General Study Notes

The study of Earth materials and processes operating on and beneath its surface.

The study of Earth's origin and development through time.

The principle that the processes shaping Earth today have been operating throughout its history.

The theory that Earth's landscapes were formed by sudden catastrophic events.

The study of how humans interact with the natural environment, including natural hazards, resources, and environmental issues.

The science that helps us understand the formation and age of Earth.

The vast timescale over which Earth's history unfolds, encompassing billions of years.

The use of radioactive decay to determine the age of rocks and fossils.

A chemical bond formed when atoms share electrons.

A chemical bond formed when atoms transfer electrons, resulting in oppositely charged ions that attract each other.

A specific arrangement of atoms in a mineral that defines its crystal structure.

Different crystal structures of the same mineral with the same chemical composition.

The external shape of a mineral, reflecting its internal crystal structure.

How a mineral reflects light.

The color of a mineral, but not always a reliable identifier due to impurities.

A very common mineral, often found in various colors due to impurities.

A type of igneous rock that is formed when fragments of rock are ejected during a volcanic eruption.

A pyroclastic rock composed of ash-sized fragments.

A pyroclastic rock formed when hot ash fuses together.

A pyroclastic rock composed of particles larger than ash.

A type of igneous rock that is ultra-mafic in composition and dominates the upper mantle.

The mobility of magma, which is influenced by its composition, temperature, and gas content.

The amount of silica in a magma.

The force that drives magma out of a volcanic vent or conduit.

Silica (SiO2) is a key component in igneous rocks, ranging from 40% in ultramafic rocks to over 70% in felsic rocks.

The rate of cooling of magma or lava has a direct impact on the size of crystals formed in igneous rocks. Slow cooling allows for larger crystals, while fast cooling results in smaller crystals.

Igneous rocks can be broadly categorized based on their texture, which describes the size, shape, and arrangement of their crystals.

Aphanitic texture is characterized by fine-grained crystals that are too small to be seen with the naked eye, formed by rapid cooling.

Phaneritic texture is distinguished by large, easily visible crystals, often found in rocks that cooled slowly beneath the Earth's surface.

Porphyritic texture is a combination of large crystals (phenocrysts) embedded in a matrix of smaller crystals (groundmass), formed due to a change in cooling rates during the rock's formation.

Vesicular texture is characterized by holes (vesicles) within the rock, formed by trapped gas bubbles in the cooling lava or magma.

Volatiles are dissolved gases present in magma, and their presence can influence the texture of the resulting igneous rock.

Sedimentary environments are classified based on their location and the processes that dominate them.

Continental environments are characterized by erosion and deposition, often driven by streams and glaciers.

Transitional environments are at the interface of land and water, featuring a variety of features formed by shifting water levels and energy.

Marine environments are further divided into shallow and deep zones, each with unique characteristics and sediment types.

Sedimentary facies are laterally varying units of sedimentary rock that reflect changes in the depositional environment over time.

The transition between adjacent sedimentary facies is often gradual, indicating a slow and continuous change in depositional conditions.

Detrital sedimentary rocks are formed from fragments of pre-existing rocks that have been weathered and transported.

Chemical sedimentary rocks are formed from dissolved minerals that precipitate out of solution.

Organisms like plants, animals, and microbes contribute to the formation of soil by adding organic matter, breaking down dead material, and mixing the soil.

Steep slopes have less developed soil due to erosion. Lowlands tend to have thicker, darker, and richer soil because of water accumulation. Ideal soil forms on flat-to-undulating land, allowing for good drainage and minimal erosion.

Sedimentary rocks are formed from weathered fragments of existing rocks, minerals, and organic matter that are deposited, compacted, and cemented together. They represent a vast majority of Earth's surface and contain valuable resources.

Diagenesis involves the physical, chemical, and biological changes that occur after sediments are deposited, but before they become solid rock. It happens within Earth's crust at relatively low temperatures.

Lithification is the process by which loose sediment is transformed into solid rock through compaction (pressure squeezing out water) and cementation (minerals bind particles together).

A sedimentary environment is the place where sediment accumulates. Factors like climate, water flow, and biological activity influence the type of sediment deposited.

Uniformitarianism applies the idea that the processes shaping Earth today have always operated similarly. Scientists use present-day observations to understand past environments.

Sedimentary rocks are important economically because they contain valuable resources like coal, oil, natural gas, iron, aluminum, and materials for construction.