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

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.

Early Proterozoic Collisional Orogeny along the Northern Thelon Tectonic Zone, Northwest Territories, Canada: Evidence from the foreland

Tectonics ◽  
1990 ◽  
Vol 9 (5) ◽  
pp. 1015-1036 ◽  
Author(s):  
Rein Tirrul ◽  
John P. Grotzinger
Keyword(s):  
Northwest Territories ◽  
Tectonic Zone ◽  
Early Proterozoic ◽  
Collisional Orogeny

Microfossils from the Early Proterozoic Hornby Bay Group, District of Mackenzie, Northwest Territories, Canada

1985 ◽  
Vol 22 (5) ◽  
pp. 758-767 ◽  
Author(s):  
Robert J. Horodyski ◽  
Kathleen B. Dudek ◽  
Gerald M. Ross ◽  
J. Allan Donaldson
Keyword(s):  
Northwest Territories ◽  
Organic Material ◽  
Carbonate Rocks ◽  
Three Dimensional ◽  
Filamentous Bacteria ◽  
Carbonate Minerals ◽  
Early Proterozoic ◽  
Pressure Dissolution ◽  
Micro Structures ◽  
The Relationship

Spheroidal and filamentous organic-walled microfossils have been detected in ca. 1.7 Ga old cherts of the Hornby Bay Group, Northwest Territories, Canada. The majority of the spheroidal forms range from 1 to 4 μm in diameter, are referable to the genus Sphaerophycus, and probably represent the preserved sheaths of chroococcacean cyanophytes. A single, robust-walled, 27 μm diameter, spheroidal microfossil of undetermined affinity is also present. The filamentous forms are tubular, unbranched, and range from 1 to 8 μm in diameter. They appear to represent the preserved sheaths of nostocalean cyanophytes or filamentous bacteria. The filaments illustrate the relationship between matrix mineralogy and the fidelity of preservation of organic-walled microfossils. Where they occur in silica the filaments are preserved as three-dimensional tubular micro-structures, which are readily recognized as microfossils. In contrast, where they extend from silica into adjacent dolomite they are highly compressed and not readily discernable as microfossils. This compression appears to have been caused by aggrading neomorphism and pressure dissolution of the carbonate minerals, and it illustrates the contribution of diagenesis, in addition to decomposition of organic material, in causing the paucity of microfossils in Precambrian carbonate rocks.

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