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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  15-Aug-96 by Keith J. Mountjoy(KJM)

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NMI 082E6 Mo1
Name MO, MATT, TUZO CREEK Mining Division Greenwood
BCGS Map 082E035
Status Prospect NTS Map 082E06E
Latitude 49º 22' 20" N UTM 11 (NAD 83)
Longitude 119º 07' 54" W Northing 5471021
Easting 345255
Commodities Molybdenum, Zinc, Lead, Copper Deposit Types L04 : Porphyry Cu +/- Mo +/- Au
Tectonic Belt Intermontane Terrane Plutonic Rocks, Harper Ranch
Capsule Geology

The Mo property is located at approximately 1432 metres elevation on the west side of West Kettle River, between Tuzo and Big Goat creeks, 7.5 kilometres south-southwest of Beaverdell. The area of principal interest lies on the former Mo 6, 8, 17, 18, 19 and 20 claims.

The occurrence was first staked on the Matt 1 to 75 claims, held by Kennco Explorations (Western) Ltd. in 1961 and 1962. An exploration program consisting of geochemical and induced potential geophysical surveys, geological mapping and trenching failed to identify any significant mineralization and the property was dropped. In 1964, Amax Exploration Inc. acquired the Mo 1 to 36 claims covering the Mo occurrence. A geochemical survey and 57.3 metres of diamond drilling in three holes were completed in that year. Mineralized areas of potential interest were extensively drilled in 1966 but the program results were not reported. In 1981, E & B Explorations Ltd. carried out 756 metres of diamond drilling in 1 hole. In 1982, Canamax Resources Inc. held a 100 per cent interest in the property. The occurrence was part of a Master thesis study by G.M. Leary at the University of British Columbia in 1970. The following description is summarized from his work.

Hostrocks of the Mo occurrence are intrusions including hornblende granodiorite of the Middle Jurassic Nelson intrusions which encloses a porphyritic biotite quartz monzonite stock of the Cretaceous to Tertiary Okanagan batholith. The stock is roughly circular and 2.4 kilometres diameter and hosts most of the molybdenite mineralization. The quartz monzonite is medium grained, porphyritic with prominent quartz phenocrysts and a pink colour due to secondary k-feldspar. A fine grained border phase called white (quartz) porphyry is seen in drill core. These granitic intrusions have been intruded by a younger Eocene quartz, albite, sanidine porphyry, known as the Tuzo Creek porphyry stock. Large pink sanidine phenocrysts (up to 7.6 centimetres long), variable coloured albite, clear to smoky quartz and chlorite altered biotite occur in a pale greenish-grey groundmass. The porphyry shows a strong similarlity to the Eocene other Coryell intrusions such as the Shingle Creek porphyry and the recently described Beaverdell porphyry. A potassium-argon age date yielded an age of 49.5 +/ 2 Ma from biotite (Leary, 1967). This pre-mineralization porphyry is thought to be a gently east dipping, inverted saucer-shaped intrusive mass up to 107 metres thick that was conformably and forcefully intruded between granodiorite and the top eastern flanks of the quartz monzonite stock. It is referred to as a roof-sill. Intra and post-mineralization porphyries are of similar composition. Pre and post-mineralization porphyry dikes crosscut all the these intrusive phases. Younger dikes include alkaline quartz gabbro, composite alkaline basalt to augite trachyte and altered latite compositions.

Three phases of shear and breccia zones have been delineated based on crosscutting relationships. These zones are typically up to 3 metres wide, strike 235 degrees and dip 55 to 90 degrees northwest. They are characterized by variable intergranular shearing of angular to rounded fragments with variable degrees of hydrothermal alteration. Phase one structures controlled period one hydrothermal alteration and associated molybdenite mineralization, which occurred intermittent to porphyry emplacement.

Two periods of hydrothermal alteration were controlled by fractures, and shear and breccia zones. The first period has resulted in widespread wallrock alteration, quartz veining and mineralization throughout most of the quartz monzonite stock but also affected the hornblende granodiorite and porphyry roof-sill. The alteration halo is ellipsoid-shaped in a northeast-southwest orientation and is up to 2865 metres long by 2103 metres wide. Pervasive argillic, potassic, albitic, propylitic and silicic alteration with sulphide and/or oxide mineralization occur on a large scale throughout the alteration halo. A zone of low-grade molybdenite mineralization occurs in an inner zone of more intense wallrock alteration, containing quartz stockworks with pyrite. This halo has been divided into peripheral (weak to moderate alteration) and central (intense alteration) shells (zones). The Central zone is an elongate, ellipsoidal shape and is verticall or steeply southeast dipping. The zone is up to 1646 metres long by 518 metres wide, widening at depth to 701 metres. It has a maximum vertical depth of 320 metres. The upper part has been divided into a quartz-hydromica subzone while the lower part a quartz-potassium feldspar zone. The upper subzone is up to 122 metres thick and characterized by widespread quartz veining while the lower subzone contains only local quartz veining. The two zones locally overlap as much as 46 metres. The peripheral shell consists mainly of argillic alteration of feldspars and mafics, increasing in intensity towards the Central shell. Minor propylitic alteration of mafics consists of chlorite and epidote. Minor fluorite, calcite, hematite, magnetite and pyrite are also associated. The second phase of hydrothermal activity occurred more locally and involved the development of sericite and quartz with associated sphalerite, galena, chalcopyrite, pyrite and molybdenite, and calcite and fluorite along fractures and in adjacent wallrock. It is largely confined to intra-mineralization dikes and sills at depth.

The Mo occurrence is a low-grade molybdenum deposit in a northeast trending altered shear zone. Mineralization (including oxides) consists of specular hematite, magnetite, molybdenite and minor sphalerite, galena and chalcopyrite in order of decreasing abundance. The molybdenite zone is confined to the western and east-central portions of the Central alteration shell. The zone is roughly 1219 metres long in a northeast direction and 244 to 305 metres width. At depth the zone widens to 549 metres with a maximum depth of 320 metres. A value of 0.04 per cent molybdenum has been used to defined deposit dimensions. Mineralization occurs mainly along fractures (80 per cent), and lesser in quartz veins, shear and breccia zones and as disseminations. Molybdenite occurs as coatings along planar fractures and around rock fragments in breccias and shear zones, seams and disseminations in banded discontinuous quartz veins and disseminations in discontinuous to continuous massive quartz veins and adjacent wallrocks. A foliated shear zone, largely in the porphyry roof-sill below quartz monzonite, directed hydrothermal and mineralizing fluids upwards, predominantly along fractures.

Grades range from 0.06 to 0.28 per cent molybdenum in zones 3 to 16 metres wide and with grades locally reaching 0.47 per cent molybdenum. The grade is variable due to an increase in the molybdenite content and not an increase in fracture intensity. The following table summarizes average molybdenum grades from drillholes in the molybdenum zone.

--------------------------------------------
DDH % Mo Length to Base
of Molybdenite Zone
1 0.08 227 metres*
2 0.02 168 metres*
3 0.03 161 metres**
4 0.04 313 metres**
* to base of the sulphide field
** to base of the quartz-k-feldspar subzone
--------------------------------------------

Bibliography
EMPR AR 1961-63,114, 1962-67,130, 1965-167, 1966-192
EMPR ASS RPT 386, *654, 9369
EMPR EXPL 1995 (in press)
EMPR FIELDWORK 1975, pp. 27-31
GSC MAP 538A; 539A; 37-21; 15-1961; 1738A
GSC OF 481; 637; 1505A; 1565; 1969
CIM *Special Volume 15, 1976, Table 1, No.3 - Characteristics of Some  Canadian Cordilleran Porphyry deposits, in pocket
*Leary, G.M. (1970): Petrology and Structure of the Tuzo Creek  Molybdenite Prospect near Penticton, British Columbia,  unpublished M.Sc thesis, University of British Columbia, 141 pp.
EMR MIN BULL MR 223 (1989) B.C. 14

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