EarthSci: MINERALS AND ROCKS - EARTH MATERIALS AND PROCESSES

Volcanic or extrusive Igneous rocks

- Examples tuff and pyroclastic flow deposits (ignimbrite)

Plutonic or intrusive Igneous Rocks

- Examples: granite, diorite, gabbro

Plutonic or intrusive Igneous Rocks

- Phaneritic texture

Clastic sedimentary rocks

- are commonly classified based on particle size

Clastic sedimentary rocks

- are volcanic in origin (e.g. pyroclastics) and may have undergone some stages in the sedimentary processes that could be classified as sedimentary rock (e.g. volcanoclastic rocks).

Plutonic or intrusive Igneous Rocks

- causing slow cooling /crystallization

Non-clastic sedimentary rocks

- classified as evaporites (halite, gypsum and dolostone), precipitates (limestone) and bioclastics (coal, coquina)

Volcanic or extrusive Igneous rocks

- common textures: aphanitic, porphyritic (define groundmass vs phenocrysts), vesicular

Regional Metamorphism

- creates foliated metamorphic rocks

Non-clastic sedimentary rocks

- evaporation and precipitation from solution or lithification of organic matter

Volcanic or extrusive Igneous rocks

- examples: rhyolite, andesite, basalt

Regional Metamorphism

- examples: schist, gneiss

Volcanic or extrusive Igneous rocks

- fast rate of cooling/crystallization due to huge variance in the temperature between Earth's surface and underneath

Volcanic or extrusive Igneous rocks

- from solidified lava at or near the surface of the earth

Plutonic or intrusive Igneous Rocks

- from solidified magma underneath the earth

Clastic sedimentary rocks

- have the components of grains, matrix and cement

Contact metamorphism

- it creates non-foliated metamorphic rocks; an example is a hornfels

Contact metamorphism

- it occurs when a pre-existing rock gets in contact with magma which is the source of heat and magmatic fluids where metamorphic alterations and transformations occur around the contact / metamorphic aureole of the intruding magma and the rock layers.

Regional Metamorphism

- non-foliated rocks like marble also form through regional metamorphism, where pressure is not intense, far from the main geologic event

Regional Metamorphism

- occurs in a regional/large scale

Volcanic or extrusive Igneous rocks

- pyroclastic rocks: fragmental rocks usually associated with violent or explosive type of eruption.

1. Friedrich Mohs 2. Mohs Scale of Hardness

A German geologist/mineralogist named ______ in 1812 designed a hardness scale called the ____________

Amorphous

A mineral that do not have a crystal structure is described as ?

Metamorphism

Can involve changes in the physical and chemical properties of rocks in response to heat, pressure, and/or chemically active fluids

Saur TRUE

Can the color of a mineral can be different from its streak?

Fossil assemblages and stratification

Common sedimentary features include ____ and ____

Others - magnetism, odor, taste, tenacity, reaction to acid, etc.

For example, magnetite is strongly magnetic; sulfur has distinctive smell; halite is salty; calcite fizzes with acid as with dolomite but in powdered form; etc.

Weathering

Individual minerals can also display a variety of colors resulting from impurities from some geologic processes like ________.

Hardness

It is a measure of the resistance of a mineral to abrasion.

Color

It is the first impression in minerals but it is not very reliable because lots of minerals can occur in many different colors.

Crystal Form/Habit

It is the natural shape of the mineral before the development of any cleavage or fracture.

Mohs Scale of Hardness

It measures the scratch resistance of various minerals from a scale of 1 to 10, based on the ability of a harder material/ mineral to scratch a softer material.

Metallic

It's generally opaque and exhibit a resplendent shine similar to a polished metal

Streak

It's the TRUE color of a mineral in a powder form. It is inherent in almost every mineral and is a more diagnostic property compared to color.

Cleavage

It's the property of some minerals to break along specific planes of weakness to form smooth, flat surfaces.

Luster

It's the quality and intensity of reflected light exhibited by the mineral.

1. Plutonic Igneous Rocks 2. Volcanic Igneous Rocks

Molten rock material can solidify below the surface of the earth (_____ igneous rocks) or solidify at the surface of the Earth (_____ igneous rocks)

Stratification or layering

Results to a change in grain size and composition.

Igneous Rocks

Rocks that are formed from the solidification of molten rock material.

Rock Cycle

The constant recycling of minerals, how geologic processes occur both underneath and on the Earth's surface which allows a rock to change from one type to another.

Crystal Form/Habit

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

Crystal Form/Habit

The form reflects the supposedly internal structure (of atoms and ions) of the crystal (mineral).

Igneous Rocks

The process of solidification involves the formation of crystalline solids called minerals.

Specific Gravity

The ratio of the density of the mineral and the density of water.

Fossil assemblages

The remains and traces of plants and animals that are preserved in rocks

Minerals

These are solid, inorganic substances that are present in nature and has a definite chemical composition.

Cleavage

These planes exist because the bonding of atoms making up the mineral happens to be weak in those areas.

Sedimentary rocks

They form at surface or near surface conditions.

Specific Gravity

This parameter indicates how many times more the mineral weighs compared to an equal amount of water (SG 1).

A. Plutonic or intrusive Igneous Rocks B. Volcanic or extrusive Igneous rocks

Types of Igneous Rocks?

A. Contact metamorphism B. Regional metamorphism

Types of Metamorphic Rocks?

A. Clastic sedimentary rocks B. Non-clastic sedimentary rocks

Types of Sedimentary Rocks?

Non-metallic

Vitreous (glassy), adamantine (brilliant/diamond-like), resinous, silky, pearly, dull(earthy), greasy, among others.

i. The test is easy. ii. The test can be done anywhere and anytime. iii. The test is convenient for field geologists with scratch kits who want to make a rough identification of minerals outside the lab.

What are the advantages of the Mohs scale?

i. The Scale is qualitative, not quantitative. ii. The test cannot be used to accurately test the hardness of industrial materials.

What are the disadvantages of the Mohs scale?

1. Color 2. Streak 3. Luster 4. Hardness 5. Crystal Form/Habit 6. Cleavage 7. Specific Gravity 8. Other (ex: magnetism, odor, taste, tenacity, reaction to acid, etc.)

What are the several different mineral properties?

a. Metallic b. Non-metallic

What are the two kinds of minerals?

Igneous, Metamorphic, and Sedimentary

What are types of rocks?

Cleavage

When minerals break evenly in more than one direction, cleavage is described by the number of ______ directions, the angle(s) at which they meet, and the quality of _____.

1. Metamorphic rocks 2. Metamorphism

____ are rocks that form through the transformation of preexisting rocks (igneous, sedimentary, or metamorphic rocks) through the process of ________

Plutonic or intrusive Igneous Rocks

gradual lowering of temperature is indicated by the movement of magma from depth to surface

Contact metamorphism

heat and reactive fluids as main factors

Regional Metamorphism

pressure is the main factor which occurs in areas that have undergone considerable amount of mechanical deformation and chemical recrystallization during orogenic event which are commonly associated with mountain belts

Sedimentary rocks

rocks that form through the accumulation, compaction, and cementation of sediments.