Early Precambrian Rocks in the Saganaga Lake-Northern Light Lake Area, Minnesota-Ontario Part I. Petrology and Structure

1972 ◽  
pp. 151-178 ◽  
Author(s):  
S. S. Goldich ◽  
G. N. Hanson ◽  
C. R. Hallford ◽  
M. G. Mudrey
Keyword(s):  
Lake Area ◽  
Early Precambrian ◽  
Precambrian Rocks

U-Pb ages on single zircons from the Early Precambrian rocks of West Greenland and the Minnesota River Valley

1977 ◽  
Vol 35 (3) ◽  
pp. 449-453 ◽  
Author(s):  
Annie Michard-Vitrac ◽  
Joël Lancelot ◽  
Claude J. Allègre ◽  
Stephen Moorbath
Keyword(s):  
River Valley ◽  
Early Precambrian ◽  
West Greenland ◽  
Precambrian Rocks ◽  
Minnesota River ◽  
Minnesota River Valley

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.

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