Geology and Geothermal Potential- of the AWA Claim$koup, JAN t-l 5 2004 I Squamish, British Columbia Gold COmIniSSioner’S Office I VANCOUVER,B.C. I Prepared for Lisa Rummel & AWA Spa Glenn J. Woodsworth, P. Geo. April 2003 3 SUMMARY A geologicalstudy was done on the AWA group of 6 mineral claims with a view to assessingthe geothermalpotential. The claims are almost entirely underlain by granitic rocks of the latest JurassicCloudburst pluton and, south of the Stawamus River, by the mid-CretaceousSquamish pluton. Fracture and joint analysisshows a , weak north-northeast trend, but fractures tend to be widely spaced.No signsof faulting or of igneousactivity related to Garibaldi volcanism were seenon the .zproperty. Faults, if they exist, are likely to be narrow, making them difficult drilling targets. The low regional heat flow-. and the lack of a “plumbing system”in the granitic, rocks on the property indicate that the geothermalpotential is very low. No further work is warranted. INTRODUCTION The AWA claim group consistsof 6 mineral claims,AWA #l to 6, stakedOctober 8, 2002,and owned by Lisa Rummel. The claims are situated in and just eastof the District of Squamishmunicipality, northeast of the subdivision of Valleycliffe (Figure 1). On the southwest,the claim group abuts StawamusChief Provincial Park and private property of the Valleycliffesubdivision and Squamishwaterworks. I was contracted by the owner to make a geologicalappraisal of the geothermal potential of the claim group and to make suggestionsfor further work. Field work was done in two long days;this work was supplementedwith an air photo study and review of the recent geologicalliterature on the region. Accessto the claims is by good gravelroad along the StawamusRiver. A road to the Mamquam power station cuts through the heart of the claim group, and the Mamquam River forestry road trends northeast acrossthe southeastpart of the u: claims. -l- ‘: Mamquam Figure 1. Location of the AWA group of claims. Base map is the Land & Water BC map of the Squamish-Alice Lake area (map 0926.075). Claim boundaries are taken from mineral tenure maps on tile with the Ministry of Sustainable Resource Management. Contour interval is 20 m. -2 GEOLOGICAL SETTING The Squamishregion is part of the western belt of the Coast Mountains (seeFigure 2 and Monger and Journeay,1994 for a summary of geologyof the Coast Mountains at this latitude). Essentiallyit consistsof plutonic (granitic) rocks of Middle Jurassicto Late Cretaceousage with lesseramounts of metamorphosedvolcanic and sedimentary rocks;mainly of Triassicto Cretaceousage. These rocks havebeen affected by predominantly mid-Cretaceousfaults that strike generallynorthwest and dip very : steeply.Movement on these faults was predominantly southwest-sideup and, unliie theeastern Coast Mountains, there is little evidenceof faulting continuing into early Tertiary time. No igneous activityis known in the Squamisharea from about 86 Ma to the beginning of Garibaldi volcanismperhaps 2-3 million yearsago. The Garibaldi volcanic belt consistsof Plioceneto Pleistocenevolcanic rocks that are part of the ! Cascademagmatic arc. In the Squamisharea, Garibaldi volcanism ceasedduring or d shortly. after the end of glaciation. PROPERTYGEOLOGY Topography and Physiography The AWA claim group is in the low country betweenthe Stawamusand Mamquam ,d Rivers,both substantialrivers. Most of the claim areaconsists of knobby, hilly country with elevationsup to 320 metres. Bedrock is well exposedin this terrain, and overburden (mainly a thin layer of glacialtill and soil) is thin. The central part of the J claims is a flat-bottom valley of about 100 metres elevation; a small, swampy lake is centrally located in the claims in this valley.The southwesternparts of the claim group are in the StawamusRiver valley at an elevation of about 70 to 85 metres. ,J There is no outcrop in thesevalleys. : ‘, ,..J Bedrock Exceptfor the small portion of the property south of the StawamusRiver, the AWA claim group is entirely underlain by quartz diorite to tonalite of the latest Jurassic r (145-147 Ma) Cloudburst pluton (Figure 3). The rock is medium grained and mainly composedof plagioclasewith lesserquartz~ and hornblende. On the property, the rock Ll is unfoliated to weakly foliated and is everywherealtered to a low metamorphic grade. Chlorite and epidote are the common metamorphic minerals. This rock unit is perhapsthe dominant unit iu the region betweenthe StawamusChief and Garibaldi Lake. -3- Glacial and post-glacial Granitic rocks, mainly sediments Jurassic in age Pliocene and Pleistocene Older volcanic and volcanic rocks metamorphic rocks, Triassic to Cretaceous in age Granitic rocks, mainly 0 10 Cre&ceous in age km Figure 2. Geology of the Squamish region. Geology is slightly modified from Monger and Journeay (1994). --d The rocks are cut by basaltic dykesthat averageabout 1 m in width. The dykesare I dark greento almost black in colour, very fine grained, are heavily alteredto chlorite d and epidote, and have fracture setsconsistent with the host Cloudburst quartz diorite. \ My view (and the prevailing one among geologistswho haveworked in the area) is d that thesedykes represent feeders to Early Cretaceousvolcanic rocks of the Gambier Group and thus would be about 100-140 million yearsold. The steepcliffs south of the Stawamti River are composedof coarsegrained J granite, calledthe Squamishgranodiorite. This rock is differentiated from the : Cloudburst quartz diorite by its coarsergram size,a higher percentageof quartz, r > abundant potassium-feldspar,presence of biotite rather than hornblende, absenceof j penetrativefoliation, and lack of pervasivemetamorphic alteration. Publisheddates from this body range from 96 to 103Ma (mid-Cretaceous).Geological Survey of Canadamaps show the contact between the two units as following the StawamusRiver valley.This interpretation appearsto be correct: there is no Squamishgranodiorite on , the property: the nearestappears to be at the junction of Plateauand WestwayDrives. L4 in the Qlleycliffe subdivision.The nature of the contact, whether fault or intrusive, is not known. The GSC maps show it as an inferred fault, with southwest sideup, but , without the contact being exposedanywhere in the region, this conclusionis probable, n_rl but debatable.Certainly on a regional scalethe Stawamus-IndianRiver valley systemis controlled by faults (probably Cretaceousin age) but the structures do not always I follow the valley floor. si, No evidencewas seenon the property for dykesthat might be feedersto volcanic 1 activity of the Garibaldi Belt. Such dykesare easyto distinguish from the Cretaceous dykesthat are present on the property: they are fresher,have their own joint patterns, ‘iJ and chilled margins are commonly conspicuous. Fracture Analysis For a geothermal systemto exist, there must be a “plumbing system”whereby water can circulate,pick up heat, and return to the surface.Because the Cloudburst quartz diorite and associatedbasalt dykes have no porosity and no permeability, any plumbing systemhas to be in the form of faults and fractures. To this end, a intense searchof the property was made for faults and fracture systemsthat may serveas conduits for hot water. No faults or pervasivefracture setswere seen.Joints and fractures are spaced,on average,about 0.5 to 1.0 m apart. The most intensefracturing seenhad fractures spaced2-5 cm over a width of 1 m; thesewere cut by one of the black basaltdykes. Fracture surfacesinvariably havechlorite and epidote,the samealteration assemblage as the Cloudburst quartz diorite itself. Dating thesefractures is not feasible,but my impression,based on alteration assemblageand the crosscutting relationshipswith the dyke at one point, is that the fracture and joint pattern is relatively old. -6- Figure 4. Top: equal-areaplot of polesto the most conspicuousjoints and fractures on the AWA claims.The strongest seti are shown in red. Bottom: rose diagram of samedata set with histogram (shaded) showing the weak north-northeast maximum in the data. Seetext for discussion. -7- Joints and fractures are everywhereextremelv narrow. Many are healedand sealed by the alteration minerals; no evidenceof low-temperature (<2dO”C) alteration such as clay or zeolites.None of the observedfractures appearedcapable of hosting any sustainedflow of water. Directional analysisis shown in Figure 4. Joints and fractures tend to be very steep (most dips are greaterthan 75’). No strong directional pattern emerges,but , there is a weak,maximum at 022’ (north-northeast) and a relative absenceof west- northwest-trending structures; the significanceof this is discussedlater in this report. ! Outcrop is sparsein the central, northeast-trending valley that bisectsthe property. But an examination of the Mamquam River canyon,upstream from the hydra-electricplant, did not show any conspicuousor pervasivenorth-northeast fracture or fault systems-andthis suggeststhat extensivevalley-parallel systems are absentfrom the property. Joints and fractures in the Squamishgranodiorite south of the StawamusRiver show the samepattern as rocks to the north, but fractures are more widely spaced. Surficial Deposits Much of the lower-elevationparts of the property are underlain by thick depositsof graveland sand. The valley bottom is broad and flat and slopesvery gently from about 105 m at the north to about 85 m at the south. The sand and gravel appearto be glacialoutwash depositsdating to a time when the lower SquamishRiver valley was blocked by ice