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Topic: Welded tuff

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Bishop tuff

Rhyolite

Magma

Caldera

Pyroclastic flow

Long Valley Caldera

Geothermal areas in Long Valley

Hydrothermal

Hydrothermal vent

Chimney

Hot Creek

	Tuff - Wikipedia, the free encyclopedia
		Tuff (from the Italian "tufo") is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption.
		Where crystals are very abundant the ashes are called "crystal tuffs." In St. Vincent and Martinique in 1902, much of the dust was composed of minute crystals enclosed in thin films of glass because the lava at the moment of eruption had very nearly solidified as a crystalline mass.
		Welded tuff deposits can be highly voluminous, such as the Lava Creek Tuff erupted from Yellowstone Caldera in Wyoming 640,000 years ago.
	en.wikipedia.org /wiki/Tuff (1912 words)

	Olympus Microscopy Resource Center: Polarized Light Microscopy Gallery - Welded Tuff
		Tuff is a porous rock formed from the widespread deposition and consolidation of volcanic ejecta.
		The degree of welding is determined by how hot the volcanic ash that forms a tuff was when it accumulated at the surface of the Earth; the warmer the material, the easier it is for the glass particles to weld together under the weight of overlying deposits.
		Welded tuff is significantly harder than other types of tuff and can be found in various locations around the world.
	olympusmicro.com /galleries/polarizedlight/pages/weldedtuffsmall.html (245 words)

	image Welded tuff at Golden Gate in Yellowstone 300px JPG larger...
		image:Welded tuff at Golden Gate in Yellowstone-300px.JPG larger version larger version "Tuff" (from the Italian "tufo" and pronounced "toof") is a rock rock type consisting of consolidated volcanic ash ash ejected from vents during a volcanic eruption.
		As a matter of fact most of the tuffs found in the older formations contain admixtures of clay clay, sand, and sometimes fossil fossil shell shells, which prove that they were beds spread out under water.
		Where crystals are very abundant the ashes are called "crystal tuffs." In St. Vincent and Martinique in 1902 1902 much of the dust was composed of minute crystals enclosed in thin films of glass glass, because the lava at the moment of eruption had very nearly solidified as a crystalline mass.
	www.biodatabase.de /Tuff (1879 words)

	Joy Tuff (Site not responding. Last check: 2007-10-24)
		The Joy tuff consists of two members: a lower, widespread unit of poorly to moderately welded crystal-rich tuff and a thin, local unit of highly welded fl glass tuff.
		The tuff breccia consists of apparently randomly oriented masses of welded tuff in a matrix of the same.
		The fl glass tuff is a local ashflow deposit, limited to the vicinity of the proposed vent breccia east and south of Topaz Mountain.
	pubs.usgs.gov /of/1998/ofr-98-0524/JOYTUFF.HTM (359 words)

	CVO Website - Tuffs (Site not responding. Last check: 2007-10-24)
		Tuff is a volcanic rock made up of a mixture of volcanic rock and mineral fragments in a volcanic ash matrix.
		Tuff forms when some combination of ash, rock and mineral fragments (pyroclastics or tephra) are blasted into the air, then fall to the ground as a mixed deposit.
		Most of the rock fragments tend to be volcanic rocks that were once solidified parts of the volcano that erupted to produce the tuff, but sometimes other types of rock are blasted out and incorporated into the tuff as well.
	vulcan.wr.usgs.gov /LivingWith/VolcanicPast/Notes/tuffs.html (135 words)

	[No title] (Site not responding. Last check: 2007-10-24)
		Welded tuffs are formed during violent volcanic eruptions; gas-charged material is expelled and deposited while still partially molten, so that the droplets become attached, or "welded" to one another.
		The photos above show welded tuffs with irregularly shaped, light gray glass shards and mashed pumice clasts in a glassy matrix.
		The pictures below show (on the left) a plane polarized light view of a highly welded tuff with numerous glass shards and broken plagioclase grains, and on the right a crossed polarizers view showing extinct glass matrix, lithic clasts, and broken plagioclase grains.
	sorrel.humboldt.edu /~jdl1/web.page.images/welded.tuff1.html (132 words)

	Summary of Citation
		Is a multiple-flow simple or compound cooling unit of rhyolitic welded and nonwelded ash-flow tuff and associated ash-fall tuff.
		Is a compound cooling unit, predominantly gray to brown devitrified densely welded ash-flow tuff with minor brown and gray nonwelded to partially welded tuff at its base and top.
		Overlying tuff of Chocolate Canyon in the cauldron distinguished by increase of dark-gray phenocryst-rich collapsed pumice lenticles of quartz latite.
	ngmdb.usgs.gov /Geolex/Refsmry/sumry_6247.html (1062 words)

	Tuff definition (Site not responding. Last check: 2007-10-24)
		Tuff: "indurated pyroclastic rocks of grain generally finer than 4 mm, that is the indurated equivalent of volcanic ash or dust" Wentworth and Williams (1932)
		Pyroclastic: an adjective commonly applied to rocks produced by explosive or aerial ejection of material from a volcanic vent.
		Tuff, welded: tuffs in which the individual particles remained plastic enough to become partly or wholly welded.
	www.hanksville.org /voyage/defs/tuff.html (75 words)

	Mount Everts, Yellowstone National Park
		On these cliffs of welded tuff, scientists in the 1960s first recognized that more than one great caldera-forming eruption had occurred in the Yellowstone region.
		A key to understanding the significance of these welded tuffs was the recognition that several small stream valleys had been cut through the Huckleberry Ridge Tuff after it was emplaced here within a broad stream-cut valley but before emplacement of the Lava Creek Tuff.
		Despite its considerable distance from its source caldera, the tuff here is quite thick and is densely welded, attesting to its high temperature of eruption and emplacement.
	volcanoes.usgs.gov /yvo/images/19671016-rc-evertspaleo_caption.html (354 words)

	Tuff Abstract (Site not responding. Last check: 2007-10-24)
		The tuffs occur in different crustal blocks and are interlayered with basalt flows, lacustrine and minor fluviatile sediments, and air-fall ash deposits.
		Two regionally extensive welded tuffs are the focus of this study.
		The oldest tuff, the Dinner Creek Ash-Flow Tuff (15.3 Ma), is interlayered with flows of the Columbia River Basalt Group.
	www.sover.net /~applegat/corgsa96.html (464 words)

	Summary of Citation
		Is single cooling unit, a welded ash-flow tuff of trachytic composition and of normal polarity.
		Tuff resembling Peach Springs Tuff(?) (of Young, 1966) in age and lithology is present east and west of Stepladder Mountains in Sawtooth Range (Chemehuevi Mountains) and in Little Piute Mountains, CA.
		Consists of welded crystal-rich ash-flow tuff with blue sanidine with ages of 18.1 and 18.3 Ma.
	ngmdb.usgs.gov /Geolex/Refsmry/sumry_6121.html (547 words)

	Faulting and Fracturing of Nonwelded Bishop Tuff, Eastern California: Deformation Mechanisms in Very Porous Materials ...
		Bishop Tuff (Gilbert, 1938; Bateman, 1965; Sheridan, 1970) and
		The sequence is a fine-grained vitric tuff with lapilli
		in the nonwelded tuff adjacent to the fractures.
	vzj.scijournals.org /cgi/content/full/3/2/602 (8353 words)

	Tuff (Site not responding. Last check: 2007-10-24)
		We believe that the Tuff originated to the north of Chermside, or even further north towards Caboolture.
		Welded tuff is made up of clear quartz, white feldspar as well as fragments of pumice, Bunya Phyllite and greenstone.
		Chemicals in tuff include iron and manganese, exposure to oxidation causes tuff to turn into the colour brown.
	www.vnc.qld.edu.au /enviro/etasc02e.htm (191 words)

	My Dam Projects
		Geotechnical problems included weathered, non-welded tuff in dam foundation and toppling slope failures in welded tuff in unlined spillway cutting.
		The spillway is an unlined cutting in welded ash flow tuff which supplied the entire rock fill requirement for the construction of the dam embankment.
		The spillway excavation was designed to be located entirely in welded tuff and not to encroach on either the underlying non-welded tuff or the overlying sandstone, both of these rock types being much inferior to the welded tuff as a rock fill construction material.
	members.optusnet.com.au /~richardw2/projects.html (1639 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations (Site not responding. Last check: 2007-10-24)
		Welded tuff is one of the many candidate rocks presently being considered as a host medium for the disposal of radioactive waste.
		Although these processes have all been known about for decades, it is not clear at this time what the relative importance of each is with regard to geologic media in a waste disposal environment.
		This paper reports the measurement of water loss rate for welded tuff at various temperatures due to the action of evaporative drying.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=59404 (430 words)

	Welded Tuff (Site not responding. Last check: 2007-10-24)
		Tuff is volcanic ash that has been consolidated back into a rock.
		Ash is produced when violent (gassy) volcanic eruptions pulverize pumice and blow it into the atmosphere.
		In time, the loose, powdery ash will be compacted and cemented to form "welded" tuff.
	www.jsu.edu /depart/geography/mhill/phylabtwo/tuff.html (76 words)

	Bishop Tuff
		O zone is extremely sharp (~ 3 per mil per meter) and is located directly above the transition from partially welded tuff to densely welded fl tuff.
		This is compatible with the observation that the fumarolic areas roughly correlate with the preeruptive regional drainage patter.
		O-signature that we have correlated with fossil fumaroles in the Bishop Tuff outflow sheet.
	www.gps.caltech.edu /~hptaylor/Taylor_bishoptuff.html (475 words)

	The Ultimate Yellowstone National Park Dog Breeds Information Guide and Reference
		It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions.
		The welded tuff geologic formation created by this eruption is called the Lava Creek Tuff.
		The first and largest eruption, climaxed to the south west of the current park boundaries 2.2 million years ago and formed a caldera about 80 by 50 km in size (50 by 30 miles) and hundreds of metres deep after releasing 2,500 cubic kilometres of material (mostly ash, pumice and other pyroclastics).
	www.dogluvers.com /dog_breeds/Yellowstone_National_Park (2960 words)

	USGS WRIR 96-4109 Table 1
		Rhyolite lava and nonwelded tuff, commonly zeolitized (welded tuff)
		Tuff confining unit (lava-flow aquifer or confining unit?)
		Peralkaline welded ash-flow tuff (nonwelded tuff, commonly zeolitized)
	pubs.usgs.gov /wri/wri964109/table1.htm (1044 words)

	Table: 1-1
		For the purposes of GFM3.1, each formation in the Crater Flat Group was subdivided into six zones based on the requirements of the users of the Geologic Framework Model.
		The subdivisions are upper vitric (uv), upper crystalline (uc), moderately to densely welded (md), lower crystalline (lc), lower vitric (lv), and bedded tuff (bt) (Buesch and Spengler 1999, pp.
		Sequence 13 (Tptpv3—Tptpv2) is subdivided into 2 layers of equal thickness.
	www.ocrwm.doe.gov /documents/m2hk_a/tables/t1_1.htm (118 words)

	Estimation of fracture porosity in an unsaturated fractured welded tuff using gas tracer testing
		Estimation of fracture porosity in an unsaturated fractured welded tuff using gas tracer testing
		Printing Tips: Select 'print as image' in the Acrobat print dialog if you have trouble printing.
		Barry Freifeld, "Estimation of fracture porosity in an unsaturated fractured welded tuff using gas tracer testing" (October 1, 2001).
	repositories.cdlib.org /lbnl/LBNL-50123 (83 words)

	Find in a Library: Petrology of the welded tuff of Devine Canyon, southeastern Oregon,
		Petrology of the welded tuff of Devine Canyon, southeastern Oregon,
		To find this item in a library, enter a postal code, state, province, or country in the field above.
		WorldCat is provided by OCLC Online Computer Library Center, Inc. on behalf of its member libraries.
	www.worldcatlibraries.org /wcpa/ow/d133e3a89a1c2b3b.html (69 words)

	Hoodoo - a geomorphological formation (Site not responding. Last check: 2007-10-24)
		I have also noted hoodoos in soft tuff or other volcanoclastic rock, such as in the San Juan Mountains of Colorado, and the Superstitian Mountains of Arizona.
		Here they're composed of a soft welded tuff that has a layer of something harder (typically basalt) on top of it.
		The hoodoo forms when erosion along a canyon wall or other surface leaves a pillar, usually cone shaped, of the softer rock that is detached from the canyon wall with a cap stone of the harder rock a top it.
	www.staff.amu.edu.pl /~sgp/gw/hd/hoodoo.htm (5270 words)

	Ingrid's Rockin' Dictionary
		pyroclastic deposit; pumice, glass shards, and crystals deposited at high temperature so that resulting rocks is consolidated; same as welded tuff, although sometimes used for both welded and unwelded deposits; sometimes refers to pumice-rich deposits [PR]
		literally, "glowing avalanche" or "glowing cloud;" refers to pyroclastic flows which produce welded tuffs, specifically used for those flows which are observed [
		describes clastic material ejected from volcanic vents [PR]; also called ash, tephra, etc.; pyroclastic deposits include ignimbrites, nuées ardentes, and welded tuffs.
	www.lpl.arizona.edu /~ingrid/dictionary.html (6780 words)

	Golden Gate Photo - Welded Tuff Close-Up (Site not responding. Last check: 2007-10-24)
		Golden Gate Photo - Welded Tuff Close-Up Golden Gate Photo
		Close-up of welded tuff from Chiricahua National Monument, Arizona.
		For all photograph orders, please refer to the
	www.goldengatephoto.com /westus/weldedtuff.html (38 words)

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