Minggu, 25 Oktober 2009

What is Geology?

What is Geology? - What Does a Geologist Do?

Geology Definition


Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them.
Some of them include material organism which have inhabited our planet.
The important to study in geology must followed the latest news about this teory of geology science because the study of structures, materials, processes, organisme, materials, and tectonics have changed over time following the developing of the electronical instrumental for collecting earth data (which mean hitech-instumental) and hitech modeling researches in laboratory.

Geologist Works

A Geologists learns and researchs to understand the history of our planet Earth (Geo). The better they can understand Earth’s history the better they can foresee how events and processes of the past might influence the future (The past is the key to the future Earth). In word in geologic law “The Present is the key to the past” .Here are some examples:

Geologists study earth processes: Many processes such as orogeneis (mountain forming process such collision and subduction which put up plate higher and form mountain row), landslides (land movement), earthquakes, floods and volcanic eruptions can be hazardous and harm people.
Geologists try to understand these processes well enough to avoid building important structures where they might be damaged including classifying zone of disaster to make amap guide of disaster zone. It will help many City and Area Planning for the future.

Geologists study earth materials: earth materials are used by people every day. They use oil , metals from mines, and water from underground. Geologists studies to locate rocks that contain important metals, plan the mines that produce them and Which methods more economic in used to remove the metals from the rocks. Of course this work including how to locate and produce oil, natural gas and ground water.

Geologists study earth history:

Study Earth History to learn and form a perfect teory of many schene structure which present shows us. Ofcourse the teory must proved with hight technology modeling to learned and proved the teory of the geology history. Many model such as real miniature modeling (including scalar component) and digital 3d modeling with data parameter helps to form the global of earth history, which is formed by many geology regional phenomenon.
Today geologist are concerned about climate change. Many geologists are working to learn about the past climates of earth and how they have changed across time which is connected with the earth outer core movement. This information is valuable to understand how our current climate is changing and what the results might be.

Geology as a Career:



To be a Geologist is a very interesting and rewarding career. Of course need four year training tobe a four-year college degree in geology. Pre-college students who are interested in becoming geologists should take a full curriculum of college preparatory courses, especially those in math, science, and writing. Courses related to computers, geography and communication are also valuable knowledge to be collected.
There are variety work and project need geologist, include: government planning agencies, natural resource companies, environmental consulting companies, government resources administration, non-profit organizations, and universities. For Geologists do a field work only part of the time after field the data and sample will be processed in laboratories, classrooms or offices. All geologists reports, do calculations, technic modeling and use computers.

Although a bachelor's degree is required for entry level employment,
many geologists earn master's and/or doctorate degrees to take a speciallity in geology science.A higher level of training, often in a geology specialty area such as paleontology, mineralogy, hydrology or volcanology. Advanced degrees will often qualify to be the geologist for supervisory positions, research assignments or teaching positions at the university level.

opportunities for geologists are very good if they are willing to move to a location where work is available.

Salary of Geologist


In Present day, Salary of geologist have recently ranged from $50,000 to $100,000 per year according to their experiences.

You Become a Geologist


If you are a pre-college student who’s willing to become a geologist, can prepare to become a geologist by doing well in all of your courses. Especially earth science and training is important, but other disciplines such as math, writing, language are used by every geologist during they everyday work.

Get in touch with the geology department, let them know you are interested and make arrangements to visit the campus. Don't be hesitant. Good schools and professors want to be contacted by interested students.

One of Oldest Geology Campus in Indonesia is Geology Departement in ITB (Institute Technology of Bandung / Bandung Institute of Technology) in Bandung City, West Java . The Study Geology Facilities in Bandung such as library, room laboratory, computer laboratory, studio, nature/field laboratory, equipment facility, and include one Indonesian museum of geology. . With Indonesia Island arc as they laboratory, probably you’ll become the next Indonesian International Expert Geologist.


Harlin Pasili Ansori

Sources :
Itb.ac.id or departemen Tehnik geologi ITB (Institut Teknologi Bandung)
geology.com
discovery chanel



video sources Geological Society of America

click to :
OCTOBER 2009 INTERNATIONAL EVENTS OF GEOLOGIST

Minggu, 18 Oktober 2009

September-October 2009 Large Earthquake in Indonesia Plus Field Important Information Map Equipment on This Area


  1. September-October 2009 Large Earthquake in Indonesia
  2. Plus Field Important Information Equipment on This Area
1. Large 7,6 SR Earthquake in West Sumatra Province Indonesia

A. News Source from ESDM News

Location:










The Earthquake Disaster in Padang Indonesia at September 29th-30th 2009, has main earthquake 7,6 SR and the next following earthquake in 6,2 SR. As a Fact this earthquake didn't followed by a tsunami (overlarge wave) disaster.

From DESDM Institution announced this earthquake happened because subduction (in area of crash zone from two big plate tectonic) of Indonesian Sea Plate (Australian Plate) under Asian Plate which located along West Coast of Sumatra Island, according USGS it's in subduction zone between Australian Plate and Sunda Plate. (note this Formation of collide is Subduction Form because the two plate which is Sea Plate and Continent Plate, has a Large Differentiation of Density between them. The lower density plate later subducts under the higher density plate).

This Earthquake didnot have ability to produce Tsunami because the epicentre (earthquake source point) deep enought location, and as the result didn't produce Large Power to made a tsunami.

Information from Indonesian Meterolog, Climate and Geophysist Institution (BMKG), this earthquake appeared in afternoon (30/9), at 17:16:09 WIB in 7,6 Scala Richter (SR). Epicentre (earthquke source point) layed on coordinate 0.84 LS - 99.65 BT, 71 Km depth from water sea level, 57 Km far from South West Pariaman, Sumatera Barat. The Second (following) earthquake
appear 22 minutes later, on 17:38:52 WIB in 6,2 SR, Epicentre location on 72 LS - 99.94 BT, at 110 Km depth, 22 Km SouthWest Pariaman, Sumatera Barat.


Other Large Earthquke in September - October in Island Arc Java-Sumatra is on Sukabumi South Java and Later in Sunday October 17th 2009 at Ujung Kulon, Sunda Strait. Both of them caused by Tectonic Plate movement.

see more informations about West Padang Earthquake from The Field in:
http://www.theage.com.au/world/second-quake-hits-sumatra-as-death-toll-soars-20091001-gd43.html

B.USGS Report Padang earthquake

Earthquake Details

Magnitude7.6
Date-Time
Location 0.725°S, 99.856°E
Depth81 km (50.3 miles) set by location program
RegionSOUTHERN SUMATRA, INDONESIA
Distances60 km (35 miles) WNW of Padang, Sumatra, Indonesia
225 km (140 miles) SW of Pekanbaru, Sumatra, Indonesia
470 km (295 miles) SSW of KUALA LUMPUR, Malaysia
975 km (600 miles) NW of JAKARTA, Java, Indonesia
Location Uncertaintyhorizontal +/- 4.2 km (2.6 miles); depth fixed by location program
ParametersNST=405, Nph=405, Dmin=534.3 km, Rmss=0.92 sec, Gp= 18°,
M-type=teleseismic moment magnitude (Mw), Version=A
Source
  • USGS NEIC (WDCS-D)
Event IDus2009mebz

From USGS Report (write as in original text) about Padang Earthquake September 30th 2009

Felt Reports

At least 1100 people were killed, 2181 were injured and thousands are still unaccounted for in the Padang area. More than 2650 buildings have been damaged in the area and landslides have disrupted power and communications. Felt (VII) at Padang. Widely felt throughout Sumatra and Java, Indonesia, Malaysia, Singapore and Thailand. A small local tsunami with wave heights of 27 centimeters (amplitude measured relative to normal sea level) was generated.

Tectonic Summary

The southern Sumatra earthquake of September 30, 2009 occurred as a result of oblique-thrust faulting near the subduction interface plate boundary between the Australian and Sunda plates. At the location of this earthquake, the Australian Plate moves north-northeast with respect to the Sunda plate at a velocity of approximately 60 mm/yr. On the basis of the currently available fault mechanism information and earthquake depth of 80 km, it is likely that this earthquake occurred within the subducting Australian Plate rather than on the plate interface itself. The recent earthquake was deeper than typical subduction thrust earthquakes that generally occur at depths less than 50 km. The subduction zone surrounding the immediate region of this event has not witnessed a megathrust earthquake in the recent past, rupturing last in an earthquake of M 8.5 or larger in 1797. Approximately 350 km to the south, a 250 km section of the plate boundary slipped during an Mw 8.4 earthquake in September 2007, while approximately 300 km to the north, a 350 km section slipped during the Mw 8.7 earthquake of March 2005. In early 2008, the plate boundary updip of today’s earthquake was active in a sequence of Mw 5-6 earthquakes. It is not clear how today’s earthquake is related to the sequence of megathrust subduction zone events on the shallower section of the plate boundary.



2. Important Maps to Equipt if you want to go to Padang Earthquake area in Indonesia

With the exception of public UN sources, reproduction or redistribution of the above text, in whole, part or in any form, requires the prior consent of the original source.

For Fund emergency Disaster conect to UNOCHA.

Your Important maps to equipt in Padang............

1. Map from reliefweb "The Temporary Map about region Damage because disaster in Padang Source Ocha, Reliefweb, and rovicky.wordpress.com and

2. Map from USG Humanitarian Assistance to Indonesia Earthquake, September 30th, 2009

Klick on Image

Small view

3. Indonesia: Population Map – Padang North [with building damages] (as of 01 Oct 2009)

klick on image

4. Potential Building Damage
Source(s):
- German Aerospace Center (DLR)
- International Charter Space and Major Disasters
Klick:
Potential Buiding Damage

5. Free Bakorsurtanal Earthquake Location Maps (Basic Maps of The Location)


http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0614.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0712.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0713.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0714.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0715.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0716.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0812.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0813.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0814.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0815.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0816.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0913.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0914.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/0915.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/1013.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/1014.jpg
http://www.bakosurtanal.go.id/upl_images/gempasumbar2009/rbi250k/1015.jpg











Reuter News about Medco Gas Production in South Sumatra 2009

Source: Reuters 10/13/2009, Location: Asia

Reuter News about Medco Gas Production in South Sumatra 2009


PT Medco Energi Internasional Indonesian an energy exploreris in talks to supply 50 million cubic feet per day of natural gas to PT PGN (Nation Gas Company Indonesia), anounced on Tuesday October 13th 2009.

The president director of Medco's unit Medco E&P Indonesia Mr. Budi Basuki, told the gas would be used by upstream operations of Chevron in Central Sumatra Regional Operation.

Chevron need from Medco Gas for supporting technology used to coax more oil from its Duri field, to increase production. This steamflood technology, can enhance recovery on oil fields where output is declining.

This Chevron Company already has a gas supplier witch is ConocoPhillips, but the gas volume from ConocoPhillips isn't enough to support its upstream project.

Basuki word to the press (reuter) "The deal is expected to supply 50 million cubic feet per day of gas with price around $4 per million British thermal unit. Medco will supply for three years,We will finalise the deal as soon as possible." Medco will supply the gas from its field in South Sumatra.".

BPMIGAS institution has previously said that Chevron produced around 300,000 barrels per day of crude from South Sumatran Duri and Minas fields in Indonesia.


List of October 2009 event for International Petroleum Oil

1. PetroChem Arabia 2009
Dhahran international exhibition center DIEC, El Dammam, Saudi Arabia 4-6 October 2009. Organized by BME Global Ltd.
2. 17th Kazakhstan International Oil&Gas Exhibition & Conference 2009
Atalent Exhibition Centre, Almaty, Kazakhstan, Kazakhstan 6-9 Oct 2009, Atalent Exhibition Centre, Almaty, Kazakhstan
3. Middle East Energy Security Forum (MEESEC 2009)
Dubai, United Arab Emirates 11-14 October 2009, organized by Fleming Gulf FZ
4. Human Capital Innovation in Oil and Gas & Perochemicals 2009
Cairo, Egypt 11-13 October 2009. Organized by Fleming Gulf FZ LLC
5. Carbon World Doha 2009
Marriott Hotel Doha, Qatar 14-15 October 2009. Oranized by Centre for Managament Technology
6. Shanghai International Petroleum Petrochemical SIPPE 2009
Shanghimart Expo, Shanghai, China 14-16 October 2009. Organized by AI Expo- Exhibition
7. Deepwater Southeast Asia Congress 2009
Sheraton Imperial, Kuala Lumpur, Malaysia 15-16 October 2009. Organized by Neoventure Corporation.
8. CIPPE 2009 Shanghai
Shanghai Everbright Convention & Exhibition Centre, Shanghai, China 15-17 October 2009. Organized by Beijing zhenwei Exhibition Co. LTD.
9. Turkmenistan International Investment Forum 2009
Exhibition Palace "Sergi Koshgi" Ashgabat, Turkmenistan 15-17 October 2009. Organized by IC Energy Limited
10. Mega Machx 2009
Dhahran international exhibition center DIEC, Saudi Arabia 18-20 October 2009. Organized by BME Global Ltd.
11. China International Petroleum Equipment & Technology Exb CIPEE2009
Dongying Huanghe International Exhibition&Confeence Center Dongying, Shandong, China 18-20 Oct 2009. Organized by Beijing CEW International Fair Co., Ltd.
12. LNG TECH Global Summit 2009
Beurs-WTC Congress Center, Rotterdam, Netherlands/Holland 19-21 October 2009. Organized by World Trade Group.
13. Oil Gas Chemistry International trade show 2009
Samara, Russia 20-22 October 2009. Organized by Expo Volga.
14. The 4th International Energy Week
Moscow, Russia 26-27 October, 2009. Organized by ICC, Ltd
15. MENA Mining Congress 2009
Sheraton Bahrain Hotel, Manama, Bahrain 26-29 October 2009. Organized by Terrapinn Pte Ltd.
16. Offshore Middle East 2009
Bahrian International Exhibition Centre, Manama, Bahrain 27-29 October 2009. Organized by PennWell Corporation
17. Bioenergy Markets West Africa 2009
Accra, Ghana
18. 4th Mangystau Regional Oil, Gas and Infrastructure Exhibition 2009
Mangystau Regional Exhibition Centre. Aktau, Kazakhstan

Number 7 in South East Region.
list
source : www.gulfoilandgas.com

Rabu, 03 Juni 2009

Information of West Lampung Mine and Energy Resources

West Lampung has many potential mine and energi resources, include oil, gold, silver, copper, basalt, sand, iron sand, andesit, perlit and sand stone.
IThere are also hydro power resources utilized for power plant i.e. Besai Hydro Power Plant, begun operation on March 31, 2001, and it's capacity totally about 2 x 45 MW and produces about 402 GWh per year.


This Regional potentials considered large in Subdistrict Suoh, from Class A (Strategic) Mining until The C Class (Public Mining).
The effectivity of utilizing this potential will significantly give large contribution to Lampung Barat development. In Pertamina database recorded that Geothermal in Subdistrict Suoh contains large amount of reserve and estimated to be able to support the electric energy deman for Lampung.
Ofcourse, an intensive coordination will be required with associated department and center government.

This energy resource is surely as high capital investment, especially for electric power plant. But we must remember, it locates near by National Park, and hence very sensitvely needs a serious care on environment impact because the main function of this national park is to maintain the lower course.
Various mining prospects generally descripted are as follows:

Geothermal

Potential Suoh Geothermal is high enough which can be used as electric supplier for Province Lampung. Indication of this potential energy showed by a lot of gaseous wells such as fumarol/solfatar and hot mudhole up to 95 celcius.
In Pertamina Exploration data (1994), estimated electric energy which can be produced from these wells is up to 300 MWe. Ofcourse this data, shows this geothermal potential in Suoh surely considered large amount.

Gold

Gold mineral located at hills surrounds Suoh, about south west at the border area with Tanggamus. This mineral is contained in Granite. according to the size of hills formation, this potential deposite considered has alarge gold (but has not yet approximately counted in exact economicaly count). It just approximatelly count by size of the quartz suture.

In addition, other locations such as Pesisir Utara, Pesisir Tengah and Pesisir Selatan are considered to have gold potential.

Silver

The silver mineral is also located at the same location as gold, due to formation of gold and silver occured on the same stone formation as granite. In other word this mineral genesis formed association with gold.

Tuffa, Sand and Stone

The C class material or public quarry is considered large and currently utilized by local people without the need of using high technology. These materials are usually used as building materials and formed from volcano sediment. Tuffa is also currently utilized by local people for making brick.

Iron Sand

This material mine are formed as sediment carried by stream or water movement and usually containing with mineral such as magnetit, hematite, limenit and other minerals. Iron sand sedimentation usually locates at coastal area, river sediment, and lake.


Diatomea Soil

This material genesis are formed from trace of diatomea, radiolaria, and algae. Physically, this material caractheristic are brownish white, fatigue, contains cavities, and when it dries, it floats on water.
This material is used for :
Filler in ceramics industry, heat isolation industry and sound.
Filter in sugar industry and oil company.

Mixer materials for concrete and building materials, catalisator carrier, water glass, ultramarine, lighter and matches, etc.


In Department of Mining and Energy Province Lampung in "Book of Information and Potential of Mining and Energy Province Lampung", this mining material in Province Lampung, only locates in Lampung Barat, Subdistricts Sumber Jaya, Villages Sukajaya and Sukapura.

Location of Mining and Quarry in Lampung Barat
Types
Location
Notes
Gold - Pesisir Selatan
- Pesisir Tengah
- Suoh
Requires further research
Silver - Pesisir Selatan
- Pesisir Tengah
- Suoh
Estimated
Perlit - Village Sukabumi
- Village Serdang
No activity yet
Diatome - Village Sukapura
- Village Sukajaya Subdistrict Sumber Jaya
Requires further research
Iron Sand Pesisir Utara Requires further research
Sillica Belalau Requires further research
Tembakak Stone Pesisir Utara Exploitation
Lime Stone - Pesisir Selatan
- Pesisir Tengah
- Pesisir Utara
Requires further research
Oil Suoh Exploration
Geothermal Suoh Exploration
Source :
- Dept. Mining and Energy, Province Lampung, 2001
Geology word Editor : Harlin Pasili Ansori ST.

Rabu, 25 Februari 2009

DKP protect Petroleum Island in East Lampung

BANDAR LAMPUNG :

a small island which has been expected store a lot of oil/petroleum in EastLampung, slowly disappear from Lampung Province area because upgrading of sea water level surface.

To anticipate this situation, Sea and Fish Culture Departement of Lampung Province has been budgeting fund about 100 milion rupiahs for surveying project to secure and protecting this island and other island near lampung region boundary.

"This Island called the hidden island because it's unseen because sea water level change. Lampung Province Goverment had puted a marker to sign/mark the position of this island. If This Petroleum Island had not been being protected and marked the island would be slowly vanish.

This Island hide alot of petroleaum oil resources.This Oil is one of Big aset of East Lampung Goverment and Lampung Province Goverment. The Island claimed as Lampung Province right and property. Indonesian Goverment warned the Lampung Province Goverment to keep wathcing, keeping, and protecting this island, and save the island from vanishing to under sea water level.

Soon DKP(Bureau of Little Island Keeper) put an agreement and associate withTNI AL (Indonesian Navy), they agree to come to this island and watch for marking this island and keep this island away from vanish. To Marking the Island soon there will be a new building build and the Island structure soon renovated. Ofcourse it will be needing alot of Civil Enginer and Geology Technic Enginer to renovated this Island.

There are 69 Island in outer side of Lampung Province. Some of them probably has the same potential resources such as this Island. But they are still unmarked.


Selasa, 24 Februari 2009


Pertamina Geothermal Produced 10 MWe Geothermal in Lampung Site

Bandar Lampung - PT Pertamina Geothermal Energy (PGE) has been produced geothermal electric power on 10 MWe from well production test UBL 3, villages Ulubelu, Tanggamus District, Lampung Province Wednesday November 19th 2008.

This production is one of their first step plan to developing geothermal industry in this area, where this site aproximately has potensial reach about 300 MWe.This Well (UBL 3) is one of 15 wells at Ulubelu Region to produce electric suply untill 2×55 MWe.

For the first step PT PGE will suply geothermal power to PT PLN Power Plan at PLTP unit 1 & 2. The next step project will be totaly controled by PT PGE.

UBL 3 Well has dip direction well about 2320 mku (meter size dip), temperature reservoir 260 °C with resevoar type dominated by water. Drilling for this well begun on March 31th 08 and finish on May 31th 2008, by using local expert.

PT PGE is amember company under PT Pertamina (persero) with their bussines in Management of Geothermal Energy.PT PGE produced electric about 252 MWe from Kamojang geothermalfield, Lahendong, Sibayak. Today PT PGE has been exploring in many region such as Lumut Balai (South Sumatra), HuluLais (Bengkulu), Sungai Penuh (Jambi). Expecting target in 5 year ahead PT PGE will produce 800 MWe.

Minggu, 22 Februari 2009

Basic Geology about mineral

Basic Geology about mineral
From :

http://www.geo.utep.edu/pub/ortega/minerals.PDF

Minerals
What is a mineral?
What is a rock?
Minerals
What is a mineral?
· Naturally occurring (not man-made)
· Inorganic (not part of or a product of a (once) living organism )
· Solid (not made of liquid or gas) with a definite chemical structure which
give it unique physical properties.

Minerals vs. Rocks
· There are nearly 4000 known minerals - but most rocks are formed by
only a few dozen minerals.
· Rocks are aggregates (mixtures) of minerals. So . . . minerals are the
building blocks of rocks.
A question for the future: How do minerals come together to form a rock?
Composition and Structure of Minerals
To understand how minerals form, we need to understand the characteristics of
elements and atoms.
Chemical Elements
Elements are the basic building blocks of minerals. There are over 100 known
elements.
Composition and Structure of Minerals
Atoms - smallest particle of matter that exhibits all the characteristics of an
element.
Atoms are made up of:
· Nucleus, which contains Protons (atomic number)- positive electrical
charges and Neutrons - neutral electrical charges (P +N = atomic mass)
· Shells which surround the nucleus and contain Electrons - negative
electrical charges
· The weight (density) of an element depends on the number of protons
and neutrons in the nucleus.
Combining Elements to Form Minerals
Elements combine with each other to form a wide variety of minerals (chemical
compounds)
Atoms combine chemically by gaining, losing, or sharing and electron with other
atoms. (opposites attract)
The new mineral (compound) will have very different physical properties from
the elements that combined to form it.
Since rocks are mixtures (not chemical combinations) of minerals, minerals keep
their physical properties within a rock.
Is it possible for two different minerals to have the same chemical
composition?
YES! Both diamond and graphite are made of carbon. The difference between
these two minerals is the way in which the carbon atoms are arranged.
Mineral Properties
Minerals have lots of different properties that help us identify them.
Crystal form, Luster, Color,
Streak, Hardness, Cleavage,
Fracture, Specific gravity,
Taste, Smell, etc.
Rock Forming Minerals
The most common rock forming minerals are composed of 8 elements:
Oxygen (O), Silicon (Si),
Aluminum (Al), Calcium (Ca), Sodium (Na), Potassium (K),
Iron (Fe), and Magnesium (Mg)
There are just a few dozen minerals that we call the rock-forming minerals
Composition of the Crust
The most abundant elements in Earth's crust are:
Oxygen (46.6% by weight)
Silicon (27.7% by weight)
Silicate Minerals
Silicate minerals, minerals built primarily from silicon-oxygen tetrahedrons, are
the most common rock-forming minerals.
Silicate minerals are grouped according to how the tetrahedrons are arranged in
the mineral.
Silicate Mineral Groups
Olivine - independent tetrahedrons (Mg, Fe)
Pyroxene group - tetrahedrons are arranged in chains (Mg, Fe)
Amphibole group - tetrahedrons are arranged in double chains (Mg, Fe, Ca)
Micas - Tetrahedrons are arranged in sheets
Two common types of mica:
Biotite (dark) (K, Mg, Fe, Al),
Muscovite (light) (K, Al)
Silicate Mineral Groups
Feldspars - Three-dimensional network of tetrahedron
Two common types of feldspars:
Orthoclase (K, Al)
Plagioclase (Ca, Na)
Most plentiful mineral group
Quartz - three-dimensional network of tetrahedrons (SiO2)
Mineral Color
Mineral color is often governed by presence of Mg, Fe (dark) or absence of these
elements (light).
Non-Silicate Minerals
Major groups:
Oxides (FeO2), Sulfides (PbS), Sulfates (CaSO4),
Halides,
"Native" elements (gold),
Carbonates (limestone, marble) (CaCO2)
Mineral Resources
Ore - rock that contains useful metallic minerals that can he mined at a profit.
Since 98% of the Earth's crust is made up of 8 elements, an element/mineral has
to be concentrated at levels above normal for profitable mining.
How do minerals "mix" together to form rocks?
What is the rock cycle (Chapter 2)?
Igneous Rocks
Importance of Igneous Rocks
• Understanding potential hazard represented by volcanic activity and how to
prevent loss of life/property.
n Kilauea (Hawaii)
n Montserrat, Mount St. Helens
• Many mineral resources are associated with igneous rocks
n Copper
n Gold
Types of Igneous Rocks
• There are two main types of igneous rocks:
n Extrusive (volcanic)
Ø form at the surface
Ø molten rock "pushed out" of the earth
Ø cool quickly
Ø fine-grained (small crystals)
n Intrusive
Extrusive (Volcanic) Rocks
• What happens to material pushed out onto the Earth's surface due to volcanic
activity?
n Depends on the kind of magma:
Ø Mafic (Lo Si ; Hi Mg, Fe) lava flows more easily than Felsic lavas (Hi Si;
Low Mg, Fe).
Ø Mafic lavas also let dissolved gas, water out of the magma easily.
n Two main types: lava flows and explosive material.
Lava Flows
• Lava Flows (Gentle) - molten rock flows along surface and solidifies.
n Aa (colder, slower moving flows)
n Pahoehoe (warmer, faster moving flows)
n Obsidian (glassy)
n Vesicular (gas bubbles)
Explosive Material
• In thick gas-rich magmas, release of the gas will cause explosion of material
out of the volcanic vent.
n Pyroclastics ("fire fragment") - any fragments of volcanic rock ejected into
the air
Ø Characterized by size: ash, lapilli, cinders, bombs, blocks
n When the hot sticky fragments come to rest, they stick together to form
rock:
Ø pumice, tephra, tuff
Styles of Explosive Eruptions
n Eruption column
n Lateral blast
n Pyroclastic flow
Controls on Eruption Style
• Temperature
n High temperature --> low viscosity
Ø Hot - runny
Ø Cool(er) - syrupy
• Composition
n High Silica = gooier = high viscosity
Ø Food analogy: water vs. syrup vs. honey
n Felsic magmas have more silica than mafic magmas.
• Gas content
n Dissolved gases provide explosive force to propel material from a volcano
n Analogy: splattering spaghetti sauce
Types of Volcanoes
• Shield Volcanoes
n Built of basaltic lava flows and a small amount of pyroclastic material.
n Has the shape of a broad dome (roughly resembles a warrior's shield).
• Cinder Cones
n built of ejected lava fragments.
n Usually small (< 1000 ft high), have steep slopes, and often form near
bigger volcanoes.
• Stratovolcanoes
n Composite volcanoes built of interbedded lava flows and pyroclastic
deposits.
• Fissure eruptions
n Liquid flows (usually) from elongated fractures or cracks on the slopes of a
volcano.
• Calderas
n Large bowl-shaped crater that form by the collapse of a volcanic cone after
an eruption.
Dangers Associated with Volcanoes
• Pyroclastic flows
• Poison gases
• Tephra
n Materials of all types and sizes that are erupted from a crater or volcanic
vent and deposited from the air.
• Tsunamis (tidal waves)
n Huge (~ 50 ft high) seawave produced by a volcanic eruption, an
underwater landslide, or an earthquake.
n Waves carry a lot of a material with them.
• Mudflows (Lahars)
• Property damage
• Earthquakes
n large earthquakes are associated with volcanic activity and cause lots of
damage
Intrusive Rocks
• Form underground
n Molten rock "enters" rock from below,
n Cool slowly,
n Coarse-grained (large crystals)
Intrusive Rock Textures
• Textures
n Appearance of rock based on size and arrangement of crystals
Ø Coarse-grained - large crystals (visible to the naked eye)
Ø Porphyritic - large crystals embedded in matrix of small crystals.
Composition
• The kind of mineral that crystallizes out of a magma depends on magma
temperature and chemistry.
• Bowen's Reaction Series
Bowen's Reaction Series
n Discontinuous Branch - As magma cools slowly mineral formed at higher
temperature reacts with remaining magma to form the next mineral (e. g.
olivine will recrystallize into pyroxene)
n Continuous Branch - Same mineral forms, but has continuously changing
chemical composition calcium-rich plagioclase becomes more sodium-rich
as temperature drops).
n Exceptions: a) quick cooling; b) crystal settling (chemical composition of
magma changes)
Composition
Geometry of Plutons
• Massive bodies
n stocks
n batholiths
n laccoliths
• Tabular bodies
n dikes - vertical
n sills - horizontal
n volcanic necks (inside of a cinder cone)