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REPORT ON PRELIMINARY GEOLOGY AND GEOCHEMISTRY OF THE ILGA CLAIM GROUP CARlBOO MINING DIVISION Lat 52"45' Long 125"19' NTS 93C/11,14 FOR KERR ADDISON MINES LTD. OWNED BY KERR ADDISON MINES LTD. By Peter Holbek Nov., 1983 TABLE OF CONTENTS 1. INTRODUCTION ~ Page 1.1 Location and Access 1 1.2 Claims and History 1 1.3 Physiography and Climate 4 1.4 Present Work 4 2. GEOLOGY AND MINERALIZATION 2.1 General Statement 2.2 Geology 2.2.1 Precaldera Assemblage 2.2.2 Dome Forming Assemblages 2.2.3 Intra Caldera Assemblage 2.2.4 Shield Forming Assemblage 2.3 Alteration and Mineralization ' 3. GEOCHEMISTRY 15 3.1 Methods 10 3.2 Discussion of Results 10 4. SUMMARY AND CONCLUSIONS 10 APPENDICES I - Geochemistry Results 12 I1 - Analytical Techniques 14 111 - Statement of Costs 15 IV - Statement of Qualifications 16 LIST of FIGURES Figure 1: Location Map for Ilga Claims Page 2 NTS 93 C 11, 14 Figure 2: Location Plan, Ilga Claims Page 3 Scale 1:50,000 Figure 3: Ilga Claims - Geology - in Pocket Figure 4: Ilga Claims - Geochemistry - in Pocket 1. INTRODUCTION 1.1 Location and Access The Ilga claims are located four km south of Far Mtn., near the center of the Ilgachuz Range, at Latitude 52"45' and Longitude 125"19' (see Figures 1 and 2). The area is covered by 1:50,000 N.T.S. map sheets 93C/ll and 93C/14, and is within the Cariboo Mining Division. Access to the property is by helicopter from either Hagensborg, 96 kms to the west, or from Anahim Lake, 33 kms to the south. Helicopter bases are located at Hagensborg (Trans- west) and 70 kms south of Anahim Lake at Bluff Lake (White Saddle Air Services Ltd. ) . Both Hagensborg and Anahim Lake have airports with scheduled flights to Vancouver by Air B.C. and Wilderness Airlines Ltd. ' 1.2 Claims and History The Ilga claim group is comprised of 68 units in four claims (see Fig. 2) and is owned by Kerr Addison Mines Ltd. Claim data is summarized below. There is no record of previous claims or mineral explor- tion in the Ilgachuz range. Table 1. Ilga Group Claim Data CLAIM NAME CWNER UNITS DATE LCCATED DATE RECORDED RECORD NO. Ilga 1 Kerr Addison 20 May 28,1983 June 23,1983 4g36(6) Ilga 2 20 I, I, I, I, I, 4938(6) Ilga 3 20 I, ,I I, I, I, 4937 ( 6) Ilga 4 8 May 27,1983 " I* I, 4939(6) -1- N Figure 1: Location Map for the Ilga Claims, NTS 93C/11+14. Cariboo Mining Divi'sion I 1.3 Physiography and Climate The Ilgachuz range is situated on the western edge of the Chilcotin plateau near its contact with the Coast Mountains. The range is a product of moderate erosion of a large Tertiary shield volcano. Much of the property is zbove tree line with elevations ranging from 1615 to 2230 metres. Good outcrop exposures are mostly restricted to the higher elevations as much of the area is composed of moderate to steep talus slopes. Valleys are filled with deep colluvial material and forested with Ponderosa Pine and subalpine Fir. The climate is cool and dry; typical of higher eleva- tions of the interior plateau. 1.4 Present Work A four man crew spent four days on the property prospec- ting, mapping and sampling from June 15 to 18. Forty soil and rock samples were collected and analyzed for Au, Ag, Sb, and As. An additional 12 samples collected subsequent to staking on May 28th were analyzed by multi- element I.C.P. techniques. Mapping was done at the 1:10,000 scale but is very preliminary in nature. Prospecting and sampling covered an area of about 16 square kms. 2. GEOLOGY AND MINERALIZATION 2.1 General Statement Lithologies and geological structures were recorded during prospecting traverses but no attempt was made to follow and map out contxacts in the field. The map(Fig.3) included in this report is a preliminary attempt to fit field data into a geological framework. Data were reinter- preted in light of recent investigations by Soutkm(1984)* 2nd the author is grateful for his helpful advice. * GSC Paper 84-1A Report of Activities 4- 2.2 Geology The Ilgachuz range is a moderately eroded,. multivent, peralkaline shield volcano formed by two chemically distinct magmatic episodes; and early complex series of trachyte and rhyolite eruptions, and late extrusion of a series of basalt flows. Numerous lithologies have been subdivided by Souther (1984) into six assemblages on the basis of their morphology and age relative to construction of the shield and subsequent collapse and filling of the central caldera. Utilizing Souther's grouping and nomenclature, the more significant lithologies will be discussed below. 2.2.1 Precaldera Assemblage The best exposure of this unit is on the east side of Pipe Organ Peak (Fig. 3) where it consists of a bedded pile over 300 m thick of weakl~y consolidated, moderately to intensely altered, pyroclastics, flows and sediments of uncertain origin. Colours range from mottled green to grey, yellow, ochre, red and white depending upon original lithology and degree of alteration. Most primary textures have been obliterated by alteration but occasionally faint flow banding or bedding can be observed. A green tuff- breccia composed of pumice fragments, feldspar crystals and minor debris is still recognizable at a number of localities. The recessive nature of this assemblage results in limited exposure due to burial by talus from above; conse- quently, when it does outcrop it produces conspicuous color anomalies in contrast to surrounding dark comendite and basalt talus.Bleached white and yellow kaolinized material is typically found near and around rhyolite domes and plugs. There is -no association between anomalous geochemistry and alteration within this assemblage. A rusty weathering (pyritic?) rhyolite breccia or lahar (or recent limonite cemented debris) is often encountered at low elevations in stream beds below or within the altered units. Although no clear contact relationships were observed, an unconformable contact is suspected and therefore this unit is not included in the Precaldera Assemblage. 2.2.2 Dome Forming Assemblages These assemblages include most of the rhyolite domes, related flows and the Ilgachuz Comendite. The northerly domes are subcircular talus mounds of plate sized pieces of I~i~cjht to dark grey, slightly porphyritic, flowbanded rhyolitz with minor obsidian. Flowbands are 0.5 to 4.0mm thick and, where observed in outcrop, have moderate dips. Massive to banded chalcedony blobs and veinlets are associated with these domes. The southern domes are slightly different in character, consisting of intrusive and extrusive phases of cream colored porphyries. The Sax Dome consists of an upper section of cream colored, aphanitic to fine quartz porphyry felsite with odd green glass filled fractures, and a lower section of microsyenite with red and green glassy zenocrysts. Rhyolite similar to the upper Sax Dome may host the Caliope mineralization. The Ilgachuz Comendite consists of large, massive, sometimes jointed flows and breccias of yellow-green to brown trachyte. Thick, jointed, dark weathering flows can be easily mistaken for basalts if not examined closely. This unit overlies all of the previous mentioned units and forms most of the peaks and ridges in the south-central part of the range. -6- 2.2.3 Intra Caldera Assemblage Three units make up this assemblage and are. best exposed on the north edge of the caldera as documented by Souther(1984). The lower unit, indicative of caldera formation, is an epiclastic boulder-landslide deposit, crudely bedded and dipping into the caldera. Souther describes it as a chaotic, fragment supported, unsorted jumble of angular to sub- rounded comendite and minor basalt clasts as large as three metres. Similar material, grading up into finer debris flows and possibly lahars, has been tentatively identified in the col~between Phacelia Pk. and Caliope Mtn. suggesting this areaas the southern edge of the caldera. Alternatively, largely unsorted breccia and debris deposits exist on the ridge north of Saxifraga Peak, possibly indicating the main,or a subsidiary, caldera edge. A thin bedded, dark grey to black, finely laminated vitric tuff that resembles a glassy shale is exposed at the break in slope all around Pipe Organ Peak. This unit Ettains a maximum thickness of 30 metres and its waterlain texture implies the existence of a caldera lake. This unit was not observed in the southern area of the proposed caldera. The uppermost intracaldera unit is made up of thick flows and domes(?) of coarse to medium grained feldspar porphyry trachyte. Pipe Organ Peak (informally named because of a stunning array of massive columns on its precipitous south face) represents a thick and rapid accumulation of ponded flows. Caliope Mtn. appears to be, in part, a finer grained intrusive ~ equivalent. -1- 2.2.4 Shield Forming Assemblage The Shield Forming Assemblage consists of a series of basalt and minor comendite eruptions, and is best exposed on Far and Scot Mtns. It appears that basalts issued from fissures primarily located peripheral to the caldera(s). Brick red cinder deposits may be a late phase of this assemblage. 2.3 Alteration and Mineralization Large areas of the Precaldera Assemblage and some of the rhyolites are hydrothermally altered but devoid of any mineralization. Alteration is dominantly kaolinization, and is most intense in areas surrounding rhyolite and trachyte domes and intrusions. Silicification is conspicuously absent. Only three areas of mineralization warrant further description. In the area between Caliope Mtn. and Phacelia Pk. there are a number of small, brightly colored gossans.

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