The Borden Lake Area

Timiskaming hosted gold mineralization

A common feature of large scale Archean lode gold deposits is their spatial

association with Timiskaming clastic sediments. This holds true for a number of

major gold deposits in the Timmins, Kirkland Lake, Hemlo and Red Lake gold

camps.

An often overlooked area of Timiskaming aged metasediments are those that outcrop

on the west margin of the Kapuskasing Structural Zone (KSZ) (Percival 2008;

Thurston, Siragusa and Sage 1977). Fifteen kilometers east of Chapleau, Moser

(1989) has identified paragneissic rocks including metaconglomerate in a broad westtrending

band that underlies the north part of Borden Lake in Cochrane and Borden

townships. Clast-supported cobble conglomerates and associated metawackes, and

meta-arkose exhibit pronounced deformation and metamorphism, possibly associated

with deep burial, upper amphibolite to granulite facies metamorphic conditions and

subsequent exhumation related to Proterozoic uplift of the KSZ. The Borden Lake

conglomerate forms the uppermost 30 m thick part of the 3 km wide Borden Lake

greenstone belt (Percival 2008). U-Pb geochronology of clasts of the conglomerate

indicated an age range between 2690±2 and 2667±2 Ma (Krogh 1993).

Recent prospecting activity in the area has revealed the presence of significant iron

sulphides with reported anomalous gold mineralization. Hydromuscovite is a

ubiquitous mineral component of much of the paragneiss in the area, attesting to high

fluid-rock interactions. Consequently, the area is considered highly prospective for

Timiskaming hosted gold mineralization. The fact the rocks are highly

metamorphosed should be borne in mind when exploring the area. Carbonate

alteration assemblages that typically accompany greenschist grade Archean lode gold

deposits will be replaced by calc-silicate metamorphic assemblages. Instead of

ankerite, quartz, sericite, chlorite and pyrite, one should anticipate the presence of

quartz, epidote, diopside, amphibole, feldspar and pyrrhotite in skarn deposits and

amphibolitized to granulitized metamorphic rocks. Due to the high strain state of the

rocks around Borden Lake, economic mineralization will likely be narrow, high

grade, possibly arsenical and parallel to the pronounced stretching lineation that

developed during ductile extensional strain related to uplift of the Kapuskasing

structural zone.

Krogh, T.E., 1993. High precision U-Pb ages for granulite metamorphism and

deformation in the Archean Kapuskasing structural zone, Ontario: Implications

for the structure and development of the lower crust. Earth and Planetary

Science Letters, 119: 1-18.

Moser, D.E., 1989. Geology of the Wawa Gneiss Terrane adjacent to the

Kapuskasing Structural Zone near Chapleau, Ontario. Geological Survey of

Canada, Open File Map 2056. Scale 1:50 000.

Percival, J., 2008. Field Guide to the Kapuskasing Uplift, Chapleau-Foleyet transect:

A window on the deep crust, in Geological Society of America Field Forum

“Late Archean Crust: Magmatism and tectonics of the Abitibi Subprovince,

Canadian Shield” 19-25 July, 2008

Thurston. P.C., Siragusa, G.N. and Sage, R.P., 1977. Geology of the Chapleau area,

Districts of Algoma, Sudbury and Cochrane. Ontario Division of Mines,

Geological Report 157, 293p

The Borden Lake area was mapped possibly lots of time but most recently in 2008 by the Ontario Mines Dept and the northern part of Borden lake was recommended as a place where some exploration should be undertaken. As noted, the area is considered highly prospective for Timiskaming hosted gold mineralization. Such rock is host to major gold mining camps such as Hemlo, Red Lake, Timmins, etc. As such finding gold over significant widths and lengths are not uncommon is this rock. The paper speculates that narrow high grade gold might be found but in PRB's case low grade and hopefully lots of it might be what PRB ends up with. Maybe Dave will get the higher grade at depth, who knows.

Holding for now, possibly other companies are also exporing so I am looking for more activity in the area. I emailed REC re their geology but have not had a reply, they are south of PRB.

mh