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The collaborative federal--provincial Southern Indian Lake project in north-central Manitoba covered an area of more than 3500 [km.sup.2] of the Trans-Hudson orogen. Regional-scale geological mapping, sampling, and lithogeochemical, isotopic, and geochronological studies resulted in the identification of distinct assemblages of supracrustal rocks and varied episodes of plutonism. A granodiorite gneiss dated at ca. 2520 Ma is interpreted to represent the basement of the Southern Indian domain and is considered a separate crustal domain, named the Partridge Breast block. The Churchill River assemblage is composed of juvenile pillow basalt with intervening clastic sedimentary rocks, possibly a reflection of plume magmatism related to initial rifting of the Hearne craton margin. The Pukatawakan Bay assemblage consists mainly of massive to pillowed, juvenile metabasaltic rocks and associated basinal metasedimentary rocks. The Partridge Breast Lake assemblage is dominated by continental-arc volcanic and volcaniclastic rocks associated with basinal metasedimentary rocks. The Strawberry Island assemblage, consisting of arenite and polymictic conglomerate, is interpreted to have been deposited in a foreland-basin basin or intra-orogen pull-apart basin environment. The Whyme Bay assemblage is characterized by fluvial-alluvial orogenic sediments and is temporally linked to the Sickle Group rocks in the Lynn Lake greenstone belt. Granitoid rocks, dominantly monzogranite and granodiorite, range in age from ca. 1890 to 1830 Ma and occur throughout the Southern Indian domain, and intermediate and mafic intrusions of similar ages are also present. In this paper, we integrate these new data into a tectonic framework for the Southern Indian domain of the Trans-Hudson orogen in Manitoba. Key words: tectonics, Trans-Husdon orogen, regional geology, Manitoba, Southern Indian domain, geochemistry, detrital geochronology. Resume : Le projet du lac Southern Indian, une collaboration federale--provinciale, dans le centre-nord du Manitoba, a couvert une superficie de plus de 3500 [km.sup.2] de l'orogene trans-hudsonien. La cartographie geologique, l'echantillonnage et des etudes lithogeochimiques, isotopiques et geochronologiques a l'echelle regionale ont mene a la delimitation de differents assemblages de roches supracrustales et episodes de plutonisme. Un gneiss granodioritique ayant donne un age d'environ 2520 Ma est interprete comme representant le socle du domaine de Southern Indian et constituant un domaine crustal distinct appele le bloc de Partridge Breast. L'assemblage du fleuve Churchill est compose de basaltes en coussins juveniles dans lesquels sont intercalees des roches sedimentaires clastiques, refletant possiblement un magmatisme de panache associe au rifting initial de la bordure du craton de Hearne. L'assemblage de la baie de Pukatawakan est principalement constitue de roches metabasaltiques juveniles massives a en coussins et de roches metasedimentaires de bassin associees. Dans l'assemblage du lac Partridge Breast, des roches volcaniques et volcanoclastiques d'arc continental associees a des roches metasedimentaires de bassin sont dominantes. L'assemblage de File Strawberry, constitue d'arenites et de conglomerate polymictiques, est interprete comme ayant ete depose dans un milieu de bassin d'avant-pays ou de bassin de transtension intraorogenique. L'assemblage de la baie de Whyme est caracterise par des sediments orogeniques fluviaux-alluviaux et est relie dans le temps aux roches du Groupe de Sickle dans la ceinture de roches vertes du lac Lynn. Des roches granitoides a predominance de monzogranite et granodiorite ont des ages allant d'environ 1890 a 1830 Ma et sont presentes partout dans le domaine de Southern Indian, et des intrusions intermediaires et mafiques d'ages semblables sont egalement presentes. Le present article integre ces nouvelles donnees dans un cadre tectonique pour le domaine de Southern Indian de l'orogene trans-hudsonien au Manitoba. [Traduit par la Redaction] Mots-cles: tectonique, orogene trans-hudsonien, geologie regionale, Manitoba, domaine de Southern Indian, geochimie, geochronologie de mineraux detritiques., Introduction The 'Trans-Hudson orogen' (THO) (Hoffman 1981; Lewry et al. 1981) is the belt of deformed and metamorphosed rocks that developed as a result of the Paleoproterozoic closure of the [...]

The Cumberland Basin is one of several sedimentary basins composing the late Paleozoic Maritimes Basin complex of eastern Canada. Pennsylvanian salt tectonics in the Cumberland Basin caused two salt mini-basins to evolve on either side of the Minudie Anticline, a salt wall. South of the wall (Athol Syncline), along the Joggins World Heritage shoreline, an--3000 m succession of strata (Little River, Joggins, Springhill Mines, and Ragged Reef formations) accumulated conformably on the Boss Point Formation. North of the wall (Black Point sub-basin), the biostratigraphically equivalent, but mostly unstudied,--600 m thick succession of Grande Anse Formation lies in angular unconformity on folded and faulted Boss Point and basal Little River formations. Grande Anse Formation sedimentology indicates four lithofacies associations: floodplain (LA1), braided channel (LA2), sheet flood (LA3), and debris flow deposits (LA4). One possible model has the Black Point sub-basin with its own hydrological system, completely separated from the Athol Syncline. A low subsidence rate combined with the low sedimentation rate produced the--600 m thick sand- and mud-prone succession that was contemporaneous with the--3 km succession to the south. The second model proposes that north of the salt wall was exposed to erosion during accumulation of Joggins and Springhill Mines formation strata to the south. Subsequently, the sediment of the lithologically similar Ragged Reef and Grande Anse formations either (i) onlapped to the north, unconformably on the folded Boss Point; or (ii) unconformably-disconformably on the underlying strata after a period of time indistinguishable in the biostratigraphic record. Key words: Grande Anse Formation, Joggins, salt tectonics, stratigraphy, sedimentology. Le bassin de Cumberland estun des bassins sedimentaires qui composent le complexe tardi-paleozoique de bassins des Maritimes, dans l'est du Canada. Une tectonique salifere au Pennsylvanien dans le bassin de Cumberland a entraine la formation de deux mini-bassins de sel de part et d'autre de l'anticlinal de Minudie, un mur de sel. Au sud du mur (synclinal dAthol), le long du littoral du Patrimoine mondial de Joggins, une sequence de quelque 3000 m de strates (Formations de Little River, Joggins, Springhill Mines et Ragged Reef) s'est accumulee de maniere concordante sur la Formation de Boss Point. Au nord du mur (sous-bassin de Black Point), la sequence equivalente du point de vue biostratigraphique, mais generalement non etudiee, de --600 m de la Formation de Grande Anse repose en discordance angulaire sur des roches plissees et faillees de la Formation de Boss Point et de la base de la Formation de Little River. La sedimentologie de la Formation de Grande Anse indique quatre associations de lithofacies, a savoir, des depots de plaines inondables (LA1), de chenaux anastomoses (LA2), d'inondations en nappe (LA3) et de coulees de debris (LA4). Dans un modele possible, le sous-bassin de Black Point et son reseau hydrologique sont completement separes du synclinal dAthol. Une faible vitesse de subsidence combinee a un faible taux de sedimentation a produit la sequence de--600 m riche en sable et en boue contemporaine de la sequence de--3 km situee au sud. Le deuxieme modele propose que le nord du mur de sel ait ete expose a l'erosion durant l'accumulation de strates des Formations de Joggins et Springhill Mines au sud. Par la suite, les sediments des Formations de Ragged Reef et de Grande Anse, semblables sur le plan lithologique, ont soit (i) ete deposes en discordance sur les roches plissees de la Formation de Boss Point, qu'elles ont debordees vers le nord ou (ii) ont ete deposes en discordance sur les strates sous-jacentes apres un intervalle de temps indistinguable dans le profil biostratigraphie. [Traduit par la Redaction] Mots-cles: Formation de Grande Anse, Joggins, tectonique salifere, stratigraphie, sedimentologie., Introduction This paper provides the first detailed study of the Grande Anse Formation through the logging of its three main coastal outcrop localities on both sides of the New Brunswick-Nova [...]

Geodynamic evolution in the late Paleozoic is significant for understanding the final amalgamation of the Central Asian Orogenic Belt (CAOB). No consensus has yet been reached regarding the late Paleozoic geodynamic evolution of the northern Great Xing'an Range (GXR) in northeastern China, the eastern CAOB. Furthermore, late Paleozoic syenogranitediabase dyke association is present in the Xiaokele area in northern GXR. It provides an important opportunity to understand the nature of magmatism and the geodynamic evolution during this period. This paper presents new zircon U-Pb ages, zircon Hf isotopic compositions, and geochemical data of whole rocks for Xiaokele syenogranite and diabase. Zircon U-Pb dating suggests that the Xiaokele syenogranite (292.5 [+ or -] 0.9 Ma) and diabase (298.3 [+ or -] 1.5 Ma) were emplaced during the early Permian. The Xiaokele syenogranites have high Si[O.sub.2] contents, low MgO contents, and enriched zircon [[epsilon].sub.Hf](t) values, suggesting that their primary magma was generated by the partial melting of the juvenile crustal material. The Xiaokele diabases have low Si[O.sub.2] contents, high MgO contents, are enriched in large-ion lithophile elements, depleted in high-field-strength elements, and exhibit enriched zircon [[epsilon].sub.Hf](t) values. They derived from a lithospheric mantle source that had previously been metasomatized by slab-derived fluids. Combined with previous research results, we believe that the continent-continent collision between the Xing'an and Songliao blocks occurred during the late early Carboniferous - early late Carboniferous (330-310 Ma), and the two blocks were transformed into a post-collisional extensional setting during the latest Carboniferous - early Permian. Key words: early Permian, syenogranite, diabase, post-collisional extensional setting, Xiaokele, northern Great Xing'an Range. L'evolution geodynamique au Paleozoique tardif est importante pour la comprehension de l'amalgamation finale de la ceinture orogenique d'Asie centrale (COAC). Aucun consensus n'a encore ete etabli quant a l'evolution geodynamique au Paleozoique tardif du Grand Xing'an (GX) septentrional de l'est de la COAC dans le nord-est de la Chine. En outre, une association d'age paleozoique tardif de syenogranite et de dykes de diabase est presente dans la region de Xiaokele du GX septentrional, qui offre une bonne occasion de mieux comprendre la nature du magmatisme et de l'evolution geodynamique durant cette periode. L'article presente de nouveaux ages U-Pb sur zircons, des donnees sur la composition des isotopes de Hf des zircons et des donnees geochimiques sur roche totale pour le syenogranite et la diabase de Xiaokele. La datation U-Pb sur zircons indiquerait que le syenogranite (292,5 [+ or -] 0,9 Ma) et la diabase (298,3 [+ or -] 1,5 Ma) de Xiaokele ont ete mis en place durant le Permien precoce. Les syenogranites de Xiaokele ont des teneurs elevees en Si[O.sub.2] et faibles MgO et presentent des valeurs enrichies de [[epsilon].sub.Hf](t) des zircons, ce qui indiquerait que leur magma primaire est un produit de la fusion partielle de materiau crustal juvenile. Les diabases de Xiaokele ont des teneurs en Si[O.sub.2] faibles et en MgO elevees et sont enrichies en elements lithophiles a grand rayon ionique, appauvries en elements a forte liaison atomique et presentent des valeurs enrichies de [[epsilon].sub.Hf](t) des zircons. Elles proviennent d'une source dans le manteau lithospherique ayant prealablement subi un metasomatisme cause par des fluides issus d'une plaque subductee. A la lumiere de ces resultats et de resultats de travaux anterieurs, nous croyons que la collision continent-continent des blocs de Xing'an et de Songliao s'est produite durant l'intervalle du Carbonifere precoce tardif au Carbonifere tardif precoce (330 Ma-310 Ma) et que les deux blocs se sont transformes en un milieu d'extension post-collision durant l'intervalle de la fin du Carbonifere au Permien precoce. [Traduit par la Redaction] Mots-cles: Permien precoce, syenogranite, diabase, milieu d'extension post-collision, Xiaokele, Grand Xing'an septentrional., Introduction The tectonic evolution of orogenic belts is characterized by changes in the associated magmatic composition (Harris et al. 1986). Post-collisional magmatism, as one of the common characteristics of many [...]

The Park Spur pluton (PSP) is located in the central Cape Breton Highlands, near the eastern margin of the Aspy terrane and its tectonic contact with the adjacent Bras d'Or [...]

Small plutons of mafic to intermediate composition are locally associated with the abundant Devonian granitic plutons that intruded the Goldenville and Halifax groups in the eastern Meguma terrane of mainland [...]