25. SOME ASPECTS OF INTEGRATED EXPLORAnON

J.A. CoopeNewmont Exploration of Canada Ltd., Toronto, Ontario

M.J. DavidsonNewmont Exploration Ltd., Tucson, Arizona, U.S.A.

Coope, J.A., and Davidson M.J., Some aspects of integrated exploration; in Geophysics andGeochemistry in the Search for Metallic Ores; Peter J. Hood, editor; GeologicalSurvey of Canada.Economic Geology Report 31, p. 575-592, 1979.

Abstract

For many years. regional techniques of mineral exploration incorporating airborne geophysicalmethods and other remote-sensing techniques applied to identifY broad geological parameters havebeen used under a variety of geological and geomorphological conditions. Such use of disciplines hasserved to broadly classify areas based primarily on broad features such as physical properties andprospective mineral potential.

The better understanding of the geological processes leading to the formation of mineraldeposits, together with the enterprising development of geophysical, geochemical and other types ofexploration tools during recent years, has provided a basic framework for an integrated applicationof techniques on a more detailed scale and with the potential of improved cost and explorationeffectiveness.

Variations in geophysical and geochemical backgrounds can provide critical data which serve toelucidate geological interpretation and the evaluation of anomalous conditions. The variations arecommonly related to primary geological features or larger scale, ore-forming processes and canyield critical information when the connection is recognized and properly interpreted. Magnetic,resistivity. electrical, lithogeochemical and other selected techniques are particularly adaptable inthis more detailed integrated application.

Different disciplines and data-gathering methods within disciplines can yield the same orequivalent information interpretable in a geological context. However, recognition of the physio­chemical fingerprint of an ore environment requires a mUltidisciplined. integrated approach whensignatures observed from anyone discipline are too subtle to generate adequate confidence levels bythemselves. In any particular situation there is a sequence of application and areal coverage whichwill define targets at a minimum cost.

Resume

Depuis plusieurs annees, on utilise des techniques regionales d'exploration miniere. integrantdes methodes geophysiques aeroportees et autres techniques de teledetection pour definir desparametres geologiques larges dans divers milieux geologiques et geomorphologiques. Ces disciplinesont servi a definir grosso modo des zones, surtout en fonction de leurs caracteres physiques et deleur potentiel minier.

Une meilleure comprehension des processus geologiques qui engendrent des gites mineraux, etla mise au point ces dernieres annees de methodes d'exploration geophysique, geochimique et autres.permettent d'integrer les diverses techniques a une echelle plus detaillee et sans doute de reduire lescouts et de rendre l'exploration plus efficace.

Les variations du fond geophysique et du fond geochimique peuvent fournir des donneesessentielles pour l'interpretation geologique et l'evaluation des anomalies. Ces variations sontgeneralement liees a des elements geologiques prima ires ou. a une echelle plus grande, a desprocessus de genese des gites mineraux. £lIes peuvent aussi apporter des renseignements essentielslorsque la correlation est reconnue et proprement interpretee. Les methodes magnetique, deresistivite, electrique, lithogeochimique et autres techniques appropriees peuvent facilement etreintegrees. a une echelle plus detaillee.

Les differentes disciplines et les methodes de recueil des donnees dans ces disciplines peuventdonner les memes renseignements ou des renseignements equivalents, qui peuvent etre interpretesdans un contexte geologique. Cependant, l'identification des caracteres physico-chimiques d'unmilieu mineral eXige que l'on adopte une approche pluridisciplinaire et integree. lorsque lesobservations recueillies au moyen d'une methode particuliere sont trop peu convaincantes. Danstoute situation, on peut adopter une serie de procedes. et un mode de couverture aerienne, demaniere a definir les objectifs d'exploration au cout Ie plus bas possible.

576 J.A. Coope and M J -•. DavIdson

v»»~45° ,76

0 1536

Integrated Exploration 577

DESCRIPTIVE NOTES

C;Cale 1:25,000

ISOMAGNETIC LINES (absolute total field)

O'''.'''W10''''[.C'.'''"''''D.'SOURC'S

"'MS]{.' O,,·,.,RGILO" "",s " O"RES>CIURCES

INTRODUCTION

The predominant preoccupation of the Exploration '77 Symposium withgeochemical and geophysical methods should not detract attention from thefundamental foundation of mineral exploration which is a knowledge andunderstanding of the geology of mineral environments. Significant advances inthe geological understanding of mineral environments have been made in thepast 20 to 25 years. These advances which reflect a greater understanding ofthe processes of mineralization and the localization of economic quantities ofmetals, provide the basic foundation for the development, refinement andsophistication of mineral exploration techniques. All interpretations, whetherbased on geophysical or geochemical measurements, must relate to geology tobe meaningful and, consequently, neither the exploration geochemist nor theexploration geophysicist can f'Jnction independently of the explorationgeologist.

Exploration is progressive. In many parts of the world, the last twodecades have been marked by the rapid development and application of manyexploration geophysical and exploration geochemical techniques. Many of thesedevelopments have been extremely successful and have directly indicated sub­outcropping or near-surface orebodies and extended the search capabilities intoareas of extensive cover and difficult accessibility.

This period of rapid development and success nurtured, among many, areliance on the airborne EM method or the stream sediment method or someother technique to identify "anomalies" for detailed geological scrutiny. In somelocalities, e.g. the Bathurst Camp, New Brunswick, this approach to explorationled to the establishment of several mining operations in areas where thegeological controls on the mineral deposits were poorly known or misunderstood.Follow-up studies in these areas have corrected this imbalance. As timeprogresses, and, as it becomes apparent that additional ore reserves in theseregions will only be found in blind deposits at increasing depths beyond thelimits of detection by conventional geochemical and geophysical methods, theimportance of geology becomes overwhelminliJ and new exploration tools have tobe applied based on the latest geological understanding of the mineralenvironment of interest.

It has been proven many times that, for some combination of geological orother reasons, an orebody of the type sought will not respond dramatically to aspecific exploration technique, and will not produce a prominent anomaly. Totalreliance on a geophysical or geochemical tool as the leading technique in anexploration program is therefore predestined to imperfection.

The example provided by the discovery of the South Bay orebody atConfederation Lake in northwestern Ontario where a relatively weak airborneINPUT anomaly became enhanced by the interpretation of the geologicalrelationships in nearby outcrops, illustrates the advantage of the integration ofgeological mapping and interpretation into the exploration sequence. Knowledgeof geology and an understanding of mineral environments serves to classifyanomalies detected by the application of geophysical and geochemicaltechniques much more satisfactorily than does reliance on the magnitude of aphysical or chemical concentration.

To many, these comments will appear to be a statement of the obvious.Nevertheless, the fundamental consideration of geology must be emphasized inthe context of good exploration practice. This contribution is intended toillustrate how thoughtful integration of geological expertise with theenterprising development and application of geochemical and geophysical

THE IMPORTANCE OF GEOLOGY

Effective "integrated exploration" requires communication andco-operation between the various mineral exploration disciplines. The conceptof integrated utilization of exploration methods and tools can be applied on allscales - from the regional reconnaissance of large geographic areas to verydetailed application in the search for extensions of known orebodies. A reviewof this broad field would require consideration of the techniques that have beenreviewed during the Exploration '77 Symposium together with several explora­tion methods which have not. The latter methods include the practicalapplication of trenching, percussion and diamond drilling, and isotope geologyand geochemistry.

This paper makes general reference to some fundamental aspects ofexploration integration, and numerous principles are reviewed and illustratedwhich are consistent with good exploration practice.

4000 Feel

lZOO 1800 Melres

..............~

..............~

..............~

'000

OPEN FILEDOSSIER PUBIJC

339APRil 1976

GEOLOGICAL SURVEYCOMMiSSION GEOLOGIQUE

CYrTAWA

Universel Transverse MIOrcator Proiectlo"

@CrownCOPyrillhtsrese",ed

Feet WOO

50-100 ga1Tlllas .

5 gammas .

Magnetic depression .....

Flight altitude: 500 feet above ground level

Contour interval: 5 garmnas

PART OF 31 F/7ONTARIO

TOTAL MAGNETIC FIELD

""00"" '""" """"~ CO"",,,,,, "'''0",0"' 0" """~

This total field contour map was compiled from date recorded duringaeromagnet; c survey operat ions by a seIf-ori ent i nlJ rub; dium-vapourmagnetometer which was installed in the tail stinger of a BeechcraftB80 Oueenair aircraft. The data was digitally-recorded with aresolution of 0.02 galllllas. A second boom mounted above the tailstinger at a distance of 2.08 metres forms a vertical gradiometersystem.

The data was edited. compiled, levelled and gamma values forcontouring interpolated on a square grid (0.1" grid spacing at thepublished map scale) by automatic computer processes.

The automatic levelling process employs the two components of thedouble control line and the short segments of traverse which connectthem where they are not exactly co-incident. This data is used -tominimize and distribute non-geological contributions from the totalmagnetic field profile along the control 1ine. The corrected controllines are used to level the traverse by a method of minimal s\lm­total adjustment.

Fl ight altitude was 500 feet above ground at 1000 feet averageflight line spacing and double control lines were flown at anaverage spacing of 4 miles.

The final grid was contoured and plotted using the automatic contour­ing program and digital plotter facil Hies of the Departmerit ofEnergy. Mines and Resources. Computer Science Centre.

Airborne survey was carried out in April 1975 and digital compilationby Resource Geophysics and Geochemistry Division. Geological Surveyof Canada. The Queenair aircraft of the Geological Survey of Canadawas flown under contract to Kenting Earth Sciences Ltd.

No correction has been made for regional variation.

The photo and map base for this map was compiled by Survey and t-1appingBranch. Department of Energy. Mi nes and Resources.

578 J.A. Coope and M.J. Davidson

Figure 25.2. Vertical gradient magnetic map of part of NTS 31 F/7 southern Ontario.(Reproduced from Hood et aI., 1976.)

Integrated Exploration 579

DESCRIPTIVE NOTES

This map is based on in-flight digitally recorded high sensitivityaeromagnetic data obtained with two self-orientlng Rubidium vapourmagnetometers installed in twin tail booms inboard a Beechcraft B80aircraft. The magnetometer heads are -separated by a di stance of2.08 metres with each measuring the total magnetic field to aresolution of 0.02 ganmas.

Flight altitude was 500 feet above ground at 1000 feet average flightline spacing and double control lines were flown at an average spacingof 4 miles.

methods can accommodate the demands of our expanding societies for thediscovery of elusive economic mineral deposits in a selection of environ­ments. In addition, examples will highlight how penetrative interpretation ofgeophysical and geochemical data can extend the understanding of geologicalrelationships at depth or beneath overburden beyond the direct observation ofthe geologist.

Scale 1:25,000

Uni~e.s.1 n.nsverse Me.e.to. P,oj.ctlon

@CrownCopy.ishts.eserlled

INTEGRATED EXPLORATION

Opinions as to what constitutes "integrated exploration" vary widely.Actually, many who consider themselves to be adherents, are taking onlypartial advantage of the benefits and cost-effectiveness that full integrationoffers. True integrated exploration does not begin at some late stage in anexploration program after a geophysical or geochemical (or some other)survey has been completed. The full benefits can only be obtained whenintegration is effected at the earliest stage of the program. At this time thegeologist should raise all the possible geological questions whose answers maybe significant to the program, and the geophysicist and the geochemist shouldconsider Ute various techniques which are capable of providing partial orcomplete answers to these questions under the conditions of the proposedsurvey. It is a rare case when a given type of geophysical or geochemicalsurvey cannot provide answers to more than one geological question providedthe survey planners are aware of these multiple questions in time to designappropriate field procedures.

Geophysical Aids to Geological Mapping

The geophysicist must convert field data into physical propertyrepresentations that can be communicated and which are consistent withgeneral geological principles and with whatever is known about the geology.The step from physical proIJerty maps to interpreted geology is bestperformed by the geologist and the geophysicist working jointly. To functionefficiently in this fashion the geologist must be aware of the physicalproperties associated with various geological units, even to the extent ofmapping these properties in the field regardless of whether or not they appearto be of economic significance. This would include such features as magnetitecontent, total sulphide content, the presence of bentonitic clays, graphite,magilmenite exsolution crystals, porosity and apparent resistivity contrasts.During the process of interpretation, the geophysicist is aware of theconfidence levels associated with various physical property representationsand is best equipped to modify these towards greater consistency with theemerging geological picture. The geologist, on the other hand, is bestequipped to assess the confidence levels associated with the geologicalinformation and to formulate the overall geological model or models mostconsistent with all the observations.

Geophysical methods are often classified as "direct" when they are usedto sense economic mineralization and "indirect" when they provide moregeneral geological information. It is important to realize that this distinctionis not inherent in the method but in the questions asked of the method. It isalso important to appreciate that many anomalous responses which appear tomask or obscure the direct detection of mineralization are capable of yieldingsignificant geological information. So called "geological noise" can beconverted into a geological signal by merely asking the right question.

For example, consider a case where IP was being used to outlineSUlphide mineralizaiton in a thick sequence of dolomites. A large formationalIP response in the general area of the known mineralization was found to bedue to carbonaceous material in a black fetid dolomite. Recognizing that thedepositional environment of the dolomite was ideal for the precipitation ofmetallic sulphides if the metal ions entered the reducing basin, the IPprogram was expanded with broad-spaced regional lines to locate and mappaleochemical environments.

In the search for uranium-bearing roll fronts in sedimentary basins, thefirst phase is commonly groundwater hydrogeochemistry to establish areas ofanomalous uranium and radon. The second phase could be resistivity surveyingto map quickly and cheaply the meandering sand channels and establish sandthicknesses. In certain environments where pyrite has been deposited near rollfronts and where bentonitic clays are not ubiquitous, IP can be used to reducethe area where drilling is required.

COMMISSION aOLOGIQUE DU CANADAGEOlOGICAL$URVEYOfCANADA r

OPEN FILEDOSSIER PUBLIC

339APRil 1976

GEOLOGICAL SURVEY

COMMlSSION GEOLOGIQUE

OTtAWA

The data was edited, compiled. levelled and gradient values for contour­ing interpolated on a square grid (0.1" grid spacing at the publishedrr.ap scale) by automatic computer processes.

The vertical gradient data was filtered with a digital operator toremove noise spikes and instrument hash. The vertical gradientdata from the tie lines was not used to compile the map, instead eachline was individually adjusted as required.

The final grid was contoured and plotted usinQ the automatic contour­ing program and digital plotter facilities o( the Department ofEnergy. Mi nes and Resources. Computer Sci ence Centre.

Airborne survey was carried out in A.pril 1975 and digital compilationby ~esource Geophysics and Geochemistry Division, Geological Surveyof Canada. The Queenair aircraft of the Geoloqical Survey of Canadawas flown under contract to Kenting Earth Sciences ltd.

The photo and map base for this map was compiled by Surveys andMappi ng Branch, Department of Energy. Mi nes and Resources.

PART OF 31 F/7ONTARIO

VERTICAL GRADIENT

EQUIPOTENTIAL LTNES (vertical gradient field)

. 5 garmnas/meter .. . ~

.1 gallJllas/meter r---/

.025 gall11las/meter (above 0.0) . /-_/

.025 garrmas/meter (below 0.0) /-.... ..'

Magnetic depression ~Flight altitude: 500 feet above ground level

Contour interval: .1 gammas/meter

Intermediate contour 1nterval between +/-l.O qarrrnas/meter:0.025 garm,as/rreter .

580

40'

J.A. Coope and M.J. Davidson

35'

Figure 25.3. Geological map of part of NTS 31 FI7 southern Ontario.(Reproduced from Hood et al.. 1976.)

25'

20'

45·10

Integrated Exploration 581

SYMROLS FOf? MINERALS AND INDUSTRIAL MATF:RIALS

Cartography by the aeological Cartograp/lY Unit, 1955

Approximate magnetic declination, 12~.N·West

Where there is lithological variation and major rock units can be classifiedaccording to resistivity contrasts, it is possible to map these units broadly withresistivity measurements made during the completion of routine IP surveys. Such anapproach has a direct application in areas of extensive overburden where thedistance between outcrops is such that geological units cannot be mapped withsatisfactory accuracy.

Magnetic surveys have, of course, been widely used to aid in the geologicalmapping of areas where sufficient magnetization contrast exists between rockunits. Two papers by Boyd (1969) and Morley (1969) in the 1967 Symposiumdocumented the capability of the magnetic, gravity and seismic methods to providesignificant geological information. Papers presented during the 1977 Symposiumand published herein described the geological mapping capability of airbornetechniques such as y-ray spectrometry (for mapping alteration in some terranes)and the potential of E Phase, Radiophase and other VLF EM methods, and highresolution aeromagnetic surveys.

The magnetic gradiometer and gradient techniques are a positive develop­ment which permit resolution of composite or complex magnetic anomalies intotheir individual constituents and, on the same basis, automatically remove theregional magnetic gradient to better define shallower features which may be ofinterest. In practice the method allows a sharper delineation of geological unitswith contrasting susceptibilities. The illustrations in Figures 25.1 and 25.2 comparegradient magnetic data with total intensity magnetic data for an area in SouthernOntario (Hood et aI., 1976) and it is immediately apparent that the gradient mapreflects the geological details (Fig. 25.3) much more precisely. Late dykes, strikingapproximately west-northwest across the granite body, are prominent in themagnetic data but were not observed during the geological survey.

The three examples cited utilizing the IP and resistivity survey responsesillustrate the adaptation of other geophysical techniques to similar mapping roles.

In a recent article, Pelton (1977) explained how a careful study of the positionand magnitude of peaks in the plot of IP phase angle versus frequency can be usedto discriminate between graphite and massive sulphide mineralization, magnetiteand nickeliferous pyrrhotite and between barren pyrite halos and disseminatedeconomic mineralization in some porphyry copper systems.

Thesc few examples illustrate, in a general way, how a more objectiveinterpretation and adaptation of conventional techniques can complement thebroader geological picture and add information that is of direct and immediatevalue in thc assessment of truly anomalous responses which may be related to ore.

There is an obvious requirement for the development of the "indirect"application of geophysical techniques in order to satisfy the need to carefullyexamine and geophysically characterize the large scale environment of knowndeposits. This expertise, when developed to a satisfactory level, can then beadapted to down-hole geophysical surveying as mine-finding exploration is extendedbelow the first hundred metres.

Geochemical Aids to Geological Mapping

It has been noted that, as exploration progresses in arells where shallowmineral deposits have been found and the search expands to explore for blinddeposits at increasing depths, knowledge and understanding of the geology ofmineral environments becomes the basis for the development and application ofsophisticated geochemical, geophysical and other techniques that may be usedeffectively in these advanced exploration programs.

As an example, one can trace the recent development of lithogeochemicalexploration methods. It became apparent early in the history of geochemicalprospecting that trace element backgrounds varied according to the lithology andcomposition of rock types. Nickel, for example, enters into the crystal structuresof olivines and copper tends to be higher in certain pyroxenes.

Oi fferent background lcvels in geochemical data in areas uncomplicated bymineralization can be correlated with rock lithologies and, in greater detail, withmineralogical associations. This correlation is obviously more direct in the case ofthe lithogeochemical method but similar correlations are possible with certain soil,stream sediment and other data sets (Fig. 25.4). Multi-element data and computerprogramming can help refine these correlations.

The correlation betwecn geochemical data and mineralogy is relatively easyto demonstrate and understand. Partial analysis or "speciation" of Ii thogeochemicalsample material can be used to differentiate qualitatively elements in differentmineral phases such as certain sulphides, silicates, and oxides.

COMMISSION GtOlOGIQUE DU CANADA

Cu Limestone LeCor Molybdenite . )(0

Dol Nepheline Ne....1 Pyrite. . .. PyOs Radioactive minerals, ,R.AU Sillimanite .. Bll

A'l1 Stone (buikJ"""J .B.BtG Strontium Sf

Kq Tour...".. li,.,.. TZinc. Zn

Copper

CorundumDolomitefddsparGravel and sand .Gold._.Gold (....p"'rte<1) ..

Grsphlte...M ..gneciteH"m..titeL....d

M"anetite orebody.

GEOLOGICAL SURVEY lJF CANADA

lJase map compiJed and drawn qy the Army Survey£ ..t.bli"hmfilnt,RC.t:. Lloepar-f:ment of National D.rer,ce

Geology by ME Wilson, 1917 '1919;G,B.Leech 1949'Rr.dH A.Quinn./950

Geological campilat""n by H A QUIrl" , 1952

Air photographs ""vering this map-a",,".. may beobcained through the Nstional Air P!>c>cographieUbr3r-y, Topogr"phicIJI Sur",..y, Otta...". Ontario

Oil'A~IMENI OF ENHIGv. MONeS ANn RESOuRCES

""~ISTf,lF DE ~'£~ER,:;';:.OES ,,"'NES " NS RES>OURC(S

Beddin(j(mcHr><>d,v.>r<icB'I·. //Bedding (d"~"tion of dip k,.,own. ""p"r ~ide of bed "nk,.,own) . YFolistion or gneissosity (in.'Olin~d.....rt.;"..I. dip "nknown) /'//

Jointing (malin<>d.v.>r<kBI) //'Drag _(ol<ls (~""'w ind"oB'"'' di.~'<ion of pJ"n<p» 2..-FaultAntic/inal ~is IB"""mt>d)Sync/in.., a;ris (B"""mt>d)Glacial "tri_.Minsral occurre~

~Hornblende schi,,~ and gneiss,hornbl"nde-biotite

1 schist, quartz-biotiCs -hornblende ,"ehist. smphibolite,d,or!tlc Bnd gBbbroic r=ks

~PO.ragne.iSS' m3i"ly biotite-garnet gn..,i,>s; biotite-horqblende gn"'"""quartz-biotite gn"""'" and schist,s,fl/manlte-garn"t gneiss;· minor quar·tzite

GRENVILL.E SERIES (i-3. interbedd'Xi)

~Crystalline e ..rl.>onate rock8 compr"''''g iim..>stone,dolomite.and dolomitic limestonei minor mecamorphicpyroxenit.,.

@ C,own Cop~ri8Msr,...",~

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OROOVIC,.NU . BLACK RIVJ;:R AND TRENTON

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LEGEND

jQUATERNARY

PLEISTOCENE (mainly)

~ ":: i~·:·:·: CHAMPLAIN BEDS- mainty marine clBy, ",ien minorN ~ :::.j sand; 14a, marine ""nd; minor gravel ,,,,,1 clayo .

~ (877:.'1 GLACIAL DRIFT (mamly);errat/<;;s,boulder clay, gravel,lLJL:: ::~~: :;a~,C::::r/;'~::~dm;;'::;/lecent ueposlts or 9ravel

E'-'J+ •••+ e. Syenite, porphyritic ,..,Yenite

+ + ...

K:>T:.~ -J 7A.Granite, granodiorite (not markedly banded);

~_ ';'~~~::~;;;i~;c~::;"::;gr8nite and r;ranodiorite

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~ ~!S.• ] 5A. Mired :OCk,q (in part hybrid gnel_",,,,ea,rnigmatites}% ~ S8.Nephel,ne_Blb,u. gneiss

~.-< BRISTOL (HASTlNlGSt) SEltlES

~Thinly banded st>dimentary rocks, fin ..-grained,

4 blUish grey lim"",rone; green to black ehloritieschists and ptjyll,r;es .. quartzite

7igure 25.4. Relationship between geology and the patternof nickel in residual soil, Nguge Region, Tanzania. (Colluvialand alluvial overburden occur flanking main rivers.) AfterCoope (1958) Courtesy Hawkes, H.E. and Webb, J.S., (1962)'Geochemistry in Mineral Exploration', Harper and Row, NewYork, N.Y.

For many years, geochemical exploration was concernedprimarily with the measurement of trace element quantities.With the advance of analytical expertise, major elementanalysis has become incorporated into the exploration geo­chemical spectrum. More recent instrumental adaptation,particularly the XRD method, has allowed the quantitativemeasurement of minerals, and the work of Hausen and Kerr(1971), and Figures 25.5A to 25.5D and Franklin et a!. (1975)has clearly shown the adaptation of this method to mapquantitatively the distribution of alteration minerals.

Franklin and his co-authors (1975), utilizing XRDtechniques, have identified a pipelike alteration zone char­acterized by manganiferous siderite extending at least 300 mdirectly below the Mattabi massive sulphide deposit. Copperand zinc are concentrated in anomalous proportions in theupper central part of the pipe. The distribution of siderite anddolomite is shown in Figures 25.6 and 25.7. Figure 25.8 is acomposite illustration of the generalized distribution ofalteration and mineralization based on the Franklin et a!.studies.

Quantitati ve XRD geochemistry plus trace and majorelement data can geochemically describe a geologicalenvironment and complement geological observation and

582

v

~ 1000 feel -----1

~Picrile

IV",vvvl Olivine norile

Iv vvI Anorthosite

c==J Gneiss

r,,·:.'·J Quartzite

J.A. Coope and M.J. Davidson

understanding by portraying subtle or invisible variationswhich might otherwise go unnoticed. In the mineralizedenvironment of the volcanogenic massive sulphide deposit, forexample, the portrayal would reveal alteration patterns ofchloritic, sericitic, feldspathic, carbonate and silica intensitywhich are, in part, visible and, in part, invisible to the eye ofa trained geologist plus major and trace element variations inprimary dispersion patterns indigenous to or, superimposedon, geochemical backgrounds related to rhyolitic andandesitic volcanic products.

Such a geochemical overlay on the geological environ­ment is of immense value to the geologist in the investigationof the genesis of volcanogenic mineralization. In turn, whenthis understanding is developed, these geochemical relation­ships can be applied in prospecting in other favourablegeological situations. In such a prospecting effort, it will beapparent that the exploration geochemist will be dependenton the knowledgeable exploration geologist for guidance inselecting critical lithogeochemical samples.

The integration of the geochemical and geologicaldisciplines has been illustrated by results from the CanadianShield which indicate that, in certain mineralized districts,the felsic and intermediate formations in volcanic cycleshosting mineralization contain significantly higher back­ground zinc contents than equivalent rocks in unmineralizedcycles (Nichol et a!., 1975) (Fig. 25.9).

A note of caution should be registered with respect tothe geology and related geochemistry of volcanogenicenvironments. Conspicuous variations in the geology andalteration associated with productive deposits are frequentlyrecognized from mining camp to mining camp. For example,the relatively restricted distribution of chlorite at Mattabi inthe Sturgeon Lake Camp, (Franklin et a!., 1975) andFigure 25.8, is not a feature of the Noranda Camp wherechlorite is more common and is widely distributed in thefootwall alteration zones. Consequently a parallel study tothe Mattabi study by Franklin et a!. on a Noranda Campdeposit would outline a footwall alteration zone and otherdistinctive features related to the host and enclosing rocks,but the distribution and dominance of chlorite would bestrongly contrasting.

Similarly, the Confederation Lake-Woman Lakerelationship (Fig. 25.9) may not necessarily be reproduced inother camps although based on a geological understanding ofthese environments relationships of this or allied types can beanticipated in other volcanogenic areas.

Illustrations of how geological knowledge of a mineralenvironment can indicate useful exploration techniques canbe selected from papers in the literature dealing withvolcanogenic environments.

It can be demonstrated that anomalous amounts ofmetal occur in exhalite horizons contemporaneous in age withvolcanogenic massive SUlphide deposits. In their study of thedispersion of metals from the submarine exhalative bodies inthe Red Sea, Holmes and Tooms (1972) were able todemonstrate that dispersion of metals from the metalliferousbrines is taking place through normal seawater. Furthermore,this dispersion is detectable in both a soluble form in thewater and in suspended particulate matter (Fig. 25.10 and25.11). The net effect of the dispersion process is reflected inthe upper few centimetres of the surface sediments,(Fig. 25.12), and it is apparent that the distance of anomalousdispersion is measurable in miles.

Integrated Exploration 583

5

5

Sericite AlterationIoog Section A-D.qJpl!r Creek. AriZona

<Isolines based onpercent sericite)

\> 5QO lcp

o0.2

N

r

o

0.2

500 1000Ft, ,

Percent Copper DistributionDrill Hole Composi tes 1000-1900' Elev.Cq;per Creek. Arizona 5

A. Per cent copper distribution at Copper Creek,Arizona - drillhole omposites 1000-1900 ft. elev.

C. Sericite alteration along Section A-D, Copper Creek,Arizona (isolines based on per cent sericite).

5QO 100pFt

q;per o.stributlOl1 r.along Section A-DCqJpl!r Creek. Arizona

:::::::=t====::::::::::::===:r 0.2~-O.4

0.4

B. K-feldspathic alteration along Section A-D, CopperCreek, Arizona (isolines based on orthoclase/plagioclaseratios).

D. Copper distribution along Section A-D, Copper Creek,Arizona.

Figure 25.5. Per cent copper, sericite alteration, K-feldspar alteration, Copper Creek, Arizona.(Reproduced from Hausen and Kerr, 1971.)

584 J.A. Coope and M.J. Davidson

"397..0+00 _?

(Profile Perpendicular To Dip Direction)

o?O

\.~

\ - 7- SlOERITE - DOLOMITE BOUNDARY

/I

o

".23

DOLOMITE CONTENT

IIIII!IlIIlIII 20+%

~ 10-20%

~ 1-10 0/ 0

c:::J < 1%

500 FEET

I---.."r--....'100 METERS

Figure 25.6.Distribution of dolomitein the Mattabi Minearea. Reproduced fromFranklin et a1. (1975).

500 FEET

1---...., ----'I100 METERS

Figure 25.7.

Distribution of sideritein the Mattabi Minearea. Reproduced fromFranklin et a1. (1975).

.._7

,,,

(Profile Perpendicular To Dip DirectIOn)

II SIDERITE/--..~=C::::::-~

- 7- SIDERITE ~ DOLOMITE BOUNDARY

".

",I

ICONTENT

20 + 0/0

10 - 20 %

I - 10 %

< J %

Integrated Exploration 585

Cherty - silicified rhyolite

Figure 25.8.

Generalized distribution of alteration types inthe footwall rocks of the Mattabi Mine.Reproduced from Franklin et a1. (1975).

Confederation Lake. Woman Lake 0300 • • • ••••

•• •• •

• •• • •240 ••

• • •• • •0 .. •0 • • • •• • • •• • • • •• •180 0 • • • • ••••-\ • •• • • •Zn • • • • •0 0 ... .. • •• •..'- . •ppm 0 ~. • 0 •• • • • ,.... •

00· • •• •• • .... I •120 • • • • 0 •• •• • •00 0 • .,.0 00 • ••• a • • ••

o. 00 0 0 • ..• ••o. • • • •0••• 0 0·.'• 0 • oe • o•

~. .0 0 8 00 .~ .n 0 • •ooOo.fOOt 0080 • • • 0o •• •

C;S 0 •• 0 8. • • •60 ~ \;g orJ° d6 8 c9 0 ••• •• • ~ 00 00 o ~ •••

o.~ 0 ~. 0000• 0 0 0 0

• o~o 00 • ~• 0

00 • 0

0 0~.0 0o 0 0 0 000 00 00

0000

40 50 60 70 80 90Si02%

Figure 25.9. Comparison of zinc with SiOz between the mineralized Confederation Lake Volcanic Cycle and theunmineralized Woman Lake Volcanic Cycle; Uchi Lake Area, Ontario. (After Govett and Nichol, 1978.)

586 J.A. Coope and M.J. Davidson

:I:~

::>o(J)

20I

.6

I'2I

MILES8

I

BRINE AREA

NAUTICAL

° 4I I

...............................................-;;;/- - - - - - , .....•...• FellO

--;::o;>...<::......._"~/ ~ Zn.... , Mn

.......:I:~

lroZ

10231=================klooom3000mBOTTOM PROFI LE

Figure 25.11. Variation in particulate metal contents innear-bottom water, north-south across Nereus Deep. (AfterHolmes and Tooms, 1972.)

LOG J'9/1

EAST

10'

10·'IOOOm2000m

, ,,------.... ,'/

10 NAUTICAL MILESA~ .

Aif I ~': I (i: I t0; , Wf! i , .:: II' I i: : , .i ; , t

...··f··: /Fe ~:::> / ..;.., ,j ./.Zn 1/Cu ._.--II._Jf--r.

II

I..,'- ,.---.'

Mn

SEA LEVEL

BOTTOM PR~-FIL-E'--'-'-'- - -'-"'-'

WEST

WEST BRINE AREA EAST

Figure 25.10. Variation of dissolved metal species in near-bottom water, west-east across Atlantis II Deep (no samplesfrom brine). (After Holmes and Tooms, 1972.)

EASTWEST105 .,--------------------y-r-------------------y

Figure 25.12.

Cu, Zn, Fe, Mn contents ofsurface sediments alongtraverse across Atlantis IIDeep. (After Holmes andTooms, 1972.)

.••.....

",\............................................................ Fe

zol­e>:lr~

Z

'"UZou

!. . :...... . ....... . .

....... \ F'Jy, /l Mn

/ /,\"-fi\ \ "--,_

10 2./

\. 1/ \\," \,.... /. \\" ..... / ...

_~ ............. " /0 \,\_ .. .. ,,__ ",........ - - - .Zn

I "",,~, -- - - .......... ....-.-.-." \-.-.-.-.-- -' -- -- _W ~ CU

~ ." /..... • ...... .-' ATLA~IS :II:t.&I I ./- ./ AREA

~ 101 ,.'/::::- ..::.':...7.+='",0-"E=--- ---="~'·-=E----------=''=t8.;..:5~O'-'' E=--- I

;!; 1000 m=...............---::::::::~::::=_;:_-----_:I: _ BOTTOM PROFILE:i: 2000m-

'"o

Integrated Exploration 587

More recent work by Bignell (1975) and Bignell, Cronanand Tooms (1976), records anomalous geochemical halos ofFe, Mn, Cu, Zn and Hg detectable in surface sediments 3 kmto 10 km from the metalliferous deposits in the Atlantic IIDeep and the Nereus Deep (Fig. 25.13 and 25.14). Backgroundvalues in these diagrams have been calculated from data fromsediments collected along the axial valley sides within theRed Sea, away from the mineralized deeps.

The evidence from the modern environments of the RedSea clearly supports the concept of the exhalative processadvocated by numerous observers of massive sulphide depositsin ancient terranes and immediately suggests thatcontemporary sediments deposited at the same time aspolymetallic massive sulphide mineralization in ancientexhalative environments could contain anomalous amounts ofmetals spatially related to economic mineral deposits. Suchcontemporary sediments include the chemically precipitatedexhalites.

Figure 25.15 is a geological map published by Cameron(1977) of a volcanogenic massive sulphide deposit initiallyindicated in a lake sediment sampling survey in the NorthwestTerritories (Cameron and Durham, 1974a). The body is knownas the Yava Syndicate or the Agricola Lake deposit. Theexhalite horizon related to the mineralization, (known locallyas the "B" horizon), is highly sericitized and the generalgeological relationships of the area are shown in Figure 25.16.

Sampling of rock outcrops beyond the limits ofFigure 25.15 proved the presence of anomalous levels of Zn,Cu and Pb along the extension of the massive sulphide­bearing stratigraphy (Cameron and Durham, 1974b).Anomalous values for zinc occurring along or near the "B"horizon exhalite and its projection are located approximately300 m and approximately 900 m beyond the suboutcroppingmassive sUlphides (Fig. 25.17). Such anomalous dispersionmost likely occurred during the exhalative period yvhen themassive sulphide deposit was being formed.

There is an indication, therefore, that anomalousdispersion in horizons contemporaneous with massivesulphides is detectable in some Precambrian volcanogenicenvironments more than 300 m from the massive sulphides.This has significant implications with respect to the potentialof lithogeochemistry in mineral exploration in that, invertically dipping stratigraphy, indications of signi ficant,blind massive sUlphide concentrations buried to depths of300 m or more could be detectable in samples of exhalitehorizons from surface outcrops.

Russell (1975) described unusually high zinc values andanomalous manganese values in an exhalative sedimentaryiron formation and contemporaneous limestone facies 1 km to7 km from the Tynagh base metal deposit in LowerCarboniferous rocks in Ireland (Fig. 25.18). Gwosdz and Krebs(1977) described somewhat similar dispersion extending 5 kmfrom the Meggen deposit in Germany (Fig. 25.19)•

.....'"

Zn

100

0·1

Mn

10

%

100

11)00

Fe

ppb

Hg

Cu 2 3 4 5 6 7 8 9 10 II Km

11)00

ppm

100

Figure 25.13.

Range (Vertical Bars) and average value.s (Horizontal Bars) ofore metals in sediment cores with increasing distance frommajor metalliferous sediments. Atlantis II Deep. (AfterBignell et az', 1976.)

2 3 4 5 6 7 8 9 10 II Km

588 J.A. Coope and M.J. Davidson

Fe10

%

t - - Mn----------------~----~-~-~~-----~--~ ~

---- -- ----- t_--tt-J-tf-- --t--t

Cu1000

ppm

100

10000

Zn1000

ppm

+ +

2 3 4 5 6 7 8 9 10 II 12 Km 2 3 4 5 6 7 8 9 10 II 12 Km

Figure 25.14. Range (Vertical Bars) and average values (Horizontal Bars) of ore metals in sediment cores with increasingdistance from major metalliferous sediments. Nereus Deep. (After Bignell et aI., 1976.)

~ TONALITE PORPHYRY N 1165

G=:J META-GABBRO,60 GABBRO DYKE

~ FELSIC TUFF

l,r4 --1 MARBLE

G::J META - BASITE

[2=:J FELSIC CRYSTAL and LAPILLI TUFF

G=:J INTERMEDIATE TO FELSICFRAGMENTAL TUFF

~ MASSIVE SULPHIDE MINERALIZATION

I;:>~:/::I QUARTZ-SERICITE ALTERATION ZONE

1---1 CHLORITIC ALTERATION ZONE- -

APPROXIMATE CONTACT

ASSUMED CONTACT

FAULT (APPROXIMATE LOCATION)

FAULT (ASSUMED)o 100 METRES

8

Figure 25.15. Geology of the Agricola Lake deposit. (After Cameron, 1977.)

Integrated Exploration 589

Figure 25.16. General Geology-Agricola Lake area.(After Cameron and Durham, 1974b.)

IMETRESo 500

•D

'if'

1000

;'\:)

The dispersion patterns that are described arecompatible with the volcanogenic model. Investigationsinvolving careful sampling of exhalite horizons require theinput and guidance of the exploration geologist familiar withthe model and appreciative of the fact that the significantexhalite horizons can be thin and relatively inconspicuous.

The complete integration of the lithogeochemicaltechnique with geology can be illustrated by noting thepotential role of lithogeochemistry in the development andrefining of geological concepts leading to a better under­standing of the ore environments and ore genesis.

Potentially UsefUl Research Integrating Geophysics,Geochemistry and Geology

Pertinent information on mineralization genesis hasbeen obtained from a geochemical study of active geologicalprocesses in such localities a>s hotsprings areas wheremineral-bearing solutions are circulating, ocean floors whereprocesses related to plate-tectonism are active, and areassuch as the Red Sea and Vulcano where volcanogenicprocesses have deposited sulphide mineralization. As has beennoted with reference to Red Sea data, geochemical observa­tions in recent environments have served to confirm orexplain conceptual mineralization processes advocated byobservers of mineralized environments in ancient terranes.Parallel studies in other recent environments may providepertinent information leading to a better understanding of thegenesis of other types of mineral deposits, which, indirectly,will lead to the design of more effective explorationprograms applicable throughout the geological succession.

LOCATION - Zn VALUE in P.P.M.

~.

600 METRES

Ii\

,\

. ~.~.. ..\

14 ....

~

400

AREA OF FIGURE

200

SAMPLE.292

o

Figure 25.17. Zinc content of rock samples from the Agricola Lake area. (After Cameron and Durham, 1974.)

590 J.A. Caope and M.J. Davidson

80808 80 00

os()Ooo

10000

ppm

Mn

1000

100 I .'. . :.:... : .

A"~O 000• 0 0

8ogo .t>o 0 ....~

uo

o g

...

15 10 5 o 5 10 15km

WNW MINE ESE

Figure 25.18. Manganese content of Waulsortian limestone horizon reflecting exhalative dispersonaround the Tynagh deposit (Mine). Circles represent drill core samples. triangles represent outcropsamples. (Reproduced after Russell. 1974.)

Rhenish SchIefergebirge o

E::J:j Attendorn reef

--- Meggen orebody- - - Ore-equivalent limestones

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~ I;II;II;I~ ~ ~ ~ mmm iii

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8050, Fe5,-Zn5-Pb5 8050,Ore-equivalent, limestones

]==Oire~-~e~qu~,~va~I.~nC'~"m~.5~ta~n~.~5:c:===r=::::;:~;;E::::::;Sii;"iiiii./iLaigie.rk;a~lk~~~;;::c:=::::r:=::::JC:::C:::I::=:=C=:==IIc:::c:::r:::::=r:=T I _~! ! ! I;:;-&"

~-----3-8 km

Figure 25.19. Manganese distribution in Lagerkalk and ore-equivalent limestones in area of Meggen ore deposit:southeastern flank or Elspe synCline separated from anticline structure between Elspe and Attendorn syncline byvertical broken line; other broken line links median values (. quarry, A underground working• • drillhole).(Reproduced from Gwosdz and Krebs, 1977.)

Integrated Exploration 591

An area where meaningful geophysical results might beanticipated would be research on the post-mineralizationimpact of a large sulphide mass on the host environment. Inarid climates, the effect of acid weathering on the physicaland chemical properties of the surrounding rock is poorlydocumented although there is some evidence thatIP - responsive clay minerals are formed locally.Electrochemical effects driven by the oxidation of a sulphidemass may also produce post-mineral changes in the host rockswhich are detectable at a distance. Such a mechanism fordispersion of elements is currently understudy and aconsiderable amount of interesting data is being accumulated(Govett, 1973; Govett et aI., 1976; Bolviken and Logn, 1975).Comprehensive geochemical studies of the weathering zoneoverlying known mineralized environments similar to thosedescribed by Nickel et al. (1977) and those being carried outin other CSIRO programs in Australia, may also revealimportant geochemical parameters which would be pertinentin the identification of favourable environments from surfaceobservations.

Another area for fruitful investigation concerns thealteration mineralogy of the iron minerals. Magnetite and thevarious hematites are very difficult to distinguish by mostanalytical techniques including XRD, yet these minerals haverelatively distinct magnetic properties and appear to besensitive indicators of chemical environments. Some work ofthis type has been done by US Geological Survey personnelusing high resolution susceptibility measurements tocharacterize the chemical environment of uranium rollfronts.

COST EFFECTIVENESS

Just as integrated exploration offers significantopportunities to the exploration geologist so the selection andapplication of the variety of available techniques presents animportant challenge.

There are numerous examples on record of areas beingsystematically covered by one technique after another in thehope that the accumulation of data may reveal all significantgeological secrets. This is a bland, unimaginative approach toexploration.

Cost-effecti veness is of prime importance in goodexploration practice. Optimum cost-effectiveness is based onconsidering the incremental cost of obtaining additionalinformation from each survey in an integrated program andon establishing the proper sequence of surveys, mapping anddrilling so that each stage builds on the body of knowledgealready obtained. Confirmation of geological informationwhich has already been obtained with an adequate confidencelevel, is both time consuming and expensive.

The old adage "you will never find a mine until youbreak rock" cannot be denied and it should be the objective ofall exploration teams to strive for the geological fact asexpeditiously as possible and equate the cost of diamonddrilling or other definitive and factual geological dataacquisition against the added time and cost of additionaldiscriminatory geophysical and geochemical data gathering.

Optimum cost-effectiveness requires a flexibleapproach consistent with the level of geological knowledge,and programming in which the various exploration decisionpoints are carefully considered in advance. Within anintegrated program, there are more stages at which to placea decision point which can take advantage of appropriatetechniques to provide reliable negative or positiveinformation.

The problem of differentiation of EM anomalous zonesin Precambrian terranes of the Canadian Shield covered byextensive and complexly transported overburden, has been

attacked in several ways. The high incidence of graphite inthese regions has made systematic drilling of the EM zonesexpensive and unjustifiable. Various criteria based on thestrength of the anomalies, and their length and positionrelative to broad, complex, major anomalous trends have alsobeen applied with mixed and often negative results.Overburden drilling and sampling has been adapted to theproblem and, by examination of trace element values andheavy mineral concentrates in basal tills, di fferentiation ofgraphite, barren sulphides and metal-bearing sulphides can beachieved under certain conditions. Favourable targets thusdifferentiated are then drilled.

Provided the parameters of size and depth of anydesired massive sUlphide deposit are properly defined, surfacegravity techniques are capable of differentiating less densegraphitic sources from the denser, sulphide-rich sourceswhich are more likely to be orebodies.

Overburden geochemical drilling, under favourable con­ditions, has the property of discrimination between barrenand metal-bearing sulphide accumulations, but the cost of thegeochemical drilling, especially in complex glacial overburdendeeper than 30 m, becomes significant when anomalies arebeing investigated. The gravity technique, in concert withseismic and elevation surveys adapted for rapid, inexpensivecoverage under Canadian Shield conditions, can quickly andrelatively cheaply, eliminate anomalies related to graphiteand other low density sources. Cost-savings achieved utilizingthe gravity method at this stage of a program have beenknown to offset the additional diamond drilling costs requiredto examine remaining targets related to all higher densitysulphide concentrations and also offset the extended timeplus overburden drilling and related analytical costs thatwould be required to define the fewer targets by thealternative approach.

The principle of cost-saving and cost-efficiency is alsoillustrated by a much simpler example from Basin and RangeProvince areas where considerable exploration has beendirected towards evaluation of pediment areas for buriedporphyry copper deposits. Following a careful study ofavailable geology, certain pediment areas have been selectedfor drilling to determine if significant features correlatablewith porphyry copper mineralization in the pediment bedrockcould be identified. Repeatedly, this approach provedunsuccessful and led to the abandonment of the propertybecause, after acquisition of land, sometimes at a significantcost, holes were drilled thousands of feet without penetratingthe valley gravels.

An integrated program has been developed withidentical objectives but, instead of the first decision point inthe program being the identification of a significantgeological feature in pediment bedrock, the first decisionpoint was based on an estimation of the depth of thepediment gravel. Relatively cheap gravity profiles carried outon public roads across the valleys quickly established thelocation of the Range Front faults bounding the pediments,and also provided adequate estimates of gravel thickness. Inthis integrated program every drillhole tested bedrock, andmany areas were rejected on the basis of excessive depth ofbedrock.

CONCLUSIONS

The strength of integrated exploration is the fact thatthe geophysicist and the geochemist can sense many aspectsof a geological environment that the geologist cannotobserve. The conversion of geophysical and geochemical datainto geological information is usually ambiguous andimprecise without the input of the geologist and the objectiveof integrated exploration is to convert data into geologicalinformation at a satisfactory level of precision.

592 J.A. Coope and M.J. Davidson

REFERENCES

Bolviken, B. and Logn, D.

Franklin, J.M., Kasarda, .1., and Poulsen, K.H.1975: Petrology and chemistry of the alteration zone of

Lhe Mattabi massive sulphide deposit; Econ. Geo!.,v. 70, p. 65-79.

Govett, G.J.S.1973: Differential secondary dispersion in transported

soils and post-mineralization rocks: an electro­chemical interpretation; in Geochem. Explor.1972; Jones, M.J. (Ed.), 4th Int. Geochem. Exp!.5ymp., Inst. Min. Met., London, p. 81-91.

Govett, G.J.S., Goodfellow, W.O., and Whitehead, R.E.S.1976: Experimental aqueous dispersion of elements

around sulfides; Econ. Geo!., v. 71, p. 925-940.

Govett, G.J.5. and Nichol, I.1978: Lithogeochemistry in mineral exploration;

Paper 25 .l!:! Geophysics and Geochemistry in theSearch for metallic ores, P.J. Hood (Ed.), Geo!.Surv. Can., Econ. Geo!. Rcpt. 31.

Gwosdz, W. and Krebs, W.1977: Manganese halo surrounding Meggen ore deposit,

Germany; Inst. Min. Met. Trans., Sect. B, v. 86,p. B73-B77.

Hausen, D.M. and Kerr, P.E.1971: X-ray diffraction methods of evaluating potassium

silicate alteration in porphyry mineralization;Can. Inst. Min. Met. Spec. Vo!. 11, p. 334-340.

Hawkes, H.l=. and Webb, J.S.19p2: Geochemistry in mineral exploration; Harper and

Row, New York, 415 p.

Holmes, R. and Tooms, J.S.1972: Dispersion from a submarine exhalative orebody;

in Geochem. Explor. 1972, Jones M.J. (Ed.), Inst.Min. MeL, London, p. 193-202.

Hood, P.J., Sawatzky, P., Kornik, L.J., and McGrath, P.H.1976: Aeromagnetic gradiometer survey, White Lake,

Ontario; Geol. Surv. Can., Open File 339.

Morley, L.W.1969: Regional geophysical mapping; in Mining and

Groundwater Geophysics - 1967, Geo!. Surv. Can.,Econ. Geo!. Rept. no. 26, p. 249-258.

Nichol, I., Lavin, D.P., McConnell, J.W., Hodgson, C.J., and50puck, V.J.

1975: Bedrock composition as an indicator of Archeanmassive sulphide environments; Abstract of Paperpresented at the 77th Annual General Meeting ofthe Canadian Institute of Mining and Metallurgy,Toronto, Can. Inst. Min. Met. Bull, v. 68, no. 755,p.48.

Nickel, E.H., Allchurch, P.O., Mason, M.G., andWilmshurst, J.R.

1977: Supergene alteration at the Perseverence nickeldeposit Agnew, Western Australia; Econ. Geo!.,v. 72, p. 184-203.

Pelton, W.H.1977: New IP method may discriminate between

graphite and massive sulphides; N. Miner, v.63,no. 27, Sept. 15, 1977.

Russell, M.J.1974: Manganese halo surrounding the Tynagh ore

deposit, Ireland; a preliminary note; Inst. Min.Met. Trans., London, Sect. B, v. 83, p. B65-B66.

1975: Lithogeochemical environment of the Tynagh basemetal deposit, Ireland and its bearing on oredeposition; Inst. Min. Met. Trans., London,Sect. B, v. 84, p. B128-B133.

An electrochemical model for elementdistribution around sulphide bodies; lr:!Geochemical Exploration 1974, Elliott, I.L. andFletcher, W.K. (Eds.), 5th Int. Geochem. Explor.Symp., Elsevier Publ. Co., Amsterdam, p. 631-648.

1975:

Boyd, D.1969: The contribution of airborne magnetic survey to

geological mapping; lr:! Mining and GroundwaterGeophysics/1967, Geo!. Surv. Can., [con. Geo!.Rept. no. 26, p. 213-227.

Cameron, E.M.1977: Geochemical dispersion in mineralized soils of a

permafrost environment; J. Geochem. Explor.,v. 7(3), p. 301-326.

Cameron, E.M. and Durham, C.C.1974a: Geochemical studies in the eastern part of the

Slave structural province, 1973; Geo!. Surv. Can.,Paper 74-27.

1974b: Follow-up investigations on the Bear-Slavegeochemical operation; lr:! Report of Activities,Part A, Geo!. Surv. Can., Paper 74-1A, p. 53-60.

Coope, J.A.1958: Studies in geochemical prospecting for nickel in

Bechuanaland and Tanganyika; unpublished Ph.Dthesis, Imperial College, London.

Bignell, RD.1975: The geochemistry of metalliferous brine

precipitates and other sediments from the RedSea; unpublished Ph.D thesis, Imperial College,London.

Bignell, R.D., Cronan, D.S., and Tooms, .1.5.1976: Metal dispersion in the Red Sea as an aid to

marine geochemical exploration; Inst. Min. Met.Trans. (Sect B: Appl. Earth Sci.) v. 85, p. B274­B278.

Integrated exploration does not come into being auto­matically. Exploration geophysics, exploration geochemistryand exploration geology have, to some extent, evolvedseparately from different roots, and competition, rather thanco-operation, has been the norm. Much of the integratedexploration practiced today has resulted from the insistenceof enlightened exploration managers rather than the naturaltendencies of individuals. Fortunately, once integratedexploration has taken root under whatever impetus, mostindividuals have been quick to appreciate the benefits andhave accepted the philosophy wholeheartedly.

The contribution of the geologist is important.Integrated exploration is dependent on geologists being ableto formulate meaningful questions which .relate to theenvironment of mineral deposits and which, in some way, canbe answered by changes in J1hysical and chemical properties.

Geophysical and geochemical techniques of today canbe designed to be cost-effective in the detection of thcrelatively gross physical and chemical property contrastsassociated wi th the direct detection of mineralization and inthe provision of critical and useful geological informationrelevant to the environment of mineral deposits.

Objective application of this capability and expertise inadvancing the geological understanding of the genesis ofmineral deposits will perpetuate and improve the geologicalmomentum which we have witnessed over the past 20 to25 years. This will ensure the progressive development of ourexploration capabilities in the face of the challenging demandof our various societies.