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What does the presence of glacial deposits indicate about the continents?
Today, glacial deposits formed during the Permo-Carboniferous glaciation (about 300 million years ago) are found in Antarctica, Africa, South America, India and Australia. These show the direction of the glacier, and suggest the ice flowed from a single central point. …
What does the presence of glacial evidence near the equator suggest about the continents?
If the continents were in their current positions about 300 million years ago, this glacier would cover most of the globe and extend above the equator. This aided Wegener’s theory that the continents were once all joined as a single landmass.
What glacial deposits suggest about plate movement?
The findings suggest that sediment lubrication controls the rate at which Earth’s crust grinds and churns. Sobolev and Brown found that two major periods of worldwide glaciation, which resulted in massive deposits of glacier-scrubbed sediment, each likely caused a subsequent boost in the global rate of plate tectonics.
What is the best explanation for the presence of glacial deposits in the modern tropics?
Even though the Snowball Earth hypothesis is generally accepted as the best explanation for the presence of glacial deposits in tropical latitudes and other atypical characteristics of the Cryogenian period, the hypothesis remains controversial amongst paleontologists.
What are glacial deposits called?
Debris in the glacial environment may be deposited directly by the ice (till) or, after reworking, by meltwater streams (outwash). The resulting deposits are termed glacial drift. The resulting deposit is called a flow-till by some authors. …
Why the continents could not possibly move the way Wegener is describing?
Scientists did not accept Wegener’s theory of continental drift. Wegener suggested that perhaps the rotation of the Earth caused the continents to shift towards and apart from each other. (It doesn’t.) Today, we know that the continents rest on massive slabs of rock called tectonic plates.
Where does the rock for glacial deposits come from?
Glacial Deposits. Load. An advancing ice sheet carries an abundance of rock that was plucked from the underlying bedrock; only a small amount is carried on the surface from mass wasting. The rock/sediment load of alpine glaciers, on the other hand, comes mostly from rocks that have fallen onto the glacier from the valley walls.
Are there any glacial deposits in North America?
Within North America, credible equivalents of the two older Huronian glaciogenic formations (Ramsay Lake and Bruce formations) are known only from the Great Lakes area and Wyoming, about 2000 km to the southwest. In South Africa and Australia, many Paleoproterozoic glacial deposits appear to be locally developed.
Where are esker sands deposited in a glacier?
Eskers are long, winding ridges of outwash that were deposited in streams flowing through ice caves and tunnels at the base of the glacier. Generally well sorted and cross‐bedded, esker sands and gravels eventually choke off the waterway.
Where are glacial deposits in the Arabian Peninsula?
Glacial deposits are distributed in the Arabian Peninsula across Oman, Yemen, and Saudi Arabia. The Al Khlata Formation reaches up to 800 m in the subsurface and is well defined in the Huqf area in Oman. Its beds are interpreted as glaciofluvial to glaciodeltaic grading laterally into ice-contact lacustrine strata.