Understanding Rocks and Minerals in the Lithosphere

Lithosphere

The outer part of the Earth, consisting of the crust and upper mantle.

Geological Cycle

The cycle that describes the transformation of rocks through processes such as erosion, sedimentation, and metamorphism.

Mineral

Solid, naturally occurring, inorganic, crystalline substance.

Igneous Rocks

Rocks formed from the cooling and solidification of magma.

Sedimentary Rocks

Rocks formed by the accumulation and compaction of mineral and organic particles.

Metamorphic Rocks

Rocks that have been transformed by heat, pressure, or chemically active fluids.

Geologic Time Scale

A system of chronological dating that relates geological strata to time. The earth is 4.54 Billion years old, and the universe is 13.80 billion years old.

Quartz

A mineral composed of silicon dioxide (SiO2), the most common single mineral in Earth's crust.

Galena

A mineral composed of lead sulfide (PbS), often found in ore deposits.

Felsic

Igneous rocks that are rich in silica and light in color.

Mafic

Igneous rocks that are rich in magnesium and iron, darker in color.

Extrusive Rocks

Igneous rocks that form from lava that cools quickly on the Earth's surface.

Intrusive Rocks

Igneous rocks that form from magma that cools slowly beneath the Earth's surface.

Granite

A felsic, intrusive igneous rock with a coarse texture.

Basalt

A mafic, extrusive igneous rock with a fine texture.

Rhyolite

An extrusive igneous rock that is fine-grained and typically light in color.

Crystallization of Magma

The process by which magma cools and solidifies to form igneous rocks.

Cooling Rate

The speed at which magma cools, affecting crystal size in igneous rocks.

Fine-grained Texture

An igneous rock texture characterized by small crystals due to rapid cooling.

Coarse-grained Texture

An igneous rock texture characterized by large crystals due to slow cooling.

Porphyritic Texture

An igneous rock texture characterized by large crystals embedded in a finer-grained matrix.

Glassy Texture

An igneous rock texture that lacks crystal structure, formed by very rapid cooling.

Oceanic Plates

Tectonic plates that are primarily composed of basalt and are denser than continental plates.

Continental Plates

Tectonic plates that are primarily composed of granite and are less dense than oceanic plates.

Tephra

Volcanic material ejected during an eruption, including cinders and ash.

Igneous Rocks

Rocks formed through the cooling and solidification of magma or lava.

Sedimentary Rocks

Rocks formed from the accumulation and compaction of mineral and organic particles.

Weathering

Chemical and/or physical mechanisms that change existing rock into smaller particles.

Transportation

The movement of sediment by ice, air, or water to another area.

Deposition

The process where sediment material comes to rest.

Lithification

The process of turning sediment into rock through compaction and cementation.

Compaction

The process where the weight of overlying sediment decreases pore space.

Cementation

The process where chemical precipitation in pore spaces 'glues' the rock together.

Strata

Layers of sedimentary rock that relate to the depositional environment.

Bedding Planes

Horizontal separations between strata.

Joints

Vertical separations within beds of rock.

Clastic Sedimentary Rocks

Rocks formed from fragments of older rocks, transported by water, wind, and ice.

Bioclastic Sedimentary Rocks

Rocks made up of shell fragments.

Chemical Sedimentary Rocks

Rocks formed by the precipitation of dissolved ions in sea or lake water.

Organic Sedimentary Rock

Rocks composed of plant remains, such as coal.

Conglomerate

A type of clastic sedimentary rock consisting of angular or rounded gravel in a sand matrix.

Sandstone

A clastic sedimentary rock formed from sand deposited by oceans, rivers, or wind.

Shale

A clastic sedimentary rock that forms from mud deposited on the floor of shallow oceans.

Limestone

A chemical sedimentary rock primarily composed of calcite (CaCO3).

Dolostone

A chemical sedimentary rock primarily composed of dolomite (MgCaCO3).

Coal

A type of organic sedimentary rock composed of plant remains.

Depositional Environments

Different settings where sediment is deposited, affecting the characteristics of sedimentary rocks.

Mt. Everest

The summit at 29,029 ft above sea level, made of limestone containing ocean fossils.

Rocks

Made-up of minerals

Classes of Rocks

Broken Into 3 Classes: Igneous, Sedimentary, Metamorphic

Metamorphic Rocks

Existing rocks 'Changed' by heat and pressure

Metamorphic agents

Heat, Pressure, Fluids

Contact (Heat) metamorphism

Intruding magma forming a batholith and a dike

Regional (Pressure) metamorphism

Changes rock over very large areas (regions) due to burial and tectonic activity

Confining Pressure

Results in horizontal foliation

Differential Stress

Results in wavy foliation

Foliated Metamorphic Rocks

Rocks like Gneiss and Slate formed by heat and pressure

Non-Foliated Metamorphic Rocks

Rocks like Marble and Quartzite formed by heat and pressure

Sedimentary Rocks

Formed when fragments of material and other rocks get compressed and cemented together without heat

Igneous Rocks

Form large portions of oceans and continents

Earth's Age

4.5 billion years old

Oldest dated material on Earth

4.4 billion year old zircon crystal from Australia

Oldest rock

~ 4.0 billion years old from NW Territories, Canada

Oldest rock in WI

~ 2.8 billion year old gneiss (metamorphic)

Importance of Rocks and Minerals

Used to reconstruct much of Earth's history and provide clues to past environments

Water Resources

Limestone Groundwater Aquifers supply ~25% of Global water supply

Granite Groundwater Aquifer

Formed from cracks in rock - joints/faults

Rocks and minerals

Supply valuable raw materials including fossil fuels

Coal Formation

Deposition of organic matter in swamps during the Late Mississippian (325 million years ago)

Tourism/Recreation

Rocks and sedimentary outcrops contribute to economic activities