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	Slab gap hypothesis - Wikipedia, the free encyclopedia
		In geology, the slab gap hypothesis is one of the explanations put forward to explain several instances of extension that have seemingly paradoxically occurred near subduction zones (which otherwise would typically compact crust, not stretch it out).
		The hypothesis is that a gap forms between the two now subducting chucks of oceanic lithosphere when the spreading zone (the divergent plate boundary) of an oceanic plate is subducted under continental lithosphere.
		The slab gap hypothesis suggests that the mantle upwelling, unable to cause a spreading zone, causes the overlying continental lithosphere (and the continental crust on top of it) to spread apart.
	en.wikipedia.org /wiki/Slab_gap_hypothesis (282 words)

	[No title] (Site not responding. Last check: 2007-10-08)
		The slab gap was envisioned to be the locus of decompression melting in the asthenosphere resulting in the accretion of a several kilometers thick layer of mafic material to the base of the California crust [Liu and Furlong, 1992].
		The age of the subducted plate is 6-10 Ma [Wilson, 1986]; hence the thickness of the thermal lithosphere (to a temperature of 1300ºC) is 25-30 km.
		The pattern of increasing heat flow south of the MTJ was previously cited as evidence for a slab gap [Lachenbruch and Sass, 1980].
	woodshole.er.usgs.gov /bibliographies/current2/1933.html (1934 words)

	Leeman Research Project 1
		Cooler subduction zones (e.g, Marianas, Tonga) are characterized by older plates and faster subduction (and vice versa); associated volcanic arcs have relatively steeply dipping slabs, greater slab length (as measured down-dip from trench to deepest earthquakes), narrow arc-trench gap, and magmas exhibiting stronger enrichments of fluid-mobile trace elements (FMEs; e.g., B, As, Sb).
		Slab thermal structure appears to have a fundamental influence on the chemistry of arc magmas in that warmer slabs will dehydrate at shallower depths and thereby carry smaller inventories of water and FMEs to subarc depths.
		In essence, the fraction of initial boron retained in the slab is determined by the maximum temperature attained.
	zephyr.rice.edu /department/research/bill1/bill1.html (523 words)

	Cenozoic Geology
		Hypothesis #1: The subducted portion of the East Pacific Rise lies under Nevada and the sub-crustal spreading causes mantle upwelling and crustal extension.
		Hypothesis #3: Following the onset of transform faulting along the plate boundary, a detached portion of the subducted Pacific Plate continued to be subducted and melted beneath Nevada.
		In addition, the expansion of the slab gap underneath the Colorado Plateau region is predicted to have occurred 10-5 million years ago, around the time that uplift actually occurred.
	www.uh.edu /~geos6g/1376/cenogeology15.html (3749 words)

	HYDROLOGY
		The Lower Slab Cabin Basin is the upper part of the Lower Slab Cabin Basin south of South Atherton Street, which runs roughly east-west on the east side of town.
		The length of the Slab Cabin Basin on the Pine Grove Mills branch is approximately 12 miles.
		Slab Cabin Basin is mostly suburban and rural, with a few urban land type areas.
	www.essc.psu.edu /~tnc/hydro/spring2000_finalpaper/Meteo597_Final_paper_01.htm (4187 words)

	Slab gap hypothesis -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-08)
		The slab gap hypothesis suggests that the mantle upwelling, unable to cause a spreading zone, causes the overlying continental lithosphere (and the (additional info and facts about continental crust) continental crust on top of it) to spread apart.
		If, however, the extention is spread over a very large area then these (additional info and facts about flood basalt) flood basalt events may not occur.
		Slab gap has also been used to help explain the earlier creation of the (additional info and facts about Basin and Range Province) Basin and Range Province.
	www.absoluteastronomy.com /encyclopedia/s/sl/slab_gap_hypothesis.htm (152 words)

	USGS Western Mineral Resources Projects: Early Tertiary Slab Window in Alaska and it's Resource Implications (Site not responding. Last check: 2007-10-08)
		This project tests the hypothesis that a gap between two subducting plates is responsible for a wide array of geologic features across an enormous area in Alaska: plutons, volcanic fields, sedimentary basins, ore deposits, and hydrocarbon systems.
		The gap, or "slab window", was analogous to a moving blowtorch heating the earth's crust from below.
		We propose to test the hypothesis that an asthenosphere slab window, which opened at depth between the subducted but still diverging plates, had widespread geologic effects as far as 1000 km inland.
	minerals.usgs.gov /west/projects/slab.shtml (376 words)

	Basin and Range - Wikipedia, the free encyclopedia (Site not responding. Last check: 2007-10-08)
		Death Valley is a good example of a modified basin and range valley.
		The basins are down-fallen blocks of crust and the ranges are up-thrust slabs (actually the arrangement is a bit tilted to the east - in profile this would look similar to an encyclopedia leaning to one side - like so ///).
		As the spreading center (divergent plate boundary) of the subducting Farallon Plate moved beneath the North American plate, it formed a "slab gap", which caused heat from the mantle plume feeding the spreading zone to thin out the continental crust above it and cause the spreading (see slab gap hypothesis).
	en.wikipedia.org /wiki/Basin_and_Range_Province (773 words)

	EJGE Paper 2002-0227 (Site not responding. Last check: 2007-10-08)
		Filling this gap, the author has recently performed a theoretical study (Uddin and Gazetas 1995) that explored the potential consequences of strong seismic shaking for slabs of a typical 100 m-tall dam, using state-of-the-art finite-element (FE) analyses.
		The dynamic response of the dam is not influenced by the presence of the slab.
		Young's modulus of the slab is taken to be the same as the one used in FE analysis (= 22000 MPa).
	www.ejge.com /2002/Ppr0227/Ppr0227.htm (1647 words)

	Reports Submitted to FAMSI - J. Gregory Smith
		Here there is a 1m wide gap in the wall and there are upright jamb stones on either side of the gap.
		Two large square slabs were spotted in the rubble in the NE corner area; one measures 1.4m x.6m x.2m and could be a lintel.
		Another hypothesis is that Structure 27 predates the site center and these smaller civic buildings were built in the shadow of an older civic structure.
	www.famsi.org /reports/00051/section11.htm (5016 words)

	The Appleton Museum of Art
		Their sophistication, advancement and alienation were perhaps so complete that a cavernous gap separated artist and audience.
		A solitary vertical element in a barren field; in the sixties, a painted pole erected in a field sufficed as a Zuck sculpture.
		Pole and Shadow, Slab in a Landscape, and Beacon: a solitary vertical mark on the horizon is illuminated by ethereal light, casting a shadow across the ground.
	www.appletonmuseum.org /zuck.shtml (4261 words)

	Nat' Academies Press, Living on an Active Earth: Perspectives on Earthquake Science (2003)
		Fedotov’s map of seismic gaps include earthquakes of M 7.75 and larger; it was reproduced by K. Mogi in Earthquake Prediction, Academic Press, London, p.
		The track record of the gap hypothesis has been quite controversial, in part because early definitions were subjective.
		Mogi’s “do-nut” hypothesis is summarized succinctly in C. Scholz, The Mechanics of Earthquakes and Faulting, Cambridge University Press, New York, pp.
	www.nap.edu /books/0309065623/html/19.html (8527 words)

	Caribbean --- Coastal and Marine Geology Program - U.S. Geological Survey - Model
		Hypothesis for the formation of the island of Puerto Rico and the collapse of the Puerto Rico Trench
		Orange arrows denote tensile stresses due to the curvature of the subducting slab and tensile stress due to the subduction of Main Ridge.
		The nature of the boundary between the two slab segments is unknown and is represented here as a sharp cut for simplicity.
	woodshole.er.usgs.gov /project-pages/caribbean/modelFig9.html (282 words)

	Abstract for Brad Hacker's seminar on October 14, 2003 (Site not responding. Last check: 2007-10-08)
		New thermal-petrologic models of subduction zones show a correlation between the patterns of intermediate-depth seismicity and the locations of predicted hydrous minerals: earthquakes occur in subducting slabs where dehydration is expected, and they are absent from parts of slabs predicted to be anhydrous.
		Because the thermal gradient in the upper seismic zone is inverted in most subduction zones, and therefore the potential for dehydration increases upward, the seismicity begins at the top of the slab and then descends slowly toward the slab Moho with increasing subduction depth.
		Because the temperature in the lower seismic zone increases downward, and therefore the potential for dehydration increases downward, the seismicity begins at modest depth in the slab and then ascends slowly toward the slab Moho with increasing subduction depth.
	www.geol.vt.edu /general/abstracts/hacker_031014.html (358 words)

	CORDILLERAN MAGMATIC PATTERNS CONSISTENT WITH FAR-TRAVELED BAJA BC (Site not responding. Last check: 2007-10-08)
		In this geological setting, magmatism is largely a consequence of fluid release associated with heating of the slab and hydration melting of the super adjacent mantle wedge.
		This hypothesis has been invoked to explain a variety of geologic observations including intra-continental Laramide orogenesis, missing lithosphere beneath the southern Sierra Nevada Batholith and Mojave Desert, and uplift of the Colorado Plateau.
		Additionally, the flat slab hypothesis has been used as an argument to counter the proposal of significant transcurrent motion of Late Mesozoic Cordilleran terranes (~3,000 km) required for the Baja BC hypothesis.
	gsa.confex.com /gsa/2004AM/finalprogram/abstract_81121.htm (428 words)

	Recent Abstracts
		Slab-Mantle Chemical Exchanges between 40 and 250 km: The Makeup of Slab Fluids, and the Role of the Wedge.
		Deeper slab fluids may be richer in SiO2, due perhaps to slab sediment melting, though isotope and Sr/Nd constraints entail significant inputs from subducted basalt.
		While information on slab fluxes drawn from arc volcanic data is necessarily indirect, multi-element studies of arc suites in which data from related arc centers are compared (either along an arc segment (Miller et al 1992; 1994; Edwards et al.
	chuma.cas.usf.edu /~ryan/abstracts.html (2946 words)

	Mexica Uprising - In Support of World Wide Indigenous Revolution
		This hypothesis allows scholars to construct what they call a syllabary--a chart of all the possible syllables in the language.
		Stepping on a flat stone slab, he was surprised to feel complicated patterns under his toes.
		When the slab was hauled out of the river, experts were astonished to find a finely carved stela, with twenty-one columns of hieroglyphs.
	www.mexicauprising.net /deciphermentofmaya.html (7485 words)

	Slab gap hypothesis - TheBestLinks.com - California, Geology, Hypothesis, Oregon, ... (Site not responding. Last check: 2007-10-08)
		Slab gap hypothesis - TheBestLinks.com - California, Geology, Hypothesis, Oregon,...
		Slab gap hypothesis, California, Geology, Hypothesis, Oregon, Washington, Lava...
		Slab Gap web page at University of Colorado (http://www.colorado.edu/GeolSci/Resources/WUSTectonics/SanAndreas/SlabGap.html)
	www.thebestlinks.com /Slab_gap_hypothesis.html (315 words)

	[No title]
		Our hypothesis is that both the expanding spherical geometry of the corona and the reconnection of its magnetic fields play critical roles in the dynamics of eruptive prominences and related solar events.
		The main purpose of this proposal is to bridge the gap between the above two methods and to create a model of neutral hydrogen in the heliosphere that is both accurate and practical for an average researcher.
		The slab geometry will be used for model development and for understanding the formation and dynamics of supergranules.
	research.hq.nasa.gov /code_s/nra/current/NRA-02-OSS-01-SHP/winners.html (7522 words)

	t72b in fm98
		The N boundary of this gap moves NW from under Arizona and New Mexico to under central Nevada and central Utah between ~35 Ma and today.
		The combined effect of the upward and outward movement of mantle material from the Yellowstone plume and the N circulation of mantle material related to the slab gap could generate mantle circulation that forced melted lithospheric material from the slab upward initially near the center of the Great Basin.
		This hypothesis is supported by the similarity between the pluton age contour pattern and (1) present averaged topographic elevations and (2) the mantle mass deficit pattern based on elevation and isostasy (Parsons et al., 1994).
	www.agu.org /cgi-bin/SFgate/SFgate?&listenv=table&multiple=1&range=1&directget=1&application=fm98&database=/data/epubs/wais/indexes/fm98/fm98&maxhits=200&="T72B" (2197 words)

	Geology_of_the_Death_Valley_area - The real meaning from Timesharetalk wikipedia (Site not responding. Last check: 2007-10-08)
		The oldest rocks in the area that now compose Death Valley National Park and environs are extensively metamorphosed by intense heat and pressure and are at least 1700 million years old.
		Next, the metamorphosed Precambrian basement rocks were uplifted and a nearly 500 million year long gap in the geologic record, a major unconformity, affected the region.
		Debate still surrounds the cause of this crustal stretching, but an increasingly popular idea among geologists called the slab-gap hypothesis states that the spreading zone of the subducted Farallon Plate is pushing the continent apart.
	www.timesharetalk.co.uk /wiki.asp?k=Geology_of_the_Death_Valley_area (6033 words)

	t11a in fm00
		The presence and location of a 200-km-wide slab gap beneath northern Central America is constrained by tomographic work by van der Hilst (1990) and is projected onto maps of bedrock meanders and all dated late Neogene extrusive and intrusive units in Honduras.
		A possible correlation of the slab gap to geomorphic and bedrock features of Nicaragua is also presented.
		From the seafloor topography derived from satellite altimetry and topographic profiles, the occurrence of large earthquakes correlates with regions where the surface roughness of the ocean bottom near the trench is greater.
	www.agu.org /cgi-bin/SFgate/SFgate?&listenv=table&multiple=1&range=1&directget=1&application=fm00&database=/data/epubs/wais/indexes/fm00/fm00&maxhits=200&="T11A" (3721 words)

	Some New Results On The Kinetic Ising Model In A Pure Phase - Bodineau, Martinelli (ResearchIndex) (Site not responding. Last check: 2007-10-08)
		We rst prove that the inverse spectral gap in a large cube of side N with plus boundary conditions is, apart from logarithmic corrections, larger than N in d = 2 while the logarithmic Sobolev constant is instead larger...
		0.5: The spectral gap of the 2-D stochastic Ising model with..
		Proving The Ergodic Hypothesis for Billiards With Disjoint..
	citeseer.ist.psu.edu /bodineau02some.html (532 words)

	[No title]
		length of subducted slab (to deepest earthquakes) for different subduction zones (shaded squares are arcs with anomalously thick crust).
		Assuming that earthquake cutoff depth is controlled by a critical slab temperature, these correlations suggest a strong control on B enrichment in arc magma sources by slab thermal structure.
		Cartoon crossection of southern Washington Cascades showing present subducted slab and (inboard) and accreted terrane and fossil slab attached to the palte margin before 40 Ma.
	zephyr.rice.edu /department/research/bill1/Leeman_WWW_projects.doc (2644 words)

	January 2002 Transporter
		The main hypothesis presented by the FHWA team was that individual slab deformation related to temperature curling, moisture warping, and built-in curvature were the culprits for the cracked slabs.
		After taking samples, the FHWA team determined that their hypothesis was correct—the slabs were indeed curving because of temperature, loads, and moisture.
		Not only did the team discover that they were able to measure individual slabs using laser-based profiling equipment, but this technology might open up numerous research possibilities and applications in the future.
	www.tfhrc.gov /trnsptr/jan02/jan02.htm (3090 words)

	[No title]
		One hypothesis of this dependence is a quasi-~periodic release of accumulated tectonic energy through seismic events which rupture the whole depth of a plate boundary.
		To explain the composite form of the moments for intermediate and deep earthquakes, we propose that a crustal slab of cold material subducts into the mantle and initially is still cold enough to yield, although at a much smaller rate, aftershocks characteristic for a brittle fracture.
		According to this hypothesis, the mantle deformation outside a subducting slab should be characterized by a fractal dimension larger than 0.9 (and close to 1.0).
	moho.ess.ucla.edu /~kagan/long.txt (8184 words)

	TKS Book Series
		This appears to be a plausible hypothesis for the origin of Indus Civilization.
		At times, there is a big gap between the sites Mughal has anticipated a four tier hierarchy in the settlement pattern of early Harappans.
		In the centre of the citadel, there is an almost 13 m wide water reservoir along with a feeder channel covered with slabs and provided with manholes for occasional desilting.
	www.infinityfoundation.com /joshi_book.htm (5387 words)

	Subduction-arc lecture, plate tectonics
		Models for the thermal structure of the descending slab.
		It is likely different for the different parts of the slab, crust vs. lithospheric mantle.
		This captures some of the debate as to how far subducted slabs descend into the mantle and argues against 'conventional wisdom' of a floor at 650-670 km.
	maps.unomaha.edu /Maher/plate/week4/subduction.html (872 words)

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