Glacial History of the Great Lakes

These flashcards cover key vocabulary and concepts related to glaciers and their impact on Earth's geology and climate.

Cryosphere

The portions of the Earth where water is in solid form, including glaciers and ice caps.

Glacial Budget

The balance between ice accumulation and loss at a glacier's margin.

Alpine Glacier

A glacier that originates at high altitudes and flows downslope.

Ice Sheet

A mass of glacial ice covering more than 50,000 square kilometers that flows outward in all directions.

Antarctica

The coldest, driest, and windiest continent, containing the largest ice sheets.

Firn

Granular ice resulting from the compaction of snow, denser than snow but less dense than glacial ice.

Glacial Erosion

The process by which glaciers erode the landscape by plucking and abrasion.

Plucking

The process where glaciers loosen and lift blocks of rock from the bedrock.

Rock Flour

Fine pulverized rock produced by glacial abrasion.

Striations

Grooves carved in the bedrock by glacial movement.

Till

Unsorted sediment deposited directly by a glacier.

Moraines

Ridges of debris deposited at the edges or terminus of a glacier.

Kettles

Depressions formed when glaciers melt and leave behind isolated blocks of ice.

Drumlin

Streamlined hills formed from glacial till, indicating the direction of glacial movement.

Esker

Sinuous ridges composed of stratified drift formed by streams flowing beneath glaciers.

Kame

Steep-sided hills formed by sediment deposition from glacial meltwater.

Glacial Erratic

A large boulder transported and deposited by a glacier, often different from local geology.

Ice Ages

Periods of extensive glaciation that significantly impact Earth's surface and climate.

Milankovitch Cycles

Long-term changes in Earth's orbit and axial tilt that influence climate patterns.

Pleistocene Epoch

The geological epoch characterized by repeated glaciations, ending about 11,700 years ago.

Holocene Epoch

The current interglacial period, starting after the last significant Ice Age.

Crustal Rebound

The rise of land masses that were depressed by the weight of ice sheets after they melt.

Pluvial Lakes

Lakes formed from greater precipitation and reduced evaporation during glacial periods.

Ice Dams

Natural barriers formed by glacial ice that can trap meltwater and create proglacial lakes.

Glacial Advance

A period during which a glacier grows and moves forward due to increased accumulation.

Glacial Retreat

A period during which a glacier diminishes in size due to increased melting or decreased snowfall.