The Correlation Between the Palaeoproterozoic Orogens and Granulite Belts in the Baltic Shield and North America Craton: A Suggested Model of Palaeoproterozoic Plate Tectonics

1998 ◽  
Vol 1 (2) ◽  
pp. 235-246 ◽  
Author(s):  
M.V. Mints

The palaeomagnetic record of continental drift during the Proterozoic is reasonably complete for North America (including Greenland and the Baltic Shield), less complete for Africa and Australia, and fragmentary elsewhere. Palaeomagnetic poles of similar age from different cratons or structural provinces of any one continent tend to fall on a common apparent polar wander path (a.p.w.p.), indicating no major (> 1000 km) intercratonic movements. On this evidence, Proterozoic orogens and mobile belts are essentially ensialic in origin. However, the palaeomagnetic record has systematic gaps. In highly metamorphosed orogens (amphibolite grade and above), remagnetization dating from post-orogenic uplift and cooling is pervasive. Collisional and ensialic orogenesis cannot then be distinguished. Palaeopoles from different continents do not follow a common a.p.w.p. They record large relative rotations and palaeolatitude shifts. A recurrent pattern appears in the late Proterozoic drift of North America. At approximately 200 Ma intervals (at about 1250, 1050, 850 and 600 Ma B.P .), the continent returned to the same orientation and (equatorial) latitudes from various rotations and high-latitude excursions. Lacking detailed a.p.w.ps. from other continents, it is not possible to say if these motions represent Wilson cycles of ocean opening and closing in the Phanerozoic style, but they do require minimum drift rates of 50—60 mm/a, comparable to the most rapid present-day plate velocities.


1998 ◽  
Vol 35 (3) ◽  
pp. 280-289 ◽  
Author(s):  
H J Hofmann ◽  
A Davidson

Decimetric to metric domal stromatolites with constituent ministromatolites characterize reddish, 13C-enriched dolostones in the Watterson Formation of the Quartzite Lake area west of Hudson Bay. They provide paleontologic support for a correlation with the only other known early Paleoproterozoic stromatolite occurrences in North America: the Kona Formation of Michigan, and the Nash Formation in southern Wyoming. They also are similar to stromatolites in probable coeval Jatulian carbonates in Karelia on the Baltic Shield, and possibly to stromatolites in the Hutuo Group in China.


1980 ◽  
Vol 17 (9) ◽  
pp. 1229-1235 ◽  
Author(s):  
Glenn W. Berger ◽  
Derek York

We have reviewed the geochronology of rocks having paleopoles in the interval 800–1500 Ma from North America, Greenland, and the Baltic Shield. The present uncertainties in the acquisition times of the remanent magnitizations allow the construction of a simplified apparent polar wander curve for North America that incorporates Sveconorwegian paleopoles in a Grenville Loop, and that places poles from the El Paso, Stoer Group, and Aillik Bay rocks on the Logan Loop. Furthermore, the sense of motion through poles older than ~ 1.3 Ga is reversed to permit the shortest connection to poles older than 1.6 Ga. As well, the timing and shape of the Hadrynian Track are modified so that it begins in the Atlantic hemisphere at ~ 800 Ma and terminates in the Pacific at ~ 650 Ma, representing a minimum average continental drift rate of ~ 10 cm/year for this interval.


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