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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  09-Jun-2020 by Karl A. Flower (KAF)

Summary Help Help

NMI
Name ANITA, CHEMAINUS, CHIP Mining Division Nanaimo, Victoria
BCGS Map 092B091
Status Showing NTS Map 092B13W
Latitude 048º 54' 26'' UTM 10 (NAD 83)
Longitude 123º 57' 24'' Northing 5417583
Easting 429898
Commodities Copper, Lead, Zinc, Silver, Gold Deposit Types G06 : Noranda/Kuroko massive sulphide Cu-Pb-Zn
Tectonic Belt Insular Terrane Wrangell
Capsule Geology

The Anita occurrence is located on Chipman Creek, approximately 4.7 kilometres south of the Lara (MINFILE 092B 129) occurrence and has been explored in conjunction with it.

The occurrence lies within the Cowichan uplift, in which the Paleozoic Sicker and Buttle Lake groups are exposed. The occurrence is underlain by felsic and mafic volcanics of the Upper Devonian McLaughlin Ridge Formation, of the Sicker Group, that trend northwest and dip steeply. The volcanic rocks are flanked on the north side by the Mississippian to Pennsylvanian Fourth Lake Formation, Buttle Lake Group (formerly the Sediment-Sill Unit of Muller). These rocks are intruded by gabbro bodies (informally known as the Mount Hall Gabbro), varying from 1 to 300 metres thick, that are coeval with the Upper Triassic Karmutsen Formation (Vancouver Group). To the south, the Sicker Group rocks are unconformably overlain by the Upper Cretaceous Nanaimo Group sediments.

The original Anita showing, which occurs along the Anita Horizon, consists of quartz lenses in schist traceable for at least 60 metres in an easterly direction. The "vein" is up to 4.5 metres wide and carries chalcopyrite and pyrite. A sample assayed 10.28 grams per tonne silver and 3.3 per cent copper (Minister of Mines Annual Report 1917, page 270).

The "Anita Active Tuff" is a pyritic and quartz phyric felsic ash and lapilli tuff that occurs along the southern edge of a sericitic felsic tuff package that has an outcropping exposure width of 400 to 1300 metres. A major thrust fault that is probably a splay of the Fulford fault occurs immediately north of the Anita Active Tuff. Drilling in 1987 to 1990 revealed polymetallic sulphide mineralization within 10 metres of a felsic-mafic contact within the Anita Active Tuff. The southern contact of the Anita Active Tuff with mafic tuffs is called the "Anita Horizon". The Anita Horizon has been traced discontinuously by drilling over a length of 3.5 kilometres. From its western end, where it is terminated by a fault, the horizon trends southeast for 1.4 kilometres after which the remaining 2.1 kilometres is occupied by the "Anita Gabbro". This gabbro is a sill to dyke-like body that is also present to the west where it is adjacent to the 1.4 kilometre length of the horizon.

Mineralization consists of pyrite, sphalerite and chalcopyrite occurring as sparse veinlets, stringers and as polymetallic bands. The best drill intersections to date tested a strike length of 300 metres. Assay results of true widths are as follows (Stewart, 1990):

Hole Length Copper Lead Zinc Silver Gold

(metres) (%) (%) (%) (g/t) (g/t)

87-37 2.5 2.37 0.73 2.73 46.0 0.72

88-49 4.9 2.30 0.49 3.66 73.9 1.90

88-76 4.8 0.93 0.10 3.81 20.5 0.37

The western end of the Coronation zone of the Lara deposit (092B 129) occurs about 1.5 kilometres southeasterly (120 degrees) from the eastern end of the Anita Horizon. The two deposits are almost along strike from each other but significant differences in their settings suggest that the horizons are not identical.

In 1915, a 15-metre shaft was excavated on the Anita occurrence. More recently, since the 1980s, the area has been explored in conjunction with the nearby Lara (MINFILE 092B 129) occurrence.

Bibliography
EM EXPL 1999-25-32
EMPR AR 1917-270
EMPR ASS RPT 11345, 15504, *16710, 16825, 18293
EMPR FIELDWORK 1982, p. 46; 1987, pp. 81-91
EMPR OF 1988-8; 1999-2
EMPR PF (*Unpublished report by Robert Stewart, Falconbridge
Limited, 2 pages; Doublestar Resources Ltd., Annual Report,
December 1999)
GSC MAP 42A; 1386A; 1553A
GSC MEM 13; 96
GSC OF 463
GSC P 72-44; 75-1A, p. 23; 79-30
PERS COMM Stewart, R., Falconbridge Limited, Oct. 1990
Carson, D.J.T. (1968): Metallogenic Study of Vancouver Island with
Emphasis on the Relationship of Plutonic Rocks and Mineral
Deposits, Ph.D. Thesis, Carleton University
Kelso, L. (2007-11-15): Independent Technical Report and Mineral Resource Estimation – Lara Polymetallic Property
Kelso, L. (2008-04-02): Independent Technical Report and Mineral Resource Estimation – Lara Polymetallic Property
Falconbridge File

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