U–Pb geochronology of the Hope Bay – Elu Inlet area, Bathurst Block, northeastern Slave Structural Province, Northwest Territories

1991 ◽  
Vol 28 (12) ◽  
pp. 1925-1930 ◽  
Author(s):  
Mary Lou Bevier ◽  
James S. Gebert
Keyword(s):  
Northwest Territories ◽  
Isotopic Ratios ◽  
Magmatic Activity ◽  
Early Proterozoic ◽  
Metavolcanic Rocks ◽  
Felsic Volcanism ◽  
Hope Bay

U–Pb ages for six felsic samples from the dominantly mafic Hope Bay and Elu Inlet metavolcanic belts of the Bathurst Block provide the first constraints on the timing of felsic volcanism (2685–2677 Ma) and plutonism (2672–2608 Ma) in the northeastern corner of the Slave Structural Province. Gold veins that cut a pluton in the eastern Hope Bay belt are younger than 2672 Ma. Early Proterozoic magmatic activity is recorded in a pegmatite dyke that crosscuts metavolcanic rocks of the northern Hope Bay belt. Initial Nd and Sr isotopic ratios from the Hope Bay and Elu Inlet belts indicate a juvenile source for the magmas.

Paleomagnetism of the Great Slave Supergroup, Northwest Territories, Canada: the Stark Formation

1976 ◽  
Vol 13 (4) ◽  
pp. 563-578 ◽  
Author(s):  
D. K. Bingham ◽  
M. E. Evans
Keyword(s):  
Northwest Territories ◽  
North American ◽  
Geomagnetic Field ◽  
Pole Position ◽  
The West ◽  
Stratigraphic Sequence ◽  
Polar Wander ◽  
Early Proterozoic ◽  
The North ◽  
Polarity Reversals

Paleomagnetic results from 55 sampling sites throughout the Stark Formation are reported. The known stratigraphic sequence of these sites enables the behaviour of the geomagnetic field in these remote times (1750 m.y.) to be elucidated. Two polarity reversals are identified and these represent potentially useful correlative features in strata devoid of index fossils. One of these is investigated in detail and indicates that behaviour of the geomagnetic field during polarity reversals was essentially the same in the early Proterozoic as it has been over the last few million years. The pole position (145°W, 15°S, dp = 3.5, dm = 6.9) lies far to the west of that anticipated from earlier results, implying further complexity of the North American polar wander curve. Possible alternatives to this added complexity are discussed.

Sm-Nd and U-Pb dating of Early Proterozoic mafic-felsic volcanism in Northernmost Sweden

1984 ◽  
Vol 26 (1) ◽  
pp. 1-13 ◽  
Author(s):  
T. Skiöld ◽  
R.A. Cliff
Keyword(s):  
Early Proterozoic ◽  
Felsic Volcanism

Rb–Sr biotite and whole-rock data from the Kapuskasing uplift and their bearing on the cooling and exhumation history

1994 ◽  
Vol 31 (7) ◽  
pp. 1172-1181 ◽  
Author(s):  
J. A. Percival ◽  
Z. E. Peterman
Keyword(s):  
Fault Zone ◽  
Spatial Relationship ◽  
Paleomagnetic Data ◽  
Isotopic Ratios ◽  
The West ◽  
Rapid Cooling ◽  
Early Proterozoic ◽  
Granitoid Rocks ◽  
Relationship Of ◽  
Exhumation History

Rb–Sr isotopic ratios were measured on biotite and whole rocks from a suite of 21 granitoid rocks from the southern Kapuskasing uplift. Results of 18 of the whole-rock analyses fall on an isochron with an age of 2.677 ± 0.057 Ga and Sri = 0.70080. Biotite model ages range from 2.50 to 1.93 Ga in a general spatial relationship of decreasing age with depth in the structural section as calibrated with the igneous hornblende barometer for tonalitic rocks and garnet–pyroxene barometers for granulites. Near the Michipicoten belt in the west, biotite ages of ~ 2 Ga reflect disturbances also recorded by paleomagnetic and whole-rock Rb–Sr systems. To the east, in a 70 km long northwest–southeast transect toward the Ivanhoe Lake fault zone, ages decrease from 2.50 to 1.95 Ga. In a southern transect ages are in the range 2.30–2.38 Ga to within 15 km of the fault, reflecting consistent erosion levels corresponding to ~ 0.53 MPa, but decrease to 1.93 Ga to the east, in concert with paleopressures in the 0.7–1.0 GPa range.A plateau of low Rb–Sr biotite dates is not evident, suggesting that the Kapuskasing uplift event exposed a frozen-in cooling profile, rather than setting the Rb–Sr clock by rapid cooling of the rocks from above their closure temperature. The youngest biotite date of 1.93 Ga therefore provides a maximum age for uplift, consistent with paleomagnetic data from Archean rocks and Early Proterozoic dykes, but in conflict with some K–Ar and 40Ar/39Ar biotite age data.

scholarly journals Early Proterozoic (1.9 Ga) Thrombolites of the Rocknest Formation, Northwest Territories, Canada

Palaios ◽  
1992 ◽  
Vol 7 (3) ◽  
pp. 305 ◽  
Author(s):  
Linda C. Kah ◽  
John P. Grotzinger
Keyword(s):  
Northwest Territories ◽  
Early Proterozoic

scholarly journals A possible model of the Paleozoic sedimentary basins evolution at the North African platform

2017 ◽  
pp. 68-73
Author(s):  
M. Sh. Zamil
Keyword(s):  
Sedimentary Basins ◽  
Dual Model ◽  
Magmatic Activity ◽  
North African ◽  
Early Precambrian ◽  
Early Proterozoic ◽  
Late Proterozoic ◽  
The North ◽  
Pan African

A dual model of the Paleozoic basins development, disposing on the Late Proterozoic (Pan-African) and the Early Proterozoic (Eburnean) crust, has been proposed. The formation of the first group basins is connected with the subsiding of the sections of the cooling gneissic-domes of«rejuvenated» (Early Precambrian but tectonically reworked at the end of the Proterozoic) Pan-African crust. Accordingly, the development of the second group basins is a result of the Precambrian deep sited (mantle) magmatic chambers cooling and subsiding together with the sites of the old lithosphere, covering them. The manifestation of the Vendian volcanic units on Anti-Atlas, Ugarta, Regibat-Eglab uplifts is the most possible evidence of the mantle magmatic activity, which could create those chambers.

scholarly journals Sulfur Sources of Sulfides of The Ak-Sug Cu-Au Porphyry Deposit, Eastern Tuva

2019 ◽  
pp. 73-82
Author(s):  
R.V. Kuzhuget ◽  
A.O. Mongush ◽  
N.N. Ankusheva
Keyword(s):  
Isotopic Composition ◽  
Isotopic Ratios ◽  
Porphyry Deposit ◽  
Porphyry Deposits ◽  
Early Proterozoic ◽  
Magmatic Rocks

The paper presents the S isotopic composition of sulfdes from the Ak-Sug Au-Cu-porphyry deposit hosted by Early Proterozoic magmatic rocks. The S isotopic composition of sulfdes varies from +1.0 to +3.2 ‰: +2.5 to +3.2 ‰ for molybdenite-I, +1.0 to +3.1 ‰ for pyrite-III, –2.3 to – 0.9 ‰ for chalcopyrite-III–V,–2.9 to –2.4 ‰, for chalcopyrite-VI and –1.0 ‰ for pyrite-V. The close-to-zero S isotopic ratios of sulfdes from the Ak-Sug deposit indicate magmatic (from –5 to +5 ‰) or mantle (from –3 to +3 ‰) S source typical of most Cu-porphyry deposits of the Pacifc Fire Ring. Figures 5. Table 1. References 23.

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