| xoxoxoBruce |
03-26-2020 11:03 PM |
March 27th, 2020 : Chiricahua National Monument
So they closed Brimham and we can’t visit. To hell with them, we don’t need their rocks.
We have our own rocks that are closed so we can’t visit. How do you like them pebbles. http://cellar.org/2012/bwekk.gif
http://cellar.org/img/chicri1.jpg
Quote:
While much of the geologic history of the Precambrian, Paleozoic and Mesozoic eras is absent in Chiricahua National Monument, the rocks that are exposed record a dynamic Cenozoic history of volcanic eruptions. Remnants of the Turkey Creek caldera provide evidence for three successive large volcanic eruptions beginning about 26.9 million years ago that blasted more than 400 km3 (100 mi3) of magma from a buried magma chamber and covered a region of at least 3,100 km2 (1,200 mi2) with pyroclastic debris.
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http://cellar.org/img/chicri2.jpg
Quote:
Volcanic ash, glowing gas cloud deposits, steam vents, lava flows, and high velocity surge deposits can be found in Chiricahua National Monument. Hot glass shards fused together to form the welded tuff of the Rhyolite Canyon Tuff, a deposit at least 490 m (1,600 ft) thick. Upon cooling, vertical joints formed in the erosion-resistant Rhyolite Canyon Tuff and provided conduits for water. Continual freezing and thawing expanded the joints and dislodged pieces of the rock. Over time, chemical and physical weathering processes acted together to carve the pinnacles, spires, and columns for which the Monument is known.
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http://cellar.org/img/chicri3.jpg
Quote:
Features associated with volcanic activity, regional tectonic deformation, and weathering processes are displayed in Chiricahua National Monument.
Weathering and erosion processes have created:
Slot Canyons, Slumps, Natural Bridge, Solution Pans, Rock Varnish,
Tafoni, Spherulites, Inverted Topography
And, the Monument’s distinctive geologic features:
Pinnacles, Spires, Balanced Rocks, Columns
Volcanic features, primarily related to the Turkey Creek caldera, include:
The Caldera, Welded Tuff (Rhyolite Canyon Tuff), Fiamme, Fumarole Pipes,
Moat Deposits, Surge Deposits, Igneous Dikes
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