960 resultados para Precambrian Geologic Period.
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Audit report on a special investigation of the City of Gravity for the period January 1, 2003 through February 15, 2007
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Report on Ratna Corporation (Plaza Pantry) for the period January 1, 2006 through December 31, 2006
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Special investigation of the Haverhill Volunteer Fire Department for the period January 1, 2003 through January 29, 2007
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Report on a special investigation of the City of Clearfield for the period August 1, 2006 through June 30, 2007
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Report on a special investigation of the Fifth and Eighth Judicial Districts Department of Correctional Services (Districts) for the period January 1, 2003 through June 30, 2006
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Report on the review of selected general and application controls over the State University of Iowa (University of Iowa) PeopleSoft General Ledger system for the period June 4, 2007 through July 27, 2007
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Reaudit report on the City of Keosauqua for the period July 1, 2003 through June 30, 2004
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Special investigation of the Monona County Engineer’s Office for the period January 1, 2004 through April 20, 2007
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The Anarak, Jandaq and Posht-e-Badam metamorphic complexes occupy the NW part of the Central-East Iranian Microcontinent and are juxtaposed with the Great Kavir block and Sanandaj-Sirjan zone. Our recent findings redefine the origin of these complexes, so far attributed to the Precambrian-Early Paleozoic orogenic episodes, and now directly related to the tectonic evolution of the Paleo-Tethys Ocean. This tectonic evolution was initiated by Late Ordovician-Early Devonian rifting events and terminated in the Triassic by the Eocimmerian collision event due to the docking of the Cimmerian blocks with the Asiatic Turan block. The ``Variscan accretionary complex'' is a new name we proposed for the most widely distributed metamorphic rocks connected to the Anarak and Jandaq complexes. This accretionary complex exposed from SW of Jandaq to the Anarak and Kabudan areas is a thick and fine grain siliciclastic sequence accompanied by marginal-sea ophiolitic remnants, including gabbro-basalts with a supra-subduction-geochemical signature. New Ar-40/Ar-39 ages are obtained as 333-320 Ma for the metamorphism of this sequence under greenschist to amphibolite facies. Moreover, the limy intercalations in the volcano-sedimentary part of this complex in Godar-e-Siah yielded Upper Devonian-Tournaisian conodonts. The northeastern part of this complex in the Jandaq area was intruded by 215 +/- 15 Ma arc to collisional granite and pegmatites dated by ID-TIMS and its metamorphic rocks are characterized by Some Ar-40/Ar-39 radiometric ages of 163-156 Ma. The ``Variscan'' accretionary complex was northwardly accreted to the Airekan granitic terrane dated at 549 +/- 15 Ma. Later, from the Late Carboniferous to Triassic, huge amounts of oceanic material were accreted to its southern side and penetrated by several seamounts such as the Anarak and Kabudan. This new period of accretion is supported by the 280-230 Ma Ar-40/Ar-39 ages for the Anarak mild high-pressure metamorphic rocks and a 262 Ma U-Pb age for the trondhjemite-rhyolite association of that area. The Triassic Bayazeh flysch filled the foreland basin during the final closure of the Paleo-Tethys Ocean and was partly deposited and/or thrusted onto the Cimmerian Yazd block. The Paleo-Tethys magmatic arc products have been well-preserved in the Late Devonian-Carboniferous Godar-e-Siah intra-arc deposits and the Triassic Nakhlak fore-arc succession. On the passive margin of the Cimmerian block, in the Yazd region, the nearly continuous Upper Paleozoic platform-type deposition was totally interrupted during the Middle to Late Triassic. Local erosion, down to Lower Paleozoic levels, may be related to flexural bulge erosion. The platform was finally unconformably covered by Liassic continental molassic deposits of the Shemshak. One of the extensional periods related to Neo-Tethyan back-arc rifting in Late Cretaceous time finally separated parts of the Eocimmerian collisional domain from the Eurasian Turan domain. The opening and closing of this new ocean, characterized by the Nain and Sabzevar ophiolitic melanges, finally transported the Anarak-Jandaq composite terrane to Central Iran, accompanied by large scale rotation of the Central-East Iranian Microcontinent (CEIM). Due to many similarities between the Posht-e-Badam metamorphic complex and the Anarak-Jandaq composite terrane, the former could be part of the latter, if it was transported further south during Tertiary time. (C) 2007 Elsevier B.V. All rights reserved.
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Special investigation of the City of Rathbun for the period July 1, 2003 through November 30, 2007
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Special investigation of Hardin County Solid Waste Disposal Commission for the period January 1, 2002 through December 31, 2007
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Special investigation of the City of Postville for the period July 1, 2000 through June 30, 2006
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Audit report on the Iowa County Treasurers Egovernment Alliance (the Alliance) for the period from October 1, 2006 (inception) through June 30, 2007
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Review of Targeted Small Business (TSB) procurement activities for the period July 1, 2007 through September 30, 2007
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Reaudit report on the WACO Community School District for the period July 1, 2005 through June 30, 2006
