Geology Unit 1: Minerals, Igneous, Sedimentary, and Metamorphic Processes

Flashcards testing knowledge on mineral properties, chemical bonding, rock classification, igneous, sedimentary, and metamorphic processes from lecture notes.

What hierarchy of components combines to form the Earth?

Elements combine to form natural compounds, compounds and elements form minerals, minerals make up rocks, and rocks make up the Earth.

What four criteria must a substance meet to be classified as a mineral?

It must be naturally occurring, inorganic, have an orderly internal structure, and have a fixed (or uniformly variable) chemical composition.

What property of a mineral is observed by scratching it across unglazed porcelain?

Streak.

What mineral property describes the tendency to break along flat, shiny surfaces?

Cleavage.

How do covalent bonds compare in strength to ionic bonds?

Covalent bonds are stronger than ionic bonds.

Why are metallic bonds responsible for high conductivity and shininess in metals?

Electrons roam freely between atoms in a metallic bond.

Which elements are most common in the whole Earth compared to Earth's crust?

Iron and oxygen are most common in the whole Earth, while silicon and oxygen are most common in Earth's crust.

What is the basic building block of silicate minerals?

The silicon-oxygen tetrahedron molecule.

How do light silicates differ from dark silicates in density and composition?

Light silicates lack iron and magnesium and have a density of approximately $2.7$, whereas dark silicates contain iron and magnesium and have a higher density around $3.2$ or greater.

What is the difference between descriptive and genetic rock classifications?

Descriptive classifications group rocks by similar appearance, while genetic classifications group rocks by their process of origin.

What geological cycle is depicted in this diagram showing relationships among igneous, sedimentary, and metamorphic processes?

The Rock Cycle.

What are the three primary components that make up magma?

Liquid melt, solid silicate minerals, and volatiles (dissolved gases like water vapor, carbon dioxide, and sulfur dioxide).

How do plutonic (intrusive) and volcanic (extrusive) igneous rocks differ in crystal size and cooling rate?

Plutonic rocks cool slowly underground forming large crystals (coarse-grained/phaneritic), while volcanic rocks cool quickly at the surface forming small or no crystals (fine-grained/aphanitic).

What texture term describes an igneous rock composed of two distinct sizes of crystals?

Porphyritic.

How do felsic igneous rocks differ from mafic igneous rocks in silica content and mineral crystallization order?

Felsic rocks have the highest silica content and low melting points, crystallizing last; mafic rocks have lower silica content, higher iron/magnesium, and high melting points, crystallizing first.

How does an increase in pressure affect the melting temperature of rock?

Increasing pressure increases the melting temperature of rock.

How does silica content influence magma viscosity and volcanic eruption style?

High silica content creates high viscosity, leading to explosive eruptions; low silica content creates runnier magma, leading to flowing eruptions.

What chemical weathering process involves mineral rearrangement that incorporates water, such as turning feldspar to clay?

Hydrolysis.

What two sequential processes convert loose sediment into consolidated sedimentary rock during lithification?

Compaction and cementation.

What conditions drive metamorphism in pre-existing parent rocks?

Elevated temperature, pressure, and the presence of chemically active fluids.

What term refers to the planar arrangement or compositional banding of minerals in metamorphic rocks formed in response to stress?

Foliation.

What are index minerals used to determine in metamorphic rocks?

They are used to define and identify specific ranges of temperature and pressure conditions (metamorphic grade) under which the rock formed.

What fundamental principle of geology is expressed by the phrase 'The present is the key to the past'?

Uniformitarianism.