Shaping of the Earth's Surface Practice Flashcards

This set covers the internal and external forces shaping the Earth, including its layers, plate tectonics, types of weathering and erosion, and specific landforms created by water, wind, and ice.

W.J. Morgan

The scientist who proposed the theory of plate tectonics, explaining the movement of the Earth's crust.

Plate Tectonics

The theory describing how large pieces of the Earth's crust, called tectonic plates, move slowly over the molten mantle.

Crust

The Earth's outermost and thinnest solid layer, varying from $30-40\,km$ under continents to $5-7\,km$ beneath oceans.

Mantle

The thickest layer of the Earth, about $2,900\,km$ thick, composed mainly of hot silicate rocks rich in magnesium and iron.

Outer Core

A liquid layer mainly composed of iron and nickel, with temperatures between $4,000-6,000^{\circ}C$, responsible for the Earth's magnetic field.

Inner Core

The innermost, hottest ($5,000-6,000^{\circ}C$), and densest part of the Earth, maintained in a solid state due to high pressure.

Lithosphere

The rigid outer layer of the Earth, roughly $100\,km$ thick, made up of the crust and the uppermost part of the mantle.

Asthenosphere

A hot, partially molten layer of the upper mantle beneath the lithosphere, approximately $200\,km$ thick, that enables plate movement.

Convection Currents

Continuous circulation in the mantle driven by heat from the core that pushes and pulls tectonic plates.

Convergent Boundary

A plate boundary where two plates move towards each other, leading to the formation of fold mountains or volcanic activity through subduction.

Divergent Boundary

A plate boundary where plates move away from each other, allowing magma to rise and form new crust, such as mid-ocean ridges.

Transform Boundary

A plate boundary where plates slide horizontally past one another without creating or destroying crust, commonly causing earthquakes.

Ring of Fire

An area around the Pacific Ocean where most earthquakes and volcanoes occur along plate boundaries.

Weathering

The process of breaking rocks into smaller pieces on the Earth's surface without the movement of the material.

Erosion

The process of wearing away and transporting soil, rocks, and surface materials from one place to another.

Agents of Gradation

Natural forces such as running water, glaciers, wind, waves, and groundwater that level the Earth's surface through erosion and deposition.

Waterfall

A vertical or steep fall of a river over a cliff, formed in the upper course when soft rock erodes faster than hard rock.

Meander

A winding bend in the middle or lower course of a river formed by continuous erosion on the outer bank and deposition on the inner bank.

Delta

A fan-shaped or triangular landform formed at the mouth of a river due to the deposition of sediments as the river enters a sea or ocean.

Beach

A coastal landform made of sand, pebbles, or rocks deposited along the shoreline by waves, tides, and currents.

Sea Stack

An isolated rock pillar left standing after a sea arch collapses due to wave erosion.

Fjord

A deep, narrow sea inlet formed when seawater fills a valley previously carved by a glacier.

Moraines

Deposits of rocks, soil, and debris (till) left behind by melting glaciers, categorized as lateral, terminal, or medial.

Yardang

Long, narrow, streamlined rock ridges carved by wind in dry regions where soft rocks erode faster than hard rocks.

Barchan Dune

A crescent-shaped sand dune formed in areas where sand is limited and wind blows from a single direction.

Karst Topography

A landscape created by underground water dissolving soluble rocks like limestone, featuring caves, sinkholes, and stalactites.

Stalactite

An icicle-shaped mineral deposit hanging from the roof of a cave, formed by dripping water.

Stalagmite

A pillar-like mineral deposit rising from the floor of a cave formed by minerals accumulating from water drops.

GLOF

An acronym for Glacial Lake Outburst Flood, a sudden flood caused by the bursting of a glacial lake.

Dust Storm

A natural disaster where strong winds carry large amounts of dust and sand into the air, common in desert and semi-arid regions.