Porphyry Integration Project: Combining British Columbia’s Wealth of Datasetswith Modern Exploration Geoscience at the District Scale to Provide New Insight

into Porphyry-Deposit Exploration Strategies

F. Devine, Mer lin Geosciences Inc., Atlin, BC, fdevine@merlingeo.com

Devine, F. (2011): Por phyry In te gra tion Pro ject: com bin ing Brit ish Columbia’s wealth of datasets with mod ern ex plo ra tion geoscience atthe dis trict scale to pro vide new in sight into por phyry-de posit ex plo ra tion strat e gies; in Geoscience BC Sum mary of Ac tiv i ties 2010,Geoscience BC, Re port 2011-1, p. 1–4.

Introduction

Brit ish Co lum bia is home to one of the world’s ma joralkalic por phyry dis tricts and also hosts nu mer ous calc-alkalic por phyry de pos its. The ma jor ity of cop per pro duc -tion in the prov ince since the 1960s has come from por -phyry de pos its and six of the top ten pro duc ing or past-pro -duc ing cop per mines in BC are por phyry de pos its (BCMin is try of For ests, Mines and Lands, 2010). These de pos -its also con tain other met als as the pri mary or sec ond arycom mod ity, in clud ing mo lyb de num, gold and sil ver. The dis -covery re cord has proven Stikine and Quesnel arc ter ranesto be two of the most pro spec tive geo log i cal ter ranes in BCfor por phyry de pos its. Over 2000 por phyry-re lated show -ings, pros pects, de vel oped pros pects and de pos its havebeen re ported in BC (BC Geo log i cal Sur vey, 2010; Fig -ure 1).

The geo log i cal di ver sity of por phyry de pos its within theprov ince has proven in trigu ing to re search ers, and has pro -vided chal leng ing com plex ity to ex plor ers. Por phyry Cu-Mo-Au, Cu-Au, Cu-Mo, Mo de pos its, and tran si tional vari -a tions thereof, oc cur with vary ing ig ne ous as so ci a tions aswell as within lim ited, but vari able, geo log i cal hostrocks.More over, the geo log i cal pro cesses at work in the dif fer entphys io graphic re gions of the prov ince ef fec tively al ter their surficial sig na tures. With the va ri ety in type, age and ge ol -ogy of BC’s por phyry de pos its, ex plo ra tion for this de posittype can be a chal lenge, but de cades of ex plo ra tion his tory,com bined with new geoscience data, can pro vide di rec tionand sub tle in di ca tors, which may be used as guides to lo cat -ing de pos its. Un der stand ing the geo log i cal char ac ter is ticsof BC por phyry de pos its and de vel op ing new ex plo ra tioncri te ria are fundamental to making new discoveries anddeveloping these prospects into the mines of the future.

Recent Developments in the Understanding ofBC Porphyry Deposits

Over the past sev eral de cades, there has been sig nif i cantad vance ment in the un der stand ing of BC’s por phyry sys -tems. In the 1990s a ma jor por phyry-de posit re search pro -ject was un der taken by the Min eral De posit Re search Unit(MDRU) of the Uni ver sity of Brit ish Co lum bia, which ledto ad vance ments in the un der stand ing of the char ac ter is ticsand re gional tec tonic as so ci a tions of sev eral BC por phyryCu-Au de pos its. The widely known spe cial vol ume pub -lished by the Ca na dian In sti tute of Min ing, Met al lurgy andPe tro leum in cluded 69 pa pers con tain ing de scrip tions ofpor phyry and por phyry-re lated de pos its in West ern Can ada and the United States (Schroeter, 1995). Sev eral re centstud ies by the BC Geo log i cal Sur vey have fur ther ex am -ined the set ting of cer tain por phyry de pos its and re gionalgeo log i cal map ping pro jects have con tin ued to de fine there gional tec tonic set ting of por phyry sys tems in BC (e.g.,Nixon and Peatfield, 2003; Lo gan et al., 2007). Fur ther -more, re cent re search on alkalic de pos its in BC car ried outun der the alkalic re search pro ject jointly run by MDRU and the Cen tre for Ore De posit Re search of the Uni ver sity of Tas -ma nia (Cham ber lain et al., 2007) has led to the de vel op -ment of de pos its mod els for sev eral key de pos its, in clud ingMount Polley, Mount Milligan and Ga lore Creek.

In ad di tion to sci en tific ad vance ments, ex plo ra tion datasets and in-house com pany knowl edge of por phyry de pos itshave been grow ing as the re sult of over 50 years of por -phyry-fo cused ex plo ra tion. In dus try has con ducted de -tailed geo phys i cal and geo chem i cal sur veys, as well asgeo log i cal map ping and drill ing on nu mer ous prop er ties.Some of this data has been filed in the BC as sess ment re port sys tem (ARIS), which hosts a wealth of data from over 60de cades of ex plo ra tion. Even more data is stored withincom pany da ta bases that are not currently available to thepublic.

Building on QUEST

The avail abil ity and use of high-qual ity, re gional datasetshas vastly ex panded since the ad vent of dig i tal-files datacol lec tion, dis tri bu tion and stor age. Geoscience BC’s

Geoscience BC Re port 2011-1 1

Keywords: por phyry de pos its, data com pi la tion, in te gra tion, ex -plo ra tion tar get ing

This pub li ca tion is also avail able, free of charge, as col our dig i talfiles in Adobe Ac ro bat® PDF for mat from the Geoscience BCwebsite: http://www.geosciencebc.com/s/DataReleases.asp.

QUEST, QUEST-South and QUEST-West pro jects havegen er ated a sig nif i cant vol ume of new data cov er ing keyparts of the Stikine and Quesnel ter ranes, in clud ing air -borne-grav ity and elec tro mag netic (EM) sur veys, as wellas geo chem i cal anal y ses of new, and reanalyzed, stream-and lake-sed i ment sam ples. Geoscience BC has also re -

cently funded many stand-alone pro jects fo cused on de vel -op ing por phyry-de posit ex plo ra tion tech niques (e.g., Cookand Dunn, 2007; Dunn et al., 2007; Bouzari et al., 2010;Heberlein, 2010; Heberlein and Sam son, 2010; Mitchinson and Bissig, 2010; Heberlein and Dunn, 2011; Mitchinsonand Enkin, 2011).

2 Geoscience BC Sum mary of Ac tiv i ties 2010

Fig ure 1. Dig i tal el e va tion model of Brit ish Co lum bia show ing the lo ca tion of pro duc ing por phyry de pos its and ‘por phyry-style’ min er al -iza tion (Ca na dian Coun cil on Geomatics, 2004; BC Geo log i cal Sur vey, 2010). Clas si fi ca tion of oc cur rences fol lows the tec tonic-re -lated di vi sions high lighted by McMillan et al. (1995). Al though found else where within BC, por phyry min er al iza tion is most com monlyas so ci ated with the Stikine (green) and Quesnel (or ange) ter ranes, high light ing the prospectivity of these ter ranes for ad di tional dis cov -er ies. Blue out lines cor re spond to the por phyry dis tricts of in ter est that are cur rently un der con sid er ation by the pro ject team. Ul ti mately, dis tricts will be cho sen to rep re sent the spec trum of BC por phyry-de posit types (not all dis tricts out lined in Fig ure 1 will be in cluded in the fi nal pro ject).

The his tory of por phyry re search and ex plo ra tion in BC,com bined with im proved un der stand ing of por phyry sys -tems and sig nif i cant new re gional datasets, as well as de -tailed stud ies of de pos its and as sess ment of suit able ex plo -ra tion tech niques, cre ates an op por tu nity to in te grate thesenew datasets and knowl edge into a com pre hen sive BC por -phyry-de posit exploration framework.

Project Approach

The Por phyry In te gra tion Pro ject is based on a ‘por phyrysig na ture’ con cept. The in ten tion is to iden tify geo log i calchar ac ter is tics at the dis trict scale that will help lead to theiden ti fi ca tion of con tained de pos its. By study ing sev eralrel a tively ma ture dis tricts, some of which have pro duc ingmines, the pro ject team will ben e fit from know ing wherethe por phyry de pos its lie within those dis tricts and have ac -cess to his tor i cal ex plo ra tion data col lected within the dis -trict, both ad ja cent to and re mote from the known de -posit(s). The goals of the pro ject are to com pile, in te grateand in ter pret dis trict-scale in for ma tion in the con text of there gional-scale data con tained in in dus try, ac a demic andpub lic geoscience datasets; it fur ther aims to pro vide ex plo -ra tion guide lines di rectly use ful to ex plo ra tion com pa niesin vectoring to por phyry de pos its in comparably unknowndistricts as they follow up on regional-scale targeting pro -grams.

The dis trict-scale fo cus is key to the pro ject model. Thepro ject will not at tempt to con duct de tailed re search on in -di vid ual de pos its; it will in stead con cen trate on the in ter -me di ate scale, in be tween the de tailed de posit or prop ertyscale, which is the fo cus of in dus try, and the more ex pan -sive re gional scale, which is the fo cus of pub lic geoscienceagen cies. The dis trict scale is fa mil iar to ex plor ers work ingon min eral prop er ties and the prod ucts gen er ated throughthis pro ject will be di rectly com pa ra ble to those pro duced at the min eral-ex plo ra tion pro ject scale, thereby being ofimmediate use to explorers.

Datasets for com pi la tion and in te gra tion in clude, but arenot lim ited to

· geo log i cal map ping (BC Geo log i cal Sur vey and Geo -log i cal Sur vey of Can ada re gional map ping; prop erty-scale mapping);

· BC MINFILE min eral oc cur rences;

· re mote-sens ing data;

· re gional geo phys i cal sur veys, in clud ing re cent re gionalGeoscience BC and Nat u ral Re sources Can ada air -borne-grav ity and mag netic surveys;

· prop erty-scale geo phys i cal sur veys, in clud ing in duced-po lar iza tion, EM and mag netic datasets;

· re gional geo chem i cal sur veys;

· soil sur veys us ing var i ous ex trac tion tech niques;

· stream-sed i ment sur veys;

· whole-rock geo chem is try; and

· de tailed de posit re search, in clud ing iso tope- and min -eral-chem is try stud ies.

Lay er ing and ma nip u la tion of dig i tal data will en able aneval u a tion of any trends and fea tures vis i ble in the datasets,and as sist the pro ject team with ac cess ing their abil ity to ef -fec tively rec og nize the lo ca tion of de pos its in a given dis -trict. Based on this eval u a tion, the pro ject team will en -deavour to de velop a set of geo log i cal, geo phys i cal andgeo chem i cal tools and tech niques, which can be ap plied toporphyry exploration in other districts.

Porphyry Districts of Interest

Six teen dis tricts of in ter est have been iden ti fied (see Fig -ure 1) and com pi la tion is un der way to eval u ate the pub licdatasets and po ten tial com pany datasets that ex ist in each of these ar eas. A lim ited list of dis tricts will be cho sen to be the fo cus of this pro ject, se lec tion of which will de pend on theavail abil ity, qual ity and breadth of data.

Project Deliverables

Planned prod ucts of the pro ject in clude a hard-copy at las ofmaps for each dis trict se lected and guides to de posit char ac -ter is tics, as well as rec om men da tions on ex plo ra tion toolsand tech niques. The scale of maps be tween dis tricts will beheld con stant to max i mize the abil ity to com pare and con -trast data be tween map sets. As por phyry de pos its of dif fer -ent classes and age (e.g., alkalic Cu-Au, Cu-Mo, Mo; Tri as -sic–Ju ras sic ver sus Cre ta ceous) will be in te grated, some ofwhich oc cur in dif fer ent phys io graphic re gions, the abil ityto com pare be tween de pos i ts is im por tant to theeffectiveness and usefulness of the final product.

Project Team

The pro ject is a col lab o ra tive ef fort be tween GeoscienceBC and the MDRU at the Uni ver sity of Brit ish Co lum bia.The three branches (ge ol ogy, geo phys ics and geo chem is -try) of the pro ject all con trib ute to the com plete in te gra tionof data on each dis trict and will rely on the ex per tise pro -vided by Geoscience BC con sul tants and MDRU re search -ers. D. Heberlein (Heberlein Geoconsulting and Geo -science BC pro ject team) and F. Blaine (MDRU) will bere spon si ble for the geo chem i cal com po nents of the pro ject.D. Heberlein, an ex pert in geo chem is try-driven ex plo ra tion tar get ing, re cently com pleted two Geoscience BC-fundedpro jects fo cused on test ing the ef fec tive ness of geo chem i -cal meth ods in iden ti fy ing bur ied por phyry de pos its in cen -tral Quesnellia (Heberlein, 2010; Heberlein and Sam son,2010). F. Blaine is cur rently work ing on a Geoscience BC-spon sored pro ject en ti tled “Geo chem i cal Mod els for BCPor phyry De pos its: Out crop ping, Blind and Bur ied Ex am -ples” (http://www.geosciencebc.com/s/2009-048.asp).P. Kowalczyk (Mira Geoscience and Geoscience BC pro -ject team) and D. Mitchinson (MDRU) will be re spon si ble

Geoscience BC Re port 2011-1 3

for the geo phys i cal com po nents. P. Kowalczyk, a lead ingau thor ity on geo phys i cal tech niques ap plied to min eral ex -plo ra tion, has over 40 years of ex pe ri ence in BC min eralex plo ra tion. D. Mitchinson is near ing com ple tion on aGeoscience BC-sup ported post-doc toral re search pro jecten ti tled “In te grated Geo log i cal and Geo phys i cal Por phyryMod els: Add ing Value to Geoscience BC Geo phys i calData” (see Mitchinson and Bissig, 2010; Mitchinson andEnkin, 2011; http://www.geosciencebc.com/s/2009-001.asp). F. Devine (Mer lin Geosciences Inc. andGeoscience BC pro ject team) and T. Bissig (joint MDRU-Geoscience BC re searcher) will be re spon si ble for the geo -log i cal com po nents. F. Devine has ex per tise in re gional- toprop erty-scale ge ol ogy eval u a tion and ex pe ri ence in re cent por phyry Cu-Au ex plo ra tion and re search in BC. T. Bissigis lead ing the MDRU porphyry Cu-Au- and epithermal Au-deposit projects and brings global experience in porphyry-deposit research, including expertise on BC’s alkalicporphyry Cu-Au deposits.

Summary

This pro ject will be among the first to de velop a com pre -hen sive and com par a tive view of new multidisciplinarydatasets on key BC por phyry de pos its, spe cif i cally fo cusedon ex plo ra tion strat egy. Data com pi la tion is un der way with dis tricts cho sen for com pi la tion and in te gra tion by the endof 2010. Dis trict dataset de vel op ment will con tinuethrough 2011, with all prod ucts to be avail able in early2012. New in for ma tion on this pro ject will be avail ablethrough the Geoscience BC website (www.geosciencebc.com ).

Acknowledgments

The dig i tal el e va tion model in Fig ure 1 was pre pared byK. Shimamura of the Geo log i cal Sur vey of Can ada and thebase map was pro vided by F. Ma of Geoscience BC.

References

BC Geo log i cal Sur vey (2010): MINFILE BC min eral de pos its da -ta base; BC Min is try of For ests, Mines and Lands, URL<http://www.Minfile.ca> [No vem ber 2010].

BC Min is try of For ests, Mines and Lands (2010): Cop per in Brit -ish Co lum bia; BC Min is try of For ests, Mines and Lands, In -for ma tion Cir cu lar 2010-4.

Bouzari, F., Hart, C.J.R., Barker, S. and Bissig, T. (2010): Por -phyry in di ca tor min er als (PIMs): ex plo ra tion for con cealedde pos its in south cen tral Brit ish Co lum bia (NTS 092I/06,093A/12, 093N/01, /14); in Geoscience BC Sum mary of Ac -tiv i ties 2009, Geoscience BC, Re port 2010-1, p. 25–32.

Ca na dian Coun cil on Geomatics (2004): Ca na dian dig i tal el e va -tion data; Nat u ral Re sources Can ada, GeoBase®, URL<http://www.geobase.ca/geobase/en/data/cded/description.html> [Oc to ber 2004].

Cham ber lain, C.M., Jack son, M., Jago, C.P., Pass, H.E., Simpson,K.A., Cooke, D.R. and Tosdal, R.M. (2007): To ward and in -te grated model for alkalic por phyry cop per de pos its in Brit -

ish Co lum bia (NTS 093A, N; 104G); in Geo log i cal Field -work 2006, BC Min is try of For ests, Mines and Lands, Pa per2007-1, p. 259–273.

Cook, S.J. and Dunn, C.E. (2007): A com par a tive as sess ment ofsoil geo chem i cal meth ods for de tect ing bur ied min eraldeposits—3Ts Au-Ag pros pect, cen tral Brit ish Co lum bia;Geoscience BC, Re port 2007-7, 226 p., URL <http://www.geosciencebc.com/i/project_data/GBC_Report2007-7/2007-7_Report.pdf> [No vem ber 2010].

Dunn, C.E., Cook, S.J. and Hall, G.E.M. (2007): Halo gens in sur -face ex plo ra tion geo chem is try: eval u a tion and de vel op ment of meth ods for de tect ing bur ied min eral de pos its;Geoscience BC, Re port 2007-10, 62 p., URL <http://www.geosciencebc.com/s/2007-10.asp> [No vem ber 2010].

Heberlein, D.R. (2010): An as sess ment of soil geo chem i cal meth -ods for de tect ing cop per-gold por phyry min er al iza tionthrough Qua ter nary glaciofluvial sed i ments at the WBX-MBX and 66 zones, Mt. Milligan, north-cen tral Brit ish Co -lum bia; Geoscience BC, Re port 2010-8, 68 p., URL <http://www.geosciencebc.com/s/2010-008.asp> [No vem ber2010].

Heberlein, D.R. and Dunn, C.E. (2011): Pre lim i nary re sults of aveg e ta tion, Ah-horizon soil and char coal geo chem i cal in -ves ti ga tion at the Kwanika Cen tral zone, north-cen tral Brit -ish Co lum bia (NTS 093N/19), in Geoscience BC Sum maryof Ac tiv i ties 2010, Geoscience BC, Re port 2011-1, p. 5–16.

Heberlein, D.R. and Sam son, H. (2010): An as sess ment of soilgeo chem i cal meth ods for de tect ing cop per-gold por phyrymin er al iza tion through Qua ter nary glaciofluvial sed i mentsat the Kwanika cen tral zone, north-cen tral Brit ish Co lum -bia; Geoscience BC, Re port 2010-3, 89 p., URL <http://www.geosciencebc.com/s/2010-003.asp> [No vem ber2010].

Lo gan, J.M., Bath, A., Mihalynuk, M.G., Rees, C.J., Ullrich, T.D.and Fried man, R. (2007): Re gional ge ol ogy of the MountPolley area, cen tral Brit ish Co lum bia; Min is try of For ests,Mines and Lands, Geoscience Map 2007-1.

McMillan, W.J., Thomp son, J.F.H., Hart, C.J.R. and Johnston, S.T. (1995): Re gional geo log i cal and tec tonic set ting of por -phyry de pos its in Brit ish Co lum bia and Yu kon Ter ri tory; inPor phyry De pos its of the North west ern Cor dil lera of NorthAmer ica, T.G. Schroeter (ed.), Ca na dian In sti tute of Min ing, Met al lurgy and Pe tro leum, Spe cial Vol ume 46, p. 41–57.

Mitchinson, D.E. and Bissig, T. (2010): En hanc ing geo phys i calin ter pre ta tion and min eral de posit mod el ling throughknowl edge of phys i cal rock prop er ties: mag netic sus cep ti -bil ity stud ies for por phyry de pos its in the QUEST andQUEST-West ar eas (NTS 93E, K, N); in Geoscience BCSum mary of Ac tiv i ties 2009, Geoscience BC, Re port 2010-1, p. 53–64.

Mitchinson, D.E. and Enkin, R.J. (2011): Con tin ued in ves ti ga -tions of phys i cal property–geology re la tion ships in por -phyry-de posit set tings in the QUEST and QUEST-Westpro ject ar eas, cen tral Brit ish Co lum bia (NTS 093E, K, L, M, N); in Geoscience BC Sum mary of Ac tiv i ties 2010,Geoscience BC, Re port 2011-1, p. 17–32.

Nixon, G.T. and Peatfield, G.R. (2003): Geo log i cal set ting of theLorraine Cu-Au por phyry de posit, Duck ling Creek SyeniteCom plex, north-cen tral Brit ish Co lum bia; Min is try of For -ests, Mines and Lands, Open File 2003-4, 24 p.

Schroeter, T.G., ed i tor (1995): Por phyry De pos its of the North -west ern Cor dil lera of North Amer ica; Ca na dian In sti tute ofMin ing, Met al lurgy and Pe tro leum, Spe cial Vol ume 46.

4 Geoscience BC Sum mary of Ac tiv i ties 2010