scholarly journals Airborne Radiometric Anomalies Caused By Late Kinematic Granitic Rocks in the Molson Lake-red Sucker Lake area, East-central Manitoba

1982 ◽  
Author(s):  
W Weber ◽  
D C P Schledewitz ◽  
N M Soonawala
Keyword(s):  
Granitic Rocks ◽  
Lake Area ◽  
East Central

Composition, age, and origin of granitoid rocks in the Davin Lake area, Rottenstone Domain, Trans-Hudson Orogen, northern Saskatchewan

2005 ◽  
Vol 42 (4) ◽  
pp. 599-633 ◽  
Author(s):  
D Barrie Clarke ◽  
Andrew S Henry ◽  
Mike A Hamilton
Keyword(s):  
Granitic Rocks ◽  
Lake Area ◽  
Granitoid Magmatism ◽  
Metasedimentary Rocks ◽  
Metavolcanic Rocks ◽  
Granitic Magmatism ◽  
Deformation Features ◽  
High Grade Metamorphism ◽  
Granitoid Rocks ◽  
Host Rocks

The Rottenstone Domain of the Trans-Hudson orogen is a 25-km-wide granitic–migmatitic belt lying between the La Ronge volcanic–plutonic island arc (1890–1830 Ma) to the southeast and the ensialic Wathaman Batholith (1855 Ma) to the northwest. The Rottenstone Domain consists of three lithotectonic belts parallel to the orogen: (i) southeast — gently folded migmatized quartzo-feldspathic metasedimentary and mafic metavolcanic rocks intruded by small concordant and discordant white tonalite–monzogranite bodies; (ii) central — intensely folded and migmatized metasedimentary rocks and minor metavolcanic rocks intruded by largely discordant, xenolith-rich, pink aplite-pegmatite monzogranite bodies; and (iii) northwest — steeply folded migmatized metasedimentary rocks cut by subvertical white tonalite–monzogranite sheets. Emplacement of granitoid rocks consists predominantly of contiguous, orogen-parallel, steeply dipping, syntectonic and post-tectonic sheets with prominent magmatic schlieren bands, overprinted by parallel solid-state deformation features. The white granitoid rocks have A/CNK (mol Al2O3/(mol CaO + Na2O + K2O)) = 1.14–1.22, K/Rb ≈ 500, ΣREE (sum of rare-earth elements) < 70 ppm, Eu/Eu* > 1, 87Sr/86Sri ≈ 0.7032, and εNdi ≈ –2. The pink monzogranites have A/CNK = 1.11–1.16, K/Rb ≈ 500, ΣREE > 90 ppm, Eu/Eu* < 1, 87Sr/86Sri ≈ 0.7031, and εNdi ≈ –2. The white granitoid rocks show a wider compositional range and more compositional scatter than the pink monzogranites, reflecting some combination of smaller volume melts, less homogenization, and less control by crystal–melt equilibria. All metavolcanic, metasedimentary, and granitic rocks in the Rottenstone Domain have the distinctive geochemical signatures of an arc environment. New sensitive high-resolution ion microprobe (SHRIMP) U–Pb geochronology on the Rottenstone granitoid rocks reveals complex growth histories for monazite and zircon, variably controlled by inheritance, magmatism, and high-grade metamorphism. Monazite ages for the granitoid bodies and migmatites cluster at ~1834 and ~1814 Ma, whereas zircon ages range from ~2480 Ma (rare cores) to ~1900–1830 Ma (cores and mantles), but also ~1818–1814 Ma for low Th/U recrystallized rims, overgrowths, and rare discrete euhedral prisms. These results demonstrate that at least some source material for the granitic magmas included earliest Paleoproterozoic crust (Sask Craton?), or its derived sediments, and that Rottenstone granitic magmatism postdated plutonism in the bounding La Ronge Arc and Wathaman Batholith. We estimate the age of terminal metamorphism in the Davin Lake area to be ~1815 Ma. Petrogenetically, the Rottenstone migmatites and granitoid rocks appear, for the most part, locally derived from their metasedimentary and metavolcanic host rocks, shed from the La Ronge Arc, Sask Craton, and possibly the Hearne Craton. The Rottenstone Domain was the least competent member in the overthrust stack and probably underwent a combination of fluid-present melting and fluid-absent decompression melting, resulting in largely syntectonic granitoid magmatism ~1835–1815 Ma, analogous to granite production in the High Himalayan gneiss belt.

scholarly journals Abundance, distribution, and species assemblages of colonial waterbirds in the boreal region of west-central Manitoba and east-central Saskatchewan

2013 ◽  
Vol 127 (3) ◽  
pp. 203 ◽  
Author(s):  
Scott Wilson
Keyword(s):  
Aerial Survey ◽  
Boreal Lakes ◽  
Lake Area ◽  
East Central ◽  
Herring Gulls ◽  
The North ◽  
West Central ◽  
Common Terns ◽  
Waterbird Species ◽  
Colonial Waterbirds

Central and southern Manitoba contain some of the largest breeding populations of several colonial waterbird species in North America. Despite the value of this region for waterbirds, very little monitoring has been conducted on Lake Winnipeg, Lake Winnipegosis, or Lake Manitoba in the past three decades and little is known about the smaller boreal lakes in adjacent areas to the north. In June 2011, boat surveys were conducted on 11 boreal lakes in west-central Manitoba and east-central Saskatchewan to examine current abundance and distribution of colonial waterbirds in that region. Data from this survey were compared with abundance of colonial waterbirds on Lake Winnipegosis and Lake Manitoba from an aerial survey of these lakes in 2012. Waterbird colonies were located on 7 of the 11 lakes in 2011 and included Double-crested Cormorants (Phalacrocorax auritus) (2373 adults, 1134 pairs in 7 colonies), Common Terns (Sterna hirundo) (1367 adults, 772 pairs in 29 colonies), Forster’s Terns (Sterna forsteri) (20 adults, 11 pairs in 1 colony), Herring Gulls (Larus argentatus) (876 adults, 568 pairs in 23 colonies), and Ring-billed Gulls (Larus delawarensis) (3752 adults, 16 colonies). Common Terns and Herring Gulls appeared to be predominantly breeders and pair abundance for both species increased in a sigmoidal fashion; lakes <100 km2 in area had few breeding pairs. Numbers of Double-crested Cormorants and especially, Ring-billed Gulls, may have included a sizeable non-breeding component. Densities (pairs/lake area) of Common Terns and Herring Gulls were about 2 and 4 times higher, respectively, on these lakes than on Lake Winnipegosis and Lake Manitoba, while Double-crested Cormorant and Ring-billed Gull densities were higher on lakes Winnipegosis and Manitoba. Additional studies of productivity in relation to lake characteristics and connectivity among colonies throughout the region would further our understanding of the importance and sustainability of waterbird populations in this region of the boreal forest.

Pedogenesis of the Precambrian Rocks in the Hanson Lake Area, East-Central Saskatchewan

1971 ◽  
Vol 8 (7) ◽  
pp. 820-843
Author(s):  
J. W. Gaskarth
Keyword(s):  
Basal Part ◽  
Lake Area ◽  
Chemical Analyses ◽  
East Central ◽  
Precambrian Rocks ◽  
Metavolcanic Rocks ◽  
Orogenic Cycle ◽  
Silicate Rocks ◽  
Lower Group ◽  
Chemical Evidence

Precambrian rocks in the Hanson Lake area occur in two main groups. The first (Lower Group) consists of quartz dioritic rocks, migmatites, and agmatites which occur in two large anticlinal complexes. These rocks are overlain by and concordant with a complicated sequence of supracrustal rocks which comprise the second group (Upper Group). The basal part of the Upper Group is basaltic and the rest is made up of basaltic, andesitic, dacitic, and rhyolitic fragmental metavolcanic rocks, dacitic metalavas, calc-silicate rocks, and graywacke-type metasediments. Other rocks in the area include several bodies of intrusive granite, one of which has a mass of magnetite – amphibole – epidote rock associated with it, a body of metapyroxenite, and a number of apparently intrusive amphobolite bodies. Both beryliferous and non-beryliferous pegmatites are abundant and occur mainly within the rocks of the Lower Group.An interpretation of the petrogenesis, consistent with the available petrographic, structural, and chemical evidence (46 new chemical analyses are presented), suggests that the Upper and Lower Groups were originally parts of a conformable supracrustal sequence. The lower parts of the sequence (Lower Group) were migmatized, partially melted, and mobilized during a complicated orogenic cycle.

The Kulyk Lake monazite deposit, northern Saskatchewan

1976 ◽  
Vol 13 (3) ◽  
pp. 470-475 ◽  
Author(s):  
David H. Watkinson ◽  
Paul R. Mainwaring
Keyword(s):  
Chemical Composition ◽  
Aqueous Phase ◽  
Rare Earths ◽  
Microprobe Analysis ◽  
Granitic Rocks ◽  
Lake Area ◽  
Fold Belt ◽  
Ti Oxides ◽  
Northern Saskatchewan ◽  
Silicate Rocks

Massive monazite occurs in a zoned deposit in the Wollaston Lake fold belt, Kulyk Lake area, northern Saskatchewan. The deposit is enclosed by pegmatitic, graphic, and aplitic granite, which are slightly bleached adjacent to the contact. Ilmeno-hematite and hematite (in part after magnetite), located adjacent to the silicate rocks, are followed inward by massive monazite and then minor concentrations of apatite. Monazite has a constant chemical composition: the average microprobe analysis is CaO—0.5, La2O3—15.1, Ce2O3—36.1, Pr2O3—4.9, Nd2O3—10.1, ThO2—4.3, P2O5—27.8; total, 98.8%. Monazite grains in a small segregation in granitic gneisses have variable thoria contents. Apatite in the deposit contains about 0.2% total rare earths. The oxide–monazite–apatite deposit probably precipitated from an aqueous phase generated during crystallization of a water-rich granitic liquid. The monazite deposit and enclosing granitic rocks may have been generated during anatexis of a metasedimentary unit containing abundant monazite and Fe–Ti oxides.

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