THESE TERMS GOVERN YOUR USE OF THIS DOCUMENT
Your use of this Ontario Geological Survey document (the “Content”) is governed by the terms set out on this page (“Terms of Use”). By downloading this Content, you (the
“User”) have accepted, and have agreed to be bound by, the Terms of Use. Content: This Content is offered by the Province of Ontario’s Ministry of Northern Development and Mines (MNDM) as a public service, on an “as-is” basis. Recommendations and statements of opinion
expressed in the Content are those of the author or authors and are not to be construed as statement of government policy. You are solely responsible for your use of the Content. You should not rely on the Content for legal advice nor as authoritative in your particular circumstances. Users should verify the accuracy and applicability of any Content before acting on it. MNDM does not guarantee, or make any warranty express or implied, that the Content is current, accurate, complete or reliable. MNDM is not responsible for any damage however caused, which results, directly or indirectly, from your use of the Content. MNDM assumes no legal liability or responsibility for the Content whatsoever.
Links to Other Web Sites: This Content may contain links, to Web sites that are not operated by MNDM. Linked Web sites may not be available in French. MNDM neither endorses nor assumes any
responsibility for the safety, accuracy or availability of linked Web sites or the information contained on them. The linked Web sites, their operation and content are the responsibility of the person or entity for which they were created or maintained (the “Owner”). Both your use of a linked Web site, and your right to use or reproduce information or materials from a linked Web site, are subject to the terms of use governing that particular Web site. Any comments or inquiries regarding a linked Web site must be directed to its Owner.
Copyright: Canadian and international intellectual property laws protect the Content. Unless otherwise indicated, copyright is held by the Queen’s Printer for Ontario.
It is recommended that reference to the Content be made in the following form:
<Author’s last name>, <Initials> <year of publication>. <Content title>; Ontario Geological Survey, <Content publication series and number>, <total number of pages>p.
Use and Reproduction of Content: The Content may be used and reproduced only in accordance with applicable intellectual property laws. Non-commercial use of unsubstantial excerpts of the Content is permitted provided that appropriate credit is given and Crown copyright is acknowledged. Any substantial reproduction of the Content or any commercial use of all or part of the Content is prohibited without the prior written permission of MNDM. Substantial reproduction includes the reproduction of any illustration or figure, such as, but not limited to graphs, charts and maps. Commercial use includes commercial
distribution of the Content, the reproduction of multiple copies of the Content for any purpose whether or not commercial, use of the Content in commercial publications, and the creation of value-added products using the Content.
Contact:
FOR FURTHER
INFORMATION ON PLEASE CONTACT: BY TELEPHONE: BY E-MAIL: The Reproduction of
Content MNDM Publication Services Toll Free: 1-888-415-9845, ext. Local: (705) 670-5691 5691 (inside Canada,
United States)
Pubsales@ndm.gov.on.ca
The Purchase of
MNDM Publications MNDM Publication Sales Toll Free: 1-888-415-9845, ext. Local: (705) 670-5691 5691 (inside Canada,
United States)
Pubsales@ndm.gov.on.ca
Crown Copyright Queen’s Printer Local: (416) 326-2678 Toll Free: 1-800-668-9938
(inside Canada, United States)
ONTARIO DEPARTMENT OF MINES
THE FEDERAL-PROVINCIAL COMMITTEE
ON
HURON I A N STRATIGRAPHY
PROGRESS REPORT
BY
J. A. ROBERTSON,
K. D.CARD,and M.J. FRAREY
A paper presented to the Institute on Lake Superior Geology Superior, Wisconsin, 7 May 1968
MISCELLANEOUS PAPER
31
ONTARIO DEPARTMENT OF MINES
THE FEDERAL-PROVINCIAL COMMITTEE
ON
HURON I A N STRATIGRAPHY
PROGRESS REPORT
BY
J. A. ROBERTSON,
K. D.CARD,and M.J. FRAREY
A paper presented to the Institute on Lake Superior Geology Superior, Wisconsin, 7 May 1968
MISCELLANEOUS PAPER
31
Crown copyrights r e s e r v e d . This book may not be reproduced, i n whole o r i n p a r t , without t h e permission
of t h e Ontario Department of Mines.
P u b l i c a t i o n s of t h e Ontario Department of Mines and p r i c e l i s t
a r e o b t a i n a b l e through t h e
P u b l i c a t i o n s O f f i c e , Ontario Department of Mines, Parliament Buildings, Queen's Park,
Toronto, Ontario, Canada.
Orders f o r p u b l i c a t i o n s should be accompanied by cheque, o r money o r d e r , payable t o Treasurer of Ontario.
TO:
Dr. C.S. Lord, Chief Geologist, Geological Survey of Canada.
Dr. E.G. Pye, Chief Geologist, Ontario Department of Mines.
Sirs
:We, the undersigned members of the Federal-Provincial Committee
on Huronian Stratigraphy, appointed by the Geological Survey of Canada
and the Ontario Department of Mines, in 1967, to consider problems
of stratigraphic correlation and nomenclature of the Huronian rocks
occurring in the vicinity of the North Shore of Lake Huron, hereby
submit the attached Progress Report for your consideration.
J.A. Robertson, Chairman
M.J. Frarey
K.D. Card
Contents
Page
Preface
...
vi
Abstract
...
vii
Introduction
...
1
Federal-Provincial Committee on Huronian Stratigraphy. The
...
2
Composition of Committee
...
2
Terms of Reference
...
2
History of Geological Work in the Sault Ste
.
Marie-Elliot
Lake-Sudbury Area
...
2
Early Investigations of the Huronian (1846-1946)
...
3Initiation of Regional Systematic Mapping (1950-1960)
...
6
Regional Compilation Studies (1961-1967)
...
8Proposed Definition and Subdivision of the Huronian Supergroup
...
12
Definition of the Huronian Supergroup
...
12
Comment
...
12
Subdivision of the Huronian Supergroup
...
12
Comment
...
12
Problems Remaining
...
14
Comment
...
14
Proposed Principal Reference Sections and Reference Sections
...
1s
Further Work of the Committee
...
16
Acknowledgments
...
16
Appendix
...
17
List of Proposed Principal Reference Sections and Reference
Sections for Formations
...
17
Volcanics
...
19
Selected References
...
20Tables
1
.
Comparison of stratigraphical nomenclatures
used for NorthShore of Lake W r o n
...
back pocket
2.
Recowended Huronian stratigraphic nomenclature
...
13
Figures
1
.
Location of the Huronian area
...
ix
2
.
Key to recent geological maps. North Shore of Lake Huron
...
9
Preface
Geological mapping along t h e North Shore of Lake Huron was i n i t i a t e d by t h e Geological Survey o f Canada i n 1846. The problems i n c o r r e l a t i o n encountered by t h e numerous subsequent workers have given r i s e t o a
s t r a t i g r a p h i c nomenclature confusing t o t h e f i e l d worker and s t u d e n t a l i k e .
As d e t a i l e d mapping programs of t h a t a r e a , undertaken by t h e Geological Survey of Canada and t h e Ontario Department of Mines, were n e a r i n g completion, a Federal-Provincial Committee of t h r e e was formed i n 1967, by t h e s e o r g a n i z a t i o n s , t o review t h e c o r r e l a t i o n problems i n d e t a i l and, assuming a consensus of opinion could be reached, t o demonstrate t h e mappability of i n d i v i d u a l rock u n i t s , t o d e r i v e a mutually a c c e p t a b l e
A b s t r a c t
T h i s p a p e r : a ) reviews t h e h i s t o r y o f g e o l o g i c a l work i n t h e S a u l t S t e . M a r i e - E l l i o t Lake-Sudbury a r e a ; b) summarizes t h e terms o f r e f e r e n c e o f t h e F e d e r a l - P r o v i n c i a l Committee on Huronian s t r a t i g r a p h y ; c ) summarizes t h e work o f t h e committee t o d a t e ; and d ) o u t l i n e s t h e a n t i c i p a t e d f u r t h e r work o f t h e committee.
The p r i n c i p a l recommendations a r e : 1 ) t h e Huronian i s t o be d e f i n e d a s t h e assemblage o f s e d i m e n t a r y and v o l c a n i c r o c k s o c c u r r i n g i n t h e v i c i n i t y o f t h e North Shore o f Lake Huron, C o b a l t , Sudbury, and a d j a c e n t a r e a s and l y i n g w i t h marked unconformity on t h e Archean r o c k s and i n t r u d e d by t h e N i p i s s i n g Diabase, a s a s u b s i d i a r y d e f i n i t i o n t h e Archean i s d e f i n e d a s t h o s e r o c k s formed p r i o r t o t h e c l o s e o f t h e Kenoran Orogeny (approximately 2,500 m i l l i o n y e a r s o l d ) ; 2 ) t h e Huronian Supergroup i s t o be d i v i d e d
i n t o groups and f o r m a t i o n s from youngest t o o l d e s t , a s f o l l o w s :
Cobalt Group (Top n o t s e e n )
Bar River Formation Gordon Lake Formation
L o r r a i n Formation (Local Members)
Gowganda Formation (Local Members)
Unconformity t o Disconformity Quirke Lake Group
S e r p e n t Formation Espanola Formation Bruce Format i o n Local Disconformity Hough Lake Group
M i s s i s s a g i Formation Pecors Formation Ramsay Lake Formation
Local Disconformity
(Local Members)
- -
-E l l i o t Lake Group ( i n c l u d i n g v o l c a n i c u n i t s t o be i n d i v i d u a l l y named) McKim Format i o n
Matinenda Formation (Local Members)
Unconformity Archean
3 ) P r i n c i p a l r e f e r e n c e s e c t i o n s and r e f e r e n c e s e c t i o n s a r e t o be e s t a b l i s h e d t o d e f i n e t h e tiuronian i n t h e Bruce Mines a r e a , t h e E l l i o t Lake a r e a , and t h e Espanola-Sudbury a r e a . These a r e t o be measured, d e s c r i b e d , and marked
during t h e next few y e a r s . A composite s e c t i o n i n t h e E l l i o t Lake a r e a w i l l c o n t a i n r e f e r e n c e s e c t i o n s f o r t h e i n d i v i d u a l formations and type o r p r i n c i p a l r e f e r e n c e s e c t i o n s f o r t h e groups. This composite s e c t i o n may become t h e p r i n c i p a l r e f e r e n c e s e c t i o n f o r t h e h r o n i a n Supergroup.
I 7 5O -550 55O
-
,/' / ' I O N T A R I OI
I II
II
I I-
4s0 Scale of Milor 0 !50 100 150u
ODM 4 5 0 4 , MP. 31 9 0 ° I 1 I Figure 1Location of the Huronian area under present investigation
The Federal -Provi n c i a1 Commi t t e e on Huronian S t r a t i g r a p h y
by
J.A. ~ o b e r t s o n ' , K.D. card2, and M.J. Frarey 3
INTRODUCTION
This paper: a) reviews the history of geological work in the Sault
Ste. Marie-Elliot Lake-Sudbury area (Figure 1);
b) ~unnnarizes
the terms
of reference of the Federal-Provincial Committee on Huronian Stratigraphy;
c) summarizes the recommendations of the committee to date; and d)
outlines the anticipated further work of the committee.
Since 1846, the North Shore of Lake Huron has attracted many geologists.
The area contains igneous, metamorphic, and sedimentary rocks of several ages,
and it has been general usage to designate the bulk of relatively unmetamorphosed
sedimentary rocks as the Huronian System (time-stratigraphic nomenclature)
or the Huronian Supergroup (rock-stratigraphic nomenclaturej (Thomson 1962,
p.80).
As the map-areas of numerous early workers were not continuous and as
some units show marked similarities to each other and other units show marked
internal variations, the early regional correlations, interpretations, and
nomenclatures were numerous and confusing. W.H. Collins (1925) compiled the
then available data providing a standard of reference for the later workers.
Some subsequent workers did not accept specific correlations and questioned the
relationships of metamorphosed sedimentary rocks to non-metamorphosed sedimentary
rocks east of Blind River. After World War
I1and the discovery of uranium
in the Blind River area large amounts of geological data were collected and
published in part by various agencies, parti~ularly
the Ontario Department
of Mines and the Geological Survey of Canada.
In the early stage of this work each of the organizations mentioned
above developed stratigraphic nomenclatures for the areas being studied.
Each of these nomenclatures in the Elliot Lake area was based on that of
Collins (1925, p.17) and each was further modified in the light of experience.
Furthermore, between Sudbury and Elliot Lake-Blind River, prior to 1960,
field work had not progressed sufficiently to establish the regional
continuity of all mappable units and there remained considerable doubt as
to the units identity and relationships, particularly to the rocks exposed
at Bruce Mines, Blind River-Elliot Lake, and to those exposed northeast of
Sudbury. Since 1960, continued mapping by the present authors has led to a
consensus of opinion. This consensus has however been obscured by lack of a
common, well-defined stratigraphic nomenclature.
In 1967 therefore, the Geological Survey of Canada and the Geological
Branch of the Ontario Department of Mines instituted
aFederal-Provincial
Committee on Huronian Stratigraphy.
l~eolo~ist,
Ontario Department of Mines, Toronto.
z~eolo~ist,
Ontario Department of Mines, Sudbury.
3Geologist, Geological Survey of Canada, Ottawa.
Manuscript accepted for publication by the Chief Geologists of the
THE
FEDERAL-PROVINCIAL COMMITTEE ON HllRONIAN STRATIGRAPHY
a) Composition of Committee
The following people were appointed to the committee:
J.A. Robertson (Chairman) Geologist, Ontario Department of Mines, Toronto.
K.D.
Card
Geologist, Ontario Department of Mines, Sudbury.
M.J. Frarey
Geologist, Geological Survey of Canada, Ottawa.
In addition, other staff-members of both organizations are consulted, when
necessary, by the committee.
b) Terms of Reference
The committee is required to: 1) review the recent extensive field
programs of the two government agencies and report on present knowledge of
the hronian Supergroup; 2) reach a consensus on
acomprehensive
stratigraphic succession and apply suitable stratigraphic nomenclature
in conformity with the American Code of Stratigraphic Nomenclature
(American Commission on Strarigraphic Nomenclature 1961); and
3)measure,
delineate, and describe type and reference sections for formations and
groups
.
It should be noted that the area of interest is primarily between
Sault Ste. Marie and Sudbury with extension to the Cobalt area if necessary.
The committee is not concerned in detail with: 1) the Archean; 2) the post-
Huronian igneous, structural,
07
metamorphic events;
3)the nature and
correlation of the Whitewater Group (i.e., those rocks outcropping within
the Sudbury Basin); and
4)correlations with areas elsewhere in or beyond
North America.
HISrORY OF GEOLOGICAL WORK IN
THE SAULT STE. MARIE-
ELLIOT LAKE-SUDBURY
AREA
Since the discovery in 1846 of copper at Bruce Mines the North Shore
of Lake Huron has been under geological study, both economic and academic.
This geological study falls into three phases: 1) early work around the
mineralized areas (1846-1946);
2)the initiation of systematic regional
mapping (1950-1960); and
3)the continuation and synthesis of regional
compilation studies (1961-1967).
It is necessary to consider each of
these phases in some detail.
E a r l y I n v e s t i g a t i o n s of t h e Huronian (1846-1946)
During t h e p e r i o d 1846-1859 Alexander Murray ( s e e Murray 1849; 1850; 1857; 1858; and 1859) of t h e Geological Survey of Canada mapped much of t h e a r e a along t h e North Shore of Lake Huron. Between S a u l t S t e . Marie and Blind R i v e r , he d e s c r i b e d t h e sequence shown i n Column 1, Table 1
(back p o c k e t ) . Logan c o r r e l a t e d t h e r e l a t i v e l y unrnetamorphosed rocks of t h e Bruce Mines a r e a with rocks p r e v i o u s l y mapped a t Lake Timiskaming
( s e e Logan 1847, p.69-70; 1857b; 1863, p.50; Van Hise and L e i t h 1907 p.403-404 f o r r e f e r e n c e s t o e a r l y l i t e r a t u r e ) . In t h e Spanish River a r e a Murray recognized two groups of r o c k s ; a lower g r a n i t i c o r metamorphic group and an upper sedimentary o r "quartz rock groupw, t h e l a t t e r was c o r r e l a t e d with t h e r o c k s a t Bruce Mines (Murray 1850, p.36-42; 1857 p.171-187). These r e l a t i v e l y unmetamorphosed r o c k s were l a t e r named t h e Huronian Formation by Logan and Hunt (1855, p. 29-33) who t e n t a t i v e l y
considered them t o be Cambrian i n age. I n llGeology o f Canada" Logan
placed t h e Huronian i n t h e upper p a r t of t h e Azoic, which was below t h e S i l u r i a n (Logan 1863, p.20-21, 6 5 ) .
F u r t h e r work by I n g a l , I r v i n g , L e i t h , Pumpelly, Van Hise, and t h e Winchells ( s e e Van Hise and L e i t h 1907) i n c r e a s e d t h e knowledge o f t h e Bruce Mines a r e a and l e d t o t h e r e c o g n i t i o n o f an unconformity w i t h i n t h e Huronian sequence, i . e . a t t h e base of t h e upper s l a t e conglomerate
(Winchell i n Van Hise and L e i t h 1907, p.411, 437-438). The r e v i s e d s t r a t i g r a p h y ( s e e Column 2 , Table 1, back pocket) and a f u l l l i s t o f r e f e r e n c e s covering t h e e a r l y work a r e given by Van Hise and L e i t h (1907 p.437, 443, 444-447).
A.P. Coleman (1914), working i n t h e Sudbury a r e a , claimed t o have found f o u r d i s c o r d a n c e s (below t h e Sudbury S e r i e s , below Lower Huronian, below Animikie, and below Keweenawan) a s shown i n Column 3 , Table 1
(back p o c k e t ) . Between t h e lower two d i s c o r d a n c e s he recognized t h r e e s t r a t i g r a p h i c u n i t s , which he c a l l e d t h e Copper C l i f f Arkose, t h e McKim Greywacke, and t h e Wanapitei Q u a r t z i t e . These u n i t s were grouped t o make up t h e Sudbury S e r i e s , which he considered t o be e q u i v a l e n t t o t h e
Timiskaming S e r i e s (Coleman 1914, p . 205) a s mapped by M i l l e r (1901; 1902; and f u r t h e r d e s c r i b e d and named i n 1910, p.46-48, 113) i n t h e v i c i n i t y of
Lake Timiskaming on t h e Ontario-Quebec b o r d e r . Between t h e second and
t h i r d d i s c o r d a n c e s , Coleman recognized a sequence ( p o s s i b l y broken by a f i f t h discordance) of r e l a t i v e l y unmetamorphosed sedimentary rocks t h a t he c o r r e l a t e d with p a r t of Murray's Huronian S e r i e s o f t h e Bruce Mines a r e a . The b a s a l member o f t h i s sequence, t h e Ramsay Lake Conglomerate, had
p r e v i o u s l y been c o r r e l a t e d t e n t a t i v e l y by W.H. C o l l i n s (1913a; 1914d)
with a s i m i l a r conglomerate found a t Gowganda and Cobalt; both conglomerates were regarded a s t i l l i t e s ( C o l l i n s 1913a, p.55-58). The Whitewater S e r i e s of sedimentary rocks exposed w i t h i n t h e Sudbury b a s i n were regarded a s l y i n g unconformably over t h e Upper Huronian ( t h i r d discordance) and i n d i s c o r d a n t r e l a t i o n s h i p t o t h e Keweenawan ( f o u r t h d i s c o r d a n c e ) .
The geology of t h e r e g i o n t o t h e n o r t h o f Lake Huron was now
s u f f i c i e n t l y well known f o r t h e r e t o be some agreement a s t o t h e sequence
of e v e n t s . However, p r e c i s e c o r r e l a t i o n was n o t p o s s i b l e and terminology
had become almost meaningless. Many terms, e . g . Keweenawan and Keevatin
ages. Laurentian and Algoman had both been used f o r a l l t h e g r a n i t i c r o c k s of t h e d i s t r i c t b u t some a u t h o r s r e s t r i c t e d t h e l a t t e r term t o younger g r a n i t i c r o c k s t h a t were e i t h e r p r e - o r p o s t - h r o n i a n i n age. M i l l e r and Knight (1915, p.592) published a t a b l e showing t h e d i f f e r e n t c l a s s i f i c a t i o n s t h e n used. They proposed ( s e e Column 4,.Table 1, back pocket) t h a t t h e term !%uroniantt be dropped and be replaced by two s e r i e s ; t h e uppermost t o b e c a l l e d t h e Animikean (which was considered e q u i v a l e n t t o t h e Cobalt S e r i e s ) and t h e lowermost t o be c a l l e d t h e Timiskamian
(which was c o n s i d e r e d e q u i v a l e n t t o t h e Sudbury S e r i e s ) ; t h e l a t t e r was placed i n t h e Archean ( M i l l e r and Knight 1915, p.588-589).
I t was now n e c e s s a r y t o demonstrate whether o r n o t t h e p r e v i o u s c o r r e l a t i o n of t h e Cobalt and Sudbury sequences with t h a t o f t h e !'Original k r o n i a n t t a t Bruce Mines was v a l i d . This was undertaken by C o l l i n s ( 1 9 1 4 ~ ; 1918; 1925) a s s i s t e d by T.T. Quirke (1917) and, l a t e r by
R . C . Emmons (1927), and P . Eskola ( i n C o l l i n s 1925). C e r t a i n a r e a s were
s e l e c t e d , each was mapped and t h e n c o r r e l a t e d with t h e o t h e r s on t h e b a s i s of l i t h o l o g y , s u c c e s s i o n , and s t r u c t u r e . C o l l i n s showed t h a t i n t h e
Gowganda a r e a t h e Cobalt S e r i e s r o c k s l a y d i r e c t l y on t h e g r a n i t e s but f a r t h e r s o u t h t h e y l a y unconformably on a n o t h e r s e r i e s , t h e Bruce S e r i e s , t h a t - w a s a l s o younger t h a n t h e g r a n i t e s ( C o l l i n s 1925, p.111). The
p r e v i o u s l y proposed c o r r e l a t i o n o f t h e Cobalt and Ramsay Lake conglomerates ( C o l l i n s 1914c, p.26) was proven erroneous and d i s c a r d e d (Cooke 1946, p . 4 ) . C o l l i n s ' Table o f Formations i s given i n Column 5, Table 1 (back p o c k e t ) ; and Column 6 r e p r e s e n t s t h e nomenclature used by b o t h Coleman and C o l l i n s on t h e i r maps i n t h e a r e a s o u t h of t h e Sudbury I r r u p t i v e and s o u t h of t h e Murray F a u l t .
C o l l i n s (1925, p.22, 30-40) b e l i e v e d t h a t t h e M i s s i s s a g i Q u a r t z i t e o f t h e Bruce Mines-Blind River d i s t r i c t was e q u i v a l e n t t o t h e Wanapitei
Q u a r t z i t e o f t h e Sudbury d i s t r i c t ( p r e v i o u s l y regarded a s t h e uppermost u n i t of t h e Sudbury S e r i e s ) and t h a t an i n t e r m i t t e n t b a s a l conglomerate was t h e e q u i v a l e n t o f t h e Ramsay Lake Conglomerate.
C o l l i n s (1925, p.44, 47) showed t h a t t h e f o r m a t i o n s t h a t he considered t o be Huronian i n c r e a s e d i n t h i c k n e s s from n o r t h t o s o u t h and from west t o e a s t and it was suggested (Quirke and C o l l i n s 1930) t h a t t h e Huronian has been l a i d down i n an e a s t e r l y - t r e n d i n g b a s i n , t h e n o r t h shore of which l a y s l i g h t l y t o t h e n o r t h of Lake Huron. Post-tluronian g r a n i t i c r o c k s a t K i l l a r n e y and t h e g r a n i t i c r o c k s o f t h e G r e n v i l l e g e o l o g i c a l subprovince were b e l i e v e d t o have formed by t h e g r a n i t i z a t i o n o f t h e e a s t e r n p a r t o f t h i s b a s i n (Quirke and C o l l i n s 1930, p.39-40). G r a n i t i c b o d i e s n e a r t h e western end o f t h e Sudbury I r r u p t i v e were a l s o b e l i e v e d t o be post-tiuronian and were c o r r e l a t e d with t h e K i l l a r n e y G r a n i t e ( C o l l i n s 1925, p . 8 5 - 8 6 ) .
Two o f C o l l i n s ' key a r e a s , Blind River and Whiskey Lake, a r e i n t h e Blind River a r e a and were combined a s one map ( C o l l i n s 1925, Map 1970)
.
I n t h e Quirke Lake, Whiskey Lake and Blind River a r e a s t h e Iiuronian sequence was found by C o l l i n s t o l i e unconformably on g r a n i t e s and g r e e n s t o n e s . Near Lake Huron t h e sequence i s d i s r u p t e d by a south-dipping r e v e r s e f a u l trocks are overlain by sedimentary rocks correlated with the Huronian, (Collins 1925, Map 1970) and the area between Cutler and the Grenville Front was termed by Collins (1936) the southern Huronian belt. In the southern part of the Blind River sheet (Collins 1925, Map 1970), the Cutler batholith was shown to be post-Huronian in age although it was only observed cutting rocks placed in the Sudbury Series (Collins 1925; 1935).
In 1925, R.G. McConnell (1926) mapped the Sault Ste. yarie-Goulais Bay-Garden River area. Here he identified hornblendic schists, largely of clastic origin, intruded by granitic gneisses believed to be Algoman
(McConnell 1926, p.10). These rocks are overlain unconformably by a
sequence, considered by him to be Huronian, that was divided into the Soo Series, the Bruce Series, and the Cobalt Series. The Bruce Series was further divided into formations to correspond with Collinst succession, the Cobaft Series was divided into Upper and Lower Cobalt, and the Soo Series was divided into the Driving Creek Formation (quartzites and conglomerates)
overlain by the Duncan Formation (greenstone) overlain by the, Aweres
Formation (quartzites, conglomerates, and greywackes) (McConnell 1926, map). A.C. Lawson (1929) claimed that there was no real evidence that either the Killarney Granite or that all the diabase intrusions were Keweenawan in age and the former was correlated with the Algoman Granite. Lawson was also unable to confirm a pre-Huronian age for the Sudbury Series as mapped east of Blind River and suggested that the Sudbury Series was really the
Cobalt Series (Lawson 1929, p.377-378). Following Collins, the Wanapitei
Quartzite was placed in the Bruce Series. Lawson also doubted the existence of the Animikie north of Lake Huron (Lawson p.383).
During the years 1929 to 1932, Burrows and Rickaby (1934) carried out geological mapping in the Sudbury area and showed that the Copper Cliff arkose was really a rhyolite and that to the south of the Sudbury Irruptive various volcanic rocks were interbedded with the sedimentary rocks
(Burrows and Rickaby 1934, p.20-21, 17-18). Burrows and Rickaby therefore
considered that both the ~ a m s e ~ * (Ramsay) Lake Conglomerate and the Wanapitei
Quartzite should be placed in the Sudbury Series (Burrows and Rickaby 1934,
p. 13, 23-24)
.
Collins (1936) re-examined the question of the Sudbury Series.
Although he found difficulty in delineating an unconformity at the base of the Ramsay Lake Conglomerate between the Cutler batholith and Sudbury he re-affirmed the necessity for such an unconformity and, reluctantly, placed the Sudbury Series (McKim Greywacke) in the Archean and probably prior to
the granitic rocks (Collins 1936, p.1678-1681). This is the interpretation
shown on the 1935 edition of the Lake Huron Sheet (Collins 1935).
In 1939, Cooke (1941, p.5-8; 1946, p.29-33) discovered what he believed
* ~ a m s e ~ Lake conglomerate has been spelled with both Ite" and "av in the
literature but following the American Commission on stratigraphic nomenclature
(1961), Article 12, remark (a) If..
.
Stratigraphic names that have beenspelled variously should be made uniform by adopting the form accepted by the majority, whatever the local spelling or the original spelling in
geological literature
..."
geological usage makes Ramsay Lake the name tot o be a l a r g e f a u l t i n t h e Copper C l i f f a r e a . This made i t s t r u c t u r a l l y p o s s i b l e f o r t h e Sudbury S e r i e s t o l i e a t t h e base of t h e Bruce S e r i e s ,
but some i s o l a t e d rocks were s t i l l placed i n t h e Archean. Cooke's succession
i s given a s Column 8 of Table 1.
Also i n 1939, F a i r b a i r n (1941a, p . 7 , 9; 1941b) mapped an a r e a t o t h e south and e a s t o f t h e Sudbury I r r u p t i v e . F a i r b a i r n could not f i n d an unconformity a t t h e base of t h e Ramsay Lake Conglomerate and placed t h e McKim Greywacke conformably i n t h e Lower Huronian. The Wanapitei Q u a r t z i t e was regarded a s t h e M i s s i s s a g i Q u a r t z i t e .
I n 1940, Rice r e s t u d i e d t h e geology a d j a c e n t t o t h e Murray F a u l t e a s t of Blind River. He showed t h a t t h e f a u l t had been i n c o r r e c t l y mapped and t h a t i n t h a t a r e a some, but not a l l , of t h e rocks mapped by C o l l i n s a s Sudbury S e r i e s were Cobalt S e r i e s a s claimed by Lawson. C o r r e c t i o n s were a l s o made t o t h e mapping o f t h e boundary between t h e Bruce and Cobalt S e r i e s . C o l l i n s was aware of t h e s e c o r r e c t i o n s but t h e y were n o t published
(probably due t o war time c o n d i t i o n s ) .
Thus a t t h e end of World War 11, C o l l i n s (1925) was t h e standard work on t h e a r e a b u t v a r i a t i o n s i n i n t e r p r e t a t i o n and s t r a t i g r a p h i c nomenclature were almost a s numerous a s t h e workers. C l e a r l y b r o n i a n problems could only be solved by a prolonged period of systematic mapping.
I n i t i a t i o n of Regional Systematic Mapping (1950-1960)
I n 1950-1951, J a s .
E.
Thomson, of t h e Ontario Department of Mines, made a d e t a i l e d study o f Baldwin Township t o determine i f such a s t u d y would r e v e a l important s t r u c t u r e s and r e l a t i o n s h i p s t h a t had been missed i nreconnaissance-type surveys. The s t u d y showed t h a t many of t h e e a r l i e r concepts of t h e a r e a ' s geology r e q u i r e d r e v i s i o n . Thomson (1952, p.9-10, 18; 1953, p.64) showed t h a t d i f f e r e n t conglomerates have s i m i l a r l i t h o l o g y and had been mistakenly c o r r e l a t e d by C o l l i n s . Moreover, t h e v a r i a t i o n s within some of t h e q u a r t z i t e u n i t s were found t o be g r e a t e r t h a n t h e v a r i a t i o n s between t h e u n i t s and t h u s t h e q u a r t z i t e s were considered by Thomson t o be u n r e l i a b l e a s markers. To avoid a c h a o t i c terminology, Thomson used a ? ' s i m p l i f i e d c l a s s i f i c a t i o n t ' denoting each l i t h o l o g i c a l u n i t by a l e t t e r and leaving t h e q u e s t i o n of c o r r e l a t i o n t o await completion of d e t a i l e d r e g i o n a l mapping. Thomson found no break between t h o s e rocks which C o l l i n s had placed i n t h e Bruce and Sudbury S e r i e s . The presence of v o l c a n i c rocks and t h e g r e a t e r metamorphism of t h e l a t t e r u n i t were noted and t h e s i m i l a r i t y t o t h e Timiskaming rocks found elsewhere i n Ontario was pointed out (Thomson 1952; 1953).
In 1953, E.M. Abraham of t h e Ontario Department of Mines began semi- d e t a i l e d mapping i n t h e I r o n Bridge a r e a w i t h a view t o mapping t h e gap between C o l l i n s 1 Blind River and Thessalon a r e a s , b u t l a t e r t h a t year t h e Blind River uranium d e p o s i t s were discovered and Abraham's a c t i v i t i e s were d i v e r t e d t o t h e a r e a under e x p l o r a t i o n . I n t h e period 1953 t o 1955
During 1957, 1958, and 1959, Robertson mapped
an
additional eight townships completing coverage of the greater part of the Quirke Syncline (Robertson 1961; 1962; 1963a).Over the period 1955 to 1957, Roscoe (1957a and b; Roscoe and Steacy 1958; and in Pienaar 1963) of the Geological Survey of Canada carried out
a detailed?tudy of the subsurface geology of the Quirke Syncline as
revealed by drill holes and mine-workings. In 1955, Roscoe (1957a and b)
adopted a new nomenclature for the ~uronian of the Elliot Lake area, partly
because he had subdivided the Mississagi Formation (as mapped by Collins) into readily recognized units. Roscoe's terminology as published in 1957
is shown as Column 10, Table 1 (back pocket). However, as work proceeded
this terminology proved unsatisfactory and modifications were made (Roscoe
1960; Roscoe in Pienfar 1963). Roscoe's revised terminology is given as
Column 13 of Table 1
.
Abraham (1956; 1957) and McDowell (1957) accepted the subdivision of
Collinst Mississagi Formation into mappable units, but, while using Roscoe's
unit boundaries, they used different formation and group (series) boundaries and nomenclature was kept as close to co1'linst as possible (see Column 9,
Table 1, back pocket).
In 1956, M.J. Frarey of the Geological Survey of Canada began a revision of Collinst Bruce Mines sheet (Collins 1925, Map 1969) and the adjoining areas. Frarey (1959; 1961a and b; 1962a and b) found that the earlier work required considerable revision. In several localities it was necessary to place certain strata in different formations; in particular, conglomerate beds, previously placed at the base of the hronian and correlated with the Ramsay Lake Conglomerate, were recognized as being higher in the sequence although locally resting on the granitic basement. Near Thessalon, volcanics were recognized as an integral part of the
Huronian sequence. Subsequently Frarey (1967b) introduced new formational names for the uppermost Huronian beds exposed and for the strata between the volcanic rocks and the basement. Column 11, Table 1, (back pocket),
represents Frareyts nomenclature for the rocks of the "Original Huronian
area" as given on his maps and in his 1967 paper (Frarey 1959; 1961a and b; 1962a and b; 1967b).
In the Sault Ste. Marie area, Hay (1963; 1964) was unable to find any post-Huronian granite. Those rocks, including volcanic strata (Duncan
Formation) that constituted McConnellts (1926) Soo Series, were placed by
Hay in the B N C ~ Group.
Meanwhile, work was being continued in the Sudbury-Espanola area. Ginn (1958) concluded that there were no post-Huronian granites near the southwestern end of the Sudbury Irruptive. Speers (1957) studied the Sudbury breccias and generally confirmed Cookets (1946, p.64) observations that some
*
In
1969, Roscoe published a paper "Huronian rocks and uraniferousbreccias had been mistaken for conglomerates by Lawson (1929) and other of the earlier workers.
Thomson (1960) traced intermittent outcrops of radioactive oligomictic conglomerate, similar to that found at Blind River, around the northern rim of the Sudbury Irruptive. At Lake Wanapitei, an unconformable contact was observed between these radioactive conglomerates and the greywackes and quartzites exposed at Massey Bay and Skead (Thomson 1960, p.10-11).
Thomsonls work confirmed suggestions by Ginn (1958) and Robertson (1960)
of a pre-Huronian age for the Birch Lake Granite (Thomson 1960, p.6). Thomson
(1960, p.5, 9-12). also concluded that the unconformity at Wanapitei represented the boundary between the Huronian (Proterozoic) and the Sudbury Group
(Archean)
.
By 1960, detailed work was well-advanced in the Blind River-Elliot Lake area, the Sault Ste. Marie-Bruce Mines-Thessalon area, and in the Sudbury- Espanola area. Mapping of the first two areas had linked up and the
continuity of the Blind River-Elliot Lake area with the "Original Huronian" area was well-established (Frarey 1959 et seq.; Robertson 1960 et seq.). The lowermost formations of the Elliot E k e sequence do not outcrop in the
Bruce Mines area (Frarey 1962a)
.
In 1961, Thomson published the Espanola compilation map (the pilot map of the new Ontario Department of Mines compilation series) and in 1962 reviewed the "Extent of the kronian System between Lake Timagami and Blind
River, Ontario'' (Thomson 1961; 1962). As work in the Sudbury area was
insufficiently advanced and as continuity with the Blind River area had not been established by continuous detailed mapping, Thomson (1962, p.79)
advised placing all sedimentary rocks exposed south of the Murray Fault and west of the Grenville Front, and those rocks lying between the Sudbury Irruptive and the Murray Fault in an open category termed lfUnclassified
Pre-Cambrian1' pending completion of further detailed studies (Thomson 1960,
p.85-88). Ginn (1960), however, had previously correlated the sequence at
new'
Lake (southwest of the Sudbury Irruptive and north of the MurrayFault) with that of Elliot Lake and furthermore had used Roscoefs (in
-
Pienaar 1963*) revised nomenclature.
By 1961, those working in the Huronian of Ontario were turning from mapping individual areas to correlating those areas in the light of
stratigraphic succession, facies change, structure, metamorphism, and radioactive age-determinations.
Regional Compilation Studies (1961-1967)
Since 1961, the present authors have continued the government mapping programs. Much data accumulated by government surveys, the-mining industry, and by the universities has been made available in various maps, reports,
*
This revised nomenclature had been presented in a paper "Definition,subdivision and correlation of the Huronian rocks" given to the 13th Annual Meeting of the Geological Association of Canada, at the Royal York Hotel, Toronto, Ontario, April 24-27, 1960 and published in part in the Northern Miner
papers, and theses. Giblin and Leahy (1967) have compiled the geological maps for the Sault Ste. Marie-Elliot Lake area. The University of Western Ontario has established a field-school at Whitefish Falls (south of
Espanola) and this has led to a number of papers and theses [Blackburn
1967; Casshyap 1966; Young 1966; Young and Church 1966). Several
individuals and organizations have made radioactive age-determinations. These have been summarized by Van Schmus (1965) and Robertson (1967b). The generally accepted age-dates are shown in Column 17, Table 1 (back pocket).
Studies of the metamorphic and structural geology (Card 1964; Robertson 1965a, b y and c; Robertson and McCrindle 1967) have shown that grade of metamorphism and structural style are not valid criteria for distinguishing between Huronian and pre-Huronian rocks.
Figure 2 shows the Huronian areas mapped,by the Ontario Department of Mines and the Geological Survey of Canada, for which final or preliminary maps have been published and also that area mapped by the Geological
Survey of Canada, but not yet released (Frarey 1967a). It should be pointed
out that although not mapped in detail much is known of the 12 mile gap west of Espanola as a result of the efforts of prospectors and students. Clearly a meaningful synthesis of Huronian data is now possible.
Robertson first assembled data for the Blind River-Elliot Lake area in 1960 (Robertson 1960) and reviews were published in 1966 and 1967 (Robertson
1966a; 1967b)
*.
From mapping in the Cutler-Spanish-Massey area (Robertson1965a, b y and c; 1966b and c; 1967a; Robertson and McCrindle 1967) it is clear that the sequence south of the Murray Fault previously mapped as the Sudbury Group and placed in the Archean is the faulted extension of the
proven Huronian rocks north of the fault that have been shown to be continuous with the Blind River sequence. Robertson's nomenclatures north and south of the Murray Fault are given as Columns 14 and 15 of Table 1 (back pocket). There are steady changes (see Figure 3) in facies and thickness of
individual units in a southeasterly direction from Quirke Lake to the Denvic Lake area (north of the Murray Fault between Spanish and Massey)
and the Aird Island-Spanish Estuary area (south of the Murray Fault). The
rock units observed south of the Murray Fault in the vicinity of the Spanish Estuary may be traced, with no significant break, eastwards to the Grenville
Front (G.S.C. and O.D.M. published and unpublished maps). Since the days
of Collins (e.g. Collins 1935) and Coleman this has not been seriously questioned. The foremost questions have been: 1) the relationship between the units that lie stratigraphically below the base of the Ramsay Lake
Conglomerate, and those that lie above this geological boundary; and 2) the relationship between the strata exposed north of the Murray Fault and that exposed south of the Murray Fault east of Blind River. The authors are agreed that the base of the Ramsay Lake Conglomerate does not represent a major unconformity. Lateral changes similar in magnitude and character to
*A paper "Geology and uranium deposits of the Blind River area, Ontario" was
presented by Robertson to the 71st Annual Meeting
of
the Canadian InstituteI Aird Island I
those observed between Bruce Mines, Elliot Lake, and Massey may be observed as the rock units south of the Murray Fault (here correlated with the
Huronian units exposed north of the Murray Fault) are traced eastwards from Aird Island through Espanola to the Grenville Front and south of Sudbury (Blackburn 1967; Casshyap 1966; Young 1966; Young and Church 1966; Card 1965; 1967a, b, c, d, and e; 1968a, b, and c; Card and Blackburn
1965; and unpublished maps by
M.J.
Frarey).As a result of informal field trips held each season by those
interested in the Huronian it has become clear that there is substantial agreement between those currently working in the Huronian but that this agreement is obscured by a lack of a standard nomenclature.
In 1967, therefore, (as noted earlier in the report) the Geological Survey of Canada and the Geological Branch of the Ontario Department of Mines set up a Federal-Provincial Committee on Huronian Stratigraphy.
PROPOSED DEFINITION AND SUBDIVISION OF THE HURONIAN SUPERGROUP
1) Definition of the Huronian Supergroup: That assemblage of sedimentary and volcanic rocks occurring in the vicinity of the North Shore of Lake
Huron, Cobalt, Sudbury, and adjacent areas and lying with marked unconformity
on the Archean rocks and intruded
by
the Nipissing Diabase. The Archean,for this purpose, is regarded as comprising all rocks formed before or
during the Kenoran orogeny and would include rocks generally called Keewatin, Timiskaming, and Algoman, and post-Algoman (Matachewan?) diabase dikes.
Comment: In the present state of age-determinations the Huronian rocks would therefore have formed in the period between 2,500 million years and 2,200 million years ago; the actual period of sedimentation was probably considerably shorter.
2) Subdivision of the Huronian Supergroup: It is recommended that the Group names of Roscoe's revised nomenclature (in Pienaar 1963) be used with
the word "Lake" included in the geographical component of the name where
appropriate. It is recommended that the formational names of Collins (1925) be retained as far as possible. The Mississagi Formation as mapped by
Collins (1925, Blind River sheet) in the Elliot Lake area should be broken into five formations:
Mississagi Formation quartzite
Pecors Formation argillite and argillaceous quartzite
Ramsay Lake Formation conglomerate
McKim Formation argillite
Matinenda Formation quartzite and arkose
-
+ U-conglomerate-
13-
Table 2: Recommended Huronian Stratigraphic Nomenclature
Nipissing Diabase
Diabase Intrusive Contact Huronian Supergroup
Cobalt Group
Bar River Formation
(Top not seen) (Top not seen) Gordon Lake Formation
Lorrain Formation (Local Members)
Gowganda Format ion (Local Members)
Unconformable to Disconformable Contact Quirke Lake Group
Serpent Format ion
Espanola Formation Bruce Formation
Local Disconformable Contact Hough Lake Group
Mississagi Formation Pecors Formation Ramsay Lake Formation Local Disconformable Contact Elliot Lake Group*
McKim Format ion
Matinenda Formation Unconformity Archean
(Local Members)
(Local Members)
general usage o u t s i d e t h e immediate E l l i o t Lake a r e a ( C o l l i n s 1925; 1935). The f u l l breakdown f o r t h e b r o n i a n i s given i n Table 2 and has been included a s Column 18 of Table 1. The M i s s i s s a g i Formation of t h e recommended nomenclature i s e q u i v a l e n t t o t h e Upper M i s s i s s a g i Formation a s used by Robertson (1960 e t s e q . ) . The Pecors and Ramsay Lake Formations a r e t o g e t h e r equivalent t o E e Middle M i s s i s s a g i Formation of Robertson. The E l l i o t Lake Group i s e q u i v a l e n t t o t h e Lower M i s s i s s a g i Formation of Robertson. On t h e b a s i s of r e c e n t mapping it i s t h e committee's conclusion t h a t t h e E l l i o t Lake Group i s a l s o t h e equivalent of t h o s e rocks formerly, and g e n e r a l l y , named t h e Sudbury Group; it i s recommended t h a t t h e term Sudbury Group be dropped because of t h e entrenched Archean connotation and t h a t E l l i o t Lake Group be r e t a i n e d a s t h i s w i l l a l s o emphasize t h e r e l a t i o n s h i p t o t h e known uranium d e p o s i t s . The uppermost a r g i l l a c e o u s formation of t h e E l l i o t Lake Group w i l l be designated McKim Formation, r a t h e r t h a n Nordic Formation, because of p r i o r usage of t h i s term f o r t h e u n i t a s exposed n e a r Sudbury. The underlying arenaceous formation has
l o c a l l y , i n some of t h e e a r l i e r schemes, been c a l l e d t h e Wanapitei Formation (see Columns 6 and 7 , Table 1, back pocket). However, t h e g r e a t e r p a r t of what p r e v i o u s l y had been c a l l e d Wanapitei Formation i s r e a l l y t h e M i s s i s s a g i Formation ( t h e Upper M i s s i s s a g i o f Robertson 1960 e t s e q . ) ; t h e f a i l u r e i n c o r r e l a t i o n being due t o t h e lack of c o n t i n u o ~ ~ r n a p ~ i n g and t o a l a c k of observations of c r o s s - and graded bedding t h a t c l e a r l y show t h a t t h e Wanapitei Formation o v e r l i e s r a t h e r t h a n u n d e r l i e s t h e Ramsay Lake Formation. I t i s t h e r e f o r e recommended t h a t t h e term Wanapitei Formation be dropped and t h a t Matinenda Formation be used f o r t h e arenaceous rocks below t h e McKim Formation.
3) Problems Remaining: The major problems f a c i n g t h e k r o n i a n workers a r e 1) t h e r e c o g n i t i o n of t h e base of t h e b r o n i a n i n p a r t s of t h e Sudbury a r e a and 2) t h e r e c o g n i t i o n and c o r r e l a t i o n of v o l c a n i c rocks i n t h e
h r o n i a n sequence.
Comment: In t h e S a u l t S t e . M a r i e - E l l i o t Lake a r e a t h e r e i s no problem i n t h e r e c o g n i t i o n of t h e post-Archean unconformity. In t h e Sudbury a r e a t h i s remains a problem and t h e age of some volcanic-sedimentary rocks has not been e s t a b l i s h e d t o t h e s a t i s f a c t i o n o f a m a j o r i t y of t h e workers involved; f o r t h e s e rocks an open category must be r e t a i n e d .
I n t h e "Original Iiuronian" a r e a t h e Thessalon and Duncan assemblages mapped by Frarey (1961a and b; 1962a) and Hay (1961; 1964) a r e k r o n i a n . The underlying sedimentary rocks have been c a l l e d Livingstone Creek
Formation by Frarey (1967b); t h e s e sedimentary rocks a r e probably e q u i v a l e n t t o p a r t of t h e Matinenda Formation.
The P a t e r Volcanics a t Spragge (Robertson 1967a) and p o s s i b l e v o l c a n i c rocks i n Shedden and V i c t o r i a Townships (Robertson 1965a; 1966b) both south of t h e Murray F a u l t , a r e b e l i e v e d t o c o r r e l a t e with t h e Thessalon Volcanics. Age-determinations have been c a r r i e d out but i t was not p o s s i b l e t o
c o n f i d e n t l y p l a c e t h e rocks i n e i t h e r t h e Archean o r t h e Huronian (Knight 1967). To t h e n o r t h of t h e Murray F a u l t i n V i c t o r i a and S a l t e r Townships and extending eastwards i n t o May Township a b e l t of mafic v o l c a n i c rocks l i e s between t h e Archean g r a n i t i c rocks and t h e Huronian sedimentary rocks
t e n t a t i v e l y placed i n t h e Huronian and has been termed t h e Salmay Lake Volcanics from Salmay Lake on t h e Salter-May township boundary.
The r e l a t i o n s h i p s of v o l c a n i c r o c k s i n Baldwin Township and v i c i n i t y and o f t h e S t o b i e Volcanics l y i n g t o t h e s o u t h of t h e Sudbury I r r u p t i v e a r e n o t f u l l y e s t a b l i s h e d . In t h e s e a r e a s b o t h Archean and h r o n i a n v o l c a n i c s may be r e p r e s e n t e d (Card 1968c, p.5-9) o r a l l t h e v o l c a n i c rocks may be Archean (Thomson 1952, p.16; 1953, p.63-65; 1962, p.80-81; Ginn 1960).
The committee s u g g e s t s t h a t each v o l c a n i c u n i t be named a s above and t h a t a t t e m p t s be made t o o b t a i n d a t a on d e t a i l e d petrography and chemistry,
i n c l u d i n g t r a c e - e l e m e n t , and i s o t o p e a n a l y s e s , and t h a t d e t a i l e d s t r u c t u r a l s t u d i e s be encouraged i n t h e hope t h a t c o r r e l a t i o n between t h e u n i t s could be e i t h e r s u b s t a n t i a t e d o r r e j e c t e d and t o e s t a b l i s h t h e s t r a t i g r a p h i c p o s i t i o n and n a t u r e of t h e Huronian-pre-iiuronian boundary.
PROPOSED PRINCIPAL REFERENCE SECTIONS AND REFERENCE SECTIONS
The committee noted t h a t t h e Code o f S t r a t i g r a p h i c Nomenclature was b e s t s u i t e d f o r a r e a s i n which t h e r e was no e x t e n s i v e previous work. On t h e advice of t h e Committee on S t r a t i g r a p h i c Nomenclature o f t h e Geological Survey o f Canada t h e following g u i d e l i n e s were adopted:
Many o f t h e o l d e r Precambrian names d e r i v e from a t y p e r e g i o n but d i d n o t have form$lly d e f i n e d t y p e s e c t i o n s . Such examples were a n t i c i p a t e d when t h e code was w r i t t e n ; s e e A r t i c l e 3 (p.649) IWany formal names a n t e d a t e t h e r u l e s . The names and nomenclatural h i s t o r y o f formal u n i t s a r e recorded
.
.
. .
by t h e Committee on S t r a t i g r a p h i c Nomenclature o f t h e Geological Survey of Canada.
.
.".
To conserve names t h a t have wide c u r r e n tacceptance t h a t were i n u s e b e f o r e formalized nomenclature developed it seems d e s i r a b l e t o invoke t h e g e n e r a l i z a t i o n t h a t can be i n t e r p r e t e d i n t o A r t i c l e 13 remark
-
i ( ~ . 6 5 4 ) * ." ( i ) Reference l o c a l i t i e s may be e s t a b l i s h e d t o supplement t h e t y p e l o c a l i t y . For example, i n naming weakly c o n s o l i d a t e d r o c k s it may be n e c e s s a r y t o d e s i g n a t e a t y p e a r e a w i t h i n which t h e d i a g n o s t i c r e l a t i o n s a r e widely r e p r e s e n t e d , because good exposures a r e evanescent. Thus t h e t y p e l o c a l i t y c o n t a i n s t h e t y p e s e c t i o n , and t h e t y p e a r e a c o n t a i n s t h e t y p e l o c a l i t y . Many e a r l y d e f i n i t i o n s o f s t r a t i g r a p h i c u n i t s i n d i c a t e a t y p e a r e a o r t y p e r e g i o n without s p e c i f y i n g a t y p e s e c t i o n . "
Under remark i t h e i m p l i c a t i o n s o f a r t i c l e 13 ( i i i ) (p.653)*, " d e f i n i t i o n of u n i t i n t h e t y p z a r e a with s p e c i f i c l o c a t i o n o f t y p e s e c t i o n " , could be extended t o permit d e s i g n a t i o n of a l a r g e g e n e r a l l f t y p e l l a r e a t h a t provides t h e e x i s t i n g geographic name and a p p l i c a t i o n o f t h i s name t o a d e f i n e d p r i n c i p a l r e f e r e n c e s e c t i o n t h a t w i l l henceforward s e r v e a s a s t a n d a r d f o r t h e named r o c k - s t r a t i g r a p h i c u n i t .
The committee w i l l propose '!principal r e f e r e n c e s e c t i o n s u and
"reference s e c t i o n s t 1 f o r each of t h e formations* and groups l i s t e d i n Table 2 . These w i l l s e r v e t o d e f i n e t h e Huronian formations i n each of t h r e e a r e a s : 1 ) The "Original Huroniantl of Bruce Mines; 2 ) t h e E l l i o t Lake a r e a ; and 3) t h e llsouthern H u r ~ n i a n ~ ~ of t h e Espanola-Sudbury b e l t .
The Gowganda and Lorrain Formations w i l l be d e f i n e d from t h e Cobalt a r e a b u t i n t h a t a r e a no r e f e r e n c e s e c t i o n s f o r t h e formations o r groups i n t h e lower p a r t of t h e Iiuronian sequence have been s e l e c t e d pending f u r t h e r study of t h e a r e a n o r t h e a s t of Sudbury.
The Group names suggested by S.M. Roscoe (1960 and i n Piennar 1963)
w i l l be used with t h e a d d i t i o n of llLakell where a p p r o p r i a z . Type s e c t i o n s
f o r t h e s e w i l l be i n t h e E l l i o t Lake a r e a with r e f e r e n c e s e c t i o n s i n t h e two o t h e r a r e a s .
A composite Huronian s e c t i o n i n t h e E l l i o t Lake r e g i o n w i l l c o n t a i n r e f e r e n c e s e c t i o n s f o r t h e i n d i v i d u a l formations and type s e c t i o n s f o r t h e groups. This composite s e c t i o n w i l l s e r v e a s a r e f e r e n c e s e c t i o n f o r t h e Huronian Supergroup and, p o s s i b l y , a s t h e p r i n c i p a l r e f e r e n c e s e c t i o n ( t h e t y p e a r e a f o r t h e Wronian Supergroup i s t h e Bruce Mines a r e a ) . A second composite s e c t i o n w i l l be l o c a t e d i n t h e Whitefish Falls-McGregor Bay- K i l l a r n e y a r e a although a c c e s s t o much of t h i s a r e a i s l i m i t e d t o b o a t s .
FURTHER WORK OF THE COMMITTEE
Provided a u t h o r i z a t i o n t o proceed i s given, by t h e Geological Survey of Canada and t h e Ontario Department of Mines, t h e recommended p r i n c i p a l r e f e r e n c e s e c t i o n s and r e f e r e n c e s e c t i o n s a r e t o be examined, measured,
d e s c r i b e d , and marked. I t i s a n t i c i p a t e d t h a t t h i s w i l l be done i n conjunction with t h e normal mapping programs over t h e next few y e a r s . Robertson
w i l l be r e s p o n s i b l e f o r t h e work i n t h e E l l i o t Lake a r e a ; Frarey f o r t h a t i n t h e Bruce Mines a r e a ; and Frarey and Card f o r t h a t i n t h e llsouthern b r o n i a n l l b e l t . S p e c i a l arrangements w i l l be made f o r t h e Cobalt a r e a . Where p o s s i b l e j o i n t examination o f t h e s e c t i o n s w i l l be c a r r i e d o u t .
The Committee's f i n a l r e p o r t w i l l include maps showing t h e major
s t r u c t u r a l f e a t u r e s and t h e d i s t r i b u t i o n o f t h e major marker horizons. The l o c a t i o n of t h e measured s e c t i o n s and a s h o r t d e s c r i p t i o n t h e r e o f w i l l a l s o be given.
ACKNOWLEDGMENTS
The committee wishes t o thank a l l t h o s e who have taken p a r t i n t h e formal and informal d i s c u s s i o n s on Huronian s t r a t i g r a p h y . P a r t i c u l a r thanks a r e due t o S.M. Roscoe who has given t h e committee t h e b e n e f i t of h i s
considerable experience. Raimonds Balgalvis of t h e Ontario Department of Mines a s s i s t e d i n t h e p r e p a r a t i o n of t h e f i g u r e s .
he
proposed p r i n c i p a l r e f e r e n c e and r e f e r e n c e s e c t i o n s f o r formations i nAPPENDIX
L i s t o f Proposed P r i n c i p a l Reference S e c t i o n s and Reference S e c t i o n s f o r Formations
Bar River Formation: (Top n o t d e f i n e d )
P r i n c i p a l Reference S e c t i o n Diamond Lake, C o l l i n s 1925, Bruce Mines Sheet
Reference S e c t i o n s 1. E a s t End of Baie Fine-George Lake
2. Flack Lake-Flack Lake F a u l t
Gordon Lake Formation :
P r i n c i p a l Reference S e c t i o n
Reference S e c t i o n s
Gordon Lake-Diamond Lake, C o l l i n s 1925, Bruce Mines Sheet
1. E a s t End of Baie F i n e
2. Cobre Lake-Flack Lake
L o r r a i n F o r n a t i o n : Type Area
Reference S e c t i o n s
(Top n o t exposed) L o r r a i n Township, Cobalt s i l v e r a r e a , Thomson, R . , 1964 1. Bruce Mines-Desbarats, C o l l i n s 1925, Bruce Mines s h e e t 2 . W h i t e f i s h F a l l s 3 . Mount Lake Gowganda Formation:
I n o r d e r t o r e t a i n Gowganda Formation a s t h e name, t h e Coleman and F i r s t b r o o k Formations should be r e l e g a t e d t o members. These members a r e t o be d e f i n e d from d r i l l c o r e s t o r e d i n Henwood Township (Thomson, R, 1966, Map 2126)
P r i n c i p a l Reference S e c t i o n D r i l l - c o r e , Henwood Township (Thomson, R . ,
1966)
Reference S e c t i o n s 1. North o f Bruce Mines
2. Highway 108-Dunlop Lake
3 . W h i t e f i s h F a l l s o r Lake Penage
S e m e n t Formation:
P r i n c i p a l Reference S e c t i o n Denison Mine o r S t a n r o c k Mine, Quirke Lake
Reference S e c t i o n s 1. Aberdeen Township n e a r Ophir
2 . W h i t e f i s h F a l l s Espanola Formation:
P r i n c i p a l Reference S e c t i o n Espanola
Reference S e c t i o n s 1. Bruce Mines
2 . Q u i r k e Lake (North o f Denison Mine) The s t a t u s o f members w i t h i n t h e Espanola Formation w i l l r e q u i r e d i s c u s s i o n i n any p r e s e n t a t i o n o f k r o n i a n s t r a t i g r a p h y . Bruce Formation: P r i n c i p a l Reference S e c t i o n Reference S e c t i o n s M i s s i s s a ~ i Formation: P r i n c i p a l Reference S e c t i o n Reference S e c t i o n s Pecors Format i o n : P r i n c i p a l Reference S e c t i o n Reference S e c t i o n s
Ramsay Lake Formation: P r i n c i p a l Reference S e c t i o n
Reference S e c t i o n s
Bruce Mines o r Echo Lake
1. Quirke Lake (Denison Mine)
2 . W h i t e f i s h F a l l s o r Lake Penage
Blind R i v e r
1. Quirke Lake (North of Denison Mine)
2 . Lake Penage
3 . Bruce Mines Area?
Pecors Lake ( p o o r l y exposed; d r i l l c o r e
w i l l be u s e d )
1. Quirke Lake
2 . McCharles Lake, Denison-Graham Townships
3. Highway 69 South, Sudbury
McCharles Lake, Graham Township
1. Quirke Lake
McKim Format i o n :
P r i n c i p a l Reference S e c t i o n Aer Mine, Denison Township Reference S e c t i o n s 1. North h a l f M e r r i t t Township
2 . V i c t o r i a Township
3 . Nordic Mine ( c o r e ? ) Matinenda Formation:
P r i n c i p a l Reference S e c t i o n Mack Township
Reference S e c t i o n s 1. Pronto Mine, Long Township
2 . Agnew Lake a r e a
Volcanics Frood-Stobie n o t d e f i n e d a t p r e s e n t Baldwin probably Pre-Huronian
Volcanics i n t h e f o l l o w i n g p l a c e s a r e n o t d e f i n e d a t p r e s e n t : V i c t o r i a Township;.Pater Mine; Salmay Lake n e a r Massey.
The p r e v i o u s l y named v o l c a n i c s , Thessalon, Duncan, Aberdeen, a r e a l s o n o t d e f i n e d a t p r e s e n t .
