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Topic: Accretion (geology)

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

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. 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. Extent of Azores plume influence on the Mid-Atlantic Ridge north of the hotspot (Geology, 27, 991-994, 1999) www-sdt.univ-brest.fr /~goslin/triatnord/geology_trn.html   (306 words)

Erosional Hotspots - USACE-FRF The presence of outcropping geology (hardbottom, peat, etc) in the nearshore close to the hotspot was unknown. None of the sites reported rapid recovery (!heightened accretion) after erosion events, suggesting that fills will have to continue if the beaches are to be preserved. The objectives of the project are 1) to quantify the occurrence of hotspots, 2) to provide preliminary guidance to Corps engineers, and 3) to provide a classification system and database from which to identify candidate cases for further study on the causative processes. www.frf.usace.army.mil /hotspot/results.html   (901 words)

Buoyancy of the continental upper mantle Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA Also, at the onset of the accretion of the Kaapvaal craton, when the thermal boundary layer was thinner and hotter than today, these Kaapvaal peridotites would have been positively buoyant with respect to the convecting mantle at shallower pressures. At their temperatures and pressures of equilibration, all the low-temperature peridotites are positively buoyant with respect to the convecting mantle, which is inconsistent with the hypothesis of a neutrally buoyant thermal boundary layer. www.agu.org /pubs/crossref/2003/2002GC000399.shtml   (462 words)

Fire cycles in North American interior grasslands and their relation to prairie drought -- Brown et al. 102 (25): 8865 -- Proceedings of the National Academy of Sciences The rate of sediment accretion in Kettle Lake has been rather Kettle Lake is an unusual lake for this region, being Kettle Lake were not uniformly present throughout the late Holocene. www.pnas.org /cgi/content/full/102/25/8865   (3783 words)

Bio.html Alt, J.C., Davidson, G.J., Teagle, D.A.H., and Karson, J.A., The Isotopic Composition of Gypsum in the Macquarie Island Ophiolite: Implications for the Sulfur Cycle and the Subsurface Biosphere in Oceanic Crust, Geology, 31: 549–552; Accretion, structure and hydrology of intermediate spreading-rate oceanic crust from drillhole experiments and seafloor observations. Alt, J.C., D.A.H. Teagle,T.S. Brewer, W.C. Shanks, and A.N. Halliday, Alteration and mineralization of an oceanic forearc and the ophiolite-ocean crust analogy, J. Geophys. www-personal.umich.edu /~jalt/Bio1.html   (5151 words)

Crustal structure of the Java margin from seismic wide-angle and multichannel reflection data The Sunda convergence zone is a prime example of an accretionary margin, where sediment accretion has led to the formation of a massive accretionary prism, with a total width of >110 km between the trench and the forearc basin. It is composed of a frontal wedge which documents ongoing accretion and a fossil part behind the present backstop structure which constitutes the outer high. Index Terms: 3025 Marine Geology and Geophysics: Marine seismics (0935); 8015 Structural Geology: Local crustal structure; 8122 Tectonophysics: Dynamics, gravity and tectonics; 1219 Geodesy and Gravity: Local gravity anomalies and crustal structure. www.agu.org /pubs/crossref/2002/2000JB000095.shtml   (5151 words)

Geology 001B The Catskill Mountains records the westward advancement of the Acadian Orogeny and accretion of Avalonia. What was the tectonic setting of East Laurentia before the Taconic orogeny and what was the tectonic setting during the Taconic orogeny (ocean-ocean-arc accretion?, ocean-continent?, continent-continent?) What event occurred during the Silurian-Devonian Acadian orogney in northeast U.S. and Novia Scotia, what types of rocks were accreted, and what was the tectonic setting (ocean-ocean-arc accretion?, ocean-continent?, continent-continent?)? instruct.westvalley.edu /lopez/geo_1b/hist_que/hist_13a_east_laurentia.htm   (658 words)

STUDY GUIDES Nevadan and Sevier orogenies, cause of differences, effects of shallower angle (including shifted igneous activity and change in style of deformation); Laramide geology of Capitol Reef and Glacier National Parks. The Nevadan Orogeny and its important aspects, including Sierra Nevada Batholith, the Great Valley Group, and the Franciscan Complex; Mesozoic geology of Yosemite National Park. The Sauk sequence ; early Paleozoic geology of Grand Canyon National Park. www.pierce.ctc.edu /tbush/geol103/studyguides.htm   (658 words)

Garnets, Diamonds, Diatremes and Subduction at Bingara - Jane Barron et. al. Here we link their origin to the well documented Phanerozoic geology of the New England Orogen generated by prolonged westerly subduction (associated with terrane accretion) from Ordovician, but particularly during early Carboniferous to about mid-Triassic.             Therefore, the complex Phanerozoic tectonic history of subduction-accretion and tectonic underplating in the New England region, together with garnet-based evidence presented here for an extensive eclogitic to locally diamond eclogitic terrane with a variety of protoliths at depth, strongly supports a local origin for the diamonds that ‘belong’ in this tectonic setting. Abundant angular (proximal) garnet is widespread in the modern drainage south of Bingara, and forms the most important “indicator”of eclogitic diamond that is independent of ubiquitous diaggregated spinel lherzolite minerals from mantle xenoliths. www.smedg.org.au /nova01.htm   (744 words)

Encyclopedia of Planetary Sciences Mars: atmosphere; geology; gravity; impact cratering; magnetic field and magnetosphere; Observer mission; remote sensing; structural geology and tectonics. Processes such as accretion, differentiation, thermal evolution and impact cratering form another category of entries. Remote sensing techniques employed in investigation and exploration, such as magnetometry, photometry, and spectroscopy are described in separate articles. www.booksmatter.com /b0792367944.htm   (744 words)

Encyclopedia of Planetary Sciences Mars: atmosphere; geology; gravity; impact cratering; magnetic field and magnetosphere; Observer mission; remote sensing; structural geology and tectonics. Processes such as accretion, differentiation, thermal evolution and impact cratering form another category of entries. Remote sensing techniques employed in investigation and exploration, such as magnetometry, photometry, and spectroscopy are described in separate articles. www.booksmatter.com /b0792367944.htm   (744 words)

Main publications Yeruda and Chirimba granitoids (Yenisei Ridge) as indicators of Neoproterozoic collisions // Russian Geology and Geophysics, v. Neoproterozoic accretion-collisional events on the western margin of the Siberian Craton: New geological and geochronological evidence from the Yenisey Ridge. Popov N.V. Tectonic model for the Early Precambrian evolution of South Yenisey Ridge // Russian Geology and Geophysics, v. geology.uiggm.nsc.ru /uiggm/geology/evol/lab922/homepage/hpg4.html   (1514 words)

David E. Blake Blake, D., Bruce, M. L., and Martin, C, 1999, Mid-crustal, dip-parallel displacements across the western Idaho suture zone during arc-continent collision: in Mahoney, J. and Haugerud, R. A., Terrane Accretion along the Western Cordilleran margin: Constraints on timing and displacement, Geological Society of America Penrose Conference Field Trip Guidebook and Proceedings Abstracts, p. Robitaille, K. R., 2004, Geology and terrane relationships of the Tar River area, Franklin and Granville Counties, North Carolina: (M.S. Thesis) Wilimington, University of North Carolina at Wilmington, 167p and 2 plates. Horton, J. W., Jr., Blake, D., Wylie, A. Jr., and Stoddard, E. F., 1986, Metamorphosed melange terrane in the eastern Piedmont of North Carolina: Geology, v. people.uncw.edu /blaked   (1514 words)

Earth science in Iceland 2004-2005 In Iceland, some 400 km are exposed of the Mid-Atlantic ridge, allowing the student to observe and investigate the tectonic processes of crustal accretion, the central rift, fracture zones, submarine/subglacial volcanism and associated features and processes. Lectures cover the tectonic setting and tectonics of Iceland, general geology, geomorphology and weathering, climate and climatic history, petrology, volcanology, glaciology and glacial geology, cold and hot water geochemistry and hydraulics. Owing to Iceland's geographical position in the North Atlantic, and its geotectonic position over a mantle plume and astride the Mid-Atlantic Ridge, geological and tectonic processes are extraordinarily rapid and easily observed in Iceland. www.raunvis.hi.is /Jardedlisfr/Kennsla/2004-05.htm   (1514 words)

Tectonics of N. America - Reference List Walker, N. W., and Brown, E. H., 1991, Is the southeast Coast Plutonic Complex the consequence of accretion of the Insular superterrane?: Evidence from U-Pb zircon geochronometry in the northern Washington Cascades: v. Turner, R. W., Madrid, R. J., and Miller, E. L., 1989, Roberts Mountains allochthon: Stratigraphic comparison with lower Paleozoic outer continental margin strata of the northern Canadian Cordillera: Geology, v. Dalziel, I.W.D., 1991, Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: Evidence and implications for an Eocambrian supercontinent: Geology, v. faculty.gg.uwyo.edu /heller/classtectonicrefs.htm   (12501 words)

Litasfera (Lithosphere), 1999, No.10-11 This is illustrated by the type of evolution: vertical accretion of the Dnieper floodplains, changes of the Berezina channel and formation of alluvial strata of different age within a floodplain, peat deposition in the floor of the Zapadnaya Berezina valley (Fig. Abstract: G.I.Goretsky devoted a lot of his papers to the Quaternary geology of the Ukraine, among them "Alluvial chronicle of the Great Original Dnieper" (Goretsky, 1970) should be mentioned as a fundamental monographic essay. Gozhik P.F., Chugunny Ju.G. Contribution made by G.I.Goretsky to the development of the Quaternary geology in the Ukraine. www.ac.by /publications/litho/litho10.html   (12501 words)

Publications - Planetary Processes Lab Dusel-Bacon, C., Hansen, V.L., and Scala, J.A., 1995, High-pressure amphibolite-facies dynamic metamorphism and the Mesozoic tectonic evolution of an ancient continental margin, East-central Alaska, Journal of Metamorphic Geology, v. Hansen, V.L., 1988, A model for terrane accretion: Yukon-Tanana and Slide Mountain terranes, northwest North America: Tectonics, v. [PDF] Oliver, D.H. and Hansen, V.L., 2001, Discussion: Kilometre-scale folding in the Teslin zone, northern Canadian Cordillera, and its tectonic implications for the accretion of the Yukon-Tanana terrane to North America: Discussion, Canadian Journal of Earth Science, v. www.d.umn.edu /~vhansen/publications.html   (2143 words)

Otago Geology Publications, 2002-: Geology Department, University of Otago, New Zealand Cawood, P A, Landis, C A, Nemchin, A A, and Hada, S. Permian fragmentation, accretion and subsequent translation of a low-latitude Tethyan seamount to the high-latitude east Gondwana margin: evidence from detrital zircon age data. MacKenzie, D J and Craw, D. Structural and lithological continuity and discontinuity in the Otago Schist, Central Otago, New Zealand. Norris, R J and Nicolls, R. Strain accumulation and episodicity of fault movements in Otago. www.otago.ac.nz /Geology/publications/chron.htm   (2143 words)

William A. Thomas - University of Kentucky, Geological Sciences Thomas, W. A., and Bayona, G., 2002, Palinspastic restoration of the Anniston transverse zone in the Appalachian thrust belt, Alabama: Journal of Structural Geology, v. Bayona, G., Thomas, W. A., and Van der Voo, R., 2003, Kinematics of thrust sheets within transverse zones: A structural and paleomagnetic investigation in the Appalachian thrust belt of Georgia and Alabama: Journal of Structural Geology, v. Thomas, W. A., 2004, Genetic relationship of rift-stage crustal structure, terrane accretion, and foreland tectonics along the southern Appalachian-Ouachita orogen: Journal of Geodynamics, v. www.uky.edu /ArtsSciences/Geology/faculty/thomas.html   (2143 words)

Geology 001B The Catskill Mountains records the westward advancement of the Acadian Orogeny and accretion of Avalonia. What was the tectonic setting of East Laurentia before the Taconic orogeny and what was the tectonic setting during the Taconic orogeny (ocean-ocean-arc accretion?, ocean-continent?, continent-continent?) Note that the base of the Catskills is formed of the Devonian Oriskany and Helderberg Formations (carbonate platform sediments). instruct.westvalley.edu /lopez/geo_1b/hist_que/hist_13_wic.html   (644 words)

Carboniferous period Carboniferous period: Historical Geology of the Period- Historical Geology of the Period The Carboniferous period was marked by vast, coal-forming swamps... Table of Geological Periods- It is generally assumed that planets are formed by the accretion of gas and dust in a cosmic cloud,... Carboniferous period: Evolution of Plant and Animal Life - Evolution of Plant and Animal Life The plant life of the Carboniferous period was extensive and... www.infoplease.com /ce6/sci/A0810374.html   (176 words)

Selected Publications - Harold J. Tobin, New Mexico Tech Earth & Environmental Science Tobin, H.J., Moore, J.C., and Moore, G. F., 1994, Fluid pressure in the frontal thrust of the Oregon accretionary prism: Experimental constraints, Geology, v. Moore, J.C., and Tobin, H.J., 1997, Estimated fluid pressures of the Barbados accretionary prism and adjacent sediments: Proc. Tobin, H.J., Moore, J.C., MacKay, M.E., Orange, D.L., and Kulm, L.D., 1993, Fluid flow along a strike-slip fault at the toe of the Oregon accretionary prism: implications for the geometry of frontal accretion, Geological Society of America Bulletin, v. www.ees.nmt.edu /tobin/pubs.html   (176 words)

template It is primarily underlain by accreted rocks in the Cache Creek and Stikine terranes (see detailed geology map), and by post-accretionary plutonic rocks and overlapping sedimentary and volcanic packages. The Canadian Cordillera was formed by the accretion of two large composite superterranes: the eastern Intermontane Superterrane which accreted in Middle Jurassic time, and the western Insular Superterrane which accreted in Early Cretaceous time. The Omineca Belt lies to the east of the Intermontane Belt and the Coast Belt lies to the east of the Insular Belt. www.pgc.nrcan.gc.ca /atlintgi/terrane_map.htm   (210 words)

SPACE.com -- Earth’s Moon: Still A Puzzle Furthermore, the Moon is important because it is accessible and its surface is pure geology—without the effects of climate and biology—allowing scientists to study how silicate planets work and evolve. Foing explained that the current consensus is that a Mars-size planet embryo impacted the proto-Earth, and that the Moon resulted from the re-accretion of material ejected during the impact, coming mostly from that impacting object. Another view is that when the Moon passes through Earth’s magnetotail—a long, trailing limb of the Earth’s magnetosphere on the side facing away from the Sun—it blowtorches the Moon influencing the near side deposits. www.space.com /scienceastronomy/030529_moon_birth.html   (2067 words)

Dr. David Harding 1995, "Erosion Dynamics and Patterns on the Ethiopian Plateau of Northeast Africa: A Fractal Process", J. Weissel, A. Malinverno, D. Harding, and G. Karner, in Fractals in Petroleum Geology and Earth Processses, C. Bartonand and P. La Pointe, eds., Plenum Press, 127-142. 1986, "Comment on Structural study of intra-oceanic thrusting in the Klamath Mountains, northern California: implications on accretion geometry", G.D. Harper and D. Harding, Tectonics, 5:687-692. David Harding conducts research in the measurement and analysis of neotectonic landforms and vegetation canopies, in particular by utilizing advanced airborne and spaceborne laser altimeter systems. denali.gsfc.nasa.gov /personal_pages/harding/harding.html   (2067 words)

Studland, South Haven Peninsula - Geology and Geomorphology Field Trip Guide . West, I.M. Studland and the South Haven Peninsula; Geology of the Wessex Coast of southern England. The later part of the 19th Century, and the early years of the 20th Century saw further accretion in the central part of Studland Bay with a maximum growth of some 75 m between 1886 and 1924. Studland is a small attractive village situated on the east coast of the Isle of Purbeck, north of Swanage and the Chalk downs, the Purbeck Hills. www.soton.ac.uk /~imw/Studland.htm   (16193 words)

Human Space Exploration It will help to better understand impact cratering, catastrophic disruption of asteroids and related phenomena essential to the evolution of planetary geology and biospheres and to the accretion of solar systems. The debye lengths of particles in the solar wind are typically tens of meters, and magnetospheric particles can have debye lengths of hundreds of meters [Kivelson 1998]. Exploration of the Moon and the solar system by astronauts and robotic spacecraft in the 1960s and 1970s, demonstrated that impact cratering has been, and still is, a major process in the origin and evolution of all the solid bodies of the solar system, from Mercury to the moons of Neptune. neptune.spaceports.com /~helmut/exploration99/strategy1/2_6_3_future_science.html   (16193 words)

Observations of Impacts Caused by Hurricane Bonnie, August 1998, on the North Carolina Coast - USGS Center for Coastal Geology Beach erosion and accretion create distinctive patterns in plots showing elevation changes between the two data sets. Hurricane Bonnie struck the North Carolina coast on August 26, 1998. Although prior to landfall, Hurricane Bonnie was approximately the same strength as Hurricane Fran, Bonnie caused far fewer impacts to the barrier island environment. coastal.er.usgs.gov /hurricanes/bonnie/lidar   (16193 words)

AAS Biographical Memoirs - Martin Fritz Glaessner 1906-1989 Fossils have always had a central role in advancing the geology of this region, a role that was critical in stimulating the enthusiasms and shaping the scientific directions of the young Martin Glaessner. The arguments for establishing 'Three foraminiferal zones in the Tertiary of Australia' mark a truly fundamental change from the old to the new in the stratigraphy of southern Australia, and it was not due merely to the accretion of new facts and insights. The geologically young or Cainozoic sedimentary basins and fossils of southern Australia, in which Glaessner became interested during his Melbourne years, are very well represented in coastal exposures south of Adelaide and he established a research programme there with his first four postgraduates. www.asap.unimelb.edu.au /bsparcs/aasmemoirs/glaessne.htm   (16193 words)

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