Moose River Basin: geology and mineral potential - Geology Ontario

Mesozoic Stratigraphy
TABLE 2.2 l
SUMMARY OF FALL 1977 DRILLING ACTIVITIES.
Drillhole
Location
Elevation
(metres)
Total Depth
(metres)
77-01
81 023'48"
500 34'4B"
51
46
77-02
81 0 24'42"
500 35'09"
49
50
77-03
81 0 26'15"
500 33'10"
48
51
REGIONAL GEOLOGICAL SETTING
The Moose River Basin is a southeastern extension of the large Hudson
Bay Basin (Figure 2.1). The latter is centred on Hudson Bay and is mainly an
offshore basin with only its southern rim constituting the mainland area. In
contrast, the Moose River Basin is almost entirely an onshore basin with only a
small part of its northeastern rim extending beneath the waters of James Bay.
The boundary between the basins is defined by the prominent Cape Henrietta
Maria Arch, a northeast trending structure marked by large areas of Archaean
and Proterozoic exposures. The arch was not a complete barrier to Paleozoic
sedimentation and, in places, contains a thin cover of Middle Silurian lime
stones and dolostones resting unconformably on the Precambrian rocks (San
ford et al. 1968).
The south side of the Moose River Basin, between Burstall and Kipling
Townships, is defined very clearly by an escarpment of Precambrian granitic
rocks. This feature, which may be fault controlled, sharply truncates the Paleo
zoic and Mesozoic strata of the basin. Farther to the west and northeast the
Precambrian boundary is less well defined but there is still some evidence of
truncation of the Paleozoic strata (Sanford and Norris 1975).
The Paleozoic sequence of the Moose River Basin has been studied on a re
gional scale by the Geological Survey of Canada (Sanford et al. 1968) and con
sists of an approximately 700 m of Ordovician, Silurian, and Devonian strata.
These are comprised mainly of marine carbonate rocks, shales, and evaporites
and minor marine and continental clastic sediments. In the southeast part of
the basin the Paleozoic rocks are overlain unconformably by a sequence of un
consolidated Mesozoic nonmarine sediments which are the principal subject of
this report. They are of variable thickness.
A number of Precambrian and Paleozoic inliers protrude through the Me
sozoic cover and are concentrated especially in an area bounded by the Matta-
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