Documents complémentaires / Additional files Licence / License

I

MINISTERE DE L'ÉNERGIE ET DES RESSOURCES ,B DIRECTION GENERALE DE L'EXPLORATION GÉOLOGIQUE ET MINERALE

~

PYTHONGA LAKE AREA

J.H. Bourne

1970 DP-151 GM-28638 OPEN FILE MANUSCRIPT

Gouvernement du Québec

DEPARTMENT OF NATURAL RESOURCES

GEOLOGICAL EXPLORATION SERVICE

GEOLOGY OF PYTHONGA LAKE AREA

Preliminary report

by

James Bourne

PUBLIC

Ministère des Richesses Naturelles, Québec SERVICE DE LA DOCUMENTATION TECHNIQUE 2 5 MAI 1973 Date: ~ No GM: 1970 INTRODUCTION

The Lac Pythonga area lies between 76°00W•and 76°30'W, and between 46°15'N and 46°30'N, and includes Artois and }3eliveau

Townships as well as parts of Boureogne, Perche, Isle-De-Prance,

Angoumois, Egan, Souchette, Church and Aunis Townships. Maniwaki

Township, most of which also lies within the area delimited above, is an Indian Reservation and was not mapped. Thus the mapping covered a surface area of some 345 square miles.

LOCATION AND ACCESS

The Town of Maniwaki (population 9,000) is located approximately

1 mile east of the eastern boundary of the area. The geographic centre of the area, Turtle Lake, is 16 miles from Maniwaki by road.

There are two main access roads into the area,-: one from the

Town of Gracefield, and the other from,Maniwaki. Both Maniwaki and

Gracefield are located on the paved Provincial Highway #11, and are

84 and 57 road miles north of Hull respectively.

There are numerous bush roads which have been built and are maintained by the Canadian International Paper Company (C.I.P.)

C.I.P. Route 1.1-: Runs between Eagle Depot and Maniwaki, following the Eagle River for some 15 miles.

C.I.P. Route 12-: Goes to the northwest corner of the area, passing by Turtle Lake and several others.

C.I.P. Route 35-: Runs from Eagle Depot up the west shore of Lac Pythonga, and out of the area to the northwest: C.T.P. Route 36-: Runs southwest from route 35 and effectively côvers the southwest corner of the area.

In the southeastern part of the area the main access road runs into the interior' from Messines or Parley. In the northeast part of the area a well graded provincial road, (known locally as the Montcerf Road) has been built from Maniwaki.

Numerous secondary roadslead into the larger lakes. The following important lakes are all accessible by road.

Depot Lake Harding Lake

Doyle Lake Kingsbury Lake

Lac Pythonga Turtle Lake

Lac David Green Lake

Inman Lake Lac Cairine

Lac Hel'ene Petit Lac-Aux-Cedres

Lac Jean Grand. Lac-Aux-Cedres

An excellent road map of this area is available through the C.I.P. office in Maniwaki.

Drainaçse& Physiography

With the exception of a very few streams, all streams drain into the Eagle River. Several streams develop drainage areas of considerable size before they themselves empty into the Eagle River. The western part of the area is in large part drained by the Hibou and Turtle Rivers.

Relief in the area is less than 400' locally, usually in the order of 150'.Hills are for the most part rounded and valleys filled with glacial debris. 3

Two broad physiographic provinces can be outlined, the

Valley which is in. general a broad sand-filled plain underlain by

•marble, and'the highlands to the west of it which form the hilly

hinterland and out of which drain all the major streams.

Elevations vary from a low of 550' in the extreme eastern part

of the area along the Desert River to a high of 1592' in the north-

western corner of the area east of Lac David. The average elevation

rises from 800' in the east to 1100' in the west.

GEOLOGIC COLUI4N

Tectonic Unit Dominant Category Number Lithology

Syn and Post- 11 quartz veins Grenville Orogeny 10 lamprophyre intrusive rocks 9 diabase 8 diorite 7 granite 6 pegmatite 5 white rock Grenville Group 4 biotite - feldspar gneiss metasedimentary 3 marble rocks pre - Grenville 2 calc - silicate Group basement rocks if amphabolite 1 o le garnet (sillimanite) gneiss p.,ld biotite gneiss ôlc hornblende - biotite gneiss üilb granite gneiss la green rock complex

0 m GEOLOGY - INTRODUCTION

In the legend the writer has placed the rock units inte different "tectonic categories". In 'so doing he is following the practice established by Wynne-Edwards (1966, 1969) of mapping in this part of the Grenville Province. The proof that this concept is valid could best be arrived at by obtaining a number of Rb-Sr whole rock age determinations from each tectonic category which would then set out a rough time sequence of events. No such project has been attempted for this part of Quebec. However, in adjacent parts of Ontario such an investigation is being conducted, (Krogh et al (1968); Davis et al

(1967, 1969)) and has established a geochronologic framework for the Grenville Province of Ontario. Baer (1969), on the . basis of large scale mapping in both Ontario and this area of

Quebec under consideration felt that a correlation of the rocki across the river into adjacent western Quebec was possible, and divided up the rocks of western Quebec into three "blocks" each of which is envisaged to he of different primary age. The contact between his "Algonkin" and "Gatineau" blocks passes through the Lac Pythonga area and should, therefore, divide the rocks into groups of different age which, following the terminology of Wynne-Edwards, are, here

called "tectonic categories" and are listed below,

Tectonic Rock Types'Involved Category

III sy - and post - Grenville orogeny intrusive

rocks II Grenville Group metasâdimentary rocks and

associated rocks I a "pre - Grenville Group" basement complex

According to this concept, the rocks of tectonic category I

are considered to have been in a gneissic condition when the

limestones, aluminous shales which were destined to become the

Grenville Group, were laid down. The rocks of category I are then

considered to have been through 2 complete orogenic episodes, while

those of category II have experienced only 1. The rocks of category III

are intrusive rocks which are massive or at most slightly foliated

and must have been emplaced after most of the movement associated

with the Grenville Orogeny had taken place.

Krogh's and Davis'. work on the handed paragneisses of the

French River area of Ontario gave a value of m.y,

for those rocks which Baer tentatively correlates with tectonic

category I, while Silver & Lumbers (1965) report a value of 1310± 15 m.y,

for the Tudor metavolcanics which are considered to underlie the

Grenville Group marbles and thus place a maximum age on them and

on tectonic category II.

Finally, Doig and Barton (1968) have determined the age of some of the fresh intrusive rocks in the Maniwaki area. Their results

show that although these rocks are generally post - Grenville

Orogeny in age, they are nevertheless. still Precambrian.

The rocks were divided into the above tectonic categories• on the basis of association. For instance, only rocks which were observed to have a widespread and intimate association with the white to pinkish marbles of the Grenville Group were assumed to be members of the Grenville Group as well. The same technique was applied to the basement rocks, using as a point of departure the acceptance of the large-region of biotite gneisses and hornblende gneisses as being part of the basement.

For all it's faults, it is felt that this technique is justifiable simply for economic reasons. Baer (1969) has shown that many of the major mineral deposits of the Grenville Province, particularly zones of uranium mineralization, are located near the contact between tectonic categories I and II, It is, therefore, hoped that this style of mapping will be useful for subsequent mineral exploration.

Basement Complex (unit 1)

The 'Basement Complex' is a term used to describe all rocks

(except pegmatites) which are believed to have been in a gneissic condition at the time when the Grenville Group of metasediments were laid down. This term, therefore, covers a vast variety of rock types, including microcline-bearing gneisses of granitic composition, biotite-plagioclase gneisses, biotite-hornblende gneisses, amphibolites and quartzo-feldspathic gneisses. All these rocks are readily

recognizable at any one particular locality, but it is very difficult

to trace these rocks for any great distance.

It is probable that there is a gradation of composition along

strike so that two outcrops, both of which are along strike with

each other may be quite different lithologically. This feature is

common in other parts of the Grenville Province where the structural

geology has been carefully worked out - for example see Martignole

& Schrijver (1970). The result of this is that the spatial

distribution pattern of the various gneisses is quite irregular

and their structures difficult to determine.

Because of this problem, all gneisses believed to belong to

this tectonic category, except those with a highly distinctive bulk composition, were classified as one unit, and tin different lithologic varieties indicated by means of subunits. Where possible zones of relatively constant lithology were delimited. In the following short description, the principal lithologic units are described.

Green Rock Complex (unit la)

These rocks form a quantitatively minor group of rocks in the extreme western part of the area. The best exposures of this unit are in fact just outside the area mapped, just west of the western end of Lucy Lake.

Two. subunits of unit 1 have been recognized in the field - homogenous charnockite (?) and layered gneisses. Both have a colour which sets them apart immediately from all 'other rocks in the area - namely the pea-soup green colour. The charnockite body is homogenous and has all the aspects of

having once been an igneous rock. Quartz and hornblende are

slightly elongated in places, forming a lineation in'the rock,

but in general the rock appears massive. Quartz, perthitic K-'

feldspar and plagioclase are the rock-forming minerals, with

pyroxene and opaque minerals forming less than 2% of the rock,

The pyroxene is in large part altered toa rusty zone consisting

of red biotite and green chlorite, and its composition cannot be

determined optically.

- The gneisses associated with the charnockite also have this

characteristic green colour, however the rocks are well layered.

Hornblende is present along with plagioclase which has compositions

as basic as An44. Traces of biotite, apatite, opaque minerals,

garnet and pyroxene were observed in rocks of this association.

Granite Gneiss (unit lb)

Pink granite gneiss, so named because of its approximately

granitic composition, is found in all parts of the map area. 'It

is not oné distinct unit, but is undoubtedly a large group of rocks

of different origins. They have the following points in common.

1) pink colour in hand specimen

2) presence of microcline in great quantities. Usually where

microcline is present in any of these rocks, the potash

feldspar: total feldspar ratio is greater than 4:1

3) • perthitic feldspar is rarely developed

4) The presence of ribboned quartz, which apparently develops more easily in rocks of approximately this composition,

Hornblende-Biotite Gneiss (unit lc)

In contrast to the granitic gneisses described above, the

hornblende-biotite gneisses are grey in colour and col only consist

of approximately 25% mafic minerals of which 20% is hornblende and

5% is bioti.te. Rarely is the hornblende present without the

biotite. The plagioclase is quite commonly well twinned according

to the albite law and has a composition in the calcic oligoclase to sodic andesine range. The potash feldspar, where present, is not twinned and is in general present in quantities less than 5%.

The potash feldspar: total feldspar ratio is in general less than l:1-and is commonly less than 1:6. This is a marked contrast to the granite gneisses cited above.

Biotite"Gneiss (unit 1d)

In the field both the hornblende gneiss and the hornblende- biotite gneiss are very similar in appearance, and the dominance or absence of hornblende must be used to distinguish them.. It was mentioned that in the hornblende-biotite gneiss that the biotite content is usually around 3%, and is rarely absent in members of the former unit. However, in the biotite gneisses it is rare to find any hornblende present at all. Of five thin sections of this unit examined, the biotite content ranged from 3% - 25% but there was not even a trace of hornblende present in any of them. On the other. hand, of 12 thin sections of the hornblende-biotite gneiss which were examined, only two failed to have any biotite present and yet in no section was the ratio of biotite:total biotite plus hornblende more than .35, and in most cases it was close to .15.

It would therefore, appear that the two units can be distinguished on the basis of their mafic mineralogy, which is probably related to bulk compositional control.

Garnet Gneiss (unit le)

This particular unit is of very limited areal extent, and was mapped only because in several places the units appear to be somewhat traceable. Locally these rocks are associated with sillimanite, and probably represent a metamorphosed sequence of pelitic rocks.

Here sillimanite and the garnet together constitute approximately

20% of the rock in approximately equal amounts, with biotite quartz potash feldspar and plagioclase making up the rest of the rock.

Amphibolite (unit lf)

The term amphibolite as used here to refer to any rock in which the hornblende content exceeds 40%. As with the other units mapped, this one also is composed of rocks of more than one mode of origin.

In several cases a relict ophitic texture was observed in thin section but not in the hand specimen, and it is therefore, evident that metamorphosed diabase dykes compose part of this unit. In many other cases, however, the rock is composed of polygonal grains and there is no indication as to what the original texture may

have been. The origin of this latter group is in considerable doubt.

In the field, these rocks are never thick units, being at most several tens of feet thick and were not observed to be discordant.

Calc-silicate (unit 2)

Several zones of talc-silicate material were recognized and defined during the course of the summer. They all have several features in common which point to a common origin.

1) They are always associated with rocks of the so-called basement

complex, and never with the rocks of the Grenville Group

(marbles and sillimanite gneisses).'

2) The mineralogy of a typical outcrop consists of more than

80% diopside, scapolite and wollastonite (plus minor quartz

and biotite) and less than 20% calcite. In most cases there

is less than 10% calcite. No dolomite is present.

3) Commonly the mineral diopside is the common mafic mineral in

the rocks adjacent to the talc-silicate zones,.

Considering only the members of this unit,-there seems to be a gradual transition in structural style from the western part to the eastern parts of the area. The cale-silicate zones in the western part of the area, for instance those at the south end of

Lac David, are interbedded with the local gneisses and form long continuous layers which vary considerably in thickness and usually pinch off after 100' along strike or so. More to the east, near. Turtle Lake, Lac Marie and Lac Cairine, the calc-silicates are

virtually massive bodies having no planar features of any sort

•present nor any consistent relationship to the surrounding rocks

Marble (unit 3)

Outcrops of white marble cover extensive areas of terrane

in the eastern part of the area, south and north of the Indian

Reservation. No attempt has been made in this report to subdivide

the marble into various units based on the nature of the associated

silicate phases, although preliminary examination has shown this

to be possible. The following varieties of marble were recognized:

1) diopsidic marble

2) graphitic marble

3) chondroditic marble

4) phlogopitic marble

5) serpentenitic marble

6) relatively pure white marble with little or no silicious phases

present.

The dolomite content of these marbles is quite variable and

cannot accurately be predicted at the outcrop - staining being the

only accurate way to distinguish between dolomite and calcite. No

correlation between the dolomite:calcite ratio and the type of

silicate phase present in the sample has so far been discovered,

however it would appear that the chondrodite forms in calcite rich

layers which are interbedded with dolomitic layers. A very characteristic calc-silicate phase is associated with these marbles, and. there are several features which enable it to be distinguished from map unit 2 which has also been mapped as calc-silicate.

1) Volume-wise they are always very minor in comparison to the

volume of the associated marble.

2) The colour of these calc-silicates is a very pale green to white.

This is a sharp contrast to the deep green colour of the

other calc-silicates.

Biotite-feldspar Gneiss. (unit 4)

This unit is present only in the eastern part of the area mapped, and is intimately associated with the Grenville Group marble unit. Locally a small quantity of sillimanite is present.

The colour of this unit is very distinctive (dark slate grey), • which appears to be due to the lack of a well developed orientation of biotite grains within the rock along with an unusually high plagioclase content. The common assemblages are those bearing orthoclase, plagioclase, quartz, biotite, sillimanite and red to mauve garnets. Normally plagioclase comprises 50% of the sample, and is the dominant rock-forming mineral.

The weathered surface of this unit is characteristically rusty and weathers quite deeply. As a result, the best exposures of this unit are in road cuts along the several secondary roads. White Rock (unit 5)

The term 'white rock' is employed here tô describe a large number of coarse-grained white pegmatite's which are always associated with the marbles in the eastern part of the area. The association of these rocks with the marbles is so ubiquitous that several authors have suggested that there may be a genetic relationship between these bodies (e.g. Wynne-Edwards, et.al, 1966), however, this has yet to be demonstrated. • Compositionally these rocks are marked by a high percentage of potash feldspar and a low mafic mineral content (usually less than 1%). Quartz is present in quantities close to 20% and plagioclase generally constitutes less than 10% of the rock.

Texturally, they may or may not be foliated, if we assume that all these rocks developed roughly synchronously, then they would be classified as late syntectonic to post-tectonic in age.

Pegmatite (unit 6)

The term pegmatite is used here to refer to any pegmatitic material, be it foliated or unfoliated, which is associated with any lithology except for those associated' with the Grenville Group marbles-. Pegmatites associated with the marbles are called 'white rock' and have already been discussed.

As thus defined, the pegmatites are a diverse group, having a variety of compositions and textures Furthermore,.they are situated in varied tectonic settings. In the case of these pegmatites we cannot be so confident of a roughly synchronous age of development

because those associated' with the basement rocks may have formed during an earlier orogenic event, Indeed, in. one outcrop in the

northwest corner of the map area, there is clear evidence of four different ages of pegmatities. Only the last of these is unfoliated.

It is, therefore, to be expected that these rocks would have the variety of compositions cited above, and be a mineralogically diverse group. In some pegmatites, K-feldspar predominates greatly over plagioclase, and in others the converse is true. Some are allenite-bearing.to â minor degree.

Granite (unit 7)

Two granite bodies were located during the course of the summer. One, in the extreme northwestern part of the area is poorly exposed except along the shores of Doyle Lake. It has, therefore, been named the Doyle Lake Granite. The second granite • is located in the southeastern corner of the area, on the shores of Lac-aux-Cedres, and has, therefore, been named the Cedar Granite.

The size of these two bodies is considerably different, with the Doyle Granite covering a surface area of several square miles, while the Cedar Granite is much smaller. Nevertheless, they are quite similar both mineraogically and texturally. The rocks are composed d' 70% orthoclase and plagioclase (in the proportion of 6:1) and quartz (250). The rest of the rock is composed of biotite which has in large part altered to chlorite (pennine) and an unidentified opaque mineral. The grain boundaries between feldspar grains has been the locus of rather severe alteration of these feldspars to sericite.

The field relationships of these two bodies are poorly known

because of the lack of exposure of the contacts. They are however,

homogenous and have little or in most cases no preferred orientation- of the component minerals. This latter feature, combined with the alteration pattern, might suggest a late-syntectonic age for these bodies.

Diorite (unit 8)

One small body of diorite was located also in the southeastern corner of the area, adjacent to the Cedar Granite which has been described. The actual outcrop is on a small island•in the centre of the lake.

The body itself is essentially white in colour, with black whisps which are composed of biotite.- In thin section the rock appears to be a recrystallized porphyritic diorite in which the large porphyroblasts of feldspar have become polygonal masses of twinned plagioclase, and the material which was originally the crystallized intercumulous liquid is now a complicated quartz- hornblende intergrowth. The approximate mineral composition is as follows:

hornblende 15%

biotite 10%

plagioclase 70%

along with small to trace quantities of the following minerals: epidote, chlorite, sphene, opaque minerals, and quartz. The rock itself is in general massive and a foliation direction,

as defined by a preferred orientation of biotite flakes, is only

present locally. The fact that the rock is recrystallized, and yet still has recognizable igneous textures present, suggests that the

unit is of late syntectonic age.

Diabase (unit 9)

Several small dykes of diabase were located in the area, but

.there are insignificant in terms of volume. However, they do • apparently represent one of the latest phases of geologic activity in the area, and therefore, will be briefly mentioned.

Their field relations suggest that they am small dyke like bodies which cut across all rock with which a contact is observed.

They are aphenitic in grain size, and composed predominantly of plagioclase (70%) and clinopyroxene (20%), with 5% biotite and traces of chlorite, apatite, and opaque minerals. The lath-like texture of the feldspars is almost completely destroyed, and the biotite grains, which appear to have formed through the breakdown of.the clinopyroxene, are all oriented in one principal direction.

Lamprophyre (unit 10)

Only one small dyke of this material was located during the course of the mapping. It was approximately 3' wide and several tens of feet long, and intruded the Grenville Group marble.

The rock is easy to recognize in the field because of the dark nature of the host rock, and the presence of black phenocrysts of

pyroxene. 'The groundmass is aphenitic.

Quantitatively the rock is unimportant, but is described here

because of the presence of dykes of similar material in the area

immediately to the east as mapped by de la Rue .(1953). It is

therefore, possible that the dyke is related to the, large Kensington

syénite body as he suggested.

Compositionally the rock is composed of clinopyroxene and

hornblende is approximately equal proportions. The hornblende is

forming as a reaction product about the pyroxene. The presence

.of a considerable amount of potash feldspar is indicated by the

presence of myrmekitic intergrowths, and of feldspar by the albite

twinning, compositonally it would, therefore, be termed a kersantite

(Turner & Verhoogen, 1960).

Quartz Veins (unit 11)

Several large areas of pure snow-white quartz were located in

the extreme southeast corner of the area, also on Cedar Lake. They

were originally mapped as quartzites but thin section investigation

revealed the presence of euhedral clinopyroxenes which are unlikely

to have formed in a sedimentary environment. It is, therefore,

concluded that in the southeast corner of the area is a. large group

of thick (at least 30' in some places) quartz dykes which intrude

all formations mapped in the area. Lack of exposure prohibited

following these dykes along their length and, therefore, concluding

that this hypothesis is correct. Pleistocene and Recent (unit 12)

River and stream deposits of recent origin are widespread and, well developed throughout the area. By far the largest portion of that area shown on the map as unit 12 is a fine-grained homogenous sand which in places where it is well exposed shows a well developed cross-bedding.

In particular, all of unit 12 west of the Eagle River, (in the Turtle Lake embayrnent and the Eagle Depot area) are of this type. Only a very small part of this unit is composed of other types of material. Notable in this regard is a well developed esker which is located in the middle of Lac

Pythonga near the extreme south end of the lake, and the very minor developed of a fine-grained grey clay in the northeast corner of the area, just across the Eagle River from Pocknock Lake

As mentioned, a fine-grained sand composes all of this unit, and in places attains considerable thicknesses. In the extreme southeast corner of the area (on the railroad tracks near Lac Clament) it was observed to be at least

75' thick, but the true thickness could not be measured. In the southcentral part of the area near Nary Lake thicknesses of 25' were observed and a slightly thicker sequence was noted at the confluence of Turtle Creek and the

Eagle River ,(about 401). In the Brock Lake - Nooney Lake area at the south end of Lac Pythonga the sand cover is extensive but not too thick as the bedrock pokes through it in many places. In the extreme northwest corner of the area however, the cover is very thick. Cliffs of sand at least 301 and probably closer to 401 define the whole north shore of Lac David. For the most part the areas underlain by sand can be easily picked out on the topographic map. The sand forms a solid "blanket" cover upon the bedrock surface and consequently has filled in and Precambrian valleys in the areas which they wore deposited. The result of this is that the Quartzite (unit 13)

Very little is known about this particular unit. It is well exposed at only one place in the map area - near the shores of Lac Langevin which is located in the extreme northeast corner of the area. The colour of the weathered outcrop surface is a characteristic white and that of the fresh surface is a very light grey. The high quartz content (more than 750) combined with the presence of feldspar of unknown composition lends a very rough nature to the weathered surfaces with the relatively coarse-grained quartz grains standing out in relief. The mafic content of the unit is very low (less than 50 biotite was recognized). 4 ..

topographic relief in these is very slight - commonly less than 25t over

large areas. Metamorphism

The grade of metamorphism is quite uniform throughout the area.

Muscovite is not a stable phase except in a very few instances where it appears to be an alteration product. Most rocks are therefore, in the upper amphibolite facies, with the sillimanite -

K-feldspar assemblage being present in rocks of appropriate bulk composition. Only one outcrop of co-existing orthopyroxene and clinopyroxene was discovered during the mapping although clinopyroxene

(diopside) - hornblende - plagioclase - quartz assemblages are quite common.

In the calc silicate rocks, diopside - wollastonite - calcite and diopside - scapolite - calcite are commonly found.

In the more siliceous marbles of the Grenville Group, chondrodite - calcite - dolomite-cummingtorite - chlorite assemblages are common but their significance as an aid to the evaluation of

P-T conditions is not yet understood. '

Structural Geology

Most of the gneisses are well layered or in some cases n banded, and have a strike which in general is to the northeast and a gentle dip to the southeast, usually close to 30°. No major folds were found during the course of the mapping. There is, on

the other hand, abundant geologic. evidence of movement, since many of the outcrops contain ribbon quartz grains which commonly define a lineation direction. It is therefore, puzzling that so few structures of any scale were found.

Insufficient lineation values were measured to permit an accurate structural analysis, however the few results available suggest that two major zones may be present - a zone in the north in which the lineation values plunge gently towards the northeast, and a zone in the south in which the lineations plunge gently to the southeast. The line which - separates these two zones cuts across the strucutral grain of these rocks, and furthermore, there is no apparent lithologic difference in the two zones. The writer would, therefore, discount these preliminary results as being a geologically unrealistic basis for subdividing the area into two major zones, and would also point out that the philosophy of. correlating metamorphic rocks on this basis has recently come into some dispute (for example see Park, 1969),

The lack of structural development may suggest that the deformation may have been much more complex than the apparent simple structural nature of the outcrops would imply. The writer favours the 'flow-folding' concepts of Wynne-Edwards (1963) as the mechanism which would best explain the style of deformation which has occured in the Lac Pythonga area, ECONOMIC GEOLOGY

No important showings were discovered during the course of the summer, although the area has been heavily stabed, especially north of the Indian Reservation.

The main elements of interest are molybdenum and uranium.

At present Canadore Mining Development Corporation is actually engaged in an exploration programme for molybdenum on Range III, lots 6-13, of Egon Township.

Quebec Manitau Mines Limited is carrying out an analogous programme for uranium on Ranges IV & V, (most lots between 31 & 45) of the same township.

A number of very minor uranium showings were located along both banks of the Eagle River and up to several miles on each side of it. It would seem that pegmatites in this zone often bear minor allenite (small black crystals surrounded by a rusty red material) and possibly other radioactive minerals as well.

Thé writer would recommend a thorough investigation of this zone, especially the region between the Eagle River. and Lac - aux - Cedres in the extreme southern part of the area. REFERENCES

Baer, A,J., 1969: Subdivision of the Precambrian southern

Grenville Province, ; Abstracts for Programs, Geol.

Soc. Am., Ann, Meeting, 1969 (page 6)

Davis et al, 1967: Geochronology of the Grenville Province in

Ontario, Canada; Carnegie Inst. Wash. Yearbook #65 (379-386)

Davis et al, 1969: Geochronology of the Grenville Province;

Carnegie Inst, Wash. Yearbook #68 (224-233)

de la Rue, E. Aubert, 1953: Kensington Area, Gatineau County, Que.,

Quebec Dept, Mines, Geol. Rept. #50, (pp. 35)

Doig, R., & Barton, Jay, 1968: Age of carbonatites and other

alkaline rocks in•Quebec; Cdn. Jour, Eth. Sci., vol. 5

(1401-1408)

Holland, J.G., & Lambert, R. St. J., 1969: Structural regimes and

metamorphic facies; Tectonophysics, vol. 7, (197-217)

Karpoff, Boris S., 1966: Rapport sur les travaux executes par

Sullico Mines Ltd., Canton Egan, Comte. Gatineau, Quebec;

GM-1711'6 (avec 3 cartes)

Krogh T.E. et al, 1968: Geological history of the Grenville Province;

Carnegie Inst, Wash. Yearbook, #66 (528-536)

Martignole, J. & Schrijver, 1970: Tectonic setting and evolution

of the Morin anorthosite, Grenville Province, Quebec; Bull,

Geol. Soc. Finland, vol. 42 (165-209)

Shaw, George, 1955: Report on radioactive mineral occurances, Egan

Township; GM-3634A Silver, L.T. & Lumbers, S.B., 1965: Geochronologic studies in

the Bancroft-Madoc area of the Grenville Province, Ontario

Canada;. Geol. Soc. Am., Sp. Paper #87 (page 156)

.Turner, F.J. & Verhoogen, J., 1960: Igneous Petrology, McGraw-Hill,

New York, (pp 694)

Wilson, M.E „ 1924: Arnprior- and Maniwaki areas, Ontario

and Quebec; Geol. Surv. Can. Memoir #136 (pp 152)

Winkler, H.G.F., 1969: Petrogenesis of the metamorphic rocks;

Springer Verlag, New York, 2nd edition

Wynne-Edwards, H.R., 1963: Flow Folding; Am. Jour. Sci., Vol. 261,

(793-814)

Wynne-Edwards, H.R., 1969: Tectonic overprinting in the Grenville

Province, southwestern Quebec, Geol. Assoc. Can., Sp. Pap.

#5 (163-182)

Wynne-Edwards, H.R., et al, 1966: Mont Laurier and Kempt Lake

map areas, Quebec; Geol. Surv. Can., paper #66-32 (pp 32)