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Topic: Paleoproterozoic

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	Manitoba Geology \| Geological Survey \| Mineral Resources Division \| Manitoba Science, Technology, Energy and Mines
		Paleoproterozoic sedimentary and volcanic rocks are currently interpreted as rift-related marine basin fill deposited unconformably on the drowned Archean platform margin.
		The Flin Flon Belt (FFB) is in the juvenile internal zone of the Trans-Hudson Orogen and consists of Paleoproterozoic volcanic, plutonic and minor sedimentary rocks.
		The Paleoproterozoic Lynn Lake and Rusty Lake greenstone belts occur in the interior (Reindeer) zone of the Trans-Hudson Orogen, that is, in the zone formed as new ocean floor, or in oceanic to continental volcanic arcs and related marine and continental sedimentary basins.
	www.gov.mb.ca /itm/mrd/geo/exp-sup/mbgeology.html (4728 words)

	Abstracts - Paleoproterozoic Mineralization Research
		However, the Paleoproterozoic volcanosedimentary succession that includes the Serra do Navio Formation is widely believed to be similar in origin and laterally equivalent to the Birimian Supergroup in West Africa.
		Paleoproterozoic laterites, red beds and ironstones of the Pretoria Group with reference to the history of atmospheric oxygen.
		The sedimentary manganese ore bed is interbedded with iron-formation of the Hotazel Formation of the Early Paleoproterozoic Voëlwater Subgroup of the Transvaal Supergroup.
	general.uj.ac.za /geology/ppm/abstracts.htm (7105 words)

	Palaeos Proterozoic: The Proterozoic Era
		Acritarchs are present in the later Paleoproterozoic; but they are rare and consist of morphologically simple spheres (i.e.
		Akinetes are inactive resting stages of cyanobacteria induced by cold, lack of food, or similar environmental conditions unfavorable for growth -- the sorts of stimuli that generally lead organisms to seek metabolic stasis and/or admission to graduate school.
		In general they verify the that, after an initial burst of diversification in the later Paleoproterozoic, development was gradual or even static until the Neoproterozoic.
	www.palaeos.com /Proterozoic/Proterozoic.htm (1998 words)

	proterozoic rocks
		The primary objective is to obtain knowledge of the structural geology of the Proterozoic rocks in western Colorado, eastern Utah, Arizona, and New Mexico, and to interpret the differences in deformation between the Paleoproterozoic and Mesoproterozoic rocks, the forces required for the deformation, and their general location.
		The Paleoproterozoic rocks of the Cerbat Mountains of northwestern Arizona are described as containing metavolcanic and metasedimentary rocks that have been intruded by granitoids and which experienced two periods of deformation (Duebendorfer et al, 2001).
		Paleoproterozoic rocks are composed primarily of seven types of gneiss, one of which is a garnet-sillimanite-biotite gneiss, two types of schist, and an amphibolite (Siddoway et al, 2000).
	www.mesastate.edu /snsm/geology/classes/seminar/ahosack/protrx.html (1833 words)

	University of Helsinki \| Faculty of Science \| Department of Geology \| Personnel \| Teachers and researchers \| Yrjö ...
		Kähkönen, Y. and Leveinen, J., 1994: Geochemistry of metasedimentary rocks of the Paleoproterozoic Tampere Schist Belt, southern Finland.
		Tiainen, M. and Kähkönen, Y., 1994: Geochemistry of the Paleoproterozoic andesitic to rhyolitic arc-type metavolcanic rocks of Haukkamaa, Kuru, central Finland.
		Geology and geochemistry of Paleoproterozoic amphibolites at Kiikoinen, southern Finland
	www.helsinki.fi /geology/personnel/ykahkonen.html (806 words)

	Anais da Academia Brasileira de Ciências - Geological features and the Paleoproterozoic collision of four Archean ... (Site not responding. Last check: 2007-09-17)
		Archean and Paleoproterozoic terrains of the São Francisco Craton crop out in two geographically distinct areas, the first and large one to the north and northeast of Bahia and, the second to the south towards Minas Gerais (Fig.
		In the Archean and Paleoproterozoic terrains the rocks are predominantely orthogneiss, equilibrated either in the granulite (Jequié Complex and Itabuna-Salvador-Curaça Belt) or amphibolite metamorphic facies (Gavião Block and Serrinha Block).
		The Paleoproterozoic collision occurred with the movement of the four blocks in the NW-SE sense, identified by the presence of large thrusts and generally sinistral transcurrent zones as the kinematics of the late ductile shear zones demonstrate (Fig.
	www.scielo.br /scielo.php?pid=S0001-37652002000200009&script=sci_arttext&tlng=en (3856 words)

	Author Auteur
		Additional Paleoproterozoic emplacement ages have been determined for other variably foliated granitic - monzonitic - dioritic rocks in the region (Halbach, 2128 Ma; Illuilik, 2124 Ma; Alliger Lake, 2109 Ma), and together with the basic rocks belie the general lithological similarities shared with the younger anorogenic NPS suite.
		We speculate that the overlapping Paleoproterozoic anorthositic and associated monzonitic-granitic magmatism occurred during a period of relative tectonic quiescence between late Archean tectonic assembly of western Nain craton (ca.
		Both Meso- and Paleoproterozoic episodes of anorthositic (and associated granitoid) plutonism can be accomodated in general models of lithospheric thinning, though it is unclear why a spatial-petrological relationship persisted over a considerable interim of 800 Ma.
	www.ggl.ulaval.ca /cgi-bin/consultau.cgi?458&736& (792 words)

	Logan Club Seminars (2003-2004) - Proterozoic glacial deposits, banded iron-formations and the snowball Earth debate
		Among Paleoproterozoic glacial deposits in North America, northwestern Europe, Western Australia and South Africa, the best preserved and documented are in the Huronian of Ontario, where three glaciogenic formations have been recognized.
		In Paleoproterozoic glaciogenic successions, with the possible exception of the Espanola Formation in the Huronian Supergroup, such carbonates are absent.
		Proponents of the SEH suggest that rapid escape from the snowball condition occurred as a result of buildup of high concentrations of CO2 in the atmosphere when the weathering cycle was stopped.
	gsc.nrcan.gc.ca /loganclub/2002_2003/sem2002_10_15_e.php (797 words)

	Western Churchill NATMAP Proposal Document
		The importance of Paleoproterozoic events in determining the present geological and metallogenic configuration of the WCP has been recognised, yet we have few constraints on their distribution in either space or time.
		Taken together, potentially Paleoproterozoic metasediments (Mackenzie Lake) north of the greenstone belt, and the lack of perceptible deflection of associated Kaminak dykes, are suggestive of high grade Paleoproterozoic deformation and metamorphism much older than hitherto suspected (possibly pre-2.45 Ga).
		The MacQuoid project area is well placed to investigate the Archean and Paleoproterozoic tectonothermal and uplift histories of strategic parts of the enigmatic STZ in Chesterfield Inlet, where it represents the deepest seated, highest temperature component of the Paleoproterozoic tectonothermal overprint on the NE Hearne "province".
	www.dias.ie /~ajones/wc/Churchill_NATMAP_proposal.html (5924 words)

	David Schneider, PhD (Site not responding. Last check: 2007-09-17)
		Paleoproterozoic development of a gneiss dome corridor in the Lake Superior region, USA.
		Elucidating Paleoproterozoic geodynamics from petrogenetic constraints: granites from the Penokean orogen.
		Paleoproterozoic tectonics of the Eastern Mojave Desert Region: Investigation of crystalline basement complexes in the Ivanpah and Clark Mountains, California (USA).
	www.ohiou.edu /geology/schneider (331 words)

	Anais da Academia Brasileira de Ciências - Sr and Nd isotopic characteristics of 1.77-1.58 Ga rift-related granites ... (Site not responding. Last check: 2007-09-17)
		The dominance of Paleoproterozoic model ages seems to indicate that most of the sialic basement in the region was accreted during the Transamazonian orogeny.
		Sm-Nd model ages indicate that most of the sialic crust that originated the parental magmas to the tin granites was accreted during the Paleoproterozoic and was probably involved in the ca.
		The time-lag observed between the final stages of deformation of the Paleoproterozoic orogens and the onset of extension and bimodal magmatism is explained in terms of the thermal and tectonic state of the lithosphere (Windley 1993).
	www.scielo.br /scielo.php?script=sci_arttext&pid=S0001-37652001000200010&lng=en&nrm=iso (3953 words)

	ALAN G JONES: WC Evolution Page
		The Late Archean and Paleoproterozoic evolution of the subcontinental mantle is recorded by large-scale, widespread magmatic and structural features.
		According to existing criteria, the test of the age of the lithosphere is as follows: if it is indeed late Archean, then mantle structure should reflect the penetrative nature and orientation of the late Archean crustal structure.
		Otherwise it may reflect the discontinuous nature of Paleoproterozoic crustal deformation, or show no geometrical correlation with crustal structure at all.
	www.geophysics.dias.ie /~ajones/wc/evolution.html (823 words)

	TIMING AND PROVENANCE OF NEOARCHEAN-PALEOPROTEROZOIC UNCONFORMITY BOUNDED SEQUENCES ON THE KAAPVAAL CRATON (Site not responding. Last check: 2007-09-17)
		Most interesting is the scarcity of middle to late Archean detrital zircons suggesting that the Kaapvaal Craton itself was not a major source for the Paleoproterozoic sedimentary successions preserved on it.
		There is also no indication that any of the Neoarchean to early Paleoproterozoic successions on the craton were sourced from the 2650-2700 Ma orogenic event preserved in the Limpopo Metamorphic Complex.
		However, younger late Paleoproterozoic red bed successions contain abundant zircons of this time interval as well as a dominant population of ~2000 Ma detrital zircons.
	gsa.confex.com /gsa/2004AM/finalprogram/abstract_78610.htm (435 words)

	Paleoproterozoic gold deposit in Rantasalmi, Finland
		The results of the Osikonmäki gold exploration project at Rantasalmi, SE Finland, carried out by the Geological Survey of Finland during 1986-1991 are reported in this Special Paper.
		Seven articles cover the following topics: geology of the Osikonmäki area and the granitoid host rock, geological setting, characteristics and fluid inclusion data of the gold deposit, and beneficiation properties of the ore.
		The epigenetic Paleoproterozoic Osikonmäki gold deposit, is hosted by the synorogenic (1887+5 Ma) Osikonmäki tonalite pluton.
	www.gsf.fi /info/sp25abs.html (478 words)

	EXTECH IV: Athabasca Uranium multidisciplinary study - Geochronology
		Constrain the regional stratigraphic geochronology of Paleoproterozoic sequences with which the Athabasca Basin has been or may be correlated by empirical stratigraphy.
		SHRIMP geochronology of detrital zircon and monazite of the Paleoproterozoic Athabasca Group of Northern Saskatchewan and Alberta, to be co-led by Rob Rainbird, Richard Stern (GSC) and Dave Quirt (SRC), with input by Charlie Jefferson & Jerry Ross (GSC) and Gary Yeo (SEM).
		SHRIMP geochronology of authigenic xenotime of the Paleoproterozoic Athabasca Group of Northern Saskatchewan and Alberta, to be co-led by Rob Rainbird, Richard Stern (GSC), and Dave Quirt (SRC).
	gsc.nrcan.gc.ca /extech/extech4/geochronology_e.php (320 words)

	NASA Astrobiology Institute (Site not responding. Last check: 2007-09-17)
		Planetary scale changes in the redox state of the Paleoproterozoic atmosphere and hydrosphere have profoundly affected the evolution of life on Earth.
		The accumulation of oxygen in the atmosphere is the result of oxygenic photosynthesis, which is thought to have evolved prior to 2.7 Ga. The Paleoproterozoic carbon cycle has experienced dramatic variations with world-wide carbonate occurrences that recorded excursions of isotopically heavy carbon, consistent with the oxygenation of the atmosphere.
		Variations in the sulfur isotopic composition of Paleoproterozoic sulfides (d34S) may indicate periods of higher or lower seawater sulfate concentration and may help to understand the biogeochemical changes induced by the accumulation of atmospheric oxygen.
	nai.arc.nasa.gov /seminars/seminar_detail.cfm?ID=59&Vid=1 (265 words)

	Abstracts
		Ryan, A.B., Hamilton, M., Emslie, R. and Connelly, J.N. Paleoproterozoic and Mesoproterozoic anorthosite and grantic plutons in the Nain-Okak region, Labrador: Repetitive anorogenic magmatism.
		Tectonic evolution of the Nagssugtoqidian orogen: The Greenlandic segment of the Paleoproterozoic orogenic mosaic in the North Atlantic region.
		The Paleoproterozoic Nagssugtoqidian Orogen in west Greenland: Revisited and revised.
	www.geo.utexas.edu /faculty/connelly/abstracts.htm (1569 words)

	Home - Paleoproterozoic Mineralization Research
		The Paleoproterozoic represents one of the richest mineralized eras in geological history.
		Many of the deposits appear to be time-bounded; related to unique environmental changes like oxy-atmoversion and oxyhydroversion, and establishment of first major supercontinents with associated rift zones and collisional mountain belts.
		Characterization of the composition of time-bounded ores in the Paleoproterozoic is an important component of the applied economic geology part of the project in order to try and ensure cost-effective extraction and beneficiation of the deposits.
	general.uj.ac.za /geology/ppm (338 words)

	Layered intrusions of the Baltic Shield. (Site not responding. Last check: 2007-09-17)
		Now a database on the Paleoproterozoic layered intrusion of the Russian part of the Baltic Shield is in the process.
		The older, early Paleoproterozoic (2.5-2.44 Ga ago) one is represented by large layered intrusions within Archaean Kola and Karelian cratons.
		The younger, late Paleoproterozoic (2.0-1.9 Ga ago) type of layered intrusions in the Baltic Shield made up of olivinites, hortonolitic olivinites, wehrlites, gabbro, gabbro-anorthosites, alkali gabbro, and, sometimes, nepheline syenites and alkali granites.
	www.igem.ru /igem/petr/int6.htm (698 words)

	Amazon.com: Paleoproterozoic: Books (Site not responding. Last check: 2007-09-17)
		Paleoproterozoic intrusive igneous rocks of southeastern Stearns County, central Minnesota / T.J. Boerboom and D.K. Holm (Report of investigations) by Terrence J Boerboom (Unknown Binding - 2000)
		Geochemical characterization of paleoproterozoic volcanic and hypabyssal igneous rocks, east-central Minnesota (Report of investigations) by D. L Southwick (Unknown Binding - 2001)
		Paleoproterozoic volcanism in the Kiihtelysvaara-Tohmajärvi district, eastern Finland (Geological Survey of Finland bulletin) by L. J Pekkarinen (Unknown Binding - 1991)
	www.amazon.com /s?ie=UTF8&keywords=Paleoproterozoic&tag=httpexplaguid-20&index=books&link_code=qs&page=1 (628 words)

	Geology, mineralogy and geochemistry of the Fe-Co-Au-(U) deposits in the Paleoproterozoic Kuusamo Schist Belt, ...
		Six of the deposits (Kouvervaara, Meurastuksenaho, Konttiaho, Sivakkaharju, Hangaslampi and Juomasuo) in the central part of the schist belt were selected for a detailed study in order to investigate the mineralogy, geochemical changes and the deposition conditions during mineralization.
		The volcano-sedimentary sequence of the KSB was deposited discordantly on an Archaean granite gneiss complex in Paleoproterozoic rift environment.
		The geological surroundings, hydrothermal alteration types and major and trace element characteristics of the mineralization suggest that the deposits in the KSB belong to the extensive, recently defined Fe-oxide-Cu-Au class.
	www.gsf.fi /info/tr153abs.html (938 words)

	Paleomagnetism of a lateritic paleoweathering horizon and overlying Paleoproterozoic red beds from South Africa: ...
		Paleomagnetism of a lateritic paleoweathering horizon and overlying Paleoproterozoic red beds from South Africa: Implications for the Kaapvaal apparent polar wander path and a confirmation of atmospheric oxygen enrichment
		The concordance between directions from the paleoweathering zone and immediately overlying red beds indicates that HIG is a primary magnetic remanence for the basal Gamagara/Mapedi (BGM) Formation.
		Citation: Evans, D. Beukes, and J. Kirschvink (2002), Paleomagnetism of a lateritic paleoweathering horizon and overlying Paleoproterozoic red beds from South Africa: Implications for the Kaapvaal apparent polar wander path and a confirmation of atmospheric oxygen enrichment, J.
	www.agu.org /pubs/crossref/2002/2001JB000432.shtml (458 words)

	Subprojects - Paleoproterozoic Mineralization Research
		Each of these subprojects is constituted by several postgraduate students working together with their supervisors on interlinked research projects.
		Three research projects were initiated to investigate all three major districts of mineralization, namely the area around Griquatown, Northern Cape Province, the Pering deposit and the Zeerust District, both in the Northwestern Province of South Africa.
		Paleoproterozoic Olifantshoek-Kheiss orogen in the Northern Cape Province and its mineral potential
	general.uj.ac.za /geology/ppm/subprojects.htm (737 words)

	Geochemistry and tectonic setting of Paleoproterozoic metavolcanic rocks of the southern Front Range, lower Arkansas ...
		Geochemistry and tectonic setting of Paleoproterozoic metavolcanic rocks of the southern Front Range, lower Arkansas River Canyon and northern Wet Mountains, central Colorado -- Wobus et al.
		Geochemistry and tectonic setting of Paleoproterozoic metavolcanic rocks of the southern Front Range, lower Arkansas River Canyon and northern Wet Mountains, central Colorado
		the Paleoproterozoic evolution of the Colorado province (as
	rmg.geoscienceworld.org /cgi/content/abstract/36/2/99 (495 words)

	Glasgow ePrints Service - Sr isotope composition in paleoproterozoic carbonates extremely enriched in 13C: Kaniapiskau ...
		Sr isotope composition in paleoproterozoic carbonates extremely enriched in 13C: Kaniapiskau supergroup, the Labrador trough of the Canadian shield
		Kuznetsov, A.B. and Melezhik, V.A. and Gorokhov, I.M. and Melnikov, N.N. and Fallick, A.E. Sr isotope composition in paleoproterozoic carbonates extremely enriched in 13C: Kaniapiskau supergroup, the Labrador trough of the Canadian shield.
		Paleoproterozoic dolostones of the Dunphy, Portage, Alder, and Uve formations representing lower horizons of the Kaniapiskau Supergroup in the Labrador trough of the Canadian Shield are remarkable, as is known, owing to their extremely high
	eprints.gla.ac.uk /262 (355 words)

	Government of Saskatchewan - Late Paleoproterozoic
		Below are the top 25 results of a search for "Late Paleoproterozoic" across all Government of Saskatchewan websites.
		Late Paleoproterozoic Athabasca Basin, Saskatchewan and Alberta; in Summary...
		Late Paleoproterozoic Fluvial Strata in the Manitou Falls Formation at McClean...
	www.gov.sk.ca /topics/keyword/keyword?topic=nature-environment&keyword=4068 (118 words)

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