scholarly journals U - Pb Dates From Tonalite and Felsic Volcanic Rocks in the Brislane Lake area of the southern Slave Province

1991 ◽  
Author(s):  
R A Frith ◽  
O Van Breemen ◽  
J K Mortensen
Keyword(s):  
Volcanic Rocks ◽  
Lake Area ◽  
Slave Province ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Deposition and imbrication of a 2670-2629 Ma supracrustal sequence in the Indin Lake area, southwestern Slave Province, Canada

1999 ◽  
Vol 36 (7) ◽  
pp. 1149-1168 ◽  
Author(s):  
S J Pehrsson ◽  
M E Villeneuve
Keyword(s):  
Volcanic Rocks ◽  
Lake Area ◽  
Regional Deformation ◽  
Tectonic History ◽  
Slave Province ◽  
Gneiss Complex ◽  
Supracrustal Belt ◽  
History Of ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

New U-Pb age data from the southwestern Slave Province demonstrate that units of the Indin Lake supracrustal belt form an imbricated structural stack. The oldest rocks of the belt are undated mafic volcanic flows of the Hewitt Lake group that are crosscut by a 2670 Ma felsic sill, itself coeval with mafic through felsic volcanic rocks of the 2668-2671 Ma Leta Arm group. The youngest rocks of the belt are 2647-2629 Ma turbidites and felsic volcanic rocks of the unconformably overlying Chalco Lake group. Tonalite orthogneiss of the adjacent Cotterill gneiss complex is 2680 Ma, suggesting that it does not represent in situ basement to the supracrustal belt. Intercalation of the older Hewitt Lake and Leta Arm groups with the younger Chalco Lake group is interpreted to result from D1 imbrication and folding between 2629 and 2609 Ma, the age of a crosscutting tonalite intrusion. Subsequent D2 folding and regional low-pressure metamorphism occurred between 2609 Ma and ca. 2590 Ma. D3 normal faulting between the belt and Cotterill gneisses, ca. 2590 Ma, is interpreted to overlap with retrograde amphibolite-facies metamorphism and decompression of the gneiss complex. Comparisons between the tectonic history of the Indin Lake area and the central Slave Province show that turbidite deposition was regionally diachronous and overlapped with regional deformation elsewhere, supporting existing models favouring some form of accretionary orogenesis. The imbricated and intercalated 2670-2629 Ma supracrustal sequence may characterize a distinct crustal block in the southwestern Slave Province.

U–Pb zircon ages for the Rice Lake area, southeastern Manitoba

1989 ◽  
Vol 26 (1) ◽  
pp. 23-30 ◽  
Author(s):  
A. Turek ◽  
R. Keller ◽  
W. R. Van Schmus ◽  
W. Weber
Keyword(s):  
Greenstone Belt ◽  
Volcanic Rocks ◽  
Quartz Diorite ◽  
Granitic Rocks ◽  
Lake Area ◽  
The South ◽  
Metasedimentary Rocks ◽  
The North ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

The Archean Rice Lake greenstone belt in southeastern Manitoba is made up of mafic to felsic volcanic rocks and associated intrusive and metasedimentary rocks. The belt is flanked to the north by the Wanipigow River granitic complex and to the south by the Manigotagan gneissic belt. The Ross River quartz diorite pluton is intrusive into the centre of the greenstone belt. U–Pb zircon ages indicate a major volcanic and plutonic event in the area at 2730 Ma. Ages for two volcanic units of the Rice Lake Group are 2731 ± 3 and 2729 ± 3 Ma. The Ross River pluton yields an age of 2728 ± 8 Ma and the Gunnar porphyry gives an age of 2731 ± 13 Ma; both intrude rocks of the Rice Lake Group. Granitic rocks of the Wanipigow River granitic complex give ages of 2731 ± 10 and 2880 ± 9 Ma, while a post-tectonic granite in the Manigotagan gneissic belt has an age of 2663 ± 7 Ma.

scholarly journals U - Pb Zircon Ages of Felsic Volcanic Rocks in the Kaminak Lake area, District of Keewatin

1987 ◽  
Author(s):  
J K Mortensen ◽  
R I Thorpe
Keyword(s):  
Volcanic Rocks ◽  
Lake Area ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Geochemistry and Isotope Composition of Paleoproterozoic Granites and Felsic Volcanics of the Elash Graben: Evidence of the Heterogeneity of the Early Precambrian Crust

2021 ◽  
Vol 62 (10) ◽  
pp. 1175-1187
Author(s):  
A.D. Nozhkin ◽  
O.M. Turkina ◽  
K.A. Savko
Keyword(s):  
Isotope Composition ◽  
Volcanic Rocks ◽  
Rare Metal ◽  
Temporal Association ◽  
Metal Deposit ◽  
Wide Range ◽  
Rare Metal Deposit ◽  
Geochronological Study ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Abstract —The paper presents results of a petrogeochemical and isotope–geochronological study of the granite–leucogranite association of the Pavlov massif and felsic volcanics from the Elash graben (Biryusa block, southwest of the Siberian craton). A characteristic feature of the granite–leucogranites is their spatial and temporal association with vein aplites and pegmatites of the East Sayan rare-metal province. The U–Pb age of zircon from granites of the Pavlov massif (1852 ± 5 Ma) is close to the age of the pegmatites of the Vishnyakovskoe rare-metal deposit (1838 ± 3 Ma). The predominant biotite porphyritic granites and leucogranites of the Pavlov massif show variable alkali ratios (K2O/Na2O = 1.1–2.3) and ferroan (Fe*) index and a peraluminous composition; they are comparable with S-granites. The studied rhyolites of the Tagul River (SiO2 = 71–76%) show a low ferroan index, a high K2O/Na2O ratio (1.6–4.0), low (La/Yb)n values (4.3–10.5), and a clear Eu minimum (Eu/Eu* = 0.3–0.5); they are similar to highly fractionated I-granites. All coeval late Paleoproterozoic (1.88–1.85 Ga) granites and felsic volcanics of the Elash graben have distinct differences in composition, especially in the ferroan index and HREE contents, owing to variations in the source composition and melting conditions during their formation at postcollisions extension. The wide range of the isotope parameters of granites and felsic volcanic rocks (εNd from +2.0 to –3.7) and zircons (εHf from +3.0 to +0.8, granites of the Toporok massif) indicates the heterogeneity of the crustal basement of the Elash graben, which formed both in the Archean and in the Paleoproterozoic.

The Duck Pond and Boundary Cu–Zn deposits, Newfoundland: new insights into the ages of host rocks and the timing of VHMS mineralization

2010 ◽  
Vol 47 (12) ◽  
pp. 1481-1506 ◽  
Author(s):  
Vicki McNicoll ◽  
Gerry Squires ◽  
Andrew Kerr ◽  
Paul Moore
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Isotopic Data ◽  
Sulphide Ores ◽  
Intrusive Rocks ◽  
Felsic Volcanic ◽  
Host Rocks ◽  
Felsic Volcanic Rocks

The Duck Pond Cu–Zn–Pb–Ag–Au deposit in Newfoundland is hosted by volcanic rocks of the Cambrian Tally Pond group in the Victoria Lake supergroup. In conjunction with the nearby Boundary deposit, it contains 4.1 million tonnes of ore at 3.3% Cu, 5.7% Zn, 0.9% Pb, 59 g/t Ag, and 0.9 g/t Au. The deposits are hosted by altered felsic flows, tuffs, and volcaniclastic sedimentary rocks, and the sulphide ores formed in part by pervasive replacement of unconsolidated host rocks. U–Pb geochronological studies confirm a long-suspected correlation between the Duck Pond and Boundary deposits, which appear to be structurally displaced portions of a much larger mineralizing system developed at 509 ± 3 Ma. Altered aphyric flows in the immediate footwall of the Duck Pond deposit contained no zircon for dating, but footwall stringer-style and disseminated mineralization affects rocks as old as 514 ± 3 Ma at greater depths below the ore sequence. Unaltered mafic to felsic volcanic rocks that occur structurally above the orebodies were dated at 514 ± 2 Ma, and hypabyssal intrusive rocks that cut these were dated at 512 ± 2 Ma. Some felsic samples contain inherited (xenocrystic) zircons with ages of ca. 563 Ma. In conjunction with Sm–Nd isotopic data, these results suggest that the Tally Pond group was developed upon older continental or thickened arc crust, rather than in the ensimatic (oceanic) setting suggested by previous studies.

Post-collisional ca. 800 Ma A-type felsic volcanic rocks in the eastern Jiangnan orogen, South China

2020 ◽  
Vol 203 ◽  
pp. 104567
Author(s):  
Ji-Biao Zhang ◽  
Yan-Xue Liu ◽  
Xiao-Zhong Ding ◽  
Heng Zhang ◽  
Chuan-Heng Zhang
Keyword(s):  
South China ◽  
Volcanic Rocks ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks
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