ETROLO

U NA P

[TGS7404]

Dr. Hill. Gendoet Hartono

Semester 7, 2017-2018

2 SKS teori

GI BA

GI

T UAN

PENDAHULUAN 1X

Berisi tentang latarbelakang, bumi, batuan beku dan

batuan gunung api, dan kedudukan di bidang geologi

TATAAN TEKTONIK 2X

Berisi tentang tektonik global, regim tektonik, dan

peranannya dalam magmatisme dan volkanisme

GENERASI MAGMA 2X

Berisi tentang magmatisme, diagram fase

KLASIFIKASI 2X

Klasifikasi magma atau afinitas magma

Rock Forming Mineral 1X

Kimia Mineral Pembentuk Batuan 1X

Petrologi Batuan Intrusi Dangkal 2X

Petrologi Batuan Ekstrusi 2X

Alterasi Batuan Gunung Api 1X

(Hartono, 2010)

BATUAN GUNUNG API

•BATUAN YANG TERBENTUK SEBAGAI HASIL AKTIVITAS GUNUNG API, BAIK LANGSUNG MAUPUN TIDAK LANGSUNG

• LANGSUNG: HASIL ERUPSI MEMBEKU/MENGENDAP INSITU

• TIDAK LANGSUNG: SUDAH MENGALAMI PEROMBAKAN/ DEFORMASI

KELOMPOK UTAMA BATUAN GUNUNG API

• LAVA KOHEREN (INTRUSI DANGKAL & BATUAN BEKU LUAR)

•BATUAN KLASTIKA GUNUNG API

CIRI-CIRI BATUAN GUNUNG API

• TEKSTUR HIPOKRISTALIN -GELAS/HOLOHEALIN

•STRUKTUR MENCERMINKAN PENDINGINAN SANGAT CEPAT (embayment, glass inclusions, skeletal, etc.)

•KOMPOSISI SELALU MENGANDUNG GELAS

Hypocrystalline is a textural term describing an igneous

rock consisting of a mixture of glass and crystals where

the ratio of crystals to glass is greater than 3:5.

Porphyritic texture is an igneous rock texture in which

large crystals are set in a finer-grained or glassy

groundmass. Porphyritic textures occur in coarse,

medium and fine-grained igneous rocks. Usually the

larger crystals, known as phenocrysts, formed earlier in

the crystallisation sequence of the magma. A porphyritic

texture in which there is a continuous variation in crystal

size is termed seriate. Hypabyssal rocks with porphyritic

textures are sometimes termed porphyrys.

Hypocrystalline Texture

Porphyritic textures develop when conditions during

cooling of a magma change relatively quickly. The

earlier formed minerals will have formed slowly and

remain as large crystals, whereas, sudden cooling

causes the rapid crystallization of the remainder of the

melt into a fine grained (aphanitic) matrix. The result is

an aphanitic rock with some larger crystals (phenocrysts)

imbedded within its matrix. Porphyritic texture also

occurs when magma crystallizes below a volcano but is

erupted before completing crystallization thus forcing

the remaining lava to crystallize more rapidly with much

smaller crystals.

DASAR PENAMAAN

•DESKRIPSI NAMA (SECARA DESKRIPSI)

•DESKRIPSI GENESA NAMA (SECARA GENESA)

•KOMBINASI NAMA SECARA DESKRIPSI & GENESA

LINGKUP PENAMAAN

•MEGASKOPIK CONTOH SETANGAN

•MEGASKOPIK DI LAPANGAN

•MIKROSKOPIK

•KIMIAWI

PARAMETER DESKRIPSI

•WARNA

• TEKSTUR (BENTUK & UKURAN BUTIR/KRISTAL, KEMAS, SORTASI)

•STRUKTUR (PENDINGINAN CEPAT & PENGENDAPAN)

•KOMPOSISI (MINERAL, BATUAN)

PARAMETER GENESA

•SUMBER (ERUPSI GUNUNG API)

•PROSES (MEKANISME PEMBEKUAN/ PENGENDAPAN)

•UMUR (PEMBEKUAN/ PENGENDAPAN)

• LINGKUNGAN (PEMBEKUAN/ PENGENDAPAN

PENAMAAN DESKRIPTIF MINERALOGI LAVA KOHEREN

WARNA gelap/ hitam abu-abu

TEKSTUR afanit porfiri

STRUKTUR masif -

skoria

masif

KOMPOSISI - fenok: plg &

hbl, msdsr

afanit

NAMA Basal Andesit

PENAMAAN DESKRIPTIF SECARA KIMIA

NAMA BATUAN % Berat SiO2Basal 45 - 52

Andesit basal 53 – 57

Andesit 58 – 63

Dasit 64 – 68

Riolit 69 - 75

BASALT TYPES-MAJOR ELEMENT VARIATION

SILICA SATURATION

Silica-oversaturated: rocks contain Q (quartz or its polymorphs-

cristobalite and tridymite), such as granite

Silica-saturated: rocks contain Hy, but no Q, Ne, or Ol (no quartz,

feldspathoids, or olivine), such as diorite and andesite

Silica-undersaturated: rocks contain Ol and possibly Ne (Mg-

olivine and possibly feldspathoids, analcime, perovskite, melanite

garnet, and melilite), such as nepheline syenite

Presenter’s notes: Igneous features inthe Bight Basin are typical of intrusionsobserved elsewhere; they areexpressed as very high-amplitudeanomalies, which are typicallydiscordant to concordant with encasingstrata and are underlain by velocitypull-ups that attest to theiracoustically-fast properties. Intrusiveigneous features in the Bight Basin areoverlain by a field of genetically-related extrusive igneous features,including large features interpreted asvolcanoes and smaller featuresinterpreted as hydrothermal vents.Intrusive igneous features are alsoassociated with folding of overlyingstrata; we shall return to the genesisand importance of these folds later inthe presentation.

Presenter’s notes: Thisfigure highlights the impactthat igneous systems canhave on petroleum systemdevelopment in sedimentarybasins.This figure principallyhighlightscompartmentalisation ofbasin by vertically- andlaterally-extensive intrusions;furthermore, in the upperpart of the basin, the impactof intrusions on trapdevelopment is highlighted.A secondary aim of thispresentation, which wasnoted in anotherpresentation, is how seismicreflection data, in particularhigh-quality, three-dimensional data, can helpus understand igneousprocesses in a more generalsense.

PENAMAAN GENETIK LAVA KOHEREN

• INTRUSI DANGKAL: RETAS (DIKE), SILL, LEHER GUNUNG API

•BATUAN EKSTRUSI: KUBAH LAVA, ALIRAN LAVA

CIRI DESKRIPTIF INTRUSI DANGKAL

•BENTUK GEOMETRI

•EFEK KONTAK (WARNA, TEKSTUR, STRUKTUR & KOMPOSISI)