Slow Changes to Earth’s Surface Weathering, Erosion, and Deposition from Ice, Water, and Wind

Weathering, Erosion, and Deposition Weathering is the breaking down and wearing away of rock. Erosion is the movement of the weathered materials by ice, water, or wind. Deposition is the dropping off or depositing of the materials that were eroded by ice, water, and wind. Weathering? Erosion? Deposition?

Weathering, Erosion, and Deposition by Ice U-Valley Formation by a Glacier The land has rivers flowing along it. The rivers have weathered and eroded the land to form a V-shaped valley. The snow begins to collect and pack into the valley. The snow and ice thicken. The slope of the valley, the pressure of the snow and ice, and gravity cause the mass of snow and ice to move. The movement weathers and erodes the land beneath the glacier. Sediments become trapped under the moving mass and scrapes away at the valley. Debris, in the form of rocks and boulders, moves along the valley. As the glacier retreats or melts, a U-shaped valley is left.

Glaciers: U-Shaped Valleys Mt. Hood Wilderness: The U-shaped valley was formed by a glacier. Picture: Wikicommons

Glaciers: Fjords This picture shows Milford Sound, a fjord in the southwest of the South Island in New Zealand. Picture: Wikicommons

Weathering, Erosion, and Deposition by Ice Formation of Fjords Fjords are created when glaciers retreat. The glaciers weather and erode the land, forming the U-shaped valley. The material is deposited in various locations in the valley. When the glacier retreats and sea levels rise, the water flows into (and fills) the valley floor.

Weathering, Erosion, and Deposition by Water: Canyons Photographs: Government Canyon, A. Venegas Grand Canyon in 1872, released photo

Weathering, Erosion, and Deposition by Water: Caves Natural Bridge Caverns. A. Venegas

Weathering, Erosion, and Deposition by Water: Caves Caves can be formed by many processes, but erosion by water is one of the more common ways. In Texas, we have many limestone caves. Water enters the caves and weathers the rock by dissolving the limestone. When water levels rise, the minerals are carried away. Calcium carbonate is deposited when water precipitates through the limestone.

Weathering, Erosion, and Deposition by Water: Delta Okavango Delta, Wikicommons

Weathering, Erosion, and Deposition by Water: Delta A river delta forms at the mouth of a river. The flowing river has weathered and eroded the river bank and the river floor, carrying the sediment in the moving water. The sediment, that has been carried by the river, is deposited as the river flows into an ocean, sea, or estuary.

Weathering, Erosion, and Deposition by Wind: Sand Dunes Port Aransas, A. Venegas

Weathering, Erosion, and Deposition by Wind: Sand Dunes A sand dune can form from the movement of water or wind. Most sand dunes have one side that is steeper than the other. Wind direction Movement of the sand dune

Weathering and Erosion by Wind: Hoodoos Pinnacles Palo Duro Canyon, A. Venegas Bryce Canyon, Wikicommons

Weathering and Erosion by Wind : Rock Arches Sunset at Delicate Arch,Arches National Park, Utah). Source:Prise de vue personnelle. Author: Palacemusic . 8/23/05

Weathering and Erosion by Wind : Rock Arches Deep cracks form in sandstone. (Remember your observations of the frozen rock?) Erosion wears away the exposed rock layers. Water may enter the cracks, freeze, and widen the cracks further. Wind also wears away the rock particles. Weathering and erosion continues until an arch, or bridge, remains. Over time, with continued weathering and erosion, the arches will collapse. Picture courtesy of USG

Weathering and Erosion by Wind Boquillas Canyon, A. Venegas

Weathering, Erosion, and Deposition by Wind and Water: Beaches Picture: Newport Beach, CA. A. Venegas

Weathering, Erosion, and Deposition by Wind and Water: Beaches Beaches are the result of wave action. Waves or currents move the sand (or other sediments along the shore). Initially, the sediments on the beach were weathered and eroded from rock. Wind carried the sediment, and it is deposited either on the land or in the water. Sediment that is suspended in the water is carried in the water by ocean currents and eventually, may be deposited on the shore by waves. The waves both deposit sand from the ocean bed and erode sand as the water pulls back into the ocean.

Weathering, Erosion, and Deposition by Wind and Water: Barrier Islands Picture: Barrier Island, NOAA

Weathering, Erosion, and Deposition by Wind and Water: Sea Caves Picture: A sea cave on Santa Cruz Island, California.Photo by Dave Bunnell