Glacial Environment and Types

Questions and Answers

What is the cryosphere?

The cryosphere consists of all of Earth's frozen waters, including ice and snow in the atmosphere, lakes, rivers, oceans, on land, and under the Earth's surface.

What percentage of Earth's land surface is currently covered by glaciers?

Approximately 10%

What was the extent of glacier coverage during the Last Glacial Maximum (LGM)?

Around 32% of Earth's land surface.

Which of the following are types of glaciers?

Alpine glaciers Signup and view all the answers

What percentage of the world’s glacial ice is found in Antarctica and Greenland?

Approximately 99% Signup and view all the answers

What do the Himalayas provide for the major rivers such as the Indus, Ganges, and Brahmaputra?

They feed these rivers. Signup and view all the answers

How do continental glaciers differ from alpine glaciers in terms of flow?

Continental glaciers do not flow downhill as they cover flat areas, whereas alpine glaciers flow primarily based on the slope of the land beneath them. Signup and view all the answers

What are the effects of Quaternary glacial-interglacial cycles on landscapes?

They cause distinctive changes, including erosion, weathering, and sediment deposition. Signup and view all the answers

During warm interglacial periods, what type of weathering predominates?

Strong chemical weathering. Signup and view all the answers

What happens to valley slopes during cold stages of glacial periods?

Erosion is dominant on the upper slopes, resulting in sediment deposition in lower valleys. Signup and view all the answers

What is the molecular formula for ice?

H2O Signup and view all the answers

What is firn?

Firn is a crystalline form of snow that has not yet been compressed into ice. Signup and view all the answers

What process transforms snow into glacial ice?

Burial and compression Signup and view all the answers

Study Notes

Glacial Environment

The cryosphere encompasses all of Earth's frozen waters, including ice, snow, and sub-surface ice.
Glaciers form over hundreds or thousands of years above the snowline, resulting in thick ice masses.

Last Glacial Maxima (LGM)

Currently, glaciers cover approximately 10% of Earth’s land surface, primarily in polar regions.
During the LGM (19-20 thousand years ago), glaciers expanded to cover about 32% of the Earth's land.

Types of Glaciers

There are two main types of glaciers:
- Continental glaciers: Vast ice sheets found in polar regions like Antarctica and Greenland, containing 99% of the world's glacial ice and about 68% of Earth's fresh water.
- Alpine glaciers (valley glaciers): Originating in mountainous areas, existing in temperate, polar, and sometimes tropical regions.

Notable Glacier Systems

The Himalayas host the world’s third-largest glacier systems, significantly feeding major rivers such as the Indus, Ganges, and Brahmaputra.
Continental glaciers do not flow downhill due to their extensive flat areas, while alpine glaciers flow dictated by underlying land slopes.

Quaternary Glaciation

Quaternary glacial-interglacial cycles induce significant landscape changes, particularly at middle and high latitudes.
Cold, dry glacial periods lead to the development of permafrost, ice sheets, and cold deserts, whereas warm interglacial phases enhance chemical weathering and soil formation.

Landscape Changes During Glacial Cycles

During cold stages: Erosion dominates upper valley slopes; sediment supply increases in lower valleys, leading to river braiding.
During warm stages: Erosion patterns stabilize, soil formation is encouraged, and river channels exhibit meandering and aggradation.

Pluvial and Interpluvial Phases

In arid and semi-arid zones, variations in rainfall during pluvial (increased rainfall) and interpluvial (drier) phases cause different scales of erosion.

Ice as a Mineral

Ice, a solid form of water (H2O), is categorized as a mineral, typically forming in hexagonal structures when water freezes.
Glacial ice results from the transformation of snow through processes of accumulation, burial, compression, and recrystallization over varying timescales (from decades to millennia).

Description

Explore the fascinating world of glaciers and the cryosphere in this quiz. Learn about the formation of glaciers, their types, and the significant impact they have on Earth's land surface. Perfect for anyone interested in geology and climate science.