Program, Abstracts, and Guidebooks - University of Minnesota Duluth

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DESCRIPTION OF STOPS
Mileage count begins west of Nolalu, a small community on Highway
590, approximately 35 miles southwest of Lakehead University,
and may be reached via Highways 17—11, 588 and 590.
Mileage
0.0 1.8 miles west of Nolalu. The exposure is located in the
bed of the Whitefish River, on the north side, approximately
OO feet downstream from the bridge.
STOP 1
LOWER GUNFLINT MEMBER, LOWER ALGAL CHERT UBMEMBER OVERLYING
BASAL CONGLOMERATE AND ARCHEAN ASEMENT (FIG. 2)
Lower algal chert in the shape of concretionary, cthuli—
flower—like growths, forms an irregular, hummocky surface.
It is underlain by a thin veneer of basal (Kakabeka) conglom—
erate, resting unconformably upon metamorphosed, little
weathered Archean granodiorite.
The chert forms thiqly banded, white, red and black algal
structures resembling piles of inverted thimbles; red, white
and brown chert—hetnatite oolitic granules are dispersed within
the structures. Fossil microflora occur in the darker, almost
black, variety of chert.
Note several exposures of -algal chert mounds in the area
between the road and the river bank.
1.9 Co—op store, NolaLu.
2.4 Junction, Highways 588 and 590. Turn north on Highway 590.
17.9 Junction, Highways 590 and 17—11. Outcrop is the road cut
300 feet north of junction, west side of Highway 17—11.
STOP .2a BASAL KAKABEKA CONGLOMERATE,
(FIG. 2).
LOWER ALGAL CHERT SUBMEMBER
Basal conglomerate, grading-upward into reddish, lower
algaL chert and granular chert, consists of pebbles of white
quartz, chert and jasper set in a matrix of sandy quartz
grains and minor carbonate (calcite). Near the north end oif
the outcrop, the Gunf lint Formation is in fault contact with
Archean granitic gneiss.