GEOL 103 Exam 1 Study Guide Flashcards

Vocabulary flashcards covering key geology concepts, plate tectonics, mineral properties, rock types, igneous processes, volcanism, and earthquake dynamics for Exam 1.

Lithosphere

The rigid outer layer of Earth composed of the crust and uppermost mantle.

Asthenosphere

A layer of the mantle that can deform by flowing over long timescales, allowing overlying tectonic plates to move.

Seismic Wave Shadow Zones

The primary seismic evidence used to identify that Earth's outer core is liquid.

Outer Core

The liquid layer of Earth's interior where fluid convection generates Earth's magnetic field.

Isostasy

The flotation relationship between Earth's crust and the underlying mantle.

Continental Drift Hypothesis

Alfred Wegener's hypothesis supported by matching continental shapes and ocean-spanning fossils, which was initially criticized for lacking a convincing mechanism for continental movement.

Divergent Boundary

A tectonic plate boundary formed where plates move apart due to tension or extension.

Convergent Boundary

A tectonic plate boundary where plates move toward each other, commonly featuring subduction zones.

Ridge-Push and Slab-Pull

The primary gravitational and thermal mechanisms contributing to plate tectonic motion.

Mineral

A naturally occurring, solid substance with an ordered crystalline structure and specific chemical composition.

Covalent Bonding

A strong molecular bond formed when electrons in the outermost electron shell are shared between atoms.

Ionic Bonding

A chemical bond formed when electrons are transferred from one atom to another, such as in sodium chloride ($\text{NaCl}$).

Silicates

The mineral group defined by silicate structures that includes quartz and feldspar.

Silica Tetrahedron

An anionic complex composed of four oxygen atoms bonded to one silicon atom ($\text{SiO}_4$).

Igneous Rock

A category of rock formed when molten rock (magma or lava) cools and solidifies.

Decompression Melting

The process of magma generation caused by a reduction in pressure at constant temperature, common at divergent boundaries.

Phaneritic Texture

An igneous rock texture characterized by mineral crystals large enough to be visible without a microscope, indicating slow cooling deep underground.

Viscosity (Magma)

A magma's resistance to flow, which increases with higher silica content, causing felsic magmas to be more viscous than mafic magmas.

Conglomerate

A clastic sedimentary rock composed of large, rounded clasts that require high-energy transport and cannot be deposited by slow-flowing rivers.

Limestone

A sedimentary rock commonly formed from biological marine material in shallow, tropical environments.

Foliation

A planar texture in metamorphic rocks created by directed pressure that aligns minerals or deforms crystals and clasts.

Increasing Metamorphic Grade Sequence

The progressive order of metamorphism in foliated rocks: Slate $\rightarrow$ Phyllite $\rightarrow$ Schist $\rightarrow$ Gneiss.

Shield Volcano

A broad, low-profile volcano constructed from low-viscosity, non-explosive mafic lava flows.

Stratovolcano

A steep-sided, symmetrical volcano built from explosive, silica-rich lava and tephra eruptions.

Scientific Theory

A well-tested, broadly accepted explanation of natural phenomena based on extensive empirical evidence.

Objective Observation

An observation based on quantifiable, verifiable facts rather than personal feelings, designed to remove bias.

Passive Margin

A transition boundary between continental and oceanic crust that lacks active relative plate motion.

Elastic Rebound

The sudden release of stored elastic strain energy when stressed rock ruptures along a fault, producing seismic waves and earthquake shaking.

Moment Magnitude

An earthquake magnitude scale calculated from fault rupture area, average displacement, and rock strength.

Thrust Fault

A low-angle reverse fault formed under compressional stress where the hanging wall moves up relative to the footwall.

Unconformity

A structural gap in a sedimentary rock record caused by a period of non-deposition or erosion.