Earth Science: Rocks, Minerals & Mineral Resources

1. Sediments

2. Sedimentary Rock

3. Metamorphic Rock

4. Magma

5. Extrusive Igneous Rock

6. Intrusive Igneous Rock

1. Sediments

2. Sedimentary Rock

3. Metamorphic Rock

4. Magma

5. Extrusive Igneous Rock

6. Intrusive Igneous Rock

(1) Rocks that has gone through weathering (2) Formed through Lithification (compaction and cementation) (3) Caused by Metamorphism (heat and intense pressure) (4) Rocks that are melted due to high heat; Able to move around (5) Magma that has cooled down very quickly (6) Magma that cooled off slowly, forming large crystals

1. Weathering (transport & deposition)

2. Lithification (compaction & cementation)

3. Metamorphism (heat & intense pressure)

4. Melting

5. (a)Cooling or (b)Crystallization

(1) Breaks down rock that is transported and deposited as SEDIMENT (2) Process where sediment is compacted and cemented to form SEDIMENTARY ROCK (3) Process when sedimentary rock is buried deep in the crust, heat and pressure(stress) change it to METAMORPHIC ROCK (4) Melted metamorphic rock due to high heat beneath Earth’s surface (5) When (a)lava or (b)magma cools and solidifies, forming igneous rock: (a)Extrusive and (b)Intrusive

Uplift

lift up from the earth, as by geologic forces

Igneous rock

• rocks formed by melting, cooling and crystallization of other rocks

• the solidified products of once-molten material that was created by melting in the upper mantle or crust

Extrusive Igneous Rock

• igneous rocks produced through rapid cooling

• rocks formed above the Earth’s surface

Intrusive Igneous Rock

• igneous rocks produced through slow cooling below the Earth’s surface

Texture

• described the overall appearance of an igneous rocks, based on the SIZE and ARRANGEMENT of its interlocking crystals

Course-grained(Phaneritic)

• have inter-grown crystals that are roughly equal in size and large enough that the individual minerals within can be identified and formed by slow cooling BELOW ground

Fine-grained(Aphanitic)

• are composed of individual crystals that are too small to be identified without strong magnification and fromed by rapid cooling ABOVE ground

Porphyritic

• are composed of both visible and non-visible crystals and formed by different cooling systems

Glassy

• have no crystal structure, and probably formed by very rapid cooling(such as on the surface of a lava or when lava enters water)

Vesicular

• have voids created by rapid cooling which causes air bubbles to trapped inside

Pyroclastic(Fragmental)

• results from the consolidation of fragments that may include ash, once molten blobs or angular block that were ejected during an explosive volcanic eruption

Composition

• refers to the abundance and type of minerals it contains Ex. Igneous rocks can be divided intro groups based on the proportions of light and dark silicate minerals

Felsic(Granitic)

1. Granite

2. Rhyolite • Quartz & Potassium Feldspar

• composed mainly of the light-colored minerals. Dark-colored minerals account for no more than fifteen percent of the minerals in rocks in this group

• its dominant minerals are Quartz & Potassium feldspar

• its examples are 1 & 2 • Dominant Minerals?

Intermediate(Andesitic) 3. Diorite 4. Andesite • Amphibole & Plagioclase Feldspar

• are mixtures of both light-colored minerals and dark-colored minerals

• its dominant minerals are Amphibole and Plagioclase feldspar

• its example are 3 & 4 • Dominant Minerals?

Mafic(Basaltic) 5. Gabbro 6. Basalt • Pyroxene & Plagioclase Feldspar

• contain abundant dark-colored minerals

• its dominant minerals are Pyroxene and Plagioclase feldspar

• its examples are 5 & 6 • Dominant Minerals?

Ultramafic ? Peridotite • Olivine & Pyroxene

• composed almost entirely of the dark silicate minerals

• its dominant minerals are Olivine and Pyroxene • Dominant Minerals?

Sedimentary rocks

• formed by weathering, erosion, deposition, compaction and cementation of other rocks

• formed in areas where water, wind or gravity deposit sediments

• materials that accumulate as sediment have two principal sources: SOLID PARTICLES and SOLUBLE MATERIALS

Detrital sedimentary rocks

• rocks formed from transported solid particles

Chemical and Biochemical sedimentary rocks

• rocks formed soluble materials

1. Clay minerals

2. Quartz

3. Calcite

4. Evaporate minerals

5. Altered plant fragments

COMPOSITIONS: most sedimentary rocks contain a high percentage of one of the following

Clastic

• rocks that were made by other rock materials that have been weathered and eroded and is grouped according to the grain size they are maid of

• one of the basic TEXTURES exhibited by sedimentary rocks

1. Rudaceous

2. Arenaceous

3. Argillaceous

• types of Clastic Texture (1) made of gravel; sediment diameter greater than 2mm (2) made of sand; sediment diameter of 0.063 mm to 2mm (3) made of silt or clay; sediment size of less than 0.063 mm

Nonclastic

• rock were made chemically and organically. Its grouped into 3 types

• one of the basic TEXTURES exhibited by sedimentary rocks

Evaporites

• type of Nonclastic Texture

• formed from the evaporation of water leaving the dissolved minerals to crystallize

Precipitates

• type of Nonclastic texture

• rocks formed when minerals from a supersaturated waters start to crystallize at the bottom of the solution

Bioclastics

• type of Nonclastic textures

• rock formed from compacted organic matter

Metamorphic Rocks

• formed by heat and pressure changing one type of rock intro another type of rock

• these types of rocks are formed near lava intrusions, at plate subduction zones, and in deep mountain roots

Contact Metamorphism

• changes that occur when magma is injected or is in contact with surrounding rocks; usually happens on hot spots or magmatic plumes

Regional Metamorphism

• changes that occur because of increasing heat and pressure; happens in subduction zones or deep mountain roots

Foliated Rocks

• form when differential pressure causes minerals to form in layers

• these rocks will have stripes or planes that they will break easily along

• these “stripes” don’t usually line up with the original bedding planes in sedimentary rocks

• metamorphic rocks based on Foliation

A. Salty or Rock Cleavage B. Phyllite texture C. Schistosity D. Gneissic texture

• different foliated textures

Non-foliated Rocks

• metamorphic rocks formed in areas where the pressure from all sides was equal, so there is no “linear” quality to the rocks

• consist of inter-grown crystals of various size and are most often identified by determining their mineral composition.

• metamorphic rocks based on Foliation

E. Coarse grained F. Fine grained

• two non-foliated textures

Minerals

• any NATURAL OCCURRING INORGANIC SOLID that possesses an orderly CRYSTALLINE STRUCTURE and be represented by a CHEMICAL FORMULA

Luster

• physical property of minerals

• used to described how light is reflected from the surface of a mineral

• two main types: Metallic & Nonmetalic; with submetalic in the middle

Ability to Transmit Light

• physical property of minerals

• opaque

• translucent

• transparent

Color

• physical property of minerals

• the visible color that mineral sample appears to the naked eye

• not a reliable characteristic to use for mineral identification

Streak

• physical property of minerals

• the color of a mineral in its powdered form

• tested by rubbing a sample against an unglazed ceramic streak plate

Crystal Form or Habit

• physical property of minerals

• the external shape of a crystal or groups of crystals is a displayed/observed as these crystals grow in open spaces

Hardness

• physical property of minerals

• a measure of the resistance of a mineral to abrasion

• uses Mohs scale

Cleavage

• physical property of minerals

• the tendency of a mineral to cleave, or break, along flat, even surface

Fracture

• physical property of minerals

• uneven breakage of a mineral

Specific gravity

• physical property of minerals

• a number representing the ratio of a mineral’s weight to the weight of an equal volume of water

Silicates

• property of minerals: Mineral groups

• minerals composed of mostly silicon (Si) and oxygen (O) combined with one or more metals and other elements

• makes up over 90% of the Earth’s Crust

• its basic building block is silicon-oxygen tetrahedron

1. Olivine group

2. No Cleavage

3. Single tetrahedron silicate structure

4. Example is Olivine

• Silicate mineral made of lone SiO4 tetrahedral structure

• usually has glassy luster, small and rounded feature and conchoidal fracture

1. Pyroxene Group

2. 2 perfect cleavage directions

3. Single chain silicate structure

4. Example is Augite

• Silicate mineral made of single-chain SiO4 tetrahedral structure

• usually has white to green and dark green to black

1. Amphibole Group

2. 2 imperfect cleavage directions

3. Double chain silicate structure

4. Example is Hornblende

• generally dark-colored, like pyroxene, but differs in cleavage

1. Micas

2. Biotite

3. Muscovite

4. 1 perfect cleavage direction

5. Example is Biotite

6. Example is Muscovite

• usually has a slight silver to black color and relatively soft

1. Feldspars

2. Potassium feldspar

3. Plagioclase

4. Has 1 perfect cleavage

5. Quartz

6. Has no cleavage

7. Three-dimensional networks

8. Example is Potassium feldspar

9. Example is Quartz

• usually has light silver to black color and relatively soft; • can also be very hard, have conchoidal fractures, clear or varying color and varying habit

Oxides ? Chromite

• property of minerals: Mineral groups: NON-SILICATES

• minerals containing oxygen anion combined with one or more metals ions

Sulfates ? Anglesite

• property of minerals: Mineral groups: NON-SILICATES

• minerals containing sulfur and oxygen anion combined with other ions

Sulfides ? Arsenopyrite

• property of minerals: Mineral groups: NON-SILICATES

• minerals containing sulfur anion combined with one or more ions

Carbonates ? Calcite

• property of minerals: Mineral groups: NON-SILICATES

• minerals containing the carbonate anion combined with other elements

Halide ? Halite

• property of minerals: Mineral groups: NON-SILICATES

• minerals containing halogen elements combined with one or more elements

Native Elements

• property of minerals: Mineral groups: NON-SILICATES

• minerals that form as individual elements

• metals and inter-metals, semi-metals, non metals

Resources

• is the term used to describe the total amount of any given geological material of potential economic interest, whether discoverable or not

Reserve

• is the term used to describe the portion of a resource that has been discovered or inferred with sme degree of certainty and can be extracted for a profit

Mineral Occurrence

• concentration of a mineral that is of scientific or technical interest

Ore

• naturally-occurring material from which a mineral or minerals of economic value can be extracted

Ore Deposit

• mineral deposit that has been tested and known to be economically profitable to mine

Aggregate

• rock or mineral material used as filler in cement, asphalt, plaster, etc; generally used to describe nonmetallic deposits

Mineral Deposits

• mineral occurrence of sufficient size and grade or concentration to enable extraction under the most favorable conditions

• most rocks of the Earth’s crust contain metals and other elements but at very low concentrations

• there are naturally occurring processes(geologic processes) that can concentrate minerals and elements in rocks of a particular area

1. Metallic Minerals

2. Non-metallic minerals

• types of mineral resources (1) gold, silver, copper, platinum, iron (2) talc, fluorite, sulfur, sand, gravel

Magmatic Ore Deposits

• classification of Ore Deposits

• valuable substances are concentrated within an igneous body through magmatic processes suck as crystal fractionation, partial melting and crystal settling

• these processes can concentrate the ore minerals that contain valuable substances after accumulating elements that were once widely dispersed and in low concentration within the magma

Hydrothermal Ore Deposits

• classification of Ore Deposits

• concentration of valuable substances by hot aqueous (water-rich) fluids flowing through fractures and pore spaces in rocks

• hydrothermal solutions - are hot, residual watery fluids derived during the later stages of magma crystallization and may contain large amount of dissolved metals.

• There are numerous hydrothermal mineral deposits as compared to the different types of deposits: Vein Type, Disseminated, Massive Sulfide, and Stratabound Deposits

Sedimentary Ore Deposits

• classification of Ore Deposits

• some valuable substances are concentrated by chemical precipitation coming from lakes or seawater

• has 2 types

Evaporite Deposits

• type of Sedimentary Ore Deposits

• typically occurs in a closed marine environment where evaporation is greater than water inflow. As most of the water evaporates, the dissolved substances become more concentrated in the residual water and would eventually precipitate

Iron Formation

• type of Sedimentary Ore Deposits

• these deposits are made up of repetitive thin layers of iron-rich chert and several other iron bearing minerals such as hematite and magnetite

Placer Ore Deposits

• classification of Ore Deposits

• deposits formed by the concentration of valuable substances through gravity

• usually aided by flowing surface waters either in streams or along coastlines

• usually involves heavy minerals that are resistant to transportation and weathering

Residual Ore Deposits

• classification of Ore Deposits

• a type of deposit that results from the accumulation of valuable materials through chemical weathering processes

• during the process, the volume of the original rock is greatly reduced by leaching

• important factors for the formation of this deposit include parent rock composition, climate (tropical and sub-tropical: must be favorable for chemical decay) and relief (must not be high to allow accumulation)

• Common deposits are bauxites and nickeliferous laterites.

Project Design

• types of Mineral Exploration

• This is the INITIAL STAGE in formulating a project.

• This involves review of all available data (geologic reports, mining history, maps, etc.), government requirements in acquiring the project, review of social, environmental, political and economic acceptability of the project, and budget and organization proposals.

Field Exploration

• types of Mineral Exploration

• this stage involves PHYSICAL ACTIVITIES in the selected project area.

• this can be subdivided intro three phases

Regional Reconnaissance

• Field Exploration Phase 1

• The main objective is to identify targets or interesting mineralized zones covering a relatively large area (regional). In general, the activities involve regional surface investigation and interpretation.

Detailed Exploration

• Field Exploration Phase 2

• This involves more detailed surface and subsurface activities with the objective of finding and delineating targets or mineralized zones.

Prospect Evaluation

• Field Exploration Phase 3

• The main objective is to assess market profitability by (1) extensive resource, geotechnical and engineering drilling (2) metallurgical testing and (3) environmental and societal cost assessment.

Feasibility Study

• types of Mineral Exploration

• determines and validates the accuracy of all date and information collected from the different stages.

• the purpose is for independent assesses to satisfy interested investors to raise funds and bring the project into productions

Surface Mining

• Mining Method

• utilized to extract ore minerals that are close to Earth’s surface

• SHALLOW deposits are removed

Quarry (quarrying)

• types of surface mining

• a place from which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate has been excavated from the ground

Open-Pit Mining

• types of surface mining

• machines dig holes and remove ores, sand grave and stone

• toxic groundwater can accumulate at the bottom

Area Strip Mining

• types of surface mining

• Earth movers strips away overburden and giant shovels removes mineral deposit

• often leaves highly erodible hills of rubble called spoil banks

Contour Strip Mining

• types of surface mining

• used on hilly or mountainous terrain

• unless the land is restored, a wall of dirt is left in front of a highly erodible bank called highwall

Underground Mining

• Mining Method

• utilized to extract ore minerals from the orebody that is deep under the Earth’s surface

Smelting

• Mineral extraction

• a process of applying heat to ore in order to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals.

Heavy media separation

• Mineral extraction: Milling Recovery Method

• The crushed rocks are submerged in liquid where the heavier/denser minerals sink thus are separated from the lighter minerals.

Magnetic Separation

• Mineral extraction: Milling Recovery Method

• If the metal or mineral is magnetic, the crushed ore is separated from the waste materials using a powerful magnet.

Flotation

• Mineral extraction: Milling Recovery Method

• The powdered ore is placed into an agitated and frothy slurry where some minerals may either sink to the bottom or may stick to the bubbles and rise to the top thus separating the minerals and metals from the waste.

Cyanide Heap Leaching

• Mineral extraction: Milling Recovery Method

• This method used for low-grade gold ore where the crushed rock is placed on a “leach pile” where cyanide solution is sprayed or dripped on top of the pile.