Glaciers and Glaciation

• Glaciers are large ice bodies formed from snow accumulation and compaction over time.
• Glaciers are found in polar regions like Antarctica and Greenland, and in high-altitude mountainous areas.
• Glaciers move constantly, flowing under gravity's influence, and range from small ice patches to large ice sheets.
• Glaciers form through glaciation, where snow transforms into dense glacial ice, flowing downhill due to its weight.
• Glaciation includes ice buildup and movement on Earth's surface, resulting in formations and scars.
• Glaciation is defined formally as glacier formation, existence, or movement on the Earth's surface.
• Glaciers store freshwater and significantly impact the landscape, shaping valleys and leaving landforms.
• Climate change causes glaciers to retreat and lose mass rapidly, affecting water resources, ecosystems, and sea-level rise.

Types of Glaciers

• Continental glaciers are flatter, massive ice areas covering large land sections.
• Alpine glaciers are found in mountains and valleys.
• Valley glaciers (or alpine/mountain glaciers) are in mountainous regions and flow down valleys.
• Valley glaciers are long, narrow, confined by mountain slopes, and vary in size.
• Ice sheets (or continental glaciers) are massive ice bodies covering large areas, found in polar regions.
• Ice sheets are vast, relatively flat, and can be several kilometers thick and extend for thousands of kilometers.
• Ice caps are smaller versions of ice sheets in high-altitude regions with dome-shaped topography.
• Cirque glaciers are small, bowl-shaped glaciers in high mountain cirques.
• Cirque glaciers are found at valley heads, formed by snow and ice accumulation in sheltered areas.
• Piedmont glaciers occur when a valley glacier spills onto a flat plain or lowland area, becoming broader and shallower.
• Piedmont glaciers are often lobe-like and found at the foot of mountain ranges.
• Tidewater glaciers are valley glaciers flowing into the ocean, terminating in calving fronts where icebergs form, commonly found in fjords and coastal areas.
• Hanging glaciers are smaller glaciers suspended on mountain slopes, occupying cirques or small valleys with steep, cliff-like terminus.

Glacial Erosion

• Like flowing water, flowing ice erodes the land.
• Valley glaciers create distinctive landforms like horns, cirques, and hanging valleys.
• Glacial erosion deforms the Earth's surface after a glacier has moved.
• Glaciers pluck up and carry rocks, grind rocks and ice, and carve land features.
• Glacier erosion occurs when the weight of snow and ice causes the glacier to move downhill.
• Glaciers erode in two main ways: plucking and abrasion.
• Glacial plucking is the melting and freezing of glacial ice that breaks apart rock.
• Plucking is the process where rocks and sediments are picked up by a glacier, which then carries them.
• Abrasion is a glacier scraping underlying rock, causing scratches and grooves (glacial striations) showing the glacier's movement direction.
• Glacial abrasion happens as plucked rocks and glacial ice grind and scratch surfaces.

Glacial Deposition

• Sediments are freed as the glacier melts, differently sorted from water-transported grains.
• Diamictite is a sedimentary rock made of unsorted grains cemented together.
• Tillite is an unsorted sedimentary rock with grains deposited by ice.
• Till is loose, unlithified sediment.
• A moraine is a ridge-shaped mound of till forming as a glacier recedes, named based on sediment origin.
• A terminal moraine forms at the glacier's farthest extent edge.
• Recessional moraines form upslope from the terminal moraine as the glacier melts and recedes.
• Lateral moraines form along the sides of a retreating glacier.
• Medial moraines form from sediment-rich bands in the glacier's center when two tributary glaciers join.
• A till sheet (or ground moraine) is a thin till layer covering bedrock in the receding glacier's space.
• A drumlin is an oval or elongated hill, formed by streamlined glacial ice sheet movement.
• Moraine refers to rock debris (till) carried or deposited by a glacier.

Other information

• A fjord is a long, deep, narrow body of water that reaches far inland, set in a U-shaped valley with steep rock walls.
• Fjord are found in Norway, Chile, New Zealand, Canada, Greenland, and Alaska.
• Ice ages are caused by a chain reaction of positive feedback from periodic Earth orbit changes.
• Feedbacks involve ice spread and greenhouse gas release, reversing when the orbital cycle shifts back.
• Ice Age (Pleistocene Epoch) was a period from 2.6 million to 11,700 years ago, with glaciers and ice sheets covering large portions of Earth.
• Ice Age significantly impacted Earth's climate, geography, and ecosystems.
• Global temperatures were colder during the Ice Age, leading to glacier and ice sheet formation.
• Ice Age ice masses covered areas in North America, Europe, Asia, South America, and Australia.
• Ice weight depressed the Earth's surface, creating valleys and shaping landscapes.
• Distribution of animal/plant species was impacted.
• Some species adapted to colder climates, while others went extinct.
• Mammoths, mastodons, and sabre-toothed cats roamed ice-covered landscapes. Neanderthals also lived during this time.
• Ice Age influenced human history, leading to adaptation and innovation.
• End of the Ice Age was marked by a warming trend and establishment of modern climate patterns.
• Melting ice caused oceans to rise, reshaping coastlines and creating new landscapes.
• The Ice Age involved presence of glaciers and ice sheets, with impacts on climate, geography, ecosystems, and human history.