What are glacial striations and what evidence do they provide?
What are glacial striations and what evidence do they provide?
More evidence comes from glacial striations – scratches on the bedrock made by blocks of rock embedded in the ice as the glacier moves. These show the direction of the glacier, and suggest the ice flowed from a single central point.
What did evidence of ancient ice sheets in Africa South America India and Australia suggest to Wegener?
Alfred Wegener investigated this field and found an anomaly in the Permo-Carboniferous ice sheet that was found through glacial till deposits to have once covered all the southern major plates. This aided Wegener’s theory that the continents were once all joined as a single landmass.
What does the presence of glacial deposits and striations indicate about the continents?
The presence of glacial deposits can tell scientists that if the continents have not moved, it would suggest that an ice sheet extends from the south pole to the equator. It was known that when glaciers move across the surface of the earth, they leave marks, grooves and deposits on the rocks and in that area.
What is the formation of AU shaped valley?
Valley glaciers carve U-shaped valleys, as opposed to the V-shaped valleys carved by rivers. During periods when Earth’s climate cools, glaciers form and begin to flow downslope. Often, they take the easiest path, occupying the low V-shaped valleys once carved by rivers.
What is the difference between striations and grooves?
is that groove is a long, narrow channel or depression; eg, such a slot cut into a hard material to provide a location for an engineering component, a tyre groove, or a geological channel or depression while striation is (countable|mineralogy) one of a number of parallel grooves and ridges in a rock or rocky deposit.
What causes striation?
The striations are caused by the regular arrangement of contractile proteins (actin and myosin). Actin is a globular contractile protein that interacts with myosin for muscle contraction.
Why is glacial melt a concern?
Sea ice forms and melts strictly in the ocean whereas glaciers are formed on land. When glaciers melt, because that water is stored on land, the runoff significantly increases the amount of water in the ocean, contributing to global sea level rise.
What happens when all glaciers melt?
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet.