Minerals, Rocks: Igneous, Sedimentary, Metamorphic, Rock Cycle

What are the defining characteristics of a mineral?

Naturally occurring, inorganic, crystalline, solid, and having a distinct chemical composition

In which ways do minerals form?

Precipitation, crystallization, and biomineralization

Precipitation

Dissolved minerals come out of solution to form solids

Crystallization

Minerals crystallize in a systematic fashion as magma cools

Biomineralization

Living organism produce minerals

What are the classification properties of minerals?

Luster, color, streak, crystal habit, hardness, cleavage, and fracture

How do Igneous rock form?

By the melting and cooling of magma

What are the igneous compositions?

Ultra mafic, mafic, intermediate, and felsic

Ultra mafic composition

Very dark/green colored, rich in iron and magnesium

Mafic composition

Dark in color made up of magnesium and iron

Intermediate composition

Grey in color, the composition lying between felsic and mafic

Felsic composition

Composed almost entirely of light-colored silicates

What do igneous compositions tell us?

WHERE the rock formed

What are the igneous textures?

Phaneritic, Porphyritic, Aphanitic, Glassy, Pyroclastic

Phaneritic texture

Coarse grained minerals that are easily visible without magnification

Porphyritic texture

Two distinct sizes of crystals. Larger crystals embedded into smaller crystals

Aphanitic texture

Crystals are too small and need to be observed under a microscope

Glassy texture

Rapid cooling, crystals are able to form

Pyroclastic texture

Consolidation of individual rock fragments that are ejected during a violent volcanic eruption

What do igneous rock textures tell us?

HOW rocks were formed

How are sedimentary rocks formed?

Layers of sediment are cemented together over time

List the steps of sedimentary rock formation

Weathering, transport/erosion, deposition, lithification

What are the types of sedimentary rocks?

Clastic, chemical, and organic

Clastic rock

Composed of weathered fragments of older rock

Chemical rock

Form when minerals crystallize directly from water

Organic rock

Forms from remains of living organisms

Properties of clastic rocks

Composed of fragments of preexisting rocks

Properties of chemical rocks

Fine grain size with crystalline texture and calcite crystals

Properties of organic rocks

High carbon content

How are metamorphic rocks formed?

Preexisting rock is altered through heat and pressure

What are the driving forces of metamorphism?

Increases in heat, pressure, or a change in equilibrium

What are the types of metamorphism?

Contact, burial, hydrothermal, regional

Contact metamorphism

A type of high heat metamorphism where parent rock comes into contact with magma

Burial metamorphism

Type of high-pressure metamorphism where parent rock gets buried

Hydrothermal metamorphism

Type of high heat metamorphism occurs when very hot water reacts with rock, altering its mineralogy and chemistry

Regional metamorphism

Type of extreme pressure and high heat metamorphism driven by fluid activity along convergent boundaries covering large areas

What are the metamorphic fabrics?

Foliated, non-foliated, and porphyroblast

Foliated fabric

Distinct layering or platy minerals

Non-Foliated fabric

Homogenous appearance with no layers

Porphyroblast fabric

Minerals are embedded within other minerals

Stages of the rock cycle

Igneous to sedimentary to metamorphic

Processes of the rock cycle

weathering, destabilization, and melting

What is a depositional environment?

A depositional environment is a location where sediment accumulates, influenced by factors such as water, wind, and energy. It plays a crucial role in the formation of sedimentary rocks

What depositional environment do ripple marks form?

In a medium energy environment that indicates agitation through water or wind such as a stream

What depositional environment do mud cracks form?

In a low energy environment where sediment evaporates indicating a once wet now dry environment such as evaportic

What depositional environment does graded bedding form?

In a setting with varying energy levels, typically found in underwater landslides or turbidity currents, where larger particles settle first followed by finer sediments

What depositional environment does cross bedding form?

In environments with strong currents or wind, such as river channels or dunes, where sediment is deposited at an angle