) A simple fold trap. (B) Petroleum accumulated in a fossilized ancient coral reef. (C) A fault trap. (D) Petroleum trapped against an impermeable salt dome, which has risen up from a buried evaporite deposit. Montgomery (2008)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

  • 12

    In addition to folded domes, there other common types ofpetroleum traps and reservoirs. All traps must be overlain by a low-permeability cap rock in order to limit the ability of oiland gas to escape over time. The reservoir rock itself must be quite porous in order tostore significant quantities ofpetroleum, and also permeable enough to allow petroleum to be extracted.

    Reichard (2011)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    American Petroleum Institute, 1986

    Hydrocarbon Trap Types

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  • 13

    Gluyas & Swarbrick (2003)

    Universitas Bangka Belitung Jurusan Teknik Pertambangan

    Structural