Earth's Layers and Geological Processes

These flashcards cover essential terms and concepts related to Earth's layers, geological processes, and dating methods that are crucial for understanding geology.

Geology

The study of the Earth's rocks, minerals, and soils and how they have formed over time.

Law of Superposition

States that in undisturbed rock layers, a rock layer is older than the layers above it and younger than the layers below it.

Radioactive Dating

A process to determine the actual age of rocks by measuring the amount of radioactive elements they contain.

Half-Life

The time it takes for half of a radioactive substance to decay.

Erosion

The process by which materials are removed from the Earth's surface by natural forces such as water, wind, and ice.

Intrusion

A layer of igneous rock that forms when magma from the Earth's mantle is injected into rock and cools and solidifies.

Extrusion

Igneous rocks that form when magma seeps from the Earth and reaches the surface, cooling quickly.

Fossils

Trace or remains of organisms that lived long ago, providing evidence of past life on Earth.

Index Fossil

Fossils that are used to identify and date the rock layers in which they are found, specified by their wide distribution and short existence.

Continental Drift

The gradual movement of continents across the Earth’s surface, as evidenced by matching fossils and geological features.

Sedimentary Rock

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

Unconformity

A gap in the geological record that shows where rock layers have been lost due to erosion.

Differentiation

The process by which Earth separates into distinct layers based on density and material composition.

Accretion

The process by which particles in space collide and come together due to gravitational pull, leading to the formation of planets.

Pangaea

A supercontinent that existed during the late Paleozoic and early Mesozoic eras, before it split into the continents we know today.

Absolute Age

The actual age of a rock or fossil, often determined using techniques such as radioactive dating.

Relative Dating

A method of determining the age of rocks by comparing them to other rocks.

Strata

Layers of rock that are deposited over time, which can be studied to understand geological history.

Lateral Continuity

The principle that sediments are deposited in large, continuous sheets in all directions until they thin out or reach a barrier.

Faulting

The fracturing of rock layers that occurs when stress is applied, causing the layers to displace.

Folding

The bending of rock layers due to tectonic forces, which can result in complex structures.