GEO-100 Physical Geology Exam 2 Study Guide

A set of vocabulary flashcards covering essential terms and definitions related to Physical Geology concepts as outlined in the study guide for Exam 2.

Magma vs. Lava

Magma is molten rock beneath the Earth's surface; lava is magma that has reached the surface.

Volcanic Eruptive Styles

Effusive eruptions involve the gentle flow of lava, while explosive eruptions involve violent outbursts of gas and ash.

Intrusive vs. Extrusive Igneous Rock

Intrusive igneous rocks form from magma cooling slowly beneath the surface, while extrusive rocks form from lava cooling quickly on the surface.

Mafic and Felsic

Mafic refers to igneous rocks rich in magnesium and iron, while felsic refers to rocks high in silica.

Bowen's Reaction Series

A sequence that illustrates the order in which minerals crystallize from cooling magma.

Solidus

The temperature below which a substance is completely solid.

Geotherm

The rate of temperature increase with depth in the Earth.

Viscosity

A measure of a fluid's resistance to flow.

Pahoehoe vs Aa Lava

Pahoehoe lava is smooth and ropy, whereas aa lava is rough and jagged.

Pyroclastic Flow

A fast-moving current of hot gas and volcanic matter.

Differential Weathering

The variation in the rate of weathering of different rock types.

Clastic Sedimentary Rocks

Sedimentary rocks formed from fragments of other rocks, classified by grain size.

Lithification

The process of turning sediments into solid rock by compaction and cementation.

Biochemical Sedimentary Rocks

Sedimentary rocks formed from organic processes, such as limestone derived from shells and coral.

Replacement Chert

A type of chemical sedimentary rock formed from silica that replaces other minerals in rocks.

Caldera vs Crater

A caldera is a large depression formed from a volcanic eruption, while a crater is a smaller depression formed by an explosion.

Lahar

A destructive volcanic mudflow composed of water and volcanic materials.

Isopach Map

A geological map that shows the thickness of sedimentary layers.