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Geological Re - investiqati on Mapping , Birch P_ortage South

NTS Area 63L-15S

by R.R. MacQuarrie

The a r ea , which cover s part of t he pr eviously published Birch Portage geolog i cal

map (Pyke , 1966), i s east of and contiguous with the Jan Lake area investigated during

the 1978 fie ld season (Macdonald and MacQuarrie, 1978) . The purpose of the 1979 inves­

tiga tion i s to determine the r elationship of supracr us t al r ocks of the Tulabi Lake­

Hanson Lake- Jan Lake a reas with the economicall y important s upracrustal rocks of the

Amisk Lake-Flin Flon a reas. Preliminar y re sult s f r om four months' field work have

confirmed that these two groups of s upracrustal r ocks are different and a r e confined

t o separate Precambrian blocks.

General Geo logy

The area straddles the boundary be tween the Flin Flon Gr eenstone belt and what

may be t e rmed the Hanson Lake block. Bo th these major rock units have been affected

by me tamor phism and deformation usually ascribed to the Hudsonian Orogeny , but their

compositions and struc tures are suffic i ently diff erent t hat they are best consider ed

separately .

Hanson Lake Block

Stratif1Tgphy

The supracrustal rocks invest igated may be pr ovisionally divided stratigraphi­

call y into two units : a predominantly s edimentary unit ("A" Gr oup) , and a predo­

minantly vol cani c unit ( "B" Group) . The l a r ge antiformal s tructure occupied by the

"A" group i s t enta tively interpre ted as a r efolded antic line and the "B" gr oup is

assumed to t he younger uni t .

The "A" group is divisible i nto a l ower, predominan t l y psamrnitic , sub- group (Q) ,

and a n upper, predominantly pelitic , sub- group (B). Both sub- groups contain thin

f l ows (possibly s ills) of mafic volcanic rock (W) which incr ease in abundance near

the " B" group. Small pockets of marble (L) occur within the pelitic s trata, but

some of these may have a non-sedimentary origin, for they are closely associa t ed

with small brecciated ultramafic plugs .

The "B" group is divisible int o a predominantly pyroclastic s ub- gr oup and a

predomi nantly vo l canic sub-group. A third sub- group , which consi sts of metagreywacke

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(Qw) beds from the vicinity of Hanson Lake, may a l so be included . The pyroclastic

sub- gr oup interfingers with pelitic strata of the "A" gr oup and includes (in orde r

of decreasing abundance) blastoporphyri tic intermediate to felsic pyroc l astic rocks

(Pb) , maf ic pyroclas tic r ocks (M) , mafic volcanic r oc ks (W), and metasedimenta r y

rocks (Band Q) . The vol canic s ub-group i nc l udes mafic volcanic rocks (M), inter­

media t e to felsic volcanic r ocks (V) , inte rmediate to felsic pyroclastic rocks (P)

and sedimentar y r ocks (Band Q).

Lithology and Metamorphi sm

Psammite (Unit Q) . Psammites are pink t o pale grey medium- grained quartzofeldspathic

gneisses , and usuall y contain l ess than 15% mafic minerals (hornblende, biotite or

magnetite) concentrated in fine bands. Greywacke (Qw) containing 8 t o 20 percen t

dusty bio t ite occurs near the northern s hor e of Hanson Lake . The fine gr ain size ,

shar ed wit h volcanic rocks in this v icinity , indicates a compar a t ivel y low grade of

me tamorphism.

Pelite (Unit B) . Peli tic metasedimentary rocks occur mainl y in the vicini t y of Jan

and Chur ch Lakes. Those south of Jan Lake are mostly coarse-grained, por phyroblastic

to migma titic, s illi manite- garnet - bio ti te gniessis (Bb) and cordier ite and muscovite

a r e commonly fo und in t he migmatit ic l eucosomes. Pel i tic rocks in the Church Lake

vicinity ar e brown to dark grey bioti t e gneisses (Ba). They are medium- to fine­

grained and commonl y contain garnet c r ys tals, small graphite flakes a nd bands of

white feldspathobl as ts. Coa rse- grained pelitic b i o ti te gneisses (Bp), which are

interla yer ed wi th pyr oclastic r ocks sout h of Church Lake and eas t of Tulabi Lake ,

contain quar t z and feldspar porphyroblasts (up t o 48 percent), graphi t e f l akes , and

hornblende crystals , but no t garnet . Pelites e l sewher e a r e mos tly medium- t o coarse­

grained bioti t e gneisses without por phyrobl asts or garnet c r yst als .

Intermediate to Felsic Pyroclastic Rocks (Unit P). A broad belt of grey blas t oporphy­

ritic pyroclas tic rocks (Pb) passes through Gillingham and Winteringham Lakes and

similar rocks occur in numerous other l ocali t i es . They a r e usually well-ba nded

gnei s ses with l ayer s of scatter ed hornblende crys tals but, where not interlayered

with other supracrustal rocks , they may be diff icult to distinguish from porphyro­

blastic tonalites (Gb). In most pl aces they contain 20 to 45 per cent p l agioclase

blastophenocrysts (up to 25 mm across) a nd variabl e amount s of hornblende . Non­

porphyroblastic fel sic pyrocl astic rocks (Pg) con taining garne t and disseminated

pyrite a nd pyr rhotite encir cle the Waki sew Lake domal s tructure west of Morton River .

Ma fic Pyroc l astic Rocks (Unit M) . Laminated amphibolites (Ml) a r e common in the

western par t of the area, but r are in the east. Their laminations a r e a lterna ting

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light and dark gre en layers (0.1 to 10 cm thick) which pe r sist a l ong stri ke.

Diopside amphiboli t e s (Mc) are c l osely assoc iated with l ami na ted amp hibolites but

contai n non- per sis t ent whi te plagioc l ase-rich and pale gr een diopside- rich bands.

Inter mediate to Fe l s ic Volcanic Rocks (Unit V) . Felsic volcanic rocks a r e not common,

but garne tiferous var i e ties (Vg) a r e present southwes t of Winteringham Lake a nd i n

the vic i nity of Hanson Lake.

Mafic Volcanic Rocks (Unit W). Garne t amphibolite (Wg) i s a me dium-gr a ined dark

green rock con t a ining ga rnet crystals up t o 2 cm across . Direct evidence f or its

volcan i c or i gin i s provided by pillow s tructure s so uthwest of Winteringham Lake.

Biotite-hornblende gneiss (Wa) i s f ine- to med ium-gr a ine d and contains l ocal fe l ds­

pathobl a stic l ayers. The vol canic roc k in the vicini t y of Sewap Lake is a fine- t o

medium-gr a ined massive amphibolite (Wm) and is locally garneti fer ous . Fine - grained

porphyr i t ic andes i t e (Wp ) containing up to 20 pe r cent r eddi s h pl agioc l ase phenocr ys ts

is the pr edominant variety s outheast of Zipor k Lake.

Mafic and Ultrarnaf i c Plu tonic Rocks (Un i t D). Plugs of coarse- grained pyroxenites

occur a long the south s hor e of Jan Lake and a l ong the nor t h s hor e of Hanson Lake .

Medium-grained, s trongly linea t ed amphiboli t es t ha t a l s o exis t near Ha nson Lake seem

likely t o be of plutoni c origin as well . Brec c iated dior i t e and gabbro , c onsisting

of dark grey rocks intruded by a ne twork of whi t e t onalite v einle ts, occur i n the

southwest. Fragmented and deformed agmatitic mafic plutonic rocks outcrop north o f

Wi nter i ngham Lake and in several l ocali t ies in the v ici nity of Kistapiskaw Lake .

All these intrusions a ppear t o have been emplaced prior to regional de formation and

me t amorphism.

Pre- t o Syn-Orogenic Felsic Plutonic Rocks (Unit G). The "early" granito id i ntru­

sions have been divided into five unit s as follows:

Garnet t ona lite (Gg). considered t o be the oldes t unit, occur s throughout a

large area west of the Morton River. It is a medium- gr ained grey gn e issic r ock

containing Oto S percent garne t and 10 to 30 percent mafic minera ls . The ma fic

mineral s, c hiefly hornblende, tend to be conc entrated in flatt ened spindles s ev eral

centimetr es l ong that appear t o be relics of an or iginally coarser t exture . The rock

is s trongl y fo l iated except in the vi c inity of t he Wakisew Lake f old axis , where

lineation is s trong .

Porphyr obl astic tonalite and granodiorite (Gb), one of the most wi desprea d rock

units in the map- a r ea, is a medium- t o coarse- gra i ned pal e grey to pinki s h grey rock

containing S t o 50 per cent p l agioclase por phyroblasts, 0 to 5 percent po tash fe ldspar

porphyr oblasts, and S to 30 pe rcent angular hornblende c r ys t als .

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Ho rnbl ende syenite (Gk) (hornbl ende po tassium feldspa r gneiss of Pyke, 1966) is

a medium- t o coarse -grained pink gneissic r ock whi ch is gradational to quartz-bearing

varieties (hornblende quar tz syenite and ho rnbl ende granite) and probably to varieties

r icher in plagioclase (hornblende monzonite) . It i ntrudes and is closel y associated

wi th porphyr oblas tic granodior ite and t onalite.

Granodiorite (Gr) i s a medium-gra ined , foliated , pale grey to pink r ock that

occurs as an elongate sill adjacent to the eastern edge of the Hanson Lake block . It

has been affected by hematite a lterat i on over much of i t s length.

Foliated pegmatite (Gp) occurs as an in trusive plug east of Kistap i skaw Lake ,

and as numerous s i l l s 1 to 10 m wide in a broad band west of the Morton River . These

pegmatites are well fo liated p i nk rocks containing bioti te and muscovi t e .

Post-Orogenic Intr usive Rocks (Unit J) . Three genet ically r elated t ypes of "late"

intrusive rocks , trap dikes , gr a ni te, and pegmatite , are coll ec tively r eferr ed to as

the Jan Lake I ntrus i ve Complex.

The Jan Lake trap dikes (Jt) are narrow ,1 to 10 m acr oss) , coarse , nor t hwesterly

s tr iking , and include non-porphyri tic mafic , porphyritic mafic, porphyritic in ter­

mediate , and por phyritic felsic varieties . Mafic and in t ermediate varieties a r e rich

in biotite and may have lampr ophyric compositions . Two or more t ypes commonly occur

t ogether and comprise a breccia in which the matrix i s more felsic than the fragments.

The dike-rocks have a fine micaceous fo l iation (particularly str ong nea r the di ke

margins) that is paralle l to the dike margins and quite unrel ated to foliation in

the country r ocks . The dikes a r e internally deformed, and breccia f r agments a r e

flatt ened parall e l to the micaceous fol ia tion .

The Jan Lake granite (Jl) i s a l arge central stockwor k of pink , medium- gra ined

g r anit ic rock , with numer ous satel litic dikes and plugs . It has abrup t, irr egular

intrusive margins and contains many large blocks and angular xeno l i ths of fo l iated

count r y rock . The essential composi tion is potas h feldspar, albi t e, qua r tz and

us ually less than 10 percent bio t ite . Garnet c r ys t als (less than 1 per cent ) commonly

occur in the sou thwest , and euhedr a l magneti t e cr ystal s up t o 1 cm across are abundant

locally . Equigr anular t extures are most common, but tabul a r microcline crystal s a r e

larger in some places and give rise to a dis t inctly porphyritic texture . Apart from

a local weak biotite fo liation, seen on fresh s ur faces , a nd a preferred orien t ation

of microcline phenocrysts in some pl a ces, there is no discernible foliat i on . These

local fol i a tions are unre lated t o fo liation in the countr y rocks and seem t o be

parall e l to the intrusive mar gins.

Dikes of Jan Lake pegmatite (Jp) occur t hroughout the area west of the

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Sturge on-Weir river and are especia lly abundant n ear the intrus ive margins of the

Jan Lake granite. The granite is cut by a ne twork of small (0.1 to 2 m wide) pe gma­

tite dikes, mos t of which have gradational conta cts with the grani t e . Cross-cutting

relations hips sugges t at l ea s t three di fferent generations of post- orogenic pegma tites,

including the be r yliferous va rie ties west of Hanson Lake and northwest of Birch

Portage . Rubidium-s tront ium ana l yses indicate an age of 1800 million year s for bo th

pegmatite (Coleman, 1970) and granite (S i nha, 1970) , and a ll these pegma t i tes a r e

pr obab l y r e l ated gene ti cally.

Structural Geology

Major f old struc tures have been r ecognized west o f the Morton Rive r , eas t of

Zipork La ke , and in t he vic inity of Wyll i e Lake . The fold west o f the Morton River

is an elongated, near l y i socl ina l, overturned dome that is t he northern con t inua tion

of the Wakisew Lake antiforma l fold (J ohnson, 1967). The Zi pork Lake f old s tructures

seem to be parasitic t o a l a rge Z-shaped f old and are mos t s trongl y developed in

volcanic rocks occupying t he s outhern "c r ook" of the Z. The Wyllie Lake fold i s a

domal struc ture open to the west and may be interpret ed as a northeastern termination

of the Jackpine Lake fold (Col eman e t a l . , 1970) a nd thus pa rt of a l arge kidney­

shaped dome.

Faul ts nor t h of Hanson Lake and southwes t of Winteringham La ke wer e defined

mor e precisely. In bot h a reas narrow synforma l s tructures which flank the J an Lake

antiform are occupied by vo lca ni c rocks of comparatively l ow metamorphic grade . It

seems like l y that these structure s a r e partly synforma l, and partly graben-like.

Fl in Flon Greenstone Be lt

Stratigraphy

Both the Amisk Group and the Mis s i Group are present i n the area. The rocks

of the Amisk Group e a s t o f the Sturgeon-Weir Rive r and south of highway 106 a r e s o

heavily drift-covered tha t division into format iona l unit s may not be possible. Two

be lts of pr edominantly sedimentary rocks hav e been mapped, one extending eastward

from Ma ligne Lake towa rds Matheson Lake and another extending southward from Maligne

Lake along the Sturgeon-Wei r Rive r. These be lts appear to result from f olding of a

s ingle, later a lly variable, l ayer which may be correlated with Aroisk Group s edimen­

tary rocks in the west Amisk Lake area . The chemical affinities and s tratigraphic

position o f volcanic rocks in the a r ea a r e uncerta in at this stage.

Highly def ormed conglomerate (Cm) mapped south of Gr anite Lake has been

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i dentified as the basal forma tion of the Missi Gr oup . This conglomer a te is up-strike

from Missi conglomerate eas t of the map-area, and i s partly respons ible for a broad

aeromagnetic anoma l y similar to anomalies over other a r eas of Miss i Gr oup sedimentary

rocks .

Lith.ology and Metamorphism

Mafic Volcanic Rocks (Unit W). Mafic vo lcani c roc ks occur in a broad L- s haped band

east of Scoop Rapids and wer e also observed s outh of Matheson Lake and sporadically

among mafic pyr oclastic unit s . They are fine- gr ained unlayered dark green rocks free

of phenocrysts and amygdules . The abs ence of chlorit e and presence of hornblende

indicates lower t o middle amphibolit e g rades of metamorphism.

Maf i c Pyroclastic Rocks (Unit M) . A narrow belt o f lamina t e d ma fi c pyroclastic rocks

(Ml) , similar to those in the Sandy Nar rows area , l ies adjacent to the Sturgeon-Weir

River. These fine- grained, dark green , and thinly banded rocks are thought to have

originated as mafic tuffs. Maf ic aggl omer a te s (Ma) are pale green to dark green

he terogeneous banded rocks . Diopsidic and garnetiferous varieties a r e common, but

have not been dis tinguished as separate uni t s. The mafic agglomer ates con tain

numer.ous layers (1 to SO cm t hick) of felsic and intermediate tuffs and agglomerates

(P) as well as greywacke (Bg and Bw) .

In termedia t e to Felsic Pyroclastic Rocks (Unit P). Pyroclastic rhyolites, dacites,

and felsic andesites , common eas t of the Sturgeon-Weir River, are fine- grained, non­

porphyritic , banded , and heterogeneous, and are i nti mately interlayer ed with meta­

sedirre ntar y r ocks and mafic pyroclastic r ocks . Weather ing surfaces are commonl y

rus t y due to oxidation of disseminated pyrite and pyrrhotite.

Psammopelitic to Pelitic Sedimentary Roc ks (Unit B). Psammopeli tic r ocks east of

the Sturgeon- Weir have been divided into garnetiferous (Bg) and non-garnetifer ous

(Bw) var ieties. Both types are fine- grained grey to brown quartz-rich sc hists which

contain greenish streaks and narrow layers of pyroclastic rocks , and t hey are probably

deri ved from erosion of volcanic rocks . A belt of muscovitic non-garnetiferous

psammopelite in terlayered with an approximately equal propor tion of mafic to fel s ic

pyroc lastic r ocks (Bv) occurs just west of the Sturgeon-Weir River. Medium-grained

black pelitic biotite schist (Bs) , thought to have origina t ed as a rgillite, was

noted southeast of Gr anite Lake .

Conglomerate (Unit Cm). Missi conglomera t es south of Gr anite Lake ar e he teroge neous,

narrowly banded, quartz- rich gneisses that contain scattered hornblende crystals.

Individual cobbles have been stretched to several hundred times the ir presumed

initia l dimensions. These conglomerates resembl e those near Annabel Creek to the

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east except t ha t they do not appear to be affec t ed by brittle def ormation and

r e trograde me t amorphism.

Pre-Orogenic t o Syn-Orogen i c Mafic Plutonic Rocks (Unit D). The Snake Rapids diorite

(Da), a large body only partly i nc luded in the area, i s a coarse-grained equigranular

r ock composed of bioti te , hornblende, and translucent grey feldspar. Outer parts of

the pluton have a we ll-deve loped margin-parallel foliation. A sill of medium- t o

coarse-grained d iorite (Dd) north of the Snake Rapids diorite is s imilar in texture

but does not contain biotite. Small bodies o f green, folia ted meta-gabbro (Dg)

occur in the southeast .

Pre-Orogenic to Syn-Orogenic Felsic Plutonic Rocks (Unit G) . Two large bodies of

f ol iated granodiorite (Gr) intrude supracru s tal rocks eas t of the Sturgeon- We ir .

The pluton be tween Matheson La ke and the Wildnest River consists of medium-grained

grey to pink gneis s i c biotite granodiorite and t onal i te with narrow sills of quartz

diorite. The pluton just east of the Sturgeon-We ir River cons ist s of medium- t o

fin e-grained pink biotite granodiorite . Sills of similar composition and t exture

east of Maligne Lake and s ills of fine- grained felsic rock (Xr) at Leaf Rapids may

have been emplaced at about the same time .

structural Geo logy

The swing in regional s trike in the area appear s part ly due to a major north­

eastward trending fold through Wildnest Lake and pa rtly due t o westward thinning o f

the Amisk Group . This large fold appears to have refolded near-isoclinal folds, such

as the overturned syncline thought to be occupied by Missi conglomera t e sou th of

Granite Lake, and a north-plunging fold west of Matheson Lake.

Two ma j or faults, each associated with in situ fault breccia, lie roughly

parallel with the Sturgeon-Weir River. The westernmost fault is associated with a

500 m wide zone of hematization and narrow epidote veinlets and with a 25 m wide

zone of chloritization . The fault is ma rked by a layer of red and green breccia 1

to 10 m thick that dips about 55° east . The easternmost fault is marked by a network

of chlorite and pseudotachylite v e inle ts with little associated alteration . These

two faults appear to be terminated in the vicinity of the junction of the Morton

and Sturgeon-We ir Rivers by a series of short cross- faults marked by mylonite bands

10 to 50 cm across.

Relationships between the Han son Lake Block and the Flin Flon Greenstone Belt

The boundary between the Hanson Lake Block and the Flin Flon Greens t one Be lt

is an eastward-di pping zone r oughly parallel t o the cours e of the Sturgeon-Weir

River. This zone has been irregularly folded and displaced to some extent by later

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f aulting . Avail a ble evidence s ugges t s that the bounda r y is e ither an e ros iona l

unconformit y with Amis k Group s uprac rustal rocks l ying unconformably upon the Hanson

Lake Block , or a l ow-angle thrust fault, or pe rhaps both. The boundary s eems to be

c onformable with stra ta withi n t he Gr eenstone Belt, but slightl y oblique to strata

within the Hans on Lake Block.

Vol canic and sedimenta r y s tra t a of the Amisk Group appear to thin out or wedge

out en tir el y northwestward s , t owards the boundary , as i f t hey were deposi t ed a t the

edge of a massif.

A tec t on ic or igin for this disconformab l e boundar y i s s uggested by an adj acent

Oto 100 m wide band of blastic hornblend e-bio t i t e gnei ss which is unlike o the r

supracrustal r ocks in the a r ea and r esembles t e c t oni cally formed augen gneiss. Such

an exp l ana tion would a lso explain diff e r ences in l i thol ogy and s tructural s t yle - as

we ll a s me t amorphism, albeit grada tional - between the two bloc ks .

Remapping in this area has at least r uled out the possibility that the boundar y

is a major pos t-or ogenic f eature , a "suture" between pre- existing geol og i cal s ub­

provinces once r emote f r om each other .

Economic Geo l ogy

Previous Work

Most of the area ha s been cover ed by air borne el ec t romagne tic and radiometric

surveys . The most signi ficant mine r a l occurrence to date i n the a r ea is a t Sewap

Lake, whe r e dr i lling beneath the ice by Hudson Bay Expl or a tion and Developmen t

inte rsected 1 . 4 metres of 2 per cent copper .

The north s hore of Hanson Lake has been r e l atively heavily prospec t ed and

several small sul f ide zones in the general area have been trenched . Gal ena and

sphalerite occur at the Young showing eas t of Agnew Bay (Byers, 1957), and molybde­

nite occurs in a trench near t he southern s hore of Wyllie Lake .

The Amisk volcanic and sedi men t a ry r ocks eas t of the Sturgeon- Weir have been

systematically explored for base me t a l s by Hudson Bay using a irborne and gr ound­

based e l ectromagne tic t echn iques and follow-up diamond dr ill i ng . Sub- economic

deposits of coppe r and z inc were fo und by the company east of t he area.

Potential

Although miner a l expl or a t ion i s currentl y a t a l ow l evel , t he ar ea i ncludes

l ocalities favourabl e for deposits of volcanogenic massive sulphides, hydrothermal

base and pr ecious me t a l s , and industria l materials .

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Volcanic rocks of the Hanson Lake Block should not be overlooked in the search

for volcanogenic copper and zinc deposits, for they host the Sewap Lake occurrence

drilled by Hudson Bay. This occurrence lies near the nose of a major fold structure

where a massive sulfide body could be concentrated and where s uch a body could

escape be ing detec ted by east-west f l ight lines.

Northeast of Sewap Lake is a band of f e lsic vol canic and pyroclastic r ocks

several hundred metres wid e containing disseminated pyrite throughout its ent ire

width. This band, which encircles the Wakisew Lake fold s truc ture, represents a

favourable geological environment, and i s probably worthy of more detail ed

exploration.

One of the more promising localities for pr ecious metal exploration lies west

of the Sturgeon-Weir River and east of t he nor t h end of Morton Lake. Several small

chalcopyrite occurrences were noted near and within a 10 m wide quartz s tockwork

tha t occupies one of the major fau lts recognized in this a rea . Although these

occurrences are not important in themselves, they indicate hydrothermal minerali­

zat i on. Arsenopyrite cr ystals were noted in quartz veinle ts cutting volcanic rocks

south of Granite Lake , jus t north o f highway 106. A sampl e of t his material has

been analyzed for gold and was f ound to contain 350 ppb.

The J an Lake granite i s a potential source of dimension and facing stone. It

is accessible, has widely spaced joints (one set of which is commonly horizontal),

has predictable physical qualities of strength and splitting, has an attractive

pink colouration, is free of deleterious minerals , and takes a high polish.

Minerais for the Collector

Beryl in pegmati tes occurs in sub-economic amounts west of Hanson Lake and

northwest of Birch Portage . No new occurrences wer e found during the mapping but

probably could be found if an intensive search were undertaken. Some other minerals

potentially a ttractive to collectors were found in 1979, as follows:

De ep red spinel crysta ls occur in association with chondrodite and perhaps

other humite mi nerals in a marbl e exposed on the south shore of Jan Lake. An attrac­

tive yellow and pink rock c ons is t ing of scapolite and unidentif i ed minerals was

found in the same general area.

An occurrence of green fuchsite i n altered sedimentary rocks was found a short

distance northwest of Hanson Lake. The fuchsite band i s about a metre across, and

is very near a coarse-grained pyroxen i te, which is perhaps the source of the

chromium responsible for the fuchsite colouration, although no c hromite was present.

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Pegmatites in the southwes tern part of the map area commonly contain a yellowish

green mineral tentatively identified as lepidolite .

References

Byer s , A.R. (1957): The Geology and Mineral Deposits of the Hanson Lake Area, Saskatchewan; Sask. Dept . Mineral Resources, Rept. No. 30.

Byer s, A.R. and Dahlstrom, C. D.A . (1954): Geology and Mineral Deposits of the Amisk- Wildnest Lakes Area, Sa skatchewan; Sask. Dept . Mineral Resources Rept . No. 14 .

Coleman, L. C. (1970): Rb/Sr isochrons fo r some Precambrian rocks in the Hanson Lake area, Saskatchewan; Canadian Journ . Earth Sci., Vol. 7, 338- 345.

Coleman , L.C . ; Gaskarth , J .W . ; Smith, J.R. (1970) : Geology and Geochemistry of the Hanson Lake area; Sask. Resea r c h Council, Geology Division Rept. No. 10.

Eas twood, G.E.P. (1949): Snake Rapids, Saskatchewan; Geol. Surv. Canada, Paper 49-18 (map with descriptive notes).

Fox , J.S. (1976): Some comments on the Volcanic Stratigraphy and Economic Potential of the West Amisk Lake Area, Saskatchewan; Saskatchewan Research Council, unpublished draft of paper pr esented a t meeting of Geological Association of Canada , Edmonton, May 1976.

Johnson, R.L. (1967) : The Geology of the Hanson Lake Area (East Half), Saskat­c hewan; Sask. Dept . Minera l Resources REpt. No. 117.

Macdonald , R. and MacQuarr ie, R.R. (1978) : Geologi cal Re-investigation mapping Jan Lake Area, in Summary of I nvestigations 1978, by the Saskatchewan Geological Survey; Sask . Dept. Mineral Resources .

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