Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000001864

Record: MDI000000001864

General

Commodities

Primary Commodities: Rare Earth Elements, Uranium, Cerium, Neodymium, Lanthanum, Thorium, Ytterbium

Location

Township or Area: Walsh

Latitude: 48° 49' 4.45"    Longitude: -86° 42' 45.84"

UTM Zone: 16    Easting: 521088   Northing: 5407253    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 42D15SE

Point Location Description: GPS location taken on outcrop to the right of the trail

Location Method: Field Visit with GPS

Access Description: The McKellar Creek Diatreme can be reached by following a trail that intersects Hwy 17 just west of the highway bridge over McKellar Creek in Walsh Twp. The diatreme is approx.. 300 m north of the highway.

Exploration History

1967: J. Walker of the OGS found the breccia and interpreted it as an Animikie conglomerate. 1975: R. Sage of the OGS visited the site and identified it as a diatreme. 1976: J. Scott of the MNDM recognized the diatreme as being radioactive, following staking activity on the Dead Horse Creek diatreme. 1977: property staked by L. Kaye. 1983: V. Stenlund drilled 1 DDH totaling 32 m. 1984: V. Stenlund drilled 1 DDH totaling 109 m. 2001: Staked by J.E. Bond and R.P. Renner. 2001-03: conducted prospecting, geological mapping and sampling. 2009: conducted prospecting geological mapping and sampling. 2013: conducted claim post georeferencing, geological mapping and sampling.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wawa

Terrane: Wawa-Abitibi

Belt: Schreiber-Hemlo

Geological Age: Late Precambrian  

Geology Comments

Sep 16, 2015 (Therese Pettigrew) - On the basis of limited exposure, the diatreme has a north-south long axis of approximately 240 m and a maximum width of approximately 60 m. The site of the breccia is surrounded by extensive outcrops of Early Precambrian, fine-grained, schistose argillite and siltstone. These metasediments are rather homogeneous, rarely show good bedding, and commonly contain an estimated 20 percent or more biotite. The metasediments have been intruded by north-trending diabase dikes which were not observed to cut the breccia. Several lamprophyre dikes were observed but the relationship of these dikes to the breccia is also unknown. The diatreme occupies a topographic low and occurs within a north-trending linear. The breccia may have been emplaced within a shear or fault zone, however, geologic data supporting this possibility are lacking. The rather homogeneous lithologies east and west of the structure have prevented the identification of any offset across the topographically low ground. There is no apparent zonation of clast size, but this may be a function of lack of exposure (Sage, 1982).

Lithology

Lithology Comments

Sep 16, 2015 (Therese Pettigrew) - The metasediments enclosing the diatreme weather grey to grey brown, and on the fresh surface are grey to greenish grey. Locally crude compositional layering reflects former bedding, and on the weathered surface tiny bluish quartz grains are visible with the aid of a hand lens. In one thin section the rock is fine grained, inequigranular, and granoblastic with curved to straight grain boundaries. The mode is estimated to be 30 percent quartz, 35 percent biotite, and 35 percent plagioclase. The biotite occurs in tabular, ragged grains with a subparallel orientation which defines a schistosity. The quartz is anhedral, angular to subrounded in outline and locally occurs in aggregates of several grains. The plagioclase occurs as anhedral turbid grains interlocking with the quartz. The plagioclase is rarely twinned. Petrographically the rock is a quartz-biotite-plagioclase schist. The diatreme breccia consists of rounded to angular clasts of pink and white quartzite, metasediments, and, rarely, altered trondhjemite. The clasts generally do not exceed 0.3 m in maximum dimension, but one clast of quartzite in a small outcrop immediately east of the two main outcrops is 2 by 3 m in size. The breccia matrix is variable between sections. The variation in texture and mineralogy between samples appears to be the result of the variation in intensity of the alteration. Angular fragments of quartz and plagioclase feldspar are abundant in the breccia matrix. Carbonate is abundant in the matrix, and it envelopes some clastic grains. Carbonate also impregnates some clasts, and may presumably be stained brown from iron oxide. The lack of carbonate within the enclosing wall rocks indicates that the carbonate found in the breccia has been introduced (Sage, 1992).

Mineralization

Mineralization Comments

Sep 16, 2015 (Therese Pettigrew) - The breccia is radioactive everywhere, but highly variable in intensity. Thorium is dominant over uranium and readings of up to six or seven times background were obtained. Reddish brown carbonate veinlets cutting argillite in the first outcrop west of the trail leading to the diatreme on Highway 17 give readings of one or two times background (Sage, 1992). Rare earth elements are present, although assay values were not particularly high. Assay results include the following: Ce ranged from 280-456 ppm, La ranted from 139-232 ppm, Th ranged from 56.6-105 ppm, U ranged from 22-19 ppm (AFRI 20000000183). OGS assays on the breccias showed that Th ranged from 40-180 ppm, U3O8 ranged from 13-38 ppm, La ranged from 100-400 ppm, Ce ranged from 210-550 ppm, Nd ranged from 100-300 ppm and Yb ranged from 2-15 ppm (Sage, 1992).

Mineral Record Details

Mineral Zones - Size and Shape

Site Visit Information

Date: Sep 04, 2015

Geologist: Therese Pettigrew

Notes: Site was visited with M. Smyk, M. Puumala, R. Cundari and P. Hollings. Electronic geiger counter readings between 1400 and 2500 counts per minute were recorded on the diatreme.

References

Mono - Mineralization in diatreme structures north of Lake Superior

Publication Number: S027 Date: 1982

Author: Sage R.P.

Publisher Name: Ontario Geological Survey

Location:

Publication - Field Guide to Aspects of the Geology of the Coldwell Alkaline Complex; In: 23rd Annual Meeting, Institute on Lake Superior Geology, Abstract, p. 11-12

Publication Number: ILSG Date: 1977

Author: Mitchell, H., Platt, R.

Publisher Name: Institute on Lake Superior Geology

Location:

Map - Jackfish-Middleton area, Thunder Bay District

Publication Number: M2107 Date: 1967

Author: Walker J.W.R.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Uranium occurrences of the Thunder Bay-Nipigon-Marathon area

Publication Number: OFR5634 Page: 131-133  Date: 1987

Author: Scott J.F.

Publisher Name: Ontario Geological Survey

Location:

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For detailed information regarding this mineral record please contact the Thunder Bay South Resident Geologist District Office