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Aluminous minerals similar to those of the Lorrain Formation occpr
in quartzites in the lower part of the Animikie "Series" = Marquette
Range Supergroup (Church and Young, in press) of the south shore of Lake
Superior (Keyes Lake quartzite, Sturgeon quartzite, Ajibik quartzite and
Breakwater quartzite). Kaolinite is also present in the Baraboo and
Barron quartzites of Wisconsin and pyrophyllite and diaspore were reported
from the Sioux quartzite of Minnesota and South Dakota (Berg, 1931).
Kyanite is present in the Medicine Peak Quartzite of S.E. Wyoming, the
Petaca Schist of New Mexico and kaolinite, andalusite and diaspore have
been found in the Hurwitz C quartzites of the Keewatin District of N.W.T.
Bimodal size distribution in many of these quartzites may indicate that
much of the clastic material was wind transported prior to sedimentation
in an aqueous medium (Folk, 1968).
Similar aluminous quartzites of similar age from other continents
include those of Finland (Jatulian quartzites), Brazil (Jacobina Series),
India (Iron Ore Series) and South Africa (Witwatersrand System). Some
of these extremely widespread quartzites may be deposits formed as a
result of post-glacial transgression. If the formation of kaolinite in
the quartzites took place under climatic conditions similar to those unde,r
which present day bauxites and laterites are formed, there must have been
a significant amelioration of climate following deposition of the Cowganda
Formation and its possible correlatives.
REF ERENCES
Berg, B. L. 1937. An occurrence of diaspore in quartzite. Amer. Mineralogists
.v. 22, pp. 997—999.
Church, W. R. 1967. The occurrence of kyanite, andalusite and kaolinite
in Lower Proterozoic (Ruronian) rocks of Odtario (abst.) Tech. Prog.
Geol. Assoc. Can. Meet. Kingston, Ontario, pp. 14-15.
Church, W. ft. and Young, C. M. (in press). Discussion of the Progress
report of the Federal-Provincial Committee on Huronian stratigraphy.
Can. J. Earth Sc. v. 7.
Folk, R. L. 1968. Bimodal süpermature sandstones: product of the desert
flc,or. XXIII International Geological Congress Section 8; Genesis
and Classification of Sedimentary Rocks. pp. 9-32.
Logan, W. B. and Sterry Hunt, T. 1855.
H. Bossange et fils, Paris. 100 pp.
Esquisse geologique du Canada.
Murray, Alexander. 1849. On the north coast of Lake Huron. Geol. Surv.
Canada, Rept. Prog. pp. 93-124.
Ojakangas, R. W. 1965. Petrography arid sedimentation of the Precambrian
Jatulian quartzitesof Finland. Bull. Comm. Geol. Finlande. No. 214,
74 pp.
Young,
G. M. (in press). An extensive Early Proterozoie glaciation in
North America? Palaeogeog. Palaeoclimat. Palaeoecol.