Introduction to Geology and Formation Evaluation SMKN 2 DEPOK JURUSAN GEOLOGI PERTAMBANGAN 2009

Agenda Introduction Geology Stratigraphy Rocks and Minerals Igneous Rock Sedimentary Rock Metamorphic Rock Exercise – 1a Break . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . 14 : 30 Plate Tectonic Concept Structural Geology Exercise – 1b Sequence Stratigraphy Exercise – 1c  

Basic Petroleum Geology The Nature of Hydrocarbon Habitat of Hydrocarbon Hydrocarbon Occurrence Reservoir Rocks Hydrocarbon Traps Exercise-2a Break . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 : 00 Basic Skills Cross Sections Surface and Subsurface Mapping Exercise-2a, 2b

Geology Geo means Earth Greek’s mythology : gaea

Geology Physical Geology rocks, minerals, tectonics, economic geology, engineering geology, etc Historical Geology paleontology stratigraphy dating, other paleo~ studies physics chem bio math geo

Stratigraphy

Stratigraphy Steno’s Law Walther’s Law

Dating                                                                                                                                                                                                                                        

Stratigraphy

Rocks and Minerals Rocks are made of minerals. Only a few minerals are rock forming and most rock is made from a combination of the commonest of these such as feldspars, quartz, mica, olivine, calcite, pyroxene and amphiboles. Most other minerals, of which there are over 3000 different types, are rarely present in quantities large enough to be considered rock forming.                                                                                                                         

Rocks Igneous Rocks Sedimentary Rocks Metamorphic Rocks

Igneous rocks form when molten rock cools and solidifies (crystallizes). Molten rock trapped underground is called magma. Molten rock erupted at Earth's surface is referred to as lava. The pictures below illustrate the significant textures and compositions that enable geologists and geology students to classify igneous rocks. For convenience of presentation the igneous rocks are divided into intrusive rocks (or plutonic rocks) which form underground, and extrusive rocks (or volcanic rocks) which form at Earth's surface.

Igneous Rock Classificiation Three basic factors: A. Grain Size and Texture Vitreous - glassy, no crystals Aphanitic - fine grained < 2mm crystals Phaneritic - coase grained > 2mm crystals Pegmatitic - very coase grained > 10mm crystals Vesicular - voids or holes created by gases Amigdaloidal - filled voids created by gases Porphyritic - some large crystals (phenocrysts)in fine matrix B. Intrusive or Extrusive Intrusive Igneous Rocks - usually medium to coarse grained texture due to slow cooling. Typically light colored. Extusive Igneous Rocks - glassy or fine-grained due to rapid cooling. May have voids due to gases escaping from the magma. Typically dark in color. C. Silica Content and Mineral Composition Acid Igneous Rocks - silica rich ( > 65% by weight) composed mainly of felsic or light coloured minerals (eg. feldspars, quartz) Intermediate Igneous Rocks - silica 50-65% by weight, composed mainly of plagiocalse feldspars, some mafic minerals, with some quartz. Basic Igneous Rocks - silica poor ( < 50% by weight) contain significant amounts of mafic or dark colored ferromagnesian minerals (eg. olivines, pyroxenes, amphiboles, micas). No free quartz.

IGNEOUS ROCKS

Sedimentary Rocks Shale (mudstone) Siltstone Sandstone Conglomerate Limestone Dolomite Coal Chert Evaporite

Sedimentary Rocks Shale > < Clay

Metamorphic Rocks slate phyllite marble schist gneiss