12 Sumberdaya Geologi

1

TGD 1102TGD 1102GeologiGeologi

12. Sumberdaya Geologi12. Sumberdaya Geologi

Salahuddin HuseinSalahuddin Husein

Jurusan Teknik GeologiJurusan Teknik GeologiFakultas Teknik Universitas Gadjah MadaFakultas Teknik Universitas Gadjah Mada

20112011

2

shddin © 20111. Konsep• Sumberdaya mineral terkonsentrasi oleh proses geologi yang beroperasi

dalam sistem tektonik dan hidrologi. Sebagian besar membutuhkan waktu yang lama untuk terbentuk, sehingga bersifat terbatas dan tidakterperbaharui.

• Endapan mineral (ore deposits) dibentuk bersama proses pembentukan batuan beku, sedmen, metamorf, dan proses pelapukan. Banyak pula mineral logam yang melibatkan pergerakan fluida hidrotermal.

• Sumber energi yang bersifat tidak terperbaharui meliputi batubara, minyak dan gas bumi, dan energi nuklir. Sumber energi yang terperbaharui meliputi energi panas matahari, tenaga angin, tenaga air, tenaga pasang-surut, dan energi panasbumi. Saat ini energi terperbaharui hanya menyediakan sedikit dalam kebutuhan energi manusia.

• Lokasi dan kekayaan sumberdaya alam ditentukan secara langsung maupun tidak langsung oleh tektonika lempeng.

• Ada batas pertumbuhan populasi manusia yang ditentukan oleh keterbatasan sumberdaya alam.

3

shddin © 20112. Sumberdaya Mineral

Proses geologi dalam pembentukan sumberdaya mineral

shddin © 20113a. Sumberdaya Mineral Bentukan Batuan Beku

Sebaran endapan mineral bijih menurut tatanan tektonik.

4

shddin © 2011

Pembentukan batuan beku menghasilkan banyak endapan mineral.

3a. Sumberdaya Mineral Bentukan Batuan Beku

Beryllium Lithium

gold, silver, copper, lead,

zinc

iron, tungsten

shddin © 2011

Krom (chromite) terbentuk dari kristalisasi dan pengendapan lantai intrusi batuan beku basa. Bushveld Complex, South Africa.


chromite

olivine

5

shddin © 2011

Endapan tembaga terbentuk dari intrusi dangkal yang melibatkan fluida hidrotermal. Bingham, Utah.


shddin © 2011

Grasberg, Papua


6

shddin © 20113a. Sumberdaya Mineral Bentukan Batuan Beku

Grasberg, Papua

shddin © 20113b. Sumberdaya Mineral Bentukan Batuan Metamorf

iron, tungsten

7

shddin © 2011

Emas, intan, dan timah, umumnya ditemukan sebagai endapan tempatan di sepanjang alur sungai.

Konsentrasi mineral logam berat dalam endapan tempatan (placer deposits) oleh aliran sungai.

3c. Sumberdaya Mineral Bentukan Batuan Sedimen

shddin © 2011

Formasi Besi Berlapis (banded iron formations) terbentuk ketika mineral besi berselingan dengan rijang terendapkan di lingkungan laut dangal Pre-Kambrium.


8

shddin © 2011

Penguapan yang sangat tinggi akan menghasilkan garam dan magnesium.


Petani Garam, Madura

shddin © 20113c. Sumberdaya Mineral Bentukan Batuan Sedimen

9

shddin © 20113d. Mineral dan Proses Pelapukan – Pelarutan

shddin © 20114. Sumberdaya EnergiEnergi yang dikonsumsi oleh USAdisediakan dari banyak sumber.

10

shddin © 2011

Perkiraan konsumsi minyakbumi di USA (M. King Hubbert, 1956)

4. Sumberdaya Energi

shddin © 2011

Prediksi konsumsi energi dunia

4. Sumberdaya Energi

11

shddin © 20114a. Sumberdaya Energi TerbarukanEnergi panas matahari

shddin © 2011

Tenaga air.Hoover Dam, Colorado River.

4a. Sumberdaya Energi Terbarukan

12

shddin © 2011

Tenaga angin


shddin © 2011

Energi panasbumi


13

shddin © 2011

Lapangan Panasbumi Wayang Windu, Pengalengan


shddin © 2011

Air panas terbentuk akibat sirkulasi airtanah di sepanjang sesar yang dalam atau terpanaskan oleh tubuh intrusi magma dangkal.

4a. Sumberdaya Energi TerbarukanSistem panasbumi

14

shddin © 20114b. Sumberdaya Energi Tidak TerbarukanCoal deposits are commonly formed by the expansion and contraction of a shoreline and involve the associated movement of a swamp and barrier bar.

shddin © 20114b. Sumberdaya Energi Tidak Terbarukan

15

shddin © 2011

The origin of coal involves burial, compaction, and induration of plant material.

4b. Sumberdaya Energi Tidak Terbarukan

shddin © 2011

The principal coal deposits are concentrated in fluvial and deltaic sedimentary rocks on the continental platforms.


16

shddin © 2011

Panian Coal Mine, Semirara Island, Philliphine


shddin © 2011

The accumulation of oil and gas requires (1) a reservoir rock (a permeable formation, such as a porous sandstone) into which the petroleum can migrate and (2) a barrier (an impermeable cap rock) to trap the fluids.

Anticline. Oil, being lighter than water, migrates up the dip of permeable beds and can be trapped beneath a relatively impermeable shale bed in the crest of an anticline.


17

shddin © 2011


Fault trap. Impermeable beds can be displaced against a permeable stratum and then trap the oil as it migrates up dip.


shddin © 2011


Salt dome. Oil and gas may accumulate near the flanks of salt diapirs that pierce and arch up sedimentary layers.


18

shddin © 2011


Stratigraphic trap. Shale surrounding a sandstone lens can form and prevent the oil from escaping.


shddin © 2011

Three-Dimensional Seismic Imaging


19

shddin © 2011

Major oil and gas fields and deposits of oil shale are found on all of the continents except Antarctica. Most form in thick sedimentary deposits on continental crust.The rifted margins of Africa, South America, and Europe are important oil-producing environments.Other important fields lie in the sedimentary basins of the platform and the flanks of folded mountain belts.


shddin © 2011

Oil wells such as this in the North Sea are important symbols of our modern society


21

shddin © 2011

Methane hydrates consist of a methane molecule (CH4) trapped inside a crystalline “cage” of frozen water (left).They form on the deep seafloor as methane released by bacteria bubbles upward and is trapped in ice.They may be abundant enough to form an important source of natural gas and will burn if ignited with a match (right). However, they will be difficult to mine and pose environmental hazards because methane is a greenhouse gas.


shddin © 20114c. Energi NuklirUranium deposits and nuclear reactors may become a key part of the future production of energy, but only if the public becomes convinced that nuclear reactors are safe and that their waste products can be safely stored in repositories for long periods of time.

22

shddin © 20115. Tektonika Lempeng dan Sumberdaya MineralMineral resources are intimately related to the plate tectonic system. Some of the major ore-forming environments are shown on this schematic cross section. Plate tectonics controls igneous, sedimentary, and metamorphic processes and even the climate; it therefore exerts a major control on the types of ore deposits formed at any location and time.

shddin © 20116. Batas Pertumbuhan dan KonsumsiEarth’s human population has grown exponentially.

23

shddin © 2011

A computer model of resource consumption and its influence on other variables assumes no major changes in the physical, economic, and social relationships that historically have governed the development of the world system.

6. Batas Pertumbuhan dan Konsumsi

shddin © 20117. Pulau Easter

12 Sumberdaya Geologi

Documents

Transcript of 12 Sumberdaya Geologi