Report on the copper deposits of the Eastern Townships of Quebec with a review of the igneous rocks of the district [microform]
Sir,—I beg to submit herewith a report on the copper-bearing rocks of southeastern Quebec, with a petrographic review of the district.
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"GEOLOGICAL SURVEY OF CANADA A. P. LOW, Dinecror.
Report
Copper Deposits
Of The
Eastern Townships Of Quebec
With A
Review Of The Igneous Rocks Of The District
By
John A. Dresser, M.A., F.G.S.A.
Are.
OTTAWA ED BY 8. E. DAWSON, PRINTER TO THE KINt'S MOST EXOELLENT MAJESTY 1907 No. 974.
Caytoton : niversity
ee ion
REPORT is
Copper Deposits
Of The
Eastern Townships Of Quebec
With A = —¢
Review Of The Igneous Rocks Of The District
By
Dresser, M.A., F.G.S.A.
Shi.
OTTAWA PRINTED BY 8S. E. DAWSON, PRINTER TO THE KING'S MOST EXCELLENT MAJESTY 1907
a
A. P. Low, Esq,, B. 8c., F.H.G.S.,
Director of the Geological Survey Department, Ottawa, Canada.
Sir,—I beg to submit herewith a report on the copper-bearing rocks of southeastern Quebec, with a petrographic review of the district. The field work has been done at intervals during the seasons of 19C2-3-4-5. The map illustrating this report is based on the survey of
the areal geology of the district by Dr. R. W. Ells (Annual Reports of the Geological Survey, 1886, 1867 and 1904). I have the honour to be, sir, Your obedient servant,
JOHN A. DRESSER. Montreal. April 7th, 1906.
CONTENTS. Historical notes and miming.......... 6. 6.06.00 6: ce cceeeeenes 1-8 Classification of deposite ...... 0 ..6..ccccscccveneccee seveareeeres 8 Chaleopyrite and Pyrites deposits,...........50.ceccsecceveeevvens 9
. Chaleopyrite, Bornite, Chaloocive, ete.... 6. cssssceeeeeeeeeces. 13 vo PE ee SS SS SS 14 i. Se 16 Geography .. 16 = EE SS SS SSS SS eS 7 Sketch uf previous geological research... .............eeecee6 18
Petrography Copper-bearing voloanion..............06cccseceeesees 20 Serpentines, Diabase, eto. ..........665 ccccesceeeeees 26 Le eS oe » eae SSS $1 Monteregian hills, petrography. ................cceee Se ot
+
The District: .
The district discussed in this report lies in that part of the prov- inee of Quebec which is southeast of the St. Lawrence river and south of the city of Quebec. It comprises the counties of Stanstead, Sher- brooke, Compton, Beauce, Sutton, Brome, Shefford, Richmond, Wolfe. Arthabaska, Megantic, Lotbiniére, Bagot and Drummond. Being th first part, of southeastern Quebec to be surveyed into townships after the English manner of survey, instead of division into parishes accord- ing to the custom that prevailed during the period of French rule in Canada, the district is commonly known as the " Eastern townships." As will be shown ona later page, this district is distinguished from the rest of the province by a difference of physical features, as well as by the ascident of the mode of survey, and so '* a natural division of the country.
The settlement of the Eastern townships began about the begin- ning of the last century, bu. it was some fifty years later that the hilly portions became sufficiently opened up by settlement for their mineral resources to be made known. By that time a single line of railway, the Grand Trunk, had crossed the district with a line leading from Montreal on the St. Lawrence to Portland on the Atlantic, and a branch line from Richmond, about the central point of the Eastern townships, had also been extended to Quebec.
I Copper Mining In The Eastern Townships.
The occurrence of copper in the Eastern townships was known as early as 1841, In that year Sir William Logan examine? « copper bearing property at Carbuncle mountain, Brompton lake. 'Tis was one year prior to the organization of the Geological Survey, o: which Logan was the first Director.
In 1847 the Geological: Survey report called attention to the ~ deposits at Upton, and the reports of succeeding years mentioned or described other localities, until a compilation of these in 1866 gives a list of about five hundred localities in which copper was known: to oceur in the district. This minera] was vigorously sought for, and extensively mined between the years 1859 and 1866. With the de-
6 GEOLOGICAL sURVEY
cline in the price of copper which followed this time, from about thirty-five to nine cents per pound, the mining operations received a very severe check, and work for a time almost completely ceased.
e In this earlier work Copper was the only product of the ore that .was then of any considerable value, aud the richest sulphur ores were Cisearded when the percentage of copper was low. But after the in- tense speculative wave had passed, notwithstanding the low price of
After remaining unworked for a long interval the property known as the Cillis mine, on lot 4, range XI, of Ascot, was reopened, and
perty, called the King mine. In the King and Suffield mines the development work carried on by the present proprietor, Mr. A, 0, Norton, Boston, Mass., has been very successful A large amount of ore has been exposed and important extensions of the work are being projected.
during the last year it was in operation. The Ascot mine, in lot 8, range VIII of the township of Ascot, is another of the reopened Properties. Under the direction of Mr. John McCaw, one of its owners, this mine is at present producing an excellent quality of ore.
In short, wherever the mining has been carried on with consistent
economy ; the characters of the ore bodies properly observed in fo!low- ing the ore; the product of the mines utilized to their full value,
A APS ASCP a
"
Copper Deposits 7
and transportation facilities were at least normally favourable, success seems to have followed.
_ Since the district was first opened the conditions of mining in it have greatly changed. At that time only the Grand Trunk rail- way crossed the copper-bearing district, and it was from ten to thirty miles distant from the majority of the mines. There have since been added the Canadian Pacific, the Boston and Maine, the Quebec Central, as well as the Orford Mountain, and the Lotbiniére and Megantic, two local railways, all of which greatly facilitate transportation for mining purposes. For instance, the mines at Eustis and Capelton, which when opened were seven miles,from a railwa;, are now served by the Boston and Maine railway, which crosses the properties and gives a direct line to Boston and other Atlantic ports- The Suffield, King, Ascot, and several other properties in the southern part of the township of Ascot, which were eight or ten miles from a railway when opened, are at present about equidistant, two miles, from the Boston and Maine on the south and the Canadian Pacific railway on the north. This central locality is one hundred miles from Mont- real, three hundred from Boston, and four hundred from New York, with direct lines of railway to each.
The Quebec Ceniral railway reduces the distance of the Harvey Hill mine from a railway, from fifteen miles to seven, and affects most of the other deposits northeast of the St. Francis river in an equally favourable manner. The Canadian Pacific gives access to Roxton and vicinity, and brings the Sweet mine and other deposits of Sutton within one mile of a railway, instead of thirty, as was the case when these were formerly worked. Similarly the Orford Mountain railway has improved the means of access to the copper deposits of Shefford, Ely, and Melbourne.
This opening of the country has not yet proceeded so far as to exhaust the supply of fuel of the district, which, as well as the water supply, is still sufficient for mining purposes. Generating the electri- city from a neighbouring waterpower, the Eustis Mining Company employ electric power at their works, and ave expected eventually to light their extensive mine by the same means.
Labour in the district has advanced somewhat in price since the earlier mining operations, but is still low as compared with the more recently established mining centres. Mine foremen receive about $2.50 per day, miners $1.50, and labourers, $1.25.
8 GEOLOGICAL sURVEY
market, Ee especially for the by-products of the sulphuric acid industry, gee arsvil be readily seen that the question of copper mining in the East- : years age," 'dey is on an entirely diferent basis from that of forty 2222 Years ago.
Copper Deposits Of The Eastern Townships,
The copper deposits of the Eastern townships are of three distinct classes. These are:
Ist. Ores, chiefly chaleopyrite with small amounts of chalcocite and relatively unimportant amounts of carbonates, in pyrites. The deposits of this class occur in the porphyry-andesite schists, the oldest
which these rocks have been subjected. The gangue material when
distinct from the country rock is generally. quartz, though sometim =e. calcite.
3rd. Chaleopyrite in pyrrhotite, with a little pyrite, forms the third class, The deposits of this class are situated along the contact: of
from the ore bodies of the second class, not only by the character of the ore and the presence of pyrrhotite, but also by the fact that the second group are generally extomorphic contact bodies, while the third are principally endomorphic features of the contact. Moreover
sible exception, but in the third class it is an iron bearing slate in some cases, and other metamorphic rocks of the district in others,
+ eta hoe Rage RNa 2 -
COPPER DEPOSIT 9 1. Cuatcopyrite anp Pyraires Deposits.
In the Porphyry-Andesite Series,
The deposits of this class include the principal properties that were worked in the early development of the district, and all that are at present in operation. They comprise three principal groups:
(a) Some fifty mines and prospects, in the township of Ascot, and other townships near the city of Sherbrooke. Amongst these are the Eustis, Capelton, King, Suffield, Ascot and other less known properties.
(b) The series of deposits long known to extend through the town- ships of Sutton, St. Armand, Brome, Shefford, Ely, Melbourne, Uleve- land, Shipton, Tingwick, Arthabaska, Chester, Ham, Wolfestown, Inverness and Leeds, as well as the divisions of the seigniory of St. Giles, known as the Handkerchief, and Ste. Marguerite, in the county of Lotbiniére.
(c) Deposits in the little known district along the boundary line between the province of Quebec and the state of Maine, south and east of Lake Megantic. :
It may be seen by reference to the accompanying map that these grounds are in the form of belts, which have a general north- easterly trend, and are approximately parallel. For convenience they may be designated as the Sutton, the Ascot, and the Lake Megantic belts.
In all cases the deposits of this class occur in, or in close associa- tion with, altered volcanic rocks, generally of the porphyry class. The country rock is always highly folded, and often twisted and con- torted to a remarkable degree, and this deformation gives their shape to the ore deposits. In form the deposits are much flattened lenses, which lie in conformity with the foliation of the rock. They are arranged en échelon, generally along zones of extreme foliation. The individual lenses seldom exceed twenty or thirty, feet in width, and bodies of these dimensions would be from two hundred to three hundred feet in length, according to approximate generalization from observation of a considerable number of the smaller lenses, and from the experience of miners who have worked out many bodies. The third axis, that nearest the vertical, follows the dip of foliation. But its length relative to the other axes is not easy to ascertain, even
Arete tate cheese thee ntrehtnessi: | 6° Mapetrgenepnns
10 Geological Survey
approximately, since it is only those lenses which lie wholly beneath the surface and which have been entirely worked out that can give data of any value, and such opportunities for observation are neces- sarily rare. Experienced miners soon agree that the dimension of these hodies along the dip is sometimes greater, at others less, than the horizontal axis, and some are of the opinion that it is generally greater.
The arrangement of the ore lenses en échelon is a matter of much importance in following the ore bodies. Thus in the Capelton district the miners have learned when a lens ie exhausted to drift to the right,
southeast. '
The ore bodies correspond in their arrangement with the order of the hills of the district, and with the general structure of the Appala- chian Mountain system, in which each range when it terminates to the northward is succeeded by another lying to theeast. It is this orogra- phic feature which gives the Atlan:!- coast its general northeasterly trend.
Though rarely, the ore bodies, occasionally, cross the planes of folia- tion of the country rock. They then have the aspect of veins running slightly obliquely to the strike, or more rarely, to the dip of the enclosing rock. These vein-like massses are, however, of very limited extent, and are probably only the filling of local fractures between larger shearing planes. They are perhaps the better developed of the minor series of fracture joints.*
The walls of the ore bodies are aot usually well defined, though one is often more definite than the other. The ore, which con- sists essentially of chalcopyrite in pyrite, grows poorer towards the edges of the bodies where there are no definite walls, until the proportion:. of ore in the country rock becomes so small as to be imperceptible. From the evidence at present available it can only be said that these ores were primarily brought in by the vol- canics in which they are generally found ; that the subsequent folding
* J. B. Woodworth, Proceedings Boston Society of Natural History Vol. XVIII p. 297, 1896.
are
COPPER [BPOSITS ll
and shearing of these rocks developed planes of easier passage in which the subterranean waters, leaching out the metallic minerals from the rock, deposited them by replacement of the rock. The better defined wall on the side of the ore bodies may be due to the fact that the rock on one side of a shear plane being more highly fractured than on the other, as is often the case, the greater replacement would take
', place on the fissile side of the water bearing crevice. Then after the
first film of ore had been deposited a protection is afforded by it for the ruck face on which it is deposited and all further replacement is likely to be on the side of the more fractured rock. The foot wall is generally the one that is better defined.
The common occurrence of chalcopyrite in crevices within the pyrite, and as a thin layer upon a joint face, seems to indicate that the chal- copyrite was introduced later than the pyrite. But of this there is not enough known as yet to speak decisively. Actual crystal replacement has not yet been observed.
The average of a large number of assays of specimens from the south side of the Capelton hill, i.e. from the Eustis and Capelton mines, and other properties of the vicinity, made previous to 1886, showed the copper to range from 4 per cent to 5 per cent ; sulphur, 38 per cent to 40 per cent; and approximately 1 oz. of silver to each unit of sulphur, with small amounts of gold.
A number of assays of recent date from the north side of the same hill, from the Suffield, King and other properc.es, give a lower percent- age of sulphur, but higher metallic values, especially of silver, which here seems to vary without regard to the sulphur. As a very general statement the ores of this class of deposits may be said to carry 4 per cent of copper, 35 per cent sulphur, near the surface, and at greater depths to yield uniformly 3 per cent of copper, 40 per cent of sulphur, 3 oz. of silver, and smali amounts of gold.
Gold, which does not seem to be present in appreciable amounts at lower levels, is often an important factor near the surface. Alluvial gold occurs in many of the streams which run over these copper bear- ing rocks, and the surface rocks yield gold in many parts. At c depth of a few feet from the surface most of such prospects have been aban- doned, but in one or two notable instances the gold prospects have been developed into copper mines, through the copper increasing as the gold values decline.
Although it has not yet been found possible to get information suffi- ciently definite and accurate to make a satisfactory comparison of the
12 GROLOGICAL sURVEY
ores at sotly ne tcPth there appear to be slightly higher copper, ors eutinetly greater gold values, near the surface, thet at a depth
available is, however, insufficient, as yet, to admit of safe generaliza- tion. At present it can only be said that there probably are such
descending waters, The evidences that both the iron and the copper sulphides were deposited in their Present position after the foliation of the country rock began have been already noted.
The source of the copper and other metallic minerals seems undoubt- edly to be the volcanic rocks. The Principal deposits occur wholly within these rocks, smaller bodies, however, being not infrequently found along the contact of the voleanics with an overlying dolomite, In such cases the copper has evidently been deposited contempor-
Tt was recognized by Logan that the copper deposits were derived from the country rock. (Geology of Canada, 1863, pp. 734-5.) But, on the assumption that the country rock was of aqueous origin, they were regarded by him as an excellent example of sedimentary mineral deposits. Thus he wrote (Gsology of Canada, 1863, P. 734 et seq.) "The evidence which has been presented in the descriptions of the copper deposits of the Quebec Sroup, appears to show that the metal. like the iro.. manganese, nickel and chrome, which so often accompany it
the sediments of the period were deposited. By the agency probably of organic mutters it was reduced to the condition of a sulphuret and Precipitated with the sediments, either in a finely divided state, or more frequently, in smal] nodules, or patches, which became interstrat- ified with the limestones, the slates, the diorites, and the other rocks of the series, A subsequent action, probably contemporaneous with that which has metamorphosed and crystallized the rocks over a great part
Spars in the fissures of the rocks ; giving rise to the veins or courses
Copper Deposits 13
With the knowledge that the country rock is largely eruptive, and thateruptive rock is present at all the occurrences of copper of any
probable importance in the district, the above opinion should evidently be reversed.
2. CuAxcorraits, Bornire, Cuatcocite, &c.
Forming Contact Deposits between Cambro-Silurian Limestones and Certain Intrusives.
The ove bodies of the Acton district are the best known of the second class of copper deposits of the Eastern townships. The ores are chiefly sulphides, bornite becoming important, while it rarely, if ever, occurs in the deposits just described.
- This group of ore bodies occurs in the vicinity of a series of dikes
which extends from Roxton in the county of Shefford to Ste. Apol- ' *linaire in the county of Lotbiniére, a distance of about one hundred miles. The principal) occurrences known are at Roxton, Acton, Upton, Durham, Wickham, Drummondville, Nelson and St. Flavien. 'Ihe greater part of all the ore bodies, and practically all of many of them, is found in the sedimentary rocks, generally Trenton limestone. But in several instances, notably at Roxton, Nelson and St. Flavien, copper occurs in the intrusive rock, an amygdaloidal diabase. At Upton a little native copper is also found.
At Acton, which has been by far the most important of this class ' of deposits, a large amount of high grade copper, much of it 30 per cent ore, was produced for several years. The sedimentary rocks at this mine are a magnesian limestone, overlying a black shale. Both are cut by dikes or an irregular intrusion of diabase, or some allied greenstone. The productive part of the deposit was found in the limestone, and when this was passed through the smaller amounts of ore in the shale made the work unremunerative.
In the township of Durham, some twelve miles south of Acton there occurs a body of t xe ores, the most southerly of the group. It is located near the southern edge of the limestone, which is here only fifty feet thick. The ore supply failed, just as at Acton, when the shaft reached the underlying shale.
Upton, six miles northwest of Acton, is the most remote of the deposits in that direction. Four different properties were at one time worked in this vicinity. Nono of the workings seem to have reached
14 Geological Survey
amount of high grade ore was obtained by hand picking. machinery for crushing or mining seems to have been used.
At Wickham, eleven miles northeast of Acton, copper was mined # swall extent. The geological conditions are similar tc those Upton, but the thickness of the limestone was not reached at eit! place.
At Drummondville, Nelson, and St. Flavien, farther to the nor east, the copper occurs in the intrusive rocks, which seem to fo one or more dikes a quarter of a mile in width. The principal we was done at St. Flavien, where several shafts were sunk, and a dey of a hundred feet or more attained.
Although considerable development was carried on at all of t localities mentioned, as well as at some others, no permanent ores ha resulted. The tact that the gangue material with the ores of this cls of deposits is limestone should make them valuable to mix with. t siliceous ores of the other deposits, where even a very low percent of copper would add to the value of the limestone as a flux.
3. Cuatoopyrire in Pyaruotite.
Forming Contact Deposits between Intrusive Diabases of the Serpenti Series, and Sediments.
The ores of the third class of deposits are distinguished from t others by the predominance of pyrrhotite. Iron pyrites is also preser but chalcopyrite seems to be the only form in which copper occurs these deposits. They are known to occur at various points along tl serpentine belt, especially in the townships of Bolton, Potto Brompton, Orford, Ham, and Garthby, and are liable to be four anywhere along the contact of the later eruptives of the serpentii area.
The Huntingdon mines, in the township of Bolton, have been tl mest extensively worked of any of this group. The ore forius a boc some eight feet in width at the surface along the inner contact zor of a dike with clastic rocks, There are no structural or other featur to suggest secondary concentration of the ore, or that the deposit
Sonat sea kore etc Sa aga
ix with, the
Serpentine
d from the lso present, ir occurs in s along the n, Potton, 0 be found serpentine
e been the ims a body tact zone er features
) deposit is
other than an original segregation in the magma of the intrusive rock. The ore, of which large shipments were formerly made, is reported to have yielded an average of about 5 per cent copper.
The-mine has not been in operation for some years. During the period of its most successful operation the nearest railway was twenty- four miles distant. At present a newly completed portion of the Orford Mountain railway pazses within a few yards of the shafthouse.
The properties known as the Bolton and the Ives mines are situated about « mile and « half north of the Huntingdon, and near the village of Eastman, on the line of the Canadian Pacific railway. In the character of their ores, and their mode of occurrence, they are essen- tially similar to the last. They too are at present closed.
on the northwest slope 8 Landing, in the town-
surface. The ore-body
sight, and exposures a
ion of the same deposit.
and ten feet of ore
are exposed, without the inner limit of the ore body having been
reached. This ore varies in the amount of copper it carries from one
to mine per cent. There are also small amounts of gold, generally enough to be appreciable.
In lot 21, range of Garthby, there is a deposit of a similar ore, which is apparently of important size. It is known as the Garthby, or Lac Coulombe mine. A shaft, said to be fifty feet deep, has been sunk, and apparently much of the output remains on the ground. The shaft seems to be sunk in solid ore. The surface stripping has not been sufficient to make it possible to estimate, even approximately, the size of the ore body.
Ii.
Iengous Roces or tHe Eastern TownsHips oF QuEBEc.
Outline. 1. Area defined. 2. Geography. 3. General geology.
4. Sketch of previous geological research. 5. Petrographical Province of the Eastern townships.
HEE | aap ee bearing volcanics, and asroci f roc
J HH! 3 (6) Serpentines and diabases. HH (c) Granites. -
ea: d) Later dikes.
6. Petrographical Province of the Monteregian hills.
i] I.
: That portion of the province of Quebec which has been affect the Appalachian uplift lies wholly to the south of the St. Laws river. It comprises two some-vhat distinct parte, the mountai region of the Gaspé peninsula along the lower St, Lawrence, and hilly country from the Chaudiere river to the [international Boun Line between the province of Quebec and the States of Maine,
Hampshire, and Vermont. The interval between the two portio | marked only by a subsidence in the Appalachian hills southeast o' i city of Quebec.
Hid The second of these two areas is commonly designated as
PH | Eastern townships. Being less easily accessible, on account o
hilly character as well as its position, and also hss desirable other for settlement, this region was not surveyed until some thirty ; after the cession of Canada to England. It was then, accordi: divided into towns' ips approximately square, and it was further divided into ranges and lots, according to the Englizh method, ins of being formed inte seigniories and parishes after the old Fr mode of survey.
The general trend of the hills of the Eastern townships is a n easterly one, conforming to the direction of the Appalachian fol the successive ridges growing higher as they are more remote fron St. Lawrence valley. The principal rivers, such as the Yamaska Francis, Nicolet, Begancour and Chaudiére, cross these hills abou right angles to their course, and drain the region into the St. | rence,
2.
The tricauries of these rivers, however, take their direction the Appalachian folds and generally flow in either northeast or s
hian folding, mote from the Yamaska, St. 'ills about at » the St. Law-
direction from
east or south-
Copper Deposits 17
west courses. The tributaries are, therefore, subsequent the Appal- achian hills, while the main rivers are either antecedent to the later stages of that uplift or have been superposed on the older rocks by the extensive denudations of the region. Hence the tributaries are commonly much younger than the main rivers. From these facts, and also since the course of chief glacial action has been parallel to the valleys of the principal rivers and transverse to the tributaries, it result. that many of the iatter empty into the former by falls and rapids. The water which these furnish has given rise -everal manufacturing centres, as the city of Sherbrooke where the Magog falls into the St. Francis, and the town of Windsor Mills at the junction of the Ouatopekah with the same river. The principal rivers thus give cross sections of the region, while the tributaries usually afford much less information regarding the underlying rock.
With the exception of . few small outliers of Devonian the sedimentary rocks of the Eastern townships are now considered to
be Pre-Silurian in age. Silurian strava occur a short distance to the north of the district in question, and small outliers may be found within it, but thus far none such have been definitely Jetermined. To the Cambro-Silurian have been assigned certain of the limestones, the calcareous and ferruginous slates ; to the Cambrian, part of the quartzites, greywacké, and the clay slates; while similar rocks, with the exception of the clay slates, are referred to Pre-Cambrian, as well as the large areas of slates that are characterized by the presence of chlorite and epidote.
Igneous rocks are found to underlie the earliest sediments, and to be intercalated amongst them, and to be intrusive through even the
_ latest. Altered volcanics of both acid and basic types are the oldest ;
while closely associated with them are large areas of stratified rock, which are thought to be in part, at least, much altered tuffe. Serpen- tines occur amongst the earliest sediments, and probably also cut others of somewhat later age. The diabases and later gabbro-diorites, which are closely associated with the serpentines in position, as well as the granites which lie to the southeast of the Appalachian ridges, and the syenitic rocks of the Monteregian hills to the northwest, are later in age than any of the sediments. Still later than these are the aes camptonite, diabase and bostonite, which cut all of the rocks
—-Z
nerves
18 « Solotical Burvey
already mentioned, and are themeolves little altered in character disturbed in position.
enincetesoneneteeeene) | eee Te
Hy The group of rocks thus nawed by Logan and Billings was consi HH ered by them to be equivalent to the Culciferous and Chasy formation
foi ridges, which aze roughly parallel, run in » northeasterly course as de PA termined by the Appalachian folding and are themselves about twenty five miles apart between the St. Francis and the Chaudidre rivers The rocks composing them were, in the first investigations of the Geo. logical Survey under Sir W.E. Logan and Dr. T. 8, Hunt, named argillites, sandstones, chloritic and nacreous schists and slates, In stratigraphical arrangement these ridges were supposed to be synclinal troughs, which had resisted denudation better than the intervening
strata,
This view was first questioned by Hunt on stratigraphical grounds, and later sy Selwyn, both on stratigraphical and lithological evidence. Or. Selwyn reached the conclusion that these folded ridges are anti- clines, not synclines, and held that the rocks composing them were older than the Quebec gi. 1p and consequently formed no part of it. The results of the subsequent inv estimation by Dr. Ells substantiated this view.
* Sir W. E. Logan, Geology of Canada, 1963, et aliter.
—
A ernrePeenen tare trmemesrcmtmentreamenons | hath} shupetnuneessnc setettehirenensrntentesees
ie es cae
gabbrodiorites of Brompton, "rford and Ham. These are described at some length in the Geology of Canada, 1863, and have been previously discussed by H-nt.
that the stratigraphical questions
cated by the fact that some of the other highly netamorphosed rocks were in reality disguised volcanics. A suite of specimens of doubtful rocks submitted by him to Dr. F. D. Adams, (Annual Report, G.8.C., 1880-81-82) proved the serpentines to be altered igneous rocks gener- ally of the peridotite class, the so-called diorites to be diabases and al- lied rocks, and some of the other highly altered rocks of the region to be of sedimentary origin. :
The re-examination of the areal geology of the district which was necessitated by this iuformation, was entrusted to Dr. R. W. Ells, the results of . .«e investigations appear in the Annual reports of the ye t 1886, 1887 and 1894, and in the maps which accompany them.
In these maps the crystalline belts of Sutton and Stoke mountains are represented an Pre-Cambrian in age, and an area along the Inter- national Boundary Line is included in the same horizon. The sediments intervening are assigned 'o the Cambrian and Cambro-Silurian with the exer 'on of some very minor areas which, as has been said, were found to neve been occupied with remnants of Devonian and possibly of Silurian measures, The serpentines are included with the igneous rocks and the oceurrences of ' basic eruptives' are shown to be more numerous than appeared in the earlier maps. The great body of the Pre- Cambrian, however, remained amongst the sedimentary rocks.
In addition to the accounts of these investigations a few independ- ent papers have been published on this region.
In 1876 Sir J. Wm. Dawson discussed the mode of entombment of certain fossils, referring especially to localities in the Eastern townships. Some of the occurrences of fossils thus mentioned are of essential importance to this investigation.
9144-24
20 Geological Survey
In 1879 Dr. T.{ +: Hunt in the American Geologist discussed th structure of the region under the title 'The Quebec Group in Geology
In 1882 in an address before the Royal Society of Canada Dr. A R. C. Selwyn first outlined his views of the stcucture and genera lithology of the Quebec Group. (Trans. Roy. Soc. Can., 1882),
In 1902 the present writer showed that important parts of the Pre Cambrian are composed of volcanic rocks which by their extreme
(a.) Copper Bearina Votcanics.—(Pre-Cambrian.)
The physiographic structure of the Eastern townships, it has been id, :
One of the belts appears for only a relatively short distance along the boundary line between the Province of Quebec and the State of
The second crosses the St. Francis river between the city of Sher- brooke and the village of Lennoxville, and is commonly referred to as the Ascot or Stoke Mountain belt. It may be traced from the foot of Owls Head mountain and Lake Memphramagog through parts of the townships of Stanstead, Hatley, Ascot, Ascot Corner, Stoke, Duds- well, Weedon and Stratford. The similar rock at the Gilbert River gold
mines, in the seigaiory of De Lery, on the east side of the Chaudiére river, undoubtedly belongs to this belt, ree ee
—— SSS "Transactions of the Canadian Mining Ins: ute, Montreal, March 2, 1902" American Journal of Science, July, 1902,
cussed the | Geology.'
da Dr. A. d general 2).
f the Pre- extreme relation
suggested,
iams was
nas been e in the g paral- lich rise rests of atlying
| within
e along tate of linton, lake of
- Sher- | to as foot of of the Duds- r gold udiére
a
1902"
Copper Deposita 21
The third of these belts, which crosses the St. Francis river near
.the town of Richmond twenty-five miles northwest of the last, is gen-
erally known as the Sutton Mountain belt. This is the largest and longest of the three as far as is at present known. While the Stoke belt is nowhere more than five miles in width, that of Sutton is quite twenty miles wide at the Vermont boundary line. It has a consider- able development in the counties of Brome, Shefford, Richmond, Wolfe, Arthabaska, Megantic, Beauce, Dorchester, and probably ex- tends also into Bellechasse and Montmagny, that is, to a point at least one hundred and forty miles from the boundary of the State of Ver- mont. °
The rocks of the Sutton Mountain area were described by Logan, ('Geology of Canada,' p. 246,) as 'chloritic micaceous and epidotic rocks. Towards the province line,' he continues, 'these are of a slaty charac- ter and various shades of colour, from dark bluish-green or blackish- green to ash-grey. The green bands are more abundant than the grey, and both have cccasionally a talcoid lustre. The grey bands appear to deriv~ their colour from a large amount of very fine grains of quartz which are uniformly mixed with chlorite. These beds often contain certain nodules of while granular quartz, and crystalline pistachio-green epidote sometimes several inches in diameter, and fre- quently elongated in parallel directions. The two minerals are often in separate nodules, but ag often are intermixed; in the latter case the epidote is generally within the quartz. In the grey bands fine blackish-green lincs of chlorite often run parallel to one another, but these are contorted by the nodules of quartz and epidote, with which orthoclase feldspar is sometimes associated. 'Radiated actinolite often occurs in the rocks, together with asbestus in short parallel veins which are found cutting the epidote in the direction in which the nodules are elongated, and occasionally between the layers of slate. Crystals of specular and magnetic oxide of iron are abundant in the chloritic and epidotic bands, the magnetic species being more frequent. where the chloritic prevails.'
'Near the St. .ncis nodules of an epidotic character are richly dis- seminated througn the chief part of these chloritic strata, some of the nodules being six, eight and even ten inches in diameter. Some of the bands hold small portions of finely granular quartz which occasion- ally swell into beds of white quartzite of some importance, while many of the strata assume the aspect of fine quartzose conglomerates, or coarse sandstones with a chloritic base."
henrenensteiinnhintsneinetl enneithenbintintsnasivanpuinanbctnincasana
seiteeeemmmnanenaee nc nnn
22 GEOLOGICAL suRVEY
Regarding the rocks of the Stoke belt, Logan writes (Geology « Canada, p, 252), " The rocks of this group here at the base of Ow! mountain, branching off froin ® range of hills which come Dy
the township, and in Stoke they present two parallel ranges included in a breadth of about five miles,"
ing @ very quartzoss character, and thin layers of agalmatolite of a somewhat fibrous texture are sometimes met with, Some of the
brooke they enclose a bed of blood-red jasper, passing into a siliceous, red hematite, and another of & somewhat siliceous conglomerate."
stratified, and the other unstratified. The latter is &@ volcanic rock, finely crystalline, and of both acid and basic Phases. Quartz porphyry
geology of e of Owls
come up -
ind cross- | through hich are ed. The 8 seldom a the St. ..38e un- 2 miles orner of included
rocks in tituting
Copper Deposits 23
and andesite, or diabase, would originally have been the extreme types. Some of basic phases are altered to serpentine, and all have been highly metamorphosed. It is only by very detailed field study, together with microscopic examination, that the volcanic character of some of these rocks has been ascertained.
Associated with these are stratified rocks of similar material, but which have an original clastic structure. Part contains bands of nearly pure chlorite, abundant quartz veins, -nd much iron ore. These are thought to be stratified tufts, while other rucks, generally - more siliceous, as chloritic sandstones and grayw. >kés, are probably true sediments.
Although highly altered the volcanics of this series still show their original characters in localities in which the deformation has been least. The acid phase of the rock is largely a quartz porphyry. A specimen from the hanging wall of the Silver Star mine at Suffield is light grey in cole :r, and on the weathered surface the quartz phenocrysts are quite conspicuous. Owing tothe bleaching of the base the rock he- commonly been mistaken for quartzite, or a species of sand- stone. J ollowing is an analysis by Mr. M. F. Connor, B. A. Sc., Geologicai survey of Canada, of a specimen, of the essentially similar
rock from the quarry at Sherbrooke, which furnishes road metal for the streets of that city:
In the thin section st is found to be a porphyritic rock with a finely crystalline base, which contains phenocrysts of quartz and feldspar. The latter are both orthoclase, and plagioclase, the orthoclase being more abundant.
Small rod-like bodies of colourless mica are present in the rock, as well as irregular areas of a rhombohedral carbonate which is apparent- ly dolomite.
24 GEOLOGICAL survEy
Near Lennoxville, on the line of the Canad':n Pacific railway, tl rock becomes a granite Porphyry, differing from the rock just deseril ed chiefly in the more advarced character of its crystallization. Fa,
becomes stil) more Coarsely crystalline, and passes from quartz Porphyr: at the margin to Sranite porphyry, and finally to a Pporphyritic granit. towards the interior. The latter is the rock of Bald peak, and of othe, Principal hills of the central portion of the Stoke Mountain area, as
The acid and the basic phases of thes » :antics are not, howeve:;, pro-
ducts of Separate irruptions, but are "143 to sharply defined magmatic differentiation, This is well gh- + in several of the st
be described later, rather than to those of the present cl, are not of Pre-Cambrian age,
ilway, the st describ- ion. Far- al portion 'Porphyry lc granite d of other area, ag > portion Precisely present. ture in- acter of ite, rich pass by y found 1 to ser. ng left, derived adjoin- ructure 'mesh' bestus © been > been
'y pro- matic that rook, - one 2 the tion. ntly, cut s to they
Copper Deposits 95
early volcanics that were described by the late G. H. Williams in the ' Journal of Geology,' Jan., Feb., 1894 ; (See also Ancient Volcanics of South Mountain, by F. Bascom, Bull. U.8.G.8., No. 136).
Posstste Pre-Camprian Sepimen's.—Of the stratified rocks in the metamorphic belt which are most closely associated with these vol- canics, the extremely chloritic portions are probably ancient tuff beds, or at least are composed of fragmental volcanic material, and so are pyroclastic rocks. In the present degree of alteration they do not differ essentially from certain portions of basic rocks just described. Besides these are siliceous rocks, quartzites, greywackés and chloritic sandstones, which are possibly true sediments. | With these are fre- quent beds of dolomite, the origin of which seems a matter of doubt. The rock is frequently found resting upon a basic trap, filling pit holes and interstices within is, and enclosing fragments of it. In other cases the rock passes by a rather gradual transition intoa quartzose dolo- mite in masses of considerable extent. At the Eustis mine the portion of the country rock known to the miners as the ' green rock ' is of this type. Even in the thin sections small areas of dolomite appear some- times enci:. 'ng small quartz crystals and indicating the secondary nature of the dolomite.
Certain of the micaceous chloritic slates also contain sufficient dolo- mite to cause a slight effervescence by hydrochloric acid, when heated.
Along the St. Francis river the Sutton belt is some seven miles in its extreme width including nearly two miles of recognized Trenton measures within it. A detailed study shows the volcanics at the base with dolomite, quartzite and grey mica schist, in ascending order. Within the dolomite are certain peculiar inciusions of a bluish grey limestone which have been largely crystallized by intense regional metamorph- ism. One of these inclusions, however, contains fossil evidence of its Calciferous-Chazy age. It is, therefore, demo~strated that in this part, at least, the Sutton Mountain belt contains no Pre-Cambrian clastics.
As it thus seems certain that the Sutton series contains no Pre- Cambrian clastics in the vicinity of the St. Francis river, it is conse- quently possible, if not probable, that all the clastic rocks of this series throughout the district are, as in this section, altered members of the Quebec group.
The voleanics are the oldest rocks in this region, and from their lithologic resemblance to the Pre-Cambrian rocks of Pennsylvania and
Copper Deposits 27
twenty square miles and an average height above the surrounding country of one thousand feet, It comprises two main divisions which give the following cross section measured westward along the line of the Canadian Pacific railway near Miletta : diabase or gabbro-diorite, 7837 feet, greywacké 165 ft., serpentine 577 feet, sandstone 82 feet, serpentine 1567 feet. This section is bounded by sedimentary rocks on either side. The rock of the first and greater mass is a uniform green colour, and shows grey grains on a freshly broken surface. Quartz veins are common -and the joint plane and seams are oftzn studded with small quartz crystals. Patches of epidote sometimes as much as a foot in diameter are numerous. The texture of the rock becomes finer towards the outer edge, and also towards the top of the mountain, where the vooling of the igneous mass has taken place more rapidly. In the thin section, this rock, which is exceedingly altered, shows plagioclase feldspar with aggregates of pyroxenic decomposition products, whose relation to one another indicates that the rock has had the structuro of a diabase. In the coarser rocks of the central part of the mountain the mineral olivine appears. The rock has the mineral composition of diorite, but the hornblende is secondary and the rock therefore becomes a gabbro-diorite. The two rocks are apparently differentiation products of a single volcanic output.*
Analyses by Hunt (Rep. Geo. Sur. Can., 1853) show the composi- tion of the altered gabbro-diorite and diabase mass, under the head of diorit., to be as follows:—-
| | | |
"30 ee
99.80
I. Diorite, Brompton lake, Orford, Range XVI, Lot 2. II. Diorite, St. Frangois de Beauce. ITI. Grano-diorite, Butte co., Lassen peak, California.
Owls Head (2,465 feet) is situated on the west side of Lake Mem- phramagog, sixteen miles south of Mount Orford, which stands at
*J. A. Dresser, American Geologist, January, 1901.
28 Geological Survey
the northern end of the same lake. The level of this lake is about six hundred and eighty-two feet above the sea.
The rock at the eastern base along the lake shore is a common basic phase of the PreCambrian volcanics. On the west side the adja cent rocks are sedimentary. Between these the mass of the mountain has been intruded. It consists, as far as yet known, of extremely altered diabase which was first determined by Dr. Adains.
Sugar Loaf, the name by which a continuation of the Owls Head mass towards Orford is generally known, has been also shown by Dr, Adams to be similar in composition. (Rept. Geol. Sur. Can, 1880-1-2, 'Part A, appended.)
Besides Orford, Owls Head and Sugar Loaf, there are several hills alung this line, presumably similar in character. These are Hogs-
mountains at the south of Owls Head, and Carbuncle and other hills at the north of Orford. So far as known these hills are similar to Orford and Owls Head in general structure as well as in the char- acter of the rocks composing them. Fifty miles to the northeast from Orford, Big Ham mountain appears as the next prominent point along the serpentine belt, although that belt is almost continuous through- out that distance. The mountain rises fourteen hundred feet above the neighbouring land, or twenty-four hundred feet above mean sea level.
This mountain, as far as known, is a mass of much altered diabase. Near the eastern edge of the summit the diabase passes into a rock intermediate betweeu hornblende granite and diorite, which may be tentatively classed as ® grano-diorite. The transition is a rather sharp one, a distance of only a few yards separating typical specimens of the two rocks. The grano-diorite seems to form only a small body, and is probably the residual filling of the neck of the volcano which gave rise to the mass of the mountain.
Moose mountain, in the township of Cranbourne, beyond the north- eastern limit of this map, is thought to belong to this series, although there is not much definite evidence concerning it yet available. A specimen from a spur of the mountain in the township of Frampton is a porphyrite, a not uncommon marginal phase of these rocks, and, a8 Dr. Ells reports the mountain to be intrusive in its relation to the sediments of the district, it may apparently be safely correlated with the diabase series.
Copper Deposits 29
Rocks very similar to those of Orford have been described from Adstock mountain, and also from the township of Potton, by Dr. F. .D. Adams (op. cit.) Dr. Adams found a specimen from the summit of Adatock to be a diabase, and one from another part of the same movr' >» be a diorite, both being much altered rocks. Concerning #l he wi'tes: 'It is a rather coarsely crystalline, massive, and «. . gteyish-green colour, and is composed of hornblende and plagio- clase. "ac hornblende is green, or, in some places, brownish in colour, and is distinctly plechroic. . . . . It is often twinned. Much of the hornblende is decomposed to chlorite. In many cases the altera- tion appears to pass through an intermediate stage in which the horn- blende assumes a very finely fibrous appearance. The fibres are generally approximately parallel, but do not as a general rule extin- guish simultaneously. Individual fibres can often be seen to have an extinction inclined at a small angle to their longer axes. Some of these fibrous grains show a distinct biaxial figure. The plagioclase is dull from incipient decomposition but generally shows well defined polysynthetic twins, of which two sets are frequently present crossing one another. Although the two minerals have interfered with each other in crystallizing, both show good crystal forms. The feldspar is pethaps upon the whole the better crystallized of the two, The fibrous hornblende is found everywhere to be mixed with chlorite.'
The igneous origin of the serpentine was alan first pointed out by Dr. Adams in the same publication. Ina specimen from Melbourne the rock was found to be wholly reduced to serpentine, with the exception of a few grains of bastite or other mineral derived from rhombic pyroxene. In specimens from townships of Ham remnants ot the primary olivine were also found.
The following analyses of serpentine of the Eastern townships are taken from the Geology of Canada, 1863.
-—— Orford Ham Bolton. ee Deere = = = = * be a age Sea eee Nickel oxide...... ....... Sere : ee See be a ee re | 7°02 3°60 3°51
SS eee ee ee | 13°35 13°00 12°45 100°00 100°00 100°34
30 Grological Survey
Hornblende granite also occurs within this belt and is commonly intrusive through the serpentine. In other parts it seems to form an acid portion rather sharply differentiated from the magma of the. parent rock of the serpentine. It has been deseribed by Dr. Adams Lop. eit.) as composed essentially of quarts, orthoclase, plagioclase, and
contact with the quarts it displays « terminating in tutte of fine needles running into the quartz opposed to this marginal facies. The hornblende displays an ordinary even edge when in contact with the feldspar.
Dikes of this rock cutting the serpentine are considered by miners to be indicative of the occurrence of good asbestus. Whether the fracturing of the serpentine accompanying the intrusion of the granite has in any way furnished lines of weakness for the formation nf aabestus veins has not yet been established.
Serpentine, apparently quite different in origin, occurs at several places within the porphyry andesite belt already described. Here, within a distance of ten to twenty feet, well exposed rock may be trac- ed from a quartz-porphyrite to serpentine carrying narrow veins of asbestus. Such occurrences are found in the townships of Ham and Leeds, and several other places within the volcanic belt. So faras yet known none of these are of large extent. That in Leeds is probably half a mile in length. The importance lies, however, in showing the range of magmatic differentiation, and consequently that the quartz- porphyry and serpentine are differentiates of a single original magma. 'As these are the extremes of chemical composition amongst the various rocks of the region the probability of all being differentiation products
of a single primary magma is quite apparent.
(c.) GRANITES.
The granites of the Eastern townships occupy six principal areas, none of comparatively great extent. They form the granite masses of Stanstead, Hereford mountain, Big Megantic mountain, Little Megantic mountain, a small area on the east side of Lake Mem- phremagog, and another near Danville. There are probably numerous other small occurrences in this district, but it is noticeable that all of the granites lie to the south of the volcanics of the Sutton ridge.
None of the granite bodies have as yet been studied in detail, but all are believed to be intrusive through Lower Silurian sediments, and are thought to be of late Devonian age. The extensive quarries at
Copper Deposits 31
Stanstead have made the economic importance of that occurrence well known in the provinceof Quebec, where Stanstead granite is largely used for structural purposes. A specimen of this granite has been described by Dr. F. D, Adams, * and shown to consist essentis'ly of orthoclase, quarts, and biotite, with acvessory amounts of microciine and plagio- clase, and secondary muscovite and epidote.
Of Hereford mountain nothing definite is known, save that its prox- imity to Stanstead and the generally similar appearance of the rock in the hand specimen suggest ite close relation to thet body. Its contact with the sediments is undoubtedly intrusive.
Even leas is known of the Big, and the Little Megantic mountains. The material in the talus slopes of the former is a very acid granite.
The granite from Scotstown contains pyroxene, in addition to bio- tite and muscovite, as ferro-magnesian constituents.
The granite near Lake Merphremagog is also of the type of that of Stanstead.
Near Danville there is a small body of granite whose relation to the surrounding rocks has not been ascertained, nor has it received any detailed study. Biotite is the only dark constituent that is notic- eable in the hand specimen. It is mentioned in the geology of Canada, (page 811), that it furnished part of the material for the Grand Trunk Railway bridge which crosses the Nicolet river in the vicinity.
The granite from the quarries at Stanstead shows an incipient cata- clastic st:acture in the microscopic section, anc in the mass, a some- what distinct foliation, known by the quarrymen as the 'rift.' This structure is apparently due to dynamic metamorphism, and shows the granites to have shared in the folding of the Appalachian uplift, and consequently to have been intruded before that movement had entirely ceased. As dikes of adjacent granite raasses cut Devonian (Lower Helderberg) strata on the shore of Lake Memphramagog, these intru- sives are thought to be of late Devonian aye.
(d.) Later Dixes.
A series of dikes of much later age than any of the rocks hitherto described is widely distributed throughout the region. They are comparatively fresh in composition and little disturbed in position. Camptonite, diabase and bostonite are the chief rock types repre- sented amongst them.
* "Description ot & Series of Thin Sections of Typical Rocks," by Frank D. Adams, Ph. D., F.G., Montreal, 1896.
32 Geological Survey
A camptonite* at Richmond was found by the writer to consist of hornblende and plagioclase with magnetite and -etite. A little leucoxene and small aggregates of chlorite, serpent? and calcite indi- cate that some degree of decomposition has' y begun in the rock.
The hornblende is brown in colour, and shows the extinction angle, to be as high +3 17°.
This dike, which is about three feet vide, cute lower Trenton lime- stone which has been greatly folded and distorted prior to the injge- tion of the dike. One or two smaller dikes occur in the vicinity and a small hill nearby is thourht to be underlain by the same igneous rock.
In the vicinity of Sherbrooke, twenty-five miles south of this locality, dikes are known to occur in several localities.
Near the line of the Canadian Pacific railway, in the northern outskirts of the village of Lennoxville, there is a camptonite very similar to the above.
It cuts both Pre-Cambrian volcanics and sedimentary slates of Trenton age.
At the Howard mine, Ascot, a dike of olivine diebase cuts Pre- Cambrian eruptives.
In a paper entitled 'Camptonites and other Intrusives about Lake Memphramagog' (Amer. Geo., July, 1895), Mr. V. F. Masters dis- cusses a large number of dikes in Leke Memphramagog tasin, distin- guishing the granites, &c., connected with the intrusions off McGoon point already mentioned, from camptonites and allied dike rocks.
Between Roxton in the county of Stefford, and St. Nicholas in the county of Lotbiniére, a distance of more than one hundred miles, there are several occurrences of intrusive rock in lower Palaeozoic strata. It is little known except in connexion with copper deposits in the region, which it seems invariably to accompany. It is found at Rox- ton, Acton, Upton, Durham, Wickham, Drummondville, Nelson, St. Flavien, St. Apollinaire and St. Nicholas, and seems to form a series of dikes in a comparatively narrow belt throughout this distance. The dikes vary in width from a few inches to a thousand feet or even more. and run parallel to the length of the belt in which they occur, i.¢. in a northeast- southwesterly direction.
* A hornblende, lamprophyre dike at Richmond, P.Q., J. A. Dresser, Can. Ree. Sec., Jan., 1901.
At Roston there is 4 light coloured intrusive of the trachyte class, but in most of these occurrences the voleanics are diabase, and are
commonly amygdaloidal.
'The largest exposures are at St. "lavien, Nelson aad Drummond. ville. At 8, Flavien the intrusion ie nearly « quarter of a mile wide and appears to be a wide dike, extending for « distance of about a mile through the country. Similar rock appears at St. Apollinaire, seven miles distant.
These are the principal rock exposures. It is a level district cov- ered with a heavy mantle of drift. The rock is amygdaloidal in many parts, the amygydules being moat commonly filled with calcite ; some- times epidote and chlorite or quarts form the filling material. frequently oovurrs in this rock, and also at Rexton, Nelson and Wend- over, neat Deummondville. In other places, as at Acton, Upton and Wickham, the copper occurs in the extomorpbie contact zone of the enclosing rock. The exposure at Nelson is smaller than that at St. Flavien, while that at Drummondville is apparently quite as large as the latter.
It is thus cleseribed by Logan, (Geo. of Can. 1863, p. 243,). "The greenish sandstones on the St. Francis are intersected by several dikes of diovite, the courses of which are in a general way down stream. The rock of the fall at Drummondville appears also to be a diorite and is of a grey or greenish colour ; it probably belongs to the stratification and is not known to have any connexion with the dikes. It has a breath f ahout half a mile, and some parts are porphyritic from the presence of small crystals of light, greenish feldspar while others are amygdaloidal, holding small portions of a light and calc spar and occasional nodules of agate. Much of it bears the aspect of breocia, in which fragments of the diorite are held together by a close grained bat highly crystalline calcareous cement, approaching in colour the general mass of the rock. The rovk bears a resemblance to that of St. Flavien, of which it may be a continuation, and like it highly cupriferous.'
So far as yet examined, some half dozen specimens, the diorite of the above description proves to be a fine grained diabase. The diabase forms two bands crossing the St. Francis river here—one having a width of a quarter of a mile and the other of about fifty feet. The distance between them is rather more than a quarter of a mile
and is — very dark graphite limestone and greenish 9144— : 7
34 Grological Survey
grey sedimentary slates. What appears to be devitrified glass was found along the contact of the diabase and the latter rock. These rocks have been here mentioned under the head of 'Later Dikes,' because of their lithological similarity to known dikes, and the absence as yet of satisfactory proof that they are not them- selves also of that class. This entire series offers an excellent field for an interesting and important detailed investigation.
6. PerroGRAPHICAL Province OF THE MONTEREGIAN HILLS.
This name, which has now gained general currency in geological nomenclature, was proposed by Dr. F. D. Adams, in 1903,* to designate a series of volcanic hills which crosses the St. Lawrence valley in the southwestern part of the Province of Quebec. These hills, which are sight in number, are of volcanic origin, either stocks or laccolites ; they 'owe their present relief to differential erosion, and consequently are hills of the butte type.
Six of the eight hills form a nearly east and west line, standing about ten miles apart. In order from west to east they are Mount Royal, at the foot of which stands the city of Montreal (Mont Royal), Montarville or St. Bruno, Belceil or St. Hilaire, Rougemont, Yamaska and Shefford. The remaining stand at the south of this line, Brome being two and a half miles from Shefford, and Mount Johnson, six miles from Rougemont.
The lithological characters of these hills are such as to show them to be a distinct. petrographical province, and to bear little, if any, relation to the rocks hitherto described in this article. In every hill there is a large development of essexite, which frequently passes into theralite, and in every one which has been studied in detail, an alkali- syenite such as nordmarkite, pulaskite, or nepheline-syenite. A list of the analyses thus far made from these rocks may serve to indicate their general character.
Saas ae of Seokeg: » vol. xi., No. 3, 'The Monteregian hills, a Canadian
Copper Deposits 35
CHEMICAL ANALYSES OF TYPE ROCKS FROM THE Monterecian Hints.
| 2: — 2 ees ees SESS em == 1) om | a! iv v | ve] vir| vir] rx
ae
| i
FS ped & & E
ee
3383 3 3
+00 Be 2
SSSSSSRSSSES FO meme
ses wee
&S>
Ssse te eo coro SS
—s Re eh
— cL dehaebictetctc
sesssssevgse me tome: SS
+ Busse (Keogzowe) Mt. Johnson. | VI. Nordmarkite(Nordmarkosg) Brome
VII. Puleskite(Lourviboss) 260. ohnson eg Caren) Beate Shefford. VIII. Shefford.
IX. Tinguaite(Leurdalose) Brome. v. Nordinar meme} Brome. Sheffordl| nguaiteLaurdaloe)
A better knowledge of the igneous rocks of the Eastern townships, especially of the granites and diabases, is necessary before their gene- tic relations can be satisfactorily discussed. Yet certain general relations may now be deduced, and these conclusions, it is hoped, may be amplified and more precisely applied at some later time when all the rocks in question have become better known.
In general terms it may be said that those rocks of a definite dis- trict belong to the same province, (Dr. H. 8S. Washington, Journal of Geology, Vol. VI and VII, " Petrographic Province of Essex county,
Mass."), whose phases in their nearest approach to one another do not differ more widely than the various differentiates of any single mass. Thus the porphyry-andesite series differs in its acid phase from the granites, as far as the latter are known, chiefly in degree of crystal- lization, not. in composition. The more basic phase of the old vol- canics, as has been shown, passes by differentiation in situ into a rock which has altered into serpentine. Hence the oldest group seems to form a connecting link between the granites on one hand and the dia- bases, serpentines, etc., on the other, and, accordingly, these three groups form part of a single petrographic province according to the definition quoted above. The Monteregian rocks appear more distinct
36 Ghological Survey
throughout the quite extensive range of variation within themselves. The individual hills differ from one another in a comparatively small degree. Also their distinctive characteristics are not yet found in any measure in the other groups of rocks mentioned. Should a detailed study of the granites show that within them are differen- tiated portions of more basic rocks, as, for example, should nepheline syenite be found in association with them, as it has been found in some cases in the Hastings district by Drs, Adams and Barlow, they would then appear as an acid extreme toward the east of the Monteregian series. But this has not been done, nor is there at pre- sent any valid reason for expecting such phenomena to be found. While the Monteregians appear at regular intervals at upwards of ten miles across the plain, no rocks of consanguineous types have been found to the east of Shefford mountain, although a careful examina- tion has been made in that direction throughout the district wherever igneous rocks are known to occur. In the later dikes an indication of rocks of the Mon'eregian type exists. Though it is conceivable that almost any rock might be differentiated in small amounts from almost
rocks described in this article more widely than any of these from one another, that is, that the difference is a generic rather than a specific one. Hence the relation could be best defined as that of two con- tiguous provinces rather than as parts of one province even in the larger sense.
The study of the consanguinity of rocks tends toward the hypo- thesis that the interior of the earth may br 'garded as containing a single magma of uniform character which,'. rocess of differentiation within the crust of the earth, or during the process of extrusion, or during the process of cooling after extrusion, gives rise to all classes
Copper Deposits 37
versal common magma and are differentiated only by the rock material with which they come in contact. Nor could it be counted a directly essential character in large extrusive volcanic outputs. But in the consideration of intrusive rocks, where the invading lava may for long periods of time have been slowly taking in and dissolvir.g the sur- rouding rock material, the process of magmatic stoping may have made the assimilation factor an important one in the modification of igneous rocks.
The Monteregian hills are all intrusive, and are comparatively small igneous masses ; they have penetrated strata of different mineral- ogical and chemical composition. Thus the Hudson River mud stones, Trenton limestones, the graphitic limestone and black slates of the Farnham snd Philipsburg series, as well as the quartz mica schists of the Sillery, have been penetrated by these rocks, without producing any material change in the rocks themselves, beyond a generally well marked endomorphic contact zone. Moreover, the sedimentary rocks through which the granites and the diabase series have been intruded are generally very similar to those surrounding the Mo-teregian hills ; in fact, the Hudson River shales are the only roc'. latter region not found in the former. Hence, it would seen: ' whatever the cause may be of the primary magmatic differentiation '\.. magma which gave rise to the Monteregian hills was primarily different from that which produced the other rocks discussed, with the partial exception already mentioned of the later di?vc. In summarising it may be said that the rocks of southeastern Quebec present two petrographical provinces, and their differences are due to primary differentiation, i.e. to differences in the original magmas.
I. (a) Porphyry andesite series, extrusive a probably of Pre-Cambrian age.
*Dr. R. A. Daly, Am. Jour. Sci. On the Mechanics of Igneous Instrusions.
Gbological Suryby
(b) The diabase serpentine group ranging in. age from early Cambrian to late Silurian or Devonian, a
(e) The granites, late Devonian age.
IL The second province comprises properly only the unique group of the Monteregian hills. ; 2
Addendum.
1c cM RM Nt
oveauenneretnes
art een suey ee
Department
How. W. Temecem A.B Low, Deru: wor
Geological Survey
Stmaurice
THREE Rivens
Tueonard Junc. |
M
a
€.O.Senécal. Geographer & Chief Draughtsman
Lanadn tment of Mines
TEMPLEMAN. MINISTER. 1, DePutTy MINISTER.
07
——~~
we MEGANTIC \ Lake _
Mauce Ville
"Older Copper-Bearing Rocks |
~
* DORC eosft ea
\
= < z cm) "ey
%,
Map
showing the
of the | EASTERN TOWNSHIPS PROVINCE OF QUEBEG. to illuswate Report by J.A.DRESSER, M.A. 1906 Scale of 8 Miles to 1 inch
sic aro OROTURTEN Rte onnecet onthe: tba aM a a
TRIER arco 5
en ee
ties wapetoeerse:
a cranes
Selected List Of Reports
(Since 1885)
Of Special Economic Interest
PUBLISHED BY THE MINES DEPARTMENT OF CANADA (A.—Published by the Geological Survey.)
MINERAL RESOURCES BULLETINS 818. Plistinum. 851. Cual.
S67. Iefusoriai Earth 858. Mangances.
745. Altitudes of Canada, by J. White. 1899. (40e.) BRITISH COLUMBIA.
vases" se * ~s aa (between latitudes 49° and 51° 30'), by G. M. Dawson. 285. Vanoouver laand, by G. M. Dawson. 1886.
tains, Structure, by distrlet by As Bowman. 1887. ¢
Yukon And Mackenzie,
oy —_. ees A (250
.) ), by R. G, sa 1900. '(10¢.)
Saskatchewan,
ie oe
cost tet by D. B. Dowling 1008. (10e.) MANITOBA.
4. B. b+ 3887-8, (100.)
See ei
Es
Serssre>
Bes3
= —_
Bes33
Keewatin And Franklin.
and 5 15¢.) Hen ay, eet nb pte ha Northern portion of the on, by 0. Dowese, 'tos (20¢.) foherias WEE Eee Dertbe) : — yy wri e end D <a 1900, (25¢,) Ekwan River and a Laken B. Dowling. . (Ibe. The Cruise of the Nepsune, res . 1905, (82.00). ' ONTARIO.
Lake of the Woods mgion, by A. C. Lawson, 1885. (25e.) Rainy Lake region, by A. C. La 1887, (250. Labs Gapatlon eines eel wick - Gh? 7,0, neal. ees (25¢e.) Hunter island, by W. Y. ott 1890-91. (20e.) Toturel Gee and ew eee g ad ee inte? pees. (3f0) (108) On the French river sheet, by Be. bel iso. 0) "a a h wifi beets by AE Ba "ia De oe
a Hemel tnd Pienets seman re ee iene (25e.)(See No, . Otawe ted nha mre R. W. Ells, 3000 (18e.) Bodbury Nick: Lia Phe IE aay A. E. Barlow. (In Vol. XIV. 80c.) Report on Pembroke sheet, Out., by R. W. Ells. (10c.) a : Reprint of No, 873.
" —— . *
Quebec.
Mistassini expedition A. P. Low. 1884-5. (100. or ipemamrlapeag ee by R. W. Ells. 1886,
ste, Dorchester, Lévis, Bellechasse and Montmagny counties, by
W. Elis. , by 8. be.) Mineral resou 1889. a) 3 Portneuf, Que Quakes 2% 'Susie counties, by A. P. Low. 1890-01. (15c.) Eastern Montreal sheet, nM. ead F. D. Adams 1894. (15c). Auriferous deposits, Southeastern
y R. Chalmers. , mapa nad one y af Manto by F. DB. Fang 1895. (15c.) Timiskaming map-sheet, by A. E. Barlow. 1800. | (30e.) (in = "sg 8
P's Gee 1901. (30c.) : region, by A. P. Low. 1905. (10c.)
Pay
Ungava And Labrador
. Strait and Ba R. Bell. 1885, (150 ier and pp Pade lea Pr. oh 1857-88, (26¢.) P. Low. 1805. (30s) 657 Bay A. P. Low (100.)
ay by Pk by AE P. Low.)
is shore), by R. Bell. 1898, (20e.) j _ by A. P. Low. igot. sy Fidson Bay, by A. P. Low. 1901. (10e8.)
New Brunswick And Nova Scotia.
218. Western New Brunawick and Eastern Nova Scotia, W. Ells, bo Carleton and Victoria com. by Le Ww. Bailey. 1 ae = Hoey = one Meta nish, r perades and Hall : les, NS, b ntigon tou, t! ugh Fi cher and BR Faribault. 1886. (25e.) a .. . Northern portion and adjacent areas, by L. W. Bailey and W. Mofnnes. 1887-88,
(25e.) [ gee ant Rseds counties, by L, W. Bailey and W. McInnes, 1890-01,
243. 269. 330. 331, Pictou and Colchester counties, N.8., by Ht. Fete. 1800-01. (20e.)
358, Southwestern Nova Scotia in (Prelimanary) by = paar ~ 1802-03. (100.) 628
661
707.
709,
803.
: Miner resouren, Wb ye W, W. Bailey. "igor i106.)
. Cambrian rocks of Cape "Rioten, ¢ G. F. other 1900. (50e.)
. Carboniferous « in N.B., b W. Bail 1900. (10c.)) . N-B.. by H'8 Poole. 1900. toe.) >} Bound together.
. Coal 871. Pictou coal field, by H. 8. Poole, 1902. (10¢.)
IN PRESS, 970, jpepert on Mingere Palla, by Dr. J. W. Spencer. = supers te eseomeany Joint —_— gay qe , by D. D. Catrnes, w rhe . Dresser. og ay ict, n, airnes. (10 988. Telkwa valley, B.C., by W. Leach. ( ) ;
Transcontinental Croton between Lake Nipigon and Sturgeon lake, Ont., by W. H. Nanaimo and New Westminster districts, B.C., by O. E. LeRoy.
(B.—Published by the Mines Branch.)
On the location and examination of magnetic ore deposits by magnetometric measure- ments. Eugene Haanel. 1904
Report of the Commission appointed to inv estigate the different electro-thermic pro- ceases for the smelting of iron ores and the making of steel in operation in in ee (Only a few copies of this report are available.) By Eugene Haanel.
904. Final report on the ge made at Sault Ste, Marie, under Government auspices, : in the 'smelting of Canadian iron ores by the electro-thermic Process. Eugene Haanel. 1907. +
Pang