Search results
Results From The WOW.Com Content Network
Exfoliating slabs of granite, on Half Dome in Yosemite National Park, USA. Exfoliating granite is a granite undergoing exfoliation, or onion skin weathering (desquamation).The external delaminated layers of granite are gradually produced by the cyclic variations of temperature at the surface of the rock in a process also called spalling.
Spheroidal or woolsack weathering in granite on Haytor, Dartmoor, England Spheroidal weathering in granite, Estaca de Bares, A Coruña, Galicia, Spain Woolsack weathering in sandstone at the Externsteine rocks, Teutoburg Forest, Germany Corestones near Musina, South Africa that were created by spherodial weathering and exposed by the removal of surrounding saprolite by erosion.
Exfoliation (or onion skin weathering) is the gradual removing of spall due to the cyclic increase and decrease in the temperature of the surface layers of the rock. Rocks do not conduct heat well, so when they are exposed to extreme heat, the outermost layer becomes much hotter than the rock underneath causing differential thermal expansion .
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
Exfoliation joints wrapping around Half Dome in Yosemite National Park, California. Exfoliation joints in granite at Enchanted Rock State Natural Area, Texas, US. Detached blocks have slid along the steeply-dipping joint plane.
The use of weathering rinds in relative dating is widely used in Arctic, Antarctic, and alpine regions and in the correlation of glacial moraines and tills and fluvial sediments and terraces. [6] [7] [8] In addition, weathering rinds have been used to determine the absolute amount of time gravel-size rock has been exposed to the weathering ...
An example of using thermal modeling in P-T-t path reconstruction. The above diagram shows the calculated geothermal gradients upon crustal thickening at 0 million year (m.y.) followed by an immediate uplift event at a rate of 1 mm per year. The P-T-t evolution of a rock originally at 40 km below ground is marked as red dots on the diagram.
Allium bisceptrum, also known as the twincrest onion or aspen onion, is a high elevation plant native to western United States. It is a perennial that thrives under damp and shady conditions or open meadows in California , Arizona , New Mexico , Nevada , Oregon , Washington , Idaho , and Utah .