Industrial Mineral Studies INDUSTRIAL MINERALS IN SOME TERTIARY BASINS SOUTHERN BRITISH COLUMBIA* (92H, 921) By P. B. Read Geotex Consultants Ltd., Vancouver, British Columbia

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INTRODUCTION more than 22 metres with neither contact exposed, and in length from 400 metres at Bromley Vale to 3500 metres for the Tailing This report summarizes results from12 days of fieldwork inves- tephra (Figure4-1-1). The zeoliteisheulandite-clinoptilolite whkh tigating the occurrence of industrial minerals, and those aspects of replacesoriginal glass shards in waterlain vitric-crystal (biotite, the Tertiary stratigraphy and stmcture which control the develop- plagioclase, sanidine, quartz) tuff, and rhyolitf glass in volcanic ment of industrial minerals, in the Princeton, 'Mameen, Merritt- breccia lenses of the Allenby Formation. Guichon Creek-Quilchena Creek, McAbee, and Hat Creek basins. The industrial minerals ,ofmajor interest are bentonite, zeolites and The tephra horizons and surrounding sedimentary stratigraphy diatomaceous earth, aswell as clays for brick and ceramic uses, and have been mapped at 1:25 OOO scale throughout the basin. Four of materials suitable for concrete aggregates. Laboratory investiga- the horizons have been sampled in detail at 0.9-metre intends tions of samples are in progress, but tests of materials relative to acrosstheir exposed thicknesses at selectedlocalities. They are ASTM specifications have not yet been started. briefly described following. The Sunday Creek tephra is the only zeolitized horizon in tne STRATIGRAPHY AND STRUCTURE Friday Mountain portionof thebasin; it lies within100 metres of tne OF THE PRINCETON BASIN AND base of the Allenby Formation. The tephrais mainly a fine (1 tc, 4- PLACER MOUNTAIN OUTLIER centimetre) rhyolite breccia with a vitric-crystal (biotite, feldspu, quartz) matrix and afew per cent subangular andesite clasts up5 to The PrincetonBasin is anortherly trending trough tilled by centimetres in diameter. Although unbedded to crudely bedded, it Eocene volcanic rocks of mainly intermediate composition com- contains fragments of wood up to 50centimetres long which ird- prising the Lower Volcanic Formation, and an overlying Eocene cate thatit is waterlain. The breccia outcrops over a distanceof up to sedimentary sequence of sandstone, shale. waterlain rhyolite tephra 500 metres south of the fork of Sunday Creek, in a 5-metre-high and coal, up to 2000 metres thick, comprising the Allenby Form- roadcutonthewestsideofHighway3. Theonlyotherexposuresiue ation (Rice, 1947; McMechan, 1983). The trough is the site of a in the south forkof Sunday Creek downstream from Highway3; the major northerly trending half graben bounded on the east by the creek twice intersects the tephra which outlines an open, gently northerly to north-northeasterly trending Boundary fault (Figure northerly plunging syncline. In a section sampled in detail about 4-1-1). South of Princeton, northwesterly to westerly trending folds 100 metresdownstream from Highway 3, thecreek exposera and faults break thehalf graben intoa northern sediment-dominated volcanic pebble to cobble conglomerate underlying a section of segment centred on Princeton, and a southern, volcanic-dominated tephraat least 30 metresthick which grades into an overlying portion centred on Friday Mountain. The Princeton segment con- brownish weathering sandstone (Figure 4-L-Za). The tephra ha; a tains up to 1370 metresof volcanic rocks overlain by 1600 to 2100 strike length of 1300 metres with both ends passing beneath dlift. metres of sandstone, tuffaceous sandstone, shale, waterlain rhyolite In the Princeton portion of the basin, Asp Creek tephra is the tephra and coal (McMechan,1983, page 13). In contrast, the Friday stratigraphically lowest zeolitized horizon that has been sampledin Mountain portion contains at least 1500 metres of volcanic rocks detail. It lies about 30 metres below the unzeolitized PrincetonAsh overlain by no more than 100 metres of volcanic conglomerate, and is exposed on thehighway to 'Mameen at the northwest endof sandstone and waterlain rhyolite breccia.A briefexamination of the the single-lane bridgeacross 'Mameen River within Princetontwwn Placer Mountain outlier of Tertiary volcanic rocks shows some 500 limits. The tephra contains scattered plant fragments and consistsof metres of medium grey aphanitic flows and overlying porphyritic bedded, white ash with intercalated layers of vilric-crystal (biarite, (plagioclase, hornblende) rhyodacite flows resting onbasement of a plagioclase,sanidine, quartz) tuff. Becauseneither the top 1101 volcanogenic sediments of the Upper Triassic Nicola Group. Appar- bottom contacts are exposedat this locality, the tephrawas samp ed ently an insufficient thickness of volcanic rocks remains in this indetailfromcliffsontherighthankofAspCrer:kabout500metres outlier to preserve the waterlain acid tephra present in the Friday upstream from its junction with 'Mameen River (Figure 4-I-2b). Mountain segment only 10 kilometres to the northwest. There the tephrais 7.3 metres thick, overlies a fine-grained biotite- bearing sandstone and underlies a carbonaceous shale. The str ke INDUSTRIAL MINERALS OF length of the tephrais about IMUl metres with both ends covered by THE PRINCETON BASIN drift, but with an eastem extension likely. Tailings tephra is the most extensive zeolitized horizon in he ZEOUTES Princeton Basin. It is exposed in a roadcut on the northwestside of The Princeton Basin contains the only bedded zeolite deposits Highway 3, 600 metres east of a side-road up Bromley Creek ad known in southem British Columbia southof latitude 51"N prior to I00 metres northeast of an operating gravel pit (Figure 4-1-2cl A thisinvestigation (Hora and Kwong, 1984),and also the only few exposures lieUP to 900 metres west of the highway and sevf.ral bentonitedeposit with productionrecords. With theexceptionof the lie up to 2200 metres tothe east. These outcropsall lie on the ncrtb Princeton Ash, all waterlain rhyolitetuff and volcanic breccia layers limb of a westerly trending and)gently plunging syncline. About!iOC are zeolitized. They form fivedistinct tephra lenses which rangein metres to the south, Tailings tephra outcropson The south limbol thc: thickness from 1metres, with upper and lower contacts exposed,to syncline from the left bank 01 Similkameen River to the fonner.

~ * This project is a cmtribution to the CanadaiBritish Columbia Mineral Development Agreement. British Columbia Ministry of Energy. Mines and Petroleum Resources. Geological Fieldwork, 1986, Paper 1987-1 247 120% 12003

Figure 4-1.1. Simplified geological map of the Princetonand Tulameen basinsshowing industrial mineral localities. [Geolog) om Church and Brasnet (1983), McMechan (1983) and Monger (unpublished data)]. 248 CopperMountain railway grade.Along the grade, a section Snowpatch tephra is exposed at 2825 feet(841 metres) eleva:io1 sampled in detail consists of a 4-metre thickness of vitric-crystal 23Nmetres up the road to Snuwpatch ski areafrom the Princelon- (biotite, feldspar, quartz) tuffoverlain by4.2metres ofmainly vitric Tulameen Highway (Figure 4-1-1). A rockcut on the south sid: cf rhyolite tuff. Neither the top nor bottom contacts of the zeolitized the road exposes about5 metres of yellow-ochreweathering, CO;LIS: horizon are exposed. The thick montmorillonite-bearing vitric- tuffaceous sandstonecomposed mainly of quartz, feldspar anli crystaltufflayerswithlessthan40percentzeolite,surroundingaI- biotite grains. Althoughneither the top nor lbottom contacts ar: metre-thick, fine rhyolite breccia with 40 to 60 per cent zeolite, as exposed, the zeolitized horizonis probably not much thicker than .5 exposed in the highway section (Z.D. Hora, personal communica- metres. About ENmetres to the south-southwest, at 3100 feet (94.5 tion, 1986), are absent in the railway section. The presence of metres) elevation and east of a powerline, a dip slopeexposes a 30- differing rock types in the two sections indicates that horizontal metre width of white-weathering vitric-crystal tuff. The stl-ikm: facies changes are present and these may have an affect on the extent length of the tephra horizon is 2400 mewes wirh both ends pas!.in:: of zeolitization. under drift. A 22-metre thickness of Bromley Vale rhyolite tephra is exposed in Bromley Creek upstream from the portal to Bromley Vale No. I BENTONITE mine. It contains fragments of carbonized wood and plants (Figure Bentonite is widespread throughout the Princeton portion of th': 4-1-2d). Downstream, theeasterly flowing crcckcrosses 9 metres of Princeton Basin, usually occurring in the shale and coal-rich liec- tine, white to crcam-coloured rhyolitebrecciaoverlain by 13 metres tions of the stratigraphy in layers up to 2 metre:$thick (McMechn, ofwhite to light grey vitric-crystal (biotite, feldspar, quartz) bedded 1983, page 19). Because bentonite outcrops slump shortly after tuff and a thin, dark grey silicified (?) tuff. Neithcr the top nor exposure, only a few localities were sampled. A 4.3-metre-thiclc bottom contacts are exposed and to the southvery thick overburden bentonite seam was exposed on the old Copper Mountain railwa:i mantles any possible extension. The tephra does not reappear to the grade just south of the switchback about 2.4 kilometres south af north perhaps because of truncation by Asp Creek fault. If Asp Princeton, and a I .9-metre-thick seam was f:xposed about I5CN Creek fault has a right-lateral strike-slip displacement of about 1200 metres to the east of the railway exposure (Spence, 1924, pages metres, then Bromley Vale tephra should correlate with Tailings 9-10; Cummings and McCanrmon, 1952, pages 33-34). On tha? tephra. same railway grade, about 6 kilometres south of Princeton. a st:,lm,

SC AC

T

100 0 200

mstrer

waterlain rhyolite ash waterlain interbedded ash and vitric- crystal (biotite, quartz, feldspar) tuff waterlain vitric-crystal (biotite, quartz feldspar) tuff biotite-bearing sandstone E-:::::]-a~L mb;'g waterlainrhyolite breccia carbonaceous shale volcanic conglomerate r>a covered interval

Figure 4-1-2. Geological sketch maps of sampled localities of reolitized tephra in the Princeton Basin 249 reported by Cummings and McCammon tolie 8 kilometres southof at least 3 metres thick and can be followed for about 100 metres Princeton (1952, page34), has been freshly exposed and consistsof southeastwards from an exposure on a four-wheel-drive track at a metre of carbonaceous shale underlying a 4.9-metre-thick se- locality FG (FK0663300mE, FK5486700mN). The southwesterly quence of bentonitic siltstone, shale and bentonite, capped by 1 dipping waterlain tuff lies withina sandstone-granule conglomerate metre of fine sandstone. About 400 metres east of Similkameen sectionand passes under drift along strike.A concentration of River and 7.2 kilometres south-southwest of Princeton, McMechan angular acid tephra float. containing heulandite-clinoptilolite, lies (1983,pages 19-21) reported a sandy bentonite 9 metresthick besidea barbed-wire fence at FK0662100mE, FK5486100d. which was encountered at shallow depths in boreholes. Two kilo- Bentonite layers up to a metre thick are part of the middle shale metres downstream from the mouthofwhipsaw Creek,the slumped and coal section. Cation exchange analyses of the bentonites indi- right bankof Similkameen River exposesa 20-metre-thick sequence catethat calcium and magnesium are themajor exchangeable of siltstone, bentonitic siltstone and bentonite which is part of the cations (Peaver et ai., 1980). No bentonite layers outcrop and the higheststratigraphy exposed in the basin. Shaw (1952, page 8) sparse exposures do not allow a proper assessment of the zeolite mentioned that bentonite occurs in two unspecified localities in potential. All industrial mineral localities lie within 6 kilometres of seams about 4.6 metres thick. These areprobably two of the seams the Canadian Pacific Railway at 'Mameenor Coalmont. observed by earlier workers. With the exception of Sunday Creek tephra, all of the industria: STRATIGRAPHY AND STRUCTURE mineral localities briefly described lie within 8 kilometres of the OF THE MERRITT-QUIJXHENA Canadian Pacific Railway which passes through Princeton. CREEK-GUICHON CREEK BASIN STRATIGRAPHY AND STRUCTURE Tertiaryrocks in theMerritt-Quilchena Creek-Guichon Creek OF THE TULAMEEN BASIN mas are dominantly clastic sedimentsof the Coldwater Formation. Eocene volcanic rocksof the Kamloops Group underliea small area The ?blameen Basin preserves I400 metres of Eocene volcanic southwest of Merritt and westof Lower Nicola (Figure 4-1-31, and sedimentary rocks which overlie the Upper Triassic Nicola Outcrops of the Coldwater Formation are so sparse that only local Groupand underlie two remnants of MiocenePlateau Basalt stratigraphic sections up to a few hundred metres in thickness have (Church and Brasnet, 1983). Up to 500 metres of grey sparsely been measured in the coal-mining area southwest of Merritt. Even porphyritic(hornblende) dacite flows and locally rhyodacite to Cockfield's (1948, page 33) suggested stratigraphic order of sedi- rhyolite flows and waterlain tuffsof the Lower Volcanic Formation ments of the Coldwater Formation underlying volcanic rocksof the underliesedimentary rocks of theAllenby Formation. Along Kamloops Group seemsunlikely. As Ells (1905). White (1947) and Blakebum Creek, the passage fromvolcanic to the overlying sedi- Cockfield (1948) observed, sandstone-rich sediments of the Cold- mentary rocks is transitional as breccias pass upwards into crudely water Formation form southeasterly plunging, opento tight upright bedded breccia and tuffaceous wacke (Figure1.1). 4- The lower part folds southwest of Merrin. The southwesternmost sediments oc- of thesedimentary sequence grades laterally from breccia and cupy the core of a northeasterly overturned syncline and the vol- tuffaceous sandstone inthe southwest to arkose in the east. A medialcanics of the Kamloops Group, bordering the sediments on the section of shale and coal, and an upper sectionof mainly sandstone southwest, are a lower rather than a higher stratigraphic unit. In and granule conglomerate with minor acid tephra, complete790- a Quilchena Valley, mainly pebble conglomerate and sandstone, with metre thickness of sedimentary rocks. The 90-metre-thick shale and minor shale and rare coal and bentonite, comprise a gently north- coal section is sparsely exposed in roadcuts; the 590-metre-thick easterly dipping sequence unconformably overlying the Nicola upper sandstone-conglomerate section is poorly exposed. Church Group,and dipping into a northerlytrending fault on theeast andBrasnet (1983, page 49) noted that thefrequency of felsic (Monger, 1982). In Guichon Valley, a single area of outcrop, 6 volcanic rocks increases stratigraphically upwards to where rhyolite kilometres north of Lower Nicola, exposes about 500 metres of airfall tephra forms 12 thin layers in the upper part of the coal shale, claystone, bentonite and sandstone which dips gently north- measures. The basin is a remnant of a southeasterly plunging syn- eastward into theGuichon Creek fault. Northwestof Lower Nicola, cline which has been truncated on its southeast side by Blakebum Tertiary volcanics probably pass northwards and upwards into sedi- fault. ments of the ColdwaterFormation which lie beneaththe drift- coveredvalley floor. This succession lies betweenthe Guichon INDUSTRIAL MINERALS IN Creek fault on the east and an unnamed fault splay on the west THE TULAMEEN BASIN (Figure 4-1-3). Waterlain acid tephras of the Lower Volcanic Formation and the INDUSTRIAL MINERALS IN lower andmiddle sectionsoftheAllenby Formation are suitable host MERRITT-QUILCHENA CREEK- rocksforthedevelopmentofzeolites.Pevearera/.(1980)notedthat most of the tephra layers consist of angular quartz, biotite and GUICHON CREEK BASIN sanidine in a finer matrix of quartz, clay and other minerals. In the TheGuichon and Quilchena Valleyseach have bentonite northern part of the basin, relict glass shards are altered to quartz, localities. In the GuichonValley (GC, Figure 4-1-3) roadcutson the regularly interstratified illite-smectite and minor heulandite-clinop- road to LoganLake, between 5.3 and 6.7 kilometresnorth of tilolite. Preliminary X-ray diffraction results from samplesof water- Highway 8, partly expose a section of claystone, shale, and friable lain acid tephra, collected during the present investigation, show sandstone which outcrops more completely east of the road in the that acid tephraof the Lower Volcanic Formation is locally replaced beds of the first two intermittent streams south of Morgan Creek. by laumontite on the southwestern edge of the basin at locality BC West of the road, bulldozer trenches and roads expose shale and (UTMcoordinates FK0663200mE. FK5483100mN) (Figure slumped bentonite. In the Quilchena Valley (PC, Figure4-1-3) 4-1-1). Although the lower part of the sedimentary section is VOI- bentonite and slumped bentonite, possibly 8 metres thick, outcrop caniclastic in the southwest cornerof the basin, the rocks apparently inagullyat2400feet(732metres)elevationeastofacavedadit,just do not contain zeolites. In contrast to the thin acid tephra layers in above the Quilchena Creek road. The adit and shallow trenches, the middle shale-coalsection, which contain only minor heulandite- whichexpose shale,coal and bentonite, lie 3.5 kilometres up clinoptilolite, the upper sandstone section contains a heulandite- Quilchena Creek road from Highway 5. In the Guichon Valley the clinoptilolite-rich vitric-crystal (biotite, quartz, feldspar) tuffthat is bentonite locality lies less than 7 kilometres from the Canadian 250 Quaternary Valley basalt

Miocene & Pliocene Quartz-feldspar CJ porphyry Eocene 1I Karnloops Group 1 s 1 Sediments II Volcanics

t =Pre-Tertiary

BENTONITE* GC GuichonCreek QC QuilchenaCreek

Figure 4-1-3. Simplified geological map of the Merritt-Guichon Creek-Quilchend Creek area showing industrial mineral localities [geology modified from White (1947). Preto (1979) and Monger fl982)l.

PacificRailway at Coutlee or Coyle.Bentonite occurrences in STRATIGRAPHY AND STRUCTURE: Quilchena Valley are about 27 kilometres from the railway at Mer- OF THE CACHE CREEK-McABEE rift. Although the Coldwater Formation occupies the same strat- AREA igraphic position as the reolitired tuffs of the Allenby Formation in the Princeton and Tulameen Basins, waterlain acid tephra, the North of the Trans-Canada Highway between McAbeeand Crsche most suitable host rock for zeolites. is unreported in the Mcrritt- Creek, Tertiary volcanic and minor sedimentary rocks overlie either Quilchena Creek-Guichon Creek basin. Thelack of outcrop hinders volcanic rocks of the Nicola Groupor dark grey slate of the Ashc roft an assessment of the industrial mineral potential and further invcs- Formation on an unconformity that has up to 2.50 metres of reln:f at ligation depends upon a planned examination of drill cores from the west end of the Cache Creek Hills (Figure4-4). Medium )grey the region. aphanitic flows and flow brel:cias, and grey porphyritic (plagicm- 25 1 Sediments

Rhyolite aintrusions

ZEOLITE* LOCALmE Bc Battle Creek CC Cache Creek MC Mc Abee BENTONITE LOCALIl

Figure 4-1-4. Simplified geological map of the McAbee-Cache Creek-Hat Creek area showing industrial mineral localities [geology modified from Church (1977). Ewing (1981) and Monger (1982)j. 252 clase, hornblende) andesite flows of the Kamloops Group, up to a (biotite, hornblende, quartz, feldspar) rhyolite tuff contain heulan- few hundred metres in thickness, underlie two lensesof sedimentary dite-clinoptilolite (CC, Figure 4-1-4). Neither the top nor bottom cmf rocks. The westem lens, called the McAbee sediments by Hills this section of basal Tertiary tuff outcrops and within a hundred (1965, page 23). is 2 kilometres long, up to 30 metres thick, and metres along strike it passes beneathdrift. At 15QOfeet (579metrer) outcrops in the cliffs 5 or more kilometres west of the Trans-Canada elevation and 1.5 kilometres east-northeast of the Trans-Carada Highway culvert across Battle Creek. The lower 24 metres of sec- Highwayculvert over Hattle Creek (FM0633700mE. lion is a pebble to cobble conglomeratewhich underlies 6 metres of FM5629400tnN), aminimum thickness of hmetres of beddedvnric- shale, carbonaceous shale, bentonite. and minor white tuffaceous crystal (biotite, hornblende, quartz, feldspar) tuff with heulanclite- siltstone. A medium grey aphanitic volcanic breccia overlies the clinoptilolite overlies a sedimentary breccia composed of angular McAbee sediments. fragmentsderived from the underlying Guichon intrusion I13C, The second sedimentary lens, about 2 kilometres long and up to Figure4-1-41, AtFM0624400mE. FM5630400mN. asinglesanlpl: 150 metres thick, outcrops in the cliffs less than a kilometre north- from a lens of the same basal tuffaceous sandstone not is zeolitized, west of the culvert across Battle Creek. It also contains a basal but poor exposures prevented proper sampling. polymictic pebble to cobble conglomerateup to 30 metres thickthat Within a few hundred metres above the baseof the volcanic-ncl passes upwards into white-weathering siltstone and shale. Locally Eocene section, tuffaceous sediments of the two lenses nonh cf the uppermost 6 to I0 metres is a white-weathering rhyolite tuff that McAbeeare commonly zeolitized (MC, Figure 4-1-4). Shde, inteerfingers with the andesite lahar overlying the sediments. claystone and siltstone, containing zeolitized vitric-crystal tuffs, White-weathering, aphanitic rhyolite dykes intrude slates of the comprise the upper IO to 70 metres of the lensos. The bedded tJffs Ashcroft Formation at the west end of Cache Creek Hills. The dykes range in thickness from less than a metre to more than 5 metre!. an,i do not intrude theTertiary succession. lust north of the CacheCreek in rock type from heulandite-clinoptilolite-bearing vitric-crystal village limits, abodyol‘white aphanitic rhyolite and rhyolite breccia (biotite,hornblende, quartz, feldspar)to finely laminated vtri: may intrude greenstone of the Cache Crcek Gmup. In the Trachyte tuffs. In the latter, mineralassemblages range from domin:utl,y tridymite-cristobalite through mixtures containing some of hewan- Hills, 12 kilometres west of Cache Creek, a massive aphanitic rhyolite underlies a roughly circulararea, 2 kilometres in diameter, dite-clinoptilolite, kaolinite, montmorillonite. feldspar and quartz, and either lies on or intrudes unnamed Lower to Middle Cretaceous to essentially pure heulandite-clinoptilolite. The lenses have nct sediments (Church, 1977, page G109; Monger, 1982). A6-kilo- been mapped or sampled in detail. metre-long body of porphyritic (biotite, hornblende, quartz, feld- Bentonite-bearing rocks are rare in the area. North of McAbee, spar) rhyolite, which Drysdale called the Ashcroft rhyolite porph- the upper 10 metres of the wezitem end of the western sedirnen1ar:f yry, outcrops south-southeast of Ashcroft and 13 kilometres from lens contains friable bentonite-bearing sandstone and siltstone. Cache Creek. Although long believed to be part of the Kamloops All zeolite and bentonite localities lie within I1kilometres of th’: Group volcanic suite and to rest on deformed shales of the Ashcroft Canadian National Railway at McAbee or Ashcroft and are within .3 Formation (Drysdale,1914, page141; Duffell and McTaggart. kilometres of the Trans-Canada Highway. 1952, page 67; Monger, 1982). the rhyolite locally has vertical or Sources of glassyvolcanic rocks, potentially suitable for outward dipping contac:ts and shales within a metre of its margin are pozzolan, occur within the watershed vf Arrowstone Creek anti 011 contact metamorphosed. All of these occurrences of rhyolite are Tsilsalt Ridge. probably intrusive into pre-Eocene hut not Eocene rocks, suggest- ing that the earliest phase of vulcanism in the Kamloops Group was acidic STRATIGRAPHY AND STRUCTURE, White, wdtdain, crystdl-rich (biotite. hornblende, quartz, feld- OF HAT CREEK BASIN Spar) vitric tuff locally forms thin basal lenses of Eocene sediments, The Hat Creek basin consistl

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