Earth Sci Q1 M2

Molten rock material can solidify BELOW the surface of the earth

(plutonic igneous rocks)

solidify AT the surface of the Earth

(volcanic igneous rocks)

When minerals break evenly in more than one direction, how is cleavage described?

1) by the number of cleavage directions, 2) the angles at which they meet, and 3) the quality of cleavage

- have the components of grains, matrix and cement - are commonly classified based on particle size - 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).

Clastic sedimentary rocks

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

Cleavage

- heat and reactive fluids as main factors - 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. - it creates non-foliated metamorphic rocks; an example is a hornfels

Contact metamorphism

The external shape of a crystal or groups of crystals is displayed / observed as these crystals grow in open spaces. The form reflects the supposedly internal structure (of atoms and ions) of the crystal (mineral). It is the natural shape of the mineral before the development of any cleavage or fracture.

Crystal Form/Habit

glows under UV light

Fluorescence

A German geologist/mineralogist named _______ in 1812 designed a hardness scale called the __________

Friedrich Mohs, Mohs Scale of Hardness.

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

Hardness

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

Metamorphism

- evaporation and precipitation from solution or lithification of organic matter - classified as evaporites (halite, gypsum and dolostone), precipitates (limestone) and bioclastics (coal, coquina)

Non-clastic sedimentary rocks

define minerals (5)

Now I Can Define mineralS Natural Inorganic Crystalline Definite chemical composition Solid

light emitted by a substance without combustion or perceptible heat.

Phosphorescence

the ability of certain materials to generate an electric charge in response to applied mechanical stress.

Piezoelectric Effect

- from solidified magma underneath the earth - gradual lowering of temperature is indicated by the movement of magma from depth to surface - causing slow cooling /crystallization - Phaneritic textures - Examples: granite, diorite, gabbro

Plutonic or intrusive igneous rocks

- 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 - occurs in a regional/large scale - creates foliated metamorphic rocks - examples: schist, gneiss - non-foliated rocks like marble also form through regional metamorphism, where pressure is not intense, far from the main geologic event

Regional metamorphism

classification of minerals by chemical composition (7)

Silicates, oxides, sulfates, sulfides, carbonates, native elements, and halides

the ratio of the density of the mineral and the density of water. This parameter indicates how many times more the mineral weighs compared to an equal amount of water (SG 1). For example, a bucket of silver

Specific gravity

- from solidified lava at or near the surface of the earth - fast rate of cooling/crystallization due to huge variance in the temperature between Earth's surface and underneath - common textures: aphanitic, porphyritic (define groundmass vs phenocrysts), vesicular - examples: rhyolite, andesite, basalt - pyroclastic rocks: fragmental rocks usually associated with violent or explosive type of eruption. -Examples tuff and pyroclastic flow deposits (ignimbrite)

Volcanic or extrusive Igneous rocks

what are the types of sedimentary rocks

clastic sedimentary rocks, non-clastic sedimentary rocks

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

color

enumerate the different mineral properties which must be identified and defined (8)

color, streak, luster, hardness, crystal form/habit, cleavage, specific gravity and others (magnetism, odor, tenacity etc.)

2 types of metamorphic rocks

contact metamorphism, regional metamorphism

you see "double"

double refraction

enumerate advantages of the Mohs scale

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

enumerate the common everyday objects that can be used for hardness test

fingernail (2-2.5), copper coin/wire (3-3.5), nail(5-5.5), glass (5.5), steel knife (6.5-7)

-common sedimentary features include ______ and ________

fossil assemblages and stratification.

_______________are the remains and traces of plants and animals that are preserved in rocks while _________ or layering results to a change in grain size and composition.

fossil assemblages and stratification.

-rocks that are formed from the solidification of molten rock material.

igneous rocks

what are the three basic rock types

igneous, sedimentary, metamorphic

is the quality and intensity of reflected light exhibited by the mineral

luster

generally opaque and exhibit a resplendent shine similar to a polished metal

metallic

what are the 2 kinds of minerals?

metallic and non-metallic

___________ are rocks that form through the transformation of preexisting rocks (igneous, sedimentary, or metamorphic rocks) through the process of metamorphism.

metamorphic rocks

The process of solidification involves the formation of crystalline solids called ________

minerals

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

minerals

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

non-metallic

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.

others

what are the 2 types of igneous rocks?

plutonic or intrusive igneous rocks, volcanic or extrusive igneous rocks

give examples of crystal form/habit

prismatic, tabular, bladed, platy, reniform

enumerate the disadvantages of the Mohs scale

qualitative, the test cannot be used to accurately test the hardness of industrial materials.

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

sedimentary rocks

is 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. Note that the color of a mineral can be different from its streak. An example is pyrite (FeS2) which exhibits gold color but has a black or dark gray streak.

streak

The Mohs Scale of Hardness measures _________ from a scale of 1 to 10, based on the ability of a harder material/mineral to scratch a softer material.

the scratch resistance of various minerals