Search

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Thompson Nickel Belt marks the boundary between the Archean Superior Province and the Trans-Hudson Orogen in Canada. It comprises Archean gneisses, and Paleoproterozoic rocks with metasediments and metavolcanites (Ospwagan Group) and intrusions. The gneisses are frequently migmatitic and host numerous pegmatites. The western belt boundary is a fault contact with the Kisseynew Domain of the Reindeer Zone. In the south, the transition zone between the belt and the Kisseynew Domain comprises granitoids and a detrital sequence (Grass River Group), part of which grades into turbidites in the Kisseynew Domain. The eastern belt boundary is a diffuse zone where the Archean east-west (E-W) structural trend changes into the north-northeast (NNE) trend of the belt. This paper presents U-Pb ages for granitoids and 207Pb/206Pb detrital zircon ages from the Ospwagan and Grass River groups. Ages and a comparison of events in the belt and in the eastern Reindeer Zone have major implications. The change from stable platform deposits to syn-tectonic filling and emplacement of mafic intrusions in the Ospwagan Group are attributed to the convergence between the Reindeer Zone and the Superior Province at 1891-1885 Ma. At ca. 1850 Ma, continuing convergence led to drowning of marginal basins of the Superior craton and to the development of a transpressive regime in the belt, the onset of which could be as old as ca. 1885 Ma. Metamorphic ages of 1818-1785 record closure of the Kisseynew basin and crustal thickening. Collision of the new continental block with the Superior Province was accommodated by transpression until 1750-1720 Ma. La ceinture de Thompson est située entre le Craton archéen du Supérieur et l'orogène paléoprotérozoïque du Trans-Hudson, au Canada. Elle comprend des gneiss archéens souvent migmatitiques, et des roches paléoprotéroïques, métasédiments et métavolcanites (Groupe Ospwagan), et intrusions. A l'ouest, une zone de faille marque le contact entre la ceinture et le domaine Kisseynew de la Zone de Reindeer. Vers le sud, cette zone de transition entre la ceinture et le domaine Kisseynew comprends des granitoïdes et une séquence détritique (Groupe Grass River), qui passe graduellement aux turbidites du domaine Kisseynew. Sur la bordure orientale de la ceinture, le grain structural E-W du Craton archéen se réoriente dans le grain NNE de la ceinture. Cet article présente des âges U-Pb pour différents granitoïdes et des âges 207Pb/206Pb pour les zircons détritiques des groupes Ospwagan et Grass River. Les âges et une comparaison des événements affectant la ceinture et l'est de la zone Reindeer ont des implications importantes. Dans le groupe Ospwagan, le passage de dépôts de type plate-forme à des dépôts syn-tectoniques, et l'intrusion de roches basiques, sont attribuées à la convergence entre la zone Reindeer et le Craton du Supérieur vers 1891-1885 Ma. Vers 1850 Ma, la convergence conduit à l'enfouissement des bassins de la marge du Craton et à un régime transpressif pouvant avoir débuté dès ca. 1885 Ma. La fermeture du bassin de Kisseynew et l'épaississement crustal sont enregistrés par des âges de métamorphisme entre 1818 et 1785 Ma. Le régime transpressif se poursuit jusqu'à ca. 1750-1720 Ma. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lithoprobe's sponsorship has led to the acquisition of paleomagnetic data from ~20 units throughout the Paleoproterozoic Trans-Hudson Orogen (THO) of Saskatchewan and Manitoba, essentially the first such data for the region. Discussed summarily in this paper, they provide an initial framework for the THO's tectonic evolution. They show that the Archean Hearne and Superior cratons were at subtropical and subpolar paleolatitudes, respectively, at ~1875 Ma, with the Lynn Lake – LaRonge arc midway between them in the Manikewan Ocean. By ~1855 Ma, this ocean was still ~5500 ± 700 km wide, and its seafloor was subducting northwestward under the Hearne craton and pericratonic Peter Lake domain margin with the coeval development of an Andean-type continental magmatic arc, the Wathaman–Chipewyan batholith. Between ~1855 and ~1810 Ma, coalescing apparent polar wander path (APWP) segments record closing of the ocean at a rate of ~12 cm/a, trapping and accreting the several separate intervening terranes (Flin Flon, Hanson Lake, Lynn Lake – LaRonge, Rottenstone, and presumably also other THO terranes). From ~1815 to ~1775 Ma, the assembled terranes drifted as a coherent craton, yielding a stillstand and hairpin in the APWP. [ABSTRACT FROM AUTHOR]

Middle Ordovician to Middle Devonian carbonates in the Manitoba lowlands form an extensive aquifer system along the eastern edge of the Williston Basin. The aquifer is divided into fresh and saline portions by a series of topographic lows defined by major river systems and lakes that create a north–south-trending hydraulic divide. East of this divide Ca–Mg–HCO[sub 3] fresh waters are derived by active modern-day recharge focused in the Sandilands and Interlake regions. Stable isotope and geochemical data indicate that Na–Cl saline waters west of the divide are a mixture of original basin brines and glacial melt water pushed into the basin during Pleistocene glaciation. High Na/Cl and Cl/Br ratios are consistent with significant salt dissolution by glacial melt water.Des carbonates datant de l'Ordovicien moyen au Dévonien moyen dans les basses terres du Manitoba forment un vaste système aquifère le long de la bordure est du bassin de Williston. L'aquifère est divisé en portions d'eau douce et d'eau salée par une série de creux topographiques définis par les grands systèmes de rivières et de lacs qui créent une ligne de partage des eaux à tendance nord–sud. À l'est de cette ligne de partage, les eaux douces Ca–Mg–HCO[sub 3] proviennent de recharges actives contemporaines concentrées dans les régions de Sandilands et d'Interlake. Des données géochimiques et d'isotopes stables indiquent que les eaux salées Na–Cl à l'ouest de la ligne de partage sont un mélange des saumures du bassin original et de l'eau de fonte glaciaire qui a été poussée dans le bassin au cours de la glaciation au Pléistocène. Des rapports Na/Cl et Cl/Br élevés concordent avec une grande dissolution de sel par les eaux de fonte glaciaire.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Pikwitonei Granulite Domain located at the northwestern margin of the Superior Province is one of the largest Neoarchean high-grade terranes in the world, with well-preserved granulite metamorphic assemblages preserved in a variety of lithologies, including enderbite, opdalite, charnockite, and mafic granulite. U-Pb geochronology has been attempted to unravel the protolith ages and metamorphic history of numerous lithologies at three main localities; Natawahunan Lake, Sipiwesk Lake, and Cauchon Lake. The U-Pb age results indicate that some of the layered enderbite gneisses are Mesoarchean (3.4-3.0 Ga) and the more massive enderbites are Neoarchean. The high-grade metamorphic history of the Pikwitonei Granulite Domain is complex and multistage with at least four episodes of metamorphic zircon growth identified: (1) 2716.1 ±3.8 Ma, (2) 2694.6 ±0.6 Ma, (3) 2679.6 ±0.9 Ma, and (4) 2642.5 ±0.9 Ma. Metamorphic zircon growth during episodes 2 and 3 are interpreted to be regional in extent, corresponding to M1 amphibolite- and M2 granulite-facies events, respectively, consistent with previous field observations. The youngest metamorphic episode at 2642.5 Ma is only recognized at southern Cauchon Lake, where it coincides with granite melt production and possible development of a major northeast-trending deformation zone. The timing and multistage metamorphic history recorded in the Pikwitonei Granulite Domain is similar to most Superior Province high-grade terranes and marks a fundamental break in Archean crustal evolution worldwide at the termination of prolific global Neoarchean greenstone belt formation. Le domaine de granulite Pikwitonei situé à la bordure nord-ouest de la Province du Supérieur est l'un des plus vastes terranes néoarchéens à métamorphisme élevé au monde; il comporte des assemblages métamorphiques bien préservés au faciès des granulites dans une variété de lithologies incluant des enderbites, des opdalites, des charnockites et des granulites mafiques. Une datation par U-Pb a été essayée afin de démêler les âges protolites et l'historique métamorphique des nombreuses lithologies à trois endroits principaux, les lacs Natawahunan, Sipiwesk et Cauchon. Les résultats de la datation par U-Pb indiquent que certains gneiss à enderbite rubanés datent du Mésoarchéen (3,4 - 3,0 Ga) et les enderbites plus massives datent du Néoarchéen. L'historique de métamorphise élevé du domaine de granulite Pikwitonei est complexe et comporte plusieurs étages avec au moins quatre épisodes de croissance de zircon métamorphique identifiés à (1) 2716,1 ±3,8 Ma, (2) 2694,6 ±0,6 Ma, (3) 2679,6 ±0,9 Ma et (4) 2642,5 ±0,9 Ma. La croissance des zircons métamorphiques durant les épisodes 2 et 3 est interprétée comme étant d'étendue régionale, correspondant respectivement aux événements de faciès des amphibolites M1 et au faciès des granulites M2, ce qui concorde avec des observations antérieures sur le terrain. L'épisode métamorphique le plus récent à 2642,5 Ma est uniquement reconnu au dans la partie sud du lac Cauchon où il coïncide avec la production de granite en fusion et le développement possible d'une zone de déformation majeure à tendance nord-est. Le séquencement et l'historique métamorphique à multiples étages enregistrés dans le domaine de granulite Pikwitonei sont semblables à la plupart des terranes à métamorphisme élevé de la Province du Supérieur et ils marquent une pause fondamentale dans l'évolution de la croûte archéenne à l'échelle mondiale à la fin de l'intense formation mondiale de ceintures vertes au Néoarchéen. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)