Ridge (geology) - Factbites

Ridge (geology) - Factbites
Where results make sense
About us | Why use us? | Reviews | PR | Contact us

Topic: Ridge (geology)

Note: these results are not from the primary (high quality) database.

In the News (Thu 31 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Ridge-transform intersections
		Decompression of the mantle and the formation of a melt would also a change the thermal and physical gradient at the ridge.
		Accounting for the presence of hotspot seamounts at ridge-transform intersections requires that 1) magma must be diverted or funneled to the ridge-transform intersection rather than the ridge center, and 2) this process must be governed by the lithosphere, as magma movement at the ridge appears to be governed by the lithosphere.
		The existence of seamounts with hotspot geochemical signatures (hereafter simply called hotspots with no implied inference to their origin) in the center of ridges is relatively well understood.
	www.mantleplumes.org /RTIntersections.html (1313 words)

	Oceanography and Marine Science
		Petrologic and tectonic gradients along the Southeast Indian Ridge, from a coldspot to a hotspot.
		Petrology of basic lavas from the intersection of the Tonga and Kermadec island arcs, and the southernmost Valu Fa Ridge.
		Interactions of mid-ocean ridge petrology, morphology and tectonics, especially at constant spreading rates.
	www.coas.oregonstate.edu /index.cfm?fuseaction=faculty.detail&id=387 (103 words)

	James Tull Faculty Page
		Li Li (Ph.D, 1996): The stratigraphy and structure of the Corbin and Salem Church Basement culminations in the southern Appalachian Blue Ridge, northwest Georgia;
		Drummond, M.S., Neilson, M.J., Allison, D.T., and Tull, J.F., 1997, Igneous petrogenesis and tectonic setting of granitic rocks from the eastern Blue Ridge and Inner Piedmont, Alabama Appalachians: in Sinha, A.K., Whalen, J.B., Hogan, J.P., eds., The nature of magmatism in the Appalachian orogen: Geological Society of America Memoir, p.
		Stephen Palmes (Ph.D, 1998): Structure and stratigraphy of the western Blue Ridge in north Georgia;
	www.gly.fsu.edu /faculty/tull.html (993 words)

	Appalachian Plateau province The Geology of Virginia
		Regionally, the Appalachian Plateau lies to the northwest of the Valley and Ridge.
		Regional scale folds in the Plateau formed in response to shortening on thrust faults that do not reach the present surface and are rooted to the east in the Valley and Ridge province.
		The upper Paleozoic strata of the Plateau are rich in mineral resources such as coal, natural gas, and petroleum.
	www.wm.edu /geology/virginia/app_plateau.html (146 words)

	phpr_ah
		The plateau surface is tilted to the east and is separated from the Valley and Ridge province by a prominent escarpment formed by parallel retreat.
		: Interactive geologic map (Valley and Ridge, and Plateaus provinces)
		Portions of the plateaus region that is heavily dissected are referred to as "mountains", less dissected areas are "plateaus".
	members.aol.com /gls210/phpr_ah.htm (925 words)

	Earth-Pages Archive News, Tectonics
		There are those who focus on massive mantle turnovers in the form of superplumes that build large volcanic plateaux on land and on the sea floor, suggesting that their subduction generates greater volumes of crust than usual.
		For fast-spreading ridges, such as the East Pacific Rise, there are two such models: constraint of rising mantle in two-dimensional sheets descending from beneath the ridge itself; three-dimensional plumes of mantle from which magma migrates laterally to ridge segments.
		The detachment of lithospheric masses and their falling-off into the mantle, either by delamination of deep lithosphere beneath continents or the breaking of a subducted slab, have become popular means of explaining a variety of unusual phenomena in mountain belts.
	www.earth-pages.com /archive/tectonics.asp (10251 words)

	ULB - DSTE: Kerguelen Archipelago (Weis)
		The result is transitional to alkalic parental magmas showing the effects of residual garnet during partial melting, as indicated by La/Yb >10 in archipelago lavas compared to <4 in Ninetyeast Ridge tholeiites (Weis et al., 1992; Frey and Weis, 1995; Saunders et al., 1994).
		Prior to forming the Kerguelen Archipelago and perhaps Heard Island which are on the Antarctic plate, the long-lived (~115 my) Kerguelen plume formed a very large igneous province (Kerguelen Plateau) followed by a ~5000 km hotspot track (Ninetyeast Ridge).
		The Kerguelen Archipelago on the northern Kerguelen Plateau (Fig.
	homepages.ulb.ac.be /~dweis/research/KergArch.html (478 words)

	Ascension Island Geology
		Unusually, Ascension Island is not hotspot-centred; geophysical and geochemical indications are that the Ascension hotspot lies to the east of the Mid-Atlantic Ridge at about 10°S, some 250-300 km distant from the island.
		Ascension lies close to the Mid-Atlantic Ridge (80 km to the east) and just south of the Ascension Fracture Zone (50 km to the north).
		(7.95°S, 14.37°W) is one of a number of hotspot oceanic islands in the South Atlantic (which include the sister islands of St. Helena and Tristan da Cunha).
	ags.ou.edu /~bweaver/Ascension/ai-geol.htm (1801 words)

	Abstract - Goslin et al., Geology, 1999.
		This fits well with the asymmetry of the upper mantle thermal structure, as was previously inferred from seismic tomography and geoid models, thus enhancing the links between shallow and deeper accretion processes in a hotspot-ridge interaction context.
		Extent of Azores plume influence on the Mid-Atlantic Ridge north of the hotspot (Geology, 27, 991-994, 1999)
		This new data set allows to place tentatively the northern limit of the influence of the Azores hotspot on the accretion processes between latitudes 43°N and 44°N. This limit is marked by a 1°-wide transition zone.
	www-sdt.univ-brest.fr /~goslin/triatnord/geology_trn.html (306 words)

	The American Museum of Natural History - EarthBulletin - Volcanoes - Geologic Setting
		Iceland's geology is among the most unique in the world.
		The country was formed because of an interaction between two separate geologic events: sea-floor spreading at a mid-ocean ridge and a hotspot -- from which lava sporadically erupts -- below the ridge.
		Instead, when the hotspot causes an eruption, the massive melting of the glacier produces huge floods.
	earthbulletin.amnh.org /A/5/2 (294 words)

	USGS CMG InfoBank Geology School: crust
		crust, "continental crust", "oceanic crust", granite, basalt, ocean, continent
		"plate tectonics", "oceanic crust", crust, magma, volcano, "divergent plate", "mid-oceanic ridge", rift, "sea floor spreading", plate, topography, orogeny, collision, "deep-sea trench", subduction
		"plate tectonics", plate, subduction, trench, earthquake, mantle, crust, basalt, "oceanic crust", pressure, magma, andesite, eruption, "volcanic chain", island, "island arc"
	walrus.wr.usgs.gov /infobank/programs/html/school/keypage/crust.html (1338 words)

	Kattenhorn (1994): MS References
		Bartholomew, M.J., Schultz, A.P., Henika, W.S., and Gathright, T.M., II, 1982, Geology of the Blue Ridge and Valley and Ridge at the junction of the central and southern Appalachians: in Lyttle, P.T., ed., Central Appalachian Geology, NE-SE Geological Society of America, Field Trip Guidebooks, p.
		Dahlstrom, C.D.A., 1970, Structural geology in the eastern margin of the Canadian Rocky Mountains: Bulletin of Canadian Petroleum Geology, v.
		Charlesworth, H.A.K., and Gagnon, L.G., 1985, Intercutaneous wedges, the triangle zone and structural thickening of the Mynheer coal seam at Coal Valley in the Rocky Mountain foothills of central Alberta: Bulletin of Canadian Petroleum Geology, v.
	www.webpages.uidaho.edu /~simkat/MSthesis/ms_refs.html (1706 words)

	Southeastern section of the Geological Society of America presentation
		This study draws on mapping within the Blue Ridge of Alabama, a terrane composed of Neoproterozoic metaclastic and metavolcanic rocks intruded by Paleozoic granitoid plutons.
		ALLISON, David T., Department of Geology and Geography, University of South Alabama, Mobile, Alabama 36688, and TULL, James F., Department of Geology, Florida State University, Tallahassee, FL 32306
		Recent knowledge gained from a program of converting mapping data to digital geologic maps has demonstrated that GIS is superior to traditional methods of producing geologic maps.
	www.southalabama.edu /usa/geography/allison/SEGSA2000_presentation.html (215 words)

	AllRefer.com - metamorphism : Types of Metamorphism : Regional Metamorphism (Geology And Oceanography) - Encyclopedia
		These kinds of metamorphic rocks are most commonly exposed in old mountain chains, like the Blue Ridge Mts., that have substantially eroded away over time, leaving only disturbed structure and regional metamorphic rocks.
		These metamorphic rocks pervade regions that have been subjected to intense pressures and temperatures during the development of mountain chains along boundaries between crustal plates.
		Large scale, intense regional metamorphism is particularly great in the "roots" of these mountains, which were at considerable depths when the pressures forming the mountains were active.
	reference.allrefer.com /encyclopedia/M/metamorpsm-types-of-metamorphism-regional-metamorphism.html (215 words)

	Physical Geology Slides-Crustal Deformation
		The outer surface of the ridge is a folded layer of resistant rock.
		The significance of these minor folds is that the geologist can tell which side of a large fold she is on and locate its axial plane by observing the shapes of the small folds.
		Several minor folds are visible, the foliation is parallel to their axial planes, and the thickness of the beds measured parallel to the axial planes is nearly constant.
	www.uwgb.edu /dutchs/EarthSC202Slides/struslid.htm (1752 words)

	sedanmeta.txt
		Conglomerate is present as minor ridge-forming thin beds and lenses composed of granules and pebbles of mainly western-derived Paleozoic and Mesozoic sedimentary rocks and a few well-rounded gneiss pebbles as much as 20 cm in diameter (Skipp and McGrew, 1972).
		Conglomerate is composed of cobbles of subangular to subrounded multilithologic clasts of volcanic and igneous rocks, sandstone, chert, fetid limestone, and rare gneiss and schist in southeastward- thinning tongues (Piombino, 1979; Roberts, 1972; this paper); boulders as much as 60 cm in diameter are present in upper part.
		Conglomerate and sandstone lenses are common in upper beds in southern part of quadrangle and in lower beds in northern part.
	pubs.usgs.gov /imap/i-2634/sedanmeta.txt (6999 words)

	Geology of the Sussex Sandstone - 3-D Reservoir Characterization
		Deposition of the "B" sandstone began in the southeastern corner of the field with sand ridge 1; axis orientation is about north 20 degrees west.
		Permeability barriers are mainly the low-depositional-energy mudstone and calcite-cemented sandstone facies that are concentrated toward the base of sand ridges.
		Basin morphology during deposition of Sussex and Shannon shelf sandstone beds in the Powder River Basin is illustrated on figure 4 (shelfmod.gif) (Tillman and Martinsen, 1984).
	pubs.usgs.gov /dds/dds-033/USGS_3D/ssx_txt/geology.htm (2721 words)

	UCMP Glossary: Geology
		A ridge of glacial sediment deposited by a stream flowing in and under a melting glacier.
		A fan-shaped deposit of sand, mud, etc. formed by a stream where its velocity has slowed, such as at the mouth of a ravine or at the foot of a mountain.
		A widespread, loose deposit consisting mainly of silt; most loess deposits formed during the Pleistocene as an accumulation of wind-blown dust carried from deserts, alluvial plains, or glacial deposits.
	www.ucmp.berkeley.edu /glossary/gloss2geol.html (3545 words)

	The Geology of Ohio--The Cambrian
		However, discovery (see Ohio Geology, Spring 1992) of trilobite fossils in core samples of the upper part of the younger Eau Claire Formation and the lower part of the Knox Dolomite suggests that the Mt. Simon may be even older.
		Oil and gas drillers search for buried erosional remnant hills along the subcrop, a trapping mechanism similar to that in the Copper Ridge dolomite in Morrow County.
		The package of rocks from the Precambrian unconformity to the Knox unconformity has been referred to as the Sauk Sequence.
	www.dnr.state.oh.us /geosurvey/oh_geol/97_Winter/cambrian.htm (3545 words)

	backgrnd.txt
		Greathead, Collin, 1975, The geology and petrochemistry of the greenstone belt south of Hurley and Upson, Iron County Wisconsin: Milwaukee, Wisconsin, University of Wisconsin-Milwaukee, M.S. thesis, 191 p.
		INTRODUCTION This map portrays the geology of part of the Midcontinent rift system along the southern limb of the Lake Superior syncline in northern Wisconsin and the upper peninsula of Michigan.
		The Keweenawan Supergroup volcanic strata progressively thin toward the ridge (see cross sections A-A' and B-B') and eventually pinch to a feather edge, which is approximately located on the map.
	pubs.usgs.gov /of/of99-546/backgrnd.txt (5796 words)

	Structural geology and regional geology
		Homza, T.X., 1991, Geologic, map, cross section, and structural geology of an area southwest of Bathtub Ridge, northeastern Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys, Public Data File 91-9, 21 p., scale 1:25,000, 1 sheet.
		Hanks, C.L., 1990, The structural behavior of a batholith in a foreland fold-and-thrust belt: An example from the northeastern Brooks Range, Alaska: Abstracts volume for Thrust tectonics 1990 conference, Royal Holloway and Bedford New College, University of London, p.
		Rogers, J.A., 1992, Lateral variation of range-front structures and structural evolution of the central Shublik Mountains and Ignek Valley, northeastern Brooks Range, Alaska: Master of Science thesis, University of Alaska, Fairbanks, 128 p.
	www.gi.alaska.edu /TSRG/NAKpubs/structurepubs.html (3996 words)

	Description of the Chicago District - Post Glacial and Economic Geology
		Including those indicated on the Areal Geology sheet as belonging to the Toleston Stage, there are, from [the] Calumet River at Hammond north to the south end of Lake George, ninety of these ridges, ranging from 3 to 10 feet in height.
		These are seen in the lake bluff north of Evanston, in the slopes of the Blue Island ridge and Mount Forest, in the sides of [the] Desplaines Valley through the moraine, and in the inner and outer slopes of the moraine.
		The same beds are seen in the western end of the Sag, at its junction with [the] Desplaines Valley.
	ebeltz.net /folio/cfol-5.html (3996 words)

	Maryland Geological Survey: Geology of Sideling Hill Road Cut
		However, the youngest rocks, or those highest in the stratigraphic section, are the resistant sandstones and conglomerates of the Purslane Formation, which occur in the center of the fold and cap the ridge.
		This electronic version of "The Geology of Sideling Hill" was prepared by R.D. Conkwright, Division of Coastal and Estuarine Geology, Maryland Geological Survey.
		One of the best rock exposures in Maryland and indeed in the entire northeastern United States is located approximately 6 miles west of Hancock in Washington County, where Interstate 68 cuts through Sideling Hill (Figure 1).
	www.mgs.md.gov /esic/brochures/sideling.html (1356 words)

	Tour of Some Iceland Geology
		The rift valley that lies at the crest of the ridge extends in a northeast direction along the peninsula, from Reykjanes, in the southwest, to Vogar and the airport road, in the northeast.
		The en echelon rifts are caused by the plate boundary, which runs along the peninsula, being not quite perpendicular to the spreading direction in this area.
		As the two sides of the Thingvellir rift moved apart during plate spreading, a large block on the western edge of the valley subsided and rotated, tilting the once-level strata so that they dipped into the valley.
	www.pangaeasci.com /_iceland.htm (1962 words)

	Dakota Matrix Minerals — Crystal and mineral specimens such as gold for the earth science student.
		The Geology of the Foley Ridge Gold Mine", Sept., 1990, Proceedings of the Fourth Western Regional Conference on Precious Metals and the Environment.
		Dakota Matrix Minerals — Crystal and mineral specimens such as gold for the earth science student.
		The Ross Hannibal mine, Lawrence Co., South Dakota” 1999 The Mineralogical Record V. Geological Overview of the Black Hills" 2002 MATRIX magazine V. 10 n.
	www.dakotamatrix.com /articles.asp (177 words)

	Geology 100 Telecourse Introductory lecture Part 2
		The lithosphere is solid and consists of the crust and uppermost mantle.
		Lithosphere-- Is rigid and is composed of the Crust+ Uppermost Mantle
		The youngest sea floor is near the mid-oceanic ridge.
	dl.ccc.cccd.edu /classes/telecourses/geology100/IntroLecture2.htm (2026 words)

	Geology of North Cascades National Park
		The newly-formed lithosphere is hot and thus less dense than older adjacent lithosphere; as a result it floats high on the mantle, forming the largest chains of mountains on Earth, the mid-ocean ridge systems.
		Geologists now know that the earth& crust is composed of many such tectonic plates, floating on the denser mantle.
		Some are being created and expanding by the injection of upwelling mantle, others are more passive and are moved to and fro by the movements of their neighbors.
	wrgis.wr.usgs.gov /docs/parks/noca/nocageol4c.html (762 words)

	Contributions to Zoology
		They are rimmed, and the inner orbital fossae is defined by a separate, tuberculate inner orbital ridge extending from edge of rostrum to the inner orbital septum.
		The orbits are deeply incised into anterior margin with two fossae, rimmed by granulate emarginations; the inner orbital fossa is set ahead of the outer fossa and is separated from it by a trough, bounded laterally by extraorbital and ventrally by suborbital spines.
		The inner orbital fossa is larger and bears spines on its lower and outer border, and has a suborbital drain or trough between.
	logos.uba.uva.nl /ctz/vol67/nr04/a02 (762 words)

	Morrison Geology - The Morrison Formation
		Along the west side of Dinosaur Ridge, the Morrison Formation is 280 to 320 feet thick.
		The upper third of the Morrison Formation is made up of interbedded layers of sandstone, siltstone, and red sandy shales.
		The Morrison formation takes its name from the Town of Morrison, Colorado, where varicolored shales are exposed along the west side of the Dakota Hogback.
	town.morrison.co.us /geology/morrform.html (762 words)

	WHOI : Publications : Currents Vol. 10 No. 3 : Rewriting the Story of Earth's Formation...Slowly
		They proved that Gakkel Ridge is volcanically active, but also found that the ridge spreads so slowly that large chunks of Earth's mantle, instead of volcanic magma, are deposited directly onto the seafloor.
		In fast-spreading and even slow-spreading ridges, magma rises to the seafloor through submarine volcanoes and fractures in the crust, filling in the gaps as the plates move apart.
		Dick believed a similar process was at work in the Gakkel Ridge, but studying the seafloor three miles beneath the ice cap of the Arctic Ocean was a challenge.
	www.whoi.edu /home/about/currents10_no3_earthformation.html (848 words)

Try your search on: Qwika (all wikis)

Topic: Ridge (geology)

Ads by Google

Related Topics

In the News (Thu 31 Dec 09)