"

" 1] • "

., , if - •

- THE AlLOCHTItONOUS ·ORIGIN Of "BIOHERMS"

IN THE EARLY DEVONiAN STUART SAY FORMA~IeN , ' OF BATHURST IS~ND,'~RCTic.CANADA. / 1 / / KEVIN PATRICK POLAN, / /

OEPARTMENT OF GEOLOGICA~ SCIENCES" , ~ McGItL UNIV~RSITY, MONTREAL~ '., ( DECEMBER, 1982.

A the~i s submi t'ted to the Facul ty . of Graduate Stùdies and Researeh in' partial fulfillment of the requirements, l for the degree of Master of Sci ence. , " 3 ~ ,~ ~ ~ ~ .. ! ~ j

J . J ~ .{ " ~ @ Kevin P. Palan, 1982. . ,

i! 1 ~" . ~ o i ; ~ j - \

/1' , ABSTRACT Blocks of limestone and dol9,mite 'up to tens of metres i1\ sfz.e occur • near the base of the Lower Oevonian (Siegenian-Emsian) Stuart Bay Formation 1\, . at s~x sites, on eastern Bathurst Island. These blocks occur in gro~ps of up . " , , ",. 1 : ta thirty individuals and, at the two localit'ies with the greatest numer 'of , . • 1 blacks, are disposed in two roughly linear groups reflecting,their occurrence

on two beddin9 planes. Stromatoporoids (genera: 'Cl..a.t:hJr.od.rj.ctyon, Atopo.4.tJwma.,

GeJrJUmO.4.t1r.om4, Acünccli.c.t.yon. IJr,u.pe.t:o.!).tJwma.,. 'P.6eu.d.ot:Jw.pet.o.4~IfIIJ., Sa.lai.Ir.eUa . and S~ngo.!)~ma.l and favositid corals are the MOst co~n framebuilders. <1 ,<:, . The blacks have weathered from a matrix of finelY-la~~nated deePj . water siltstone. Neighbourin9 bloc~~ differ i~ bedding orientatiqp. Although they, h~ve been described as' bioherms in place~ this evidence indicates tha~ l th~ are blocks deri~ed during cata~trophic events such as earthqu~kes from ( " a Devonian reef tract developed on the western flank of the Cornwallis Fold-

belt. The occurrence of blocks on two bedding pla~es implies two such

cat~strophic e,v.ents. ..

.. D

,

.J v ;'", !

, } " " ... " \ , RESUME , ft;' . '- fDeS bloès de calcaire et de dolomite 'aY4nt des dÎipens,ions parfois excéd~t

~ , ~ ., - y J , ., plusieUrs dizain~s de mètres, se trouvent près, de la 'base de la formation

Stuart Bay(Siegénien-Emsien) a six~endroits dans l·'Est de TIHe, Bathurst. CI. ,. Ces blocs ~nt rassembl€s en group~s de ,Jusqu 1 a trente individus. Aux deux localités 00 les blocs sont le plus abondants, ils sont dispos€s

( 1 linéairement en deux groupes reflétant le plan de, litage. Des • •• "/,.1' • ' , stromatoporol des (genres :Clathrood:r.. atyon, Atopostl"cma, ?Ge:rtloonostpoma" l ~ Aatinodiatyon" Trupetost1'oma." 2Pseudotrupetostrooma, SalaireZZa, et Sy1'ingostI:oma) e~!,s coraux' favositides sont les plus important constructeurs de récifs. Les blocs sont' situés dans' une matrice Ide siltstone finement laminée~ " ... • -..fIl ( et deposee en eau profonde. L'orientation du litage'varfe d'un bloc a l'autre. Quoique ayant été "identifie comme des biohermes en place, ces faits indiquent que les blocs ont 'etê fonmfs et deposéS pendant des catastrophes tel que des tremblements de terre. Au moins deux de ces catastrophes ont eu lieu, car les blocs se trouvent suivant deux pl?ns de litage. Ces blocs sont des fragments delo,gés d'un récif développe sur , " f le flanc ouest de la zone de plissemen~s Cornwallis.

\ • Oc

( .' ., 1 '-

,c,

. " • " , "- (': ' . text ': page ACKNOWlEDGEMENTS B6 \ \ REFERENCES 87 ~ PLATE CAPTIONS 98 figures 1. Regional geology of tne Aret;e Islands .. 2, 2. Northeastern Batpurst Island 4 • 3. Enlargement of the Arct1c Platform 9 "x 5. Polarh~ear Pass locality 28 6. Moses Robinson River .1ocality 30 J 7. Cheyne River locality '31 8. Sample eut and polished to reveal geopetal, structures 38 9. Wulff projectio~ of two lines fram sample 8-6 ~ 40 10. Wulff projection of rotated poles to geopetal ~tructures 41 , and bedding attitudes

~uring Il. Part of eastern Bathurst Island Stuart Bay time 55 4- 12. Favosites tabular density plotted against corallite diameter 69 ( 13. Three different measurements of corallite diameter 74 14. Frequency hi stograms", of Pavofi tes cora 11 i te di ameter 77 tables " . 1. Age of the Stuart Bay Formation 23 2. Perc/ntages of thin sections exhibi~in~ specifie textures 35 3. Percentages of framebuilders in the blocks 35 4. Orientation of beddipg and, geopetal structures of blocks 37 ..1 5. Three theories to account for the presence of carbonate 49 , .... masses in the Stuart Bay Formation 6. , Summary of data for the samp 1es of Favosi tes 66 7. Data from thin sections 68 68 ' 8. Statistical studY.of three possible groupings of the c Favosites samples 9a. Summary of data for 12 species of Favosites 7f , b. Summary of data for possible divisions of the Favosites samples n

't

- ,

, , , . ..

. .. 1

(' ,. 1 NTRODUCTt ON Bathurst Island is hocated in the .,centre- of the éanadian Arct;c 0 0 Islands between Latitudes 75 and nON uarx:! Longitudes 97 and 1050W{f;q.l~.. _ Because o~ i ts pro!JmftY te the nortr'l magn.èti c po)~ ordi nary compasses - "

~ are useless and di rectlons must be estimated by 'topography and sun pos; tiqn.

In genera 1 the topo~raphy of the ; s land i s gent1y rD 11 ; n9 but eut by 1 • deeply" inci sed s treimlS. , Bathurst Island was discovered in 1819 by W.E. Perry. ' Sir John " ' '. Frànkl in and ,his expedition sàiled a10ng the east coast before the winter of 1845-6. Be.tween 1850 and 1853 several groups searched for the lost

Franklin expedition and vis~ted and partial1y mapped the i~land. Various

Aretie expeditions visited the'island between 1853 and 1917. The true

nature of the Bathurst Island group of is1ands was not discovered until

( 1947. Previously all' of, the islands except for the Berkel~ Islands were . ~ - thought to belong te one landmas5. Only th'ree, wells for ail have been drilled on, Bathurst Island.

In the winter of 1963-4 thé Dominion EfCp10rers-Canso et. al. Bathurst , - ..J Ca1edonian J-34 wel1 wa5. dri11ed . In 1971 the Sun KR All'ison Ri ver N-12 , , and'Sun KR Young Inlet 0-21 ~lls were dril1ed.

< , ',Little geo1ogical work was done before the 1950's when Jenness

~.7 - • (1952 a, b) and Taylor (1~56L.investi.gated the surticial geology.of the " island. In 1953'Operat~Çlh FrankJin, a major g.eologica1 survey of the , . Arçtie Islands, took place (Fortier et at, 1963). Kerr, MeGregor' and McLaren (1965) described an unconfonnity between the Middle and U~r , ;.-. .De'vonian' strata on Bathurst Islana. Kerr (1968) deser;'bed the Devonian , rocks of the is1and in a regional paper. kèrr (1974) has published the . "

,.' \ .1,

\ 2 1 r . \ --- '"

, " " , (, 120 100 1. , . 60

J (

·Seque.oces 7,~ Aretic Coastal Plàin

SeqJ.lences 4,5,6 Sverdrup ,l~asin Sequence 3 A Franklinia~ 0 ArcÎ:ic t1l1\ Frank1inian c1astic belt 9 .MiQ-geoclin~' Platform \lLJ}

l " \ " Sequence 2 \ Proteroz.oic Bàsins

Sequence 1, Preeam~rian Shield

" Figure 1. Régional geol~gy o~ t~e A.ctic Is1anqs {aftar Thorsteinss~n and Tozer, 1970; Ke~r, 1974, 1977, 1?8l}. Bathurst Island i9 i~di~ated , \ l\ by a star.

:_,( 3

most comprehènsive geological repart on Bathurst and adjacent small islands (the Bathurst Island Group). Powell (1978) assessed the hydro­ carbon potential of the wells on Bathurst Island. Mayr (1980) corrèlated ·the subsurfaçe of the Bathurst Island Group. The lnteresting structure of Bathurst Island has been described i,n seyeral papers including those of Fortier and Thorsteinsson (1953) and McNair (1961). The Devonian paleontology of Bathurst Island has been discussed by Ormiston (1967(

(trilobites). McGregor, and Uyeno (1'972) (spores ant\c~donts), Hueber 1 (1971) (land plants), L'~nz (1973) and Smith (1980) (6ChiOPOdS)., Kerr (1974} in his description of the geology of Bathurst ls1and

not~d the presence o~two paral1el rows of limestone masses* in section 34 - . ' " (Polar Bear Pass locality of this report. see fig., 2). Bioherms were als'o " noted in ,Kerr' s sections 21, 23, 25 and 33 (Kerr" 1974). He concl uded'" ( that their fauna and lithology indicated that they were in-place bioherms. ~n' the summer of 1980 the writer discovered severa1 other 10catiQQs where these curio(2 "biohenns ll are present (see fig. 2). LithOl0g~'ca.l,· c:al ' .' "'= ànd stromatoporoid 'samp1es were taken from the blocks at these localities.

Beddihg was measured and samples taken to 10cate geopetal strutture~. The 1itho1ogy and structure of the surrounding beds were examined. The

consensus of JOOst geologists (Kerr, 197;'4; Smith, 1974; Mayr, 1980)' iS that

the Stuart Bay Formation was deposit,ed. in deep water. However th~ litho-

b logy, te,xture and fauna of the block:s ,;ndicate deposition in shallow

water, ~nd the bedding and geopeta1 structures show by their variability

1 0 the blocKs have be~n transported. For these reasons l believe that the '

6 carbonate "biohenns", in the"Stuart Bay 'Formation at Kerr's (1974) section * Hereafter referred ta as blacks or ·"biohenns". ( . ,

1 ~ \.

4

" CR.

" - :

r

, - /

/

o 20 40 60"", Figure 2. Map of northeastern Bathurst Island showing the loèations of blocks in the Stuart Bay Formation. PBP Polar Bear Pase PB~N Polar ~ar Pass North 'AS Arthur' s Seat MœUR Moses'Robinson River CR Cheyne Riyer CRN Cheyne River North • 1 } ,

f, 5

34 and at other loca~ities (see f1g.2) are allochthonous blocks derived

from reefs té' the east. .. "( t, '" •• Th i s s tlJdy .i 11 us tra tes how êas il y JJ loch t,honous \b l ocks can be mistaken for bioherms in the lield. Other examp1es of the misinterpre­ tation of allochthonous blocks have been documented by Mountjoy et al. (1972), conaghii~"-et à'1. (1976) ,and Wendt and Fürs;ch {1979}. The identifi- '\. , ,cation of the blocks as biohenns by Kerr (1974) in section 34 has led to

the conclusion that the Q.W1~ fauna found in thin caryonate beds within the si1tstone and 1aterally equiva1ent to the blocks represents _ -' a "fairly shallow, subtidal cOl1l11unity " (Lenz, 1973). Identifying allochtho .. 1 " . nous b 1ocks as reefs 1eads ta a fa l se concepti on of "he 'envi ronment of 'li deposit~f'~'he sediments in ~hich they are enclased.

( /

" t

, ,J , .

\ \ \

'-

, , 6 Î ( REGIONAL GEOLOGY Late Prote1'tl:zotc ta Late Devonian History of the Franklinian Geosyntline The rocks of the C8nadian Arctie ISlands can be divided into 8

stratigraphie-structural. provinces or sequences. (see fig.!). The Pre- cambrian basement is the oldest of these; the second oldest comprises various Proterozoic rocks. These -are '\unconfonnably overlain by Sequence 3: Proterozoic to Late'Paleofoie roeks that were deposited on the Aretic Platform and the Franklinian Geosyncline. The Upper Paleozoic to Mesozoie rocks of Sequences 4. 5 and 6 unconfonnab1y overlie Sequence 3. The Cenozoic ta modern sediments of ?equences 7 and 8 oceur at the top of the section. The history of the Aretie continental margin from Ellesmerè to ~ Banks Islands has been dominated by the Innuitan ~~obi1e Belt. The Frank1inian Geosyneline is located between the Shield and ( Aret;c Platfonm in the south and southeast and the Pearya Geanticline in the north. The geosyneline can be divided into two regions; the miogeo-

cline in the southeast,. and... the elastic belt in the northwest. The first a contains mostly carbonates and borders the Aretic Platform a10ng a hinge 1ine across which there are significant thiekness differences but ~ no major 1;thologiea1 change. The h;story of the Frank1inian Geosyncline is given in Kerr (1981);

the followi., n9 is a sunmary of this work. The history of the geosynel ; ne can be divided into 5 depositional phases. Subsidence in this basin began in Late Proterozoic or Early Canbrian time. At first the basin was narrow

but it gradua11y became wider and deeper until its maximum in Late Ordovi­ cian ta Early Silurian time. After this it shrank. g.radual1y becoming narrower and shallower until 1ts deformation during the Ellesmerian 7

( Orogeny in Late ~vonien or Early Mississippian time. The rocks studied in this thesis occur in the third stratigraphic­ structural unit of the Arctic Islands. It unconformably overlies the older Proterozoic rocks and is t~ted et the top by a major unconfor­ mit y caused by uplift due to the Ellesmerian Orogeny. There are no major orogenie episodes within Sequence 3 but several minor unconfornnties oecur in this most extensive sequence of the Innuitan Mobile Belt. It was depo- sited in a vast, continuous depositional basin that at times exceeded the

boundaries of the geosyncline and included all of the Arctic Islands.~, The sequence records the history of 4.he Franklinian Geosyncline. the Arctic Platform and the magmatic stage of the Pearya geantieline. Sequence 3 can be divided into 5 stages w;thin the Franklinian 1 Geosyncline. The first depositional phase lasted from Late Proterozoic ( (Hadrynian) to middle Late Cambrian and records the or1gin and general

wide~ing of the geosyncline. Carbonates dominated both the miGgeocline and the Arctic Platform by the end of this phase. Sedimentatlon was eontinuous into the second phase which lasted from middle Late Cambrian to middle Late Ordovician and took place in a starved basin. The inter- mittent tectonic activity- of the Pearya Geanticline during this time re-,

sulted in compllex facies changes in the nort~est of the geosyncline.

During Phase 3, from Late Ordovic~an to early Early Devonian, the geanticl ine was acti ve and became the source of flysch deposits that filled the' basin. During the early parts of this phase the sea was deep but sediment supply was low. and the graptolitic and shaly Cape Phi 11 i ps Fonnation was' depos i ted on Comwa 11 is, Bathurst, Ellesmere, \ / " Melville, Prince Patrick and Banks Islands. A gradual expansion of

( 8

c1astic deposition Qccurred at the expense of car,bonates until f1ysch

occupied the northwest, a~d sha1e, the southeast parts of the basin: , Toward the end of this .phase ~he geosync1ine became narrower and shal10wer , due to uplifts of Pearya and the Arétic P1atform during the El1esmerian Orogeny.* Substantial uplift due 'ta the El1esmerian Orogeny began ta occur during Phase 4 (ear1y Ear1y Oevonian to Middle Devonian). The Stuart Bay Formation was deposited during this phase. Progressively more wide- spread emergence during this time resulted in deposition becoming res­ tricted as the Franklinian Geosync1ine became filled. Phase 4 began with the rapid up1ift of both the geanticline and

the Platform (especially the ~ornwallis Foldbelt) which became sediment sources to the northwest and southeast of the basin respectively. With ( t;me the hinge or flexure shifted basinward until the southern and eastern

p~rts of the miogeocline became part of the Arctic Platform (the study area is in this zone, see fig.3). The uplift produced an unconformity at the base of the sequence (between xhe Bathurst Island and Stuart Bay Formations) in southern and eastern Bathurst Island. This unconformity

d;minishes ta the northwest (basinward) indicating that there deposition was continuous in deeper water. The clastics of the syn- te post­ tectonic Stuart'Bay, Peel Sound and Snowblind Bay Formations encroached upon the platform whèn uplift ended. These rocks were succeeded by a narrow but thick belt of carbonates in the miogeocline"( D-isaol)ointment Bay and Blue Fi-ora Formations) and thinner but equivalent carbonates on * According. to Kerr (1981) because the pulses of activity in Pearya and the Boothia Arch were, synchronous they must have had a common mechanism. -""9

(

1 • ".:\ ~., 1 "'- " id. tf' ~ l''l Geosyncline ~~-~ &1 #ç, \V-- 1 ~

c ~ ~ ...... i"'~ \ ,- Arctit Platform le ~ ~Q. ~ 1~ \ 'n.I LJ"'-"".,L- ~' 1 ~ - --...... : .... ~') ~~ p New Arcttc Platform cr ~""1'-""l--r-. .~d_ ~ ~ ~~I- 1) ~ @ ( y ("~ :1 Basement Complex ~ 1111 ~ It ... ~) (1 lJ; \.< ~~ ) ~ ,)

1 1 c) 5'0 1(,.

Figure 3. Enlargement of the Arette Platform resulting 'from the formation of the Cornwallis Foldbelt (after Kerr, 1977).

( ./

, _Î 10

( the platform (Kerr, 1976). On northern and western Bathurst Island the carbonates grade into the clastics,of the Eids Formation. This phase , ended in upper Middle Devonian at the base of the c1astic wedge that in­ cludes the Okse Bay Formation and its equiva1ents (Kerr, 1974,1976; Enbry and K1ovan, 1976).

~ ~ The last phase of deposition in the Frank1inian Geosync1ine, Phase 5,lasted from late Middle to Late Devonian. As the Pearya Geantic1ine rose and broadened fine grained clastics advanced south and east. The source of tbese clastics is controversia1: accortling to Kerr (1981) the source is the pearya Geanticline; according to Embry and Klovan (1976) the source is the uplifted areas in northeastern and eas tern Green 1and .

. (

o

- :- 11

( His-tory of the Boothia Upl;ft and Ordo'vician to Devonia.n Strati graphy of Bathurst Island According to Kerr {1981} the depositional history of the Franklinian Geosyncline'described above was mod1fied and disturbed by basemént uplifts in two ways. l) Periodic episodes ~f uplift l~c~lly interrupted ûeposition and caused unconformities and changes in facies and thickness. 2) The relative rigidity of the basement cored arches resulted in different structures being formed during deformation in the uplifted areas than in surrounding rocks. The Boothia Uplift, which trends and plunges north, is a strongly positive tectonio. element at least 1000 km long (Kerr, 1977). It was formed by vertical upward movement by basement faulting of a block of the Precambrian Shield called the Boothta Horst. The raising of the basement ( deformed the overlying Proterozoic to Early Devonian sediments into a • broad anticlinorium known as the Cornwallis Foldbelt. The study area is within and on'the flank of this foldbelt on1eastern Bathurst Island. From Middle te Late Ordovician (Pre Ashgill;an) carbonates and evaporates of the platfonn facies Cornwallis Group were deposited on

Bathurst Island during a period of widespread tectonic s~ability. Because sedimentation kept pàce with subsidence, deposition continued to be in shallow water. From Late Drdovician to Early Devonian the euxlnic. graptolitic black shales, shaly limestones and chert of the Cape Phil1;ps

Formation were deposited in a starved basin. The area, was still tecton;- cally stable but subsidence exceeded sedimentation, circulation became restricted and an eux; nie basin developed. This depos; tional. sequence

was interrupted by Pulse l of the COrowqllis Disturbance. 1) ~.

12

( The Boothia Up1ift was mildly positive fram Ca~rian to Early Silurian time but the main uplift octurred during. the Cornwallis Disturban­ , ' ,ce of ~ate Silurian to Devonian time. This took place in four pulses and / established the basic structure of the Cornwallis Foldbelt. After each of these pulses of denudation the seas advanced and sediments were deposited unconformab1y on the eroded surfaces. The following is a synopsis of Kerr's (1977) study which described the history of this disturbance.

Pulse 1 of the disturbance was a gentle archin~ in Late Silurian (Llandoverian) time that produced a north-trending anticline and an angu1ar unconfonni ty in the axi s of the Cornwall i s Fol dbel t. The upper Thunt> Mountain, Irene Bay and Allen Bay Formations (Upper Ordovician ta Lower Silurian) were erode,d. Later the transgressive deposits of the Middle Sil urian Cape, Stonn Fonnation overl apped them unconformably on the fa l dbelt. ( This pulse was brief and had little effect on regional facies. The result on Bathurst Island was that the Cape Phillips Formation was thinned. Eastern Bathurst Island was considerably less stable during the Early Devonian. The rate of sedimentation increased and exceeded subsiden- ce resulting in a general shallowing. The Bathurst Island, Stuart Bay, Disappointment Bay, Eids and Blue Fiord Formations were deposîted during this time. Two pulses of activity interrupted this phase of deposition. Pulse II, the strongest of the pulses, occurred in early Early Oevonian time (Bathurst Island and Stuart Bay time). The unconfonnity and conglomerates at the base of the Stuart Bay formation mark the ,beginning of this pulse. Pulse II affeJted the entire fo1dbelt; it changed facies patterns and the shape of the basin. By the end of this pulse part of the Franklinian Geosync1ine was converted into a northern extension • .. 13

( of the Arctic P1atform tectonic province due to the northwest migratiQn of the hinge1ine. This extension inc1udes. the study area (see fig.3) . The sediments' eroded f~m the Cornwallis Foldbelt during Pulse II fomed the' Stuart Bay Formation on the western part of the fol dbe1 t and

" beyond on its western flank, and the Snowblind Bay Formation in central and eastern parts of the foldbelt. As the up11fts of this pulse waned the upper parts of these formations were deposited further eastward and came to be unconfonnable on the older rocks of the foldbelt. The Stuart Bay Formation unconformably overlies the flysch-like Bathurst Island

Formation on eastern'. Bathurst Island.

~he Cornwallis Foldbelt was a north-trending anticlinorium by the end œf Pulse II. By this time the anticlinorium was emergent and may have been a high1and. Most of the movement, relief and deformation in the ~ ( foldbelt was produced during this pulse. Because much of the area had 01 been below sea level at the beginning of'the pulse the amount of uplift must

have exceeded the anDunt of , erosion. The app,roximate eastern limit of the eros;on of the anticlinorium crest 1s at Snowblind Bayon the east flanl< of thé Cape Hotham Anticline on Cornwallis Island. The approximate western 1imit is the extreme west flank of the Caledonian River Dome on Bathurst Island. Accarding ta Kerr (1981) a minimum of l800,metres of erosion took place during this pulse • .. Pulse III occurred during late Early Devonian time and is recorded

by the unconfarmity and clastic detritus at the base of the Disappointment Bay Formation. This formation consists of dolomite with a basal quartz conglomerate and sandstone that filled topographiç lows on the irregular eroded surfaces. At the end of Disappointment Bay time a gentle slope

" 14

( ex1sted from a carbonate ~latform in the east (Cornwallis Foldbelt) to a shale basin in the west (western Bathurst Island). On eastern Bathurst Island the formation is succeeded by the shallow water limestone \ of the Blue Fiord Fonnation, and on western.. Bathurst Island by the deep" water siltstone and shale of the Eids Formation and shale of the Blue Fiord Fonnation. A marked increase in the rate of subsidence and a still greater

inerease in the rate of sedimentation occurr d during Late Devonian. A

great influx of sand formed the 8ird ""-.JoO__ n Formation and the Melville Island Group on Bathurst Island and throughout most of the Aretic Archipe- lago. Pulse IV, the last of the pulses of the Cornwallis Disturbance. took place in Late Devonian (Frasnian) ti~. It is indicated by the ( distribution of the Griper Bay Fonnation which is confonnable above older formations outside the foldbelt, is unconformable Along the margins and is absent within the fol dbel t. Because the Griper Bay Formation is fine grained and because the formations deposited between Pulse III and IV are widely'll preserved in the foldbelt the uplift associated with this pulse must have been moderate. \ \ No further activity oçcurred on the Cornwallis Foldbelt or Boothia , Uplift after this pulse. Howevet the basement upli,ft blocked the south­

ward extension of the east-west structures caused by the Ellesmerian ~ Orogeny.

) 15

( Structure of Bathurst Island

Two foldbelts are exposed on Bathurst Islan~hese are the north-trending Cornwallis Fo1dbe1t on eastern Bathurst Island and the Parry Islands Foldbelt, farther west. Kerr (1974) placed the boundary between them at the boundary of north-south trending and east to northeast trending structures. The Cornwallis Foldbelt is the older of 'the two. It extends north fram the Shield across the Franklinian Geosyncline and is about 150 \m wide north of Parry Channel. It includes eastern Bathurst Island,

Cornwallis Island and niost of the Grinne11 Peninsula of Devon Island. It consists of tightly-folded north trending antic11nes and associated faults. According to Kerr (1977) four types of structures are found in the Corn­

wallis Foldbelt. These are from south (deep) to north {shallow}; vertical ( faults, high angle reverse faults, overturned folds and asymmetric fo1ds or monoclines. On1y the latter two are exposed on Bathurst Island •. The· structures are developed 1argely by concentric or flexural slip folding (Kerr, 1974).

The study area includes fnur north trending anticlin~s.' These oeeur en échelon with the most easter1y antic1ine extending farthest north. Aecording to Kerr (1977) the Scoresby Hi11s and Queens Channel Anticlines are asymmetric with east-dipping axial planes and local west­ ward overturning; the truncation of stratigraphie units at the base of the Stuart.Bay and Disappointment Bay Formations shows that these structures

were formed during Pulse II of the Co~allis Disturbance. ~\ The folds of the colnwal1iS Foldbelt were the response of th ~ ~ . sediments te the upward mo~nt of the Boothia Horst during the Devon an \ 1 1\ \ 1 \ 1 16 '\ ( Period (Kerr, 1977). \ The Parry Islands Foldbelt is about 600 km long and at least . 1 Il ,l 200 km wide (Kerr, 1974). It extends from Melville Island to western Bathurst Island and appears to be a continuation of the Ellesmere-Greenland Foldbelt east of the Cornwallis Foldbelt. e. . The Parry Islands Foldbelt consists of subparal1el anticlines and synclines striking east to northeast on Bathurst Island. Toward the

north~ast the trend of the fo1ds becomes gradually more easterly unti1 the termination against the Cornwallis Foldbelt. The geometry of the fo1ds varies considerab1y (Kèrr, 1974). According to Kerr (1974, 1977, 1981) the Parry Islands Foldbelt

developed during the Ellesmerian Orogeny. The undeforme~ sediments of the

Franklinian Basin were folded during the orogeny 50 that anticlines and ~cl ines were produced that were approximate1y para11e1 ta the pearya Geantic1ine (and to the depositional trend of the basin). The foldbelt , is underlain by a décollement (probably within the evaporites of the Bay.

il>' Fiord Formation according to Kerr, 1974). The structures formed were " distorted by the Cornwallis Foldbelt anda remarkable interference pattern resu1 ted. The Stuart Bay Formation b10cks are confined te the western edge of the Cornwallis Foldbelt and to the zone of interference within the

Par~ Islands Foldbelt.

1

,. -

( 17

( SlUART BAY FORMATION Descri pti on . The validity of the Stuart Bay Formation is controversia1. Despite their simi1ar lithologies, weathering character maphysiographic expression Kerr (1974) chose to separate the Stuart Bay and Bathurst Island Formations. He based hfs decision to distinguish them on the conglomèrate that separates

~hem, the slightly coarser nature of the sediments in. the Stuart Bay Fonnation and the progressive1y unconformab1e re1ationship between the Stuart Bay

Formation and ~rogressive1y older rocks toward the east. However, these, limestone and cong1omera7e lenses die out toward western Bathurst Island and are absent at sections 15 and 16 (Kerr. 1974) making the separation of the

two fonnations difficult (see fig.4 for all section 10ca'tions). The angular unconformi ty between the two formations disappears west of section 25 (Kerr, ( 1974) and the Stuart Bay Formation grades into andjiS inseparable from the Bathurst Island Formation. Smith {1980) stated thbt at hts section 13 (eut , . Through Creek. see fig.4) the contact between the two formations is not very marked "suggesting perhaps that at this loca1ity the two formations shou1d not be divided" (p.8). Pedder. regards the Stuart Bay Fonnation as part of the Bathurst ISfand Fonnation (Oral comm., North American Paleonto1ogy Convention. 1982). , . Certainly, the Stuart Bay Formation cannot be differentiated from - the Bathurst Island Formation on western Bathurst Island and all the rocks in question can be assigned to the latter unit. However, the status of the Stuart Bay Fonnation in the study area is still unclear. Until the existence of the Stuart Bay Formation as a separate unit on eastern Bathurst .... Island is disproved the writer will continue to assign the allochthonous ? 1 , J; 1 • , ,l

." 18 '" '04- 102- "'"" 100- 98- .. "

.. u

7(/

cp. 1 ·~a ) r- ",-,,_--.-....- \ t .'

~

(. 7~

i j 40 60Km

Figure 4. Map of Bathurst Island with the sections of Rerr(1974) } and Smith(1980) mentioned in the text. l 13 Cut Through CreekCSm1th, 1980) - l

15, ti6 Dundee Bight ~est, Central j 21 Young, Inle~ East, 'Southe~st 1 Cape Kitson Twllight Creek '(McLaren, 1963)

Half Mo~n Bay East 30 Moses Robinson River 32 Head bf\Brabridge In1et 33 Polar Bear PaS8 34 Head of Goodsir Inlet 35 Scoresby Hills West 42 Dyke Ackland Bay• .. .- \ blocks to that fonnation. The -Stuart Bay Formation consists for the most ," part of a dark gr,!!y, ca1careous quartz siltstone with fine grained sandstqne !j: and dolomite, and is up to 2100 m thick (Kerr, 1974). A pebble, bou1der or reef conglomerate usually forms the basal unit. The Stuart Bay Formation . unconformab1y over1ies the Gedinnian to Siegenian (possib1y. Ernsian) Bathurst \ Island Formation on eastern Bathurst Island but grades into this formation

westward except near the head of May In1et where there ,is local angular unconformity. The formation ;s unconfonnably overlain by the Disappoiritment, Bay Formation in the east and is conformably overla;n by the Eids Fonnation in western Bathurst Island. ln southern Bathurst Island (Kerr. 1974, section 42. see fig.4) the Stuart Bay Formation consïsts almost entire1y of dolomite with some quartz sandstone. In eastern Bathurst Island (eg. Kerr, 1974, sections 34, 35) the formation consists of two members: a lower siltstone with thin bedded dolo- mite, limestone and reefoid interva1s, red dolomite si1tstone and other sha110w water sediments; and an upper dolomite and do1omitic siltstone with sandstone interbeds which ;ncrease in abundance upward. The environment of deposition became sha1lower as the formation was deposited. Only the lower

~mber is present in Kerr's (1974) section 34, the Polar Bear Pass locality of the present report. ln eastern and southern Bathurst Island the Stuart Bay Formation is s,lightly coarser, lighter co10ured and/or trore ca1careous . than the underlying Bathurst Island Formation. This change ref1ects a 1 -

sha1lower~viropment of deposition ,for the Stuart Bay Formation. ln northern and western Bathurst Island (sections 20, 25,"'28 of

Kerr, 1~74) the Stuart Bay Formation is trost1y argil1aceous and calcareous : i fine grained quartz'si1tstone with interbeds of sandstone and sandy mudstpne (

(' 20

and 1enses of micrite and ske1etal limestone. Thin conglomerate beds occur at the base. No facies or bed persists 1ateral1y, The type section of the 4' Stuart Bay Formation defined by McLaren (1963) is at Twilight Creek (Kerr, 1974, section 25). Here the formation is simi1ar to the Bathurst Island Fonmation in gross 1itho1ogy. It is a calcareous and argi11aceous sandstone with some muddy sandstone and si1tstone and irregular beds of bioclastic 1imestone. The base is defined by the, lowest pebble beds. They conta;n grey chert and brown, very fine gra,",d limestone in a ca1careous sandy matrix.

Section 20 (Kerr, 1974) is large1y compos~d of fine to medium grained quartz si1tstone with skeletal, peloidal and detrita1 limestone interbeds. In the north and west ot th island the Stuart Bay and Bathurst Island Formations - , 1 . are similar and were probab1y deposited onder similar conditions. The depositional env;ronment of the Stuart Bay Formation was therefore deeper ( in this region than in the east or south. In a section on the unnamed river west of the Polar Bear Pass locality the writer observed that the Stuart Bay Formation cons;sts almost entirely of siltstone with sorne crinoidal debris beds. The siltstone ;s finely laminated but there are sorne small scale slump structures present. The outcrops near the Arthur's Seat locality are a1so finely laminated siltstones with some lump structures. A section in an unnamed stream flowing

north beside the Cheyne River locality consists for the most part of finely J " laminated siltstone with some crinoid debris, beds less than a metre thick. The Stuart Bay Fonnation is now found only on the Cornwallis Fold­ belt and on its western flank (Kerr, 1974). It is thickest immediately west Of the foldbelt and becomes thinner westward toward the basin and eastward toward the foldbe1t. The sedt.ment source for the formation was the uplifted f 21

( older fonnations on the Cornwallis Foldbelt. In particular. Kerr (1974) praposed that the Cape Phi11ips Formation was the source of the chert in

the conglomeratel and that the reefoid bou1ders in the cong1omerate were • eraded fram reefs fringing the fo1dbe1t. Kerr (1974. 1981) stated that the Stuart Bay Fonnation ref1ects unstable tectonic conditions. In his interpretation the first sign of up1ift was the shallowing of water suggested by the interbeds of conglomerate

and 1imestone. As the uplift continued. erosion removed parts of the fonna-

~ tions te the east and the detritus spread as the cong10merates of the Stuart

Bay Fonnation. As the rate of up1 ift dlminished deposi t'ÏOJl encroached toward the east and the younger parts of the Stuart Bay Fonnation were laid down.

In this report the conglomerates and bioc1astic limestones within the forma­ tion are interpreted as debris flows fram the older fonnations on the fold- ( belt and from deposits on the flank of the foldbelt. The so-ca11ed reefs of Kerr's (1974) section 34 (Polar Bear Pass loca1ity of this report) and of

the other localittes are determlned to be a11ochthonous b10cks derived from reefs that fringed the foldbelt. This view a1so implies unstab1e conditions

but does not require as great a change in sea leve1 or as much erosion in

Stuart Bay ti~ as the interpretation of Kerr (1974, 1981). \.... f

• 22

• Age The Stuart Bay Formation" has been dated by use of brachi opods,

conodonts and graptolites. Table 1 shows the ages determined at various 1eve1s wHhin the fonnation in severa1 of the sections recorded by Kerr , (1974).* The samp1es indicate a Siegenian to Emsian age for the formation. Because both lower and upper contacts of the fonnation are usually unconfor­ mable in these sections the fauna may not indicate the enti re temporal range of the fonnation. Mayr (1980), in his report on the Dominion Explorers well, assigned a l ate Gedinnian to early Siegenian age to the lower ment>er and an Emsian

age to the upper member. Smith (1980) stated that the presence of ~~ sp in the upper part of the fonnation indicates a Zlichovian (1ower to nid- dle Emsian) age. Uyeno (written comm .• 1982) believes that the base of the ( Stuart Bay Formation at Twi1ight Creek (section 25) is probably high in the gronbergi ZGne and that the top is in the BerotinuB zone. At section 20 the formation extends fram the dehisaens zone to within the serotinuB zone. Kerr (1974) stated that the so-called bioherms occur near the base of the formation. The writer has observed this at the Cheyne River 10ca1ity where the blocks are within 130 metres of the basal conglomerate.

A~ Kerr·s (1974) section 33 brachiopods stratigraphica11y close to the b10cks yield an ear1y Siegenian age. Therefore, the b10CKS oceur in the oldest part of the Stuart Bay Formation and were formed sometime ; n the late Gedinn;'an or early Siegenian. * Because severa1 of Kerr·s (1974) sections appear to be based on airphoto measurements or becaus1 they incorporate rocks that do not occur along the se~tion~ actua11y measured the height and thicknesses shown in the table are approximate. 23 (

..

TABLE - Age of the Stuart .Bay FormatIon

Kerr Heiqht Crlterld Age Sourc~ sect 1 on abcve (SBF bA'S"" thlckness, (S8F)

20 320, 340 ?~ ";grt:J.thLt8 {f7V'N '.at .... 111 d-late Ems Iln

(400) 190 1f000ofr'1IJ"". ;{W':me~tn8 late Slegee'an

85 PolYgrt:J.~h.... c..nzt early Emslan

23 0-75 r • rI yoM 1 d Devon un 2a (75)

25 175 Sch1..z:0ryn0.,.....~a.J'V ..l. Pr.zrc...... n{Y'ur:;ea 'lf'~ ""'Iac"08C"l"""'~...zeu8, 2b

(370) "un,0r~';/nch:....fI" 8D a, ~tJrlJD<1 "l'flttr-.. l.u-s",

Car"~r...::;_1'Il:! 7, ELytl1':fY1tl:

o ParacrOT'ilt ... s 1ft' 17'kIC1"Q8Cr-' JC...LB, Ems 1 drl lb ( A"tl'"Jpa "rett..c:u la:r1.s", Car1.na~~na ., 30 75 Atl'"dPG ''l'et1-l!ul-a.!-.... s'', Sah:JOpnor-l, ~e80(jOU!J'L :l~rlll ., earlY1Tlld Ersldn 2a

(170) F'.7V081..CP!J, [a.,....~?d...l.8 i.JIJRaVtR, LJ'Cta€n'''[1!.!!!:',J ~~ boW't Barr o LiIpta,J"'ooyr_3 cf" botLe1. Barr 51@genldn lc o IC!M-odu8 DBBTlJM S.egen •• n 2d 32 315 Brach 1 opods Ems 1 an 2a (625) 115 Brach,opods proh e arly Ems .an la

30 COl'ttJ.I!!OJ'th'18, Atrypll "r-et!.cut.az..,~a", F'avOBtt28 S.egen.an or Emsldn la 33 215 Brach. opods prob farly ilevonldn 2. (240) 115 IIIonofTl'aptus yWume1'l8U late S.egenlan 105 8rachiopods proh early Siegen.an la (Q!IadM. tJr1l'''.8 zone) 34 0-150 Brach.opods e.arly SiegenJan le (Quadrt tltl,..-8 lone) (150)

References 1 McGre~or and Uyeno(1972) 2 Kerr (1974), ident' fled by Johnson and Boucot Zb ident, fled by Boucot, Johnson and Harper 2c ident, fled by Johnson 2d "ident, fI ed' by Uyeno SBF Stuart Bay FormatIOn The thickness of the sect,ons and the he1

( 1 24

( Envi ronmenta l Dnterpreta ti on The environment of deposition of the Stuart Bay Formation has been reconstructed by severa l authors. The conglomerate at the base of the for­ mation suggestea to Kerr (1974) that the formation was deposited in shal10wer water than the flysch-1 i ke Bathurst Island Formation. Furthermore, he be1ieved that the Stuart Bay Formati~n is overa11 coarser and rrore ca1careous than the Bathurst Island Formation and therefore probab1y of shallower water origin. Kerr (1974, 1977) considered that the source of chert and 1imestone bou1ders in the basal cong1omerate was the Cape Phillips Formation on the Cornwallis Fo1dbe1t and reefs fringing the foldbelt respectively, and that the bu1k of the sediment was derived from erosion of this fo1dbe1t. Smith r (1974) studied the section at Cut Through Creek and based his postu1ate of a deep water environment for the Stuart Bay Formatlon on the presence of a ( rich grapto1ite fauna. Mayr (1980) studied the A11isson River we1l and pos­ tu1ated deposition on a she1f slope or along a shelf edge. He be1ieved that " the abundant sha1e, argi11aeeous lime mudstone and tentacu1itids in the lower member implied a pelagie or deep neritic environment. He a1so noted that

the skel~tal and pe1oida1 wackestones - unless redeposited and belonging to the basal cong1omerate - imply that, at least loea11y, the sea was sha110wer than during deposition of the deep basin flysch of the Bathurst Island Formation.

The author has observed abundant daeryoconarids (S~tina ef~ S. 6-

( within a few metres at the Arthur's Seat 10ca1ity. Because the pelagie dacryoconarids are not found with sha110w water fossi1s at these locations they indicate a deep water environment (Ludvigsen, 1972; Heckel and Witzke, 1979). The 10w fauna1 density a1so suggests a deep water origin. The dark eolour of the rocks, the lack of wave-formed structures, the overall silty 1itho1ogy and the finely laminated aspect of the Stuart Bay'Fonnation su9gest a deep or quiet water origin. If the local 1imestone 1enses and basal cong10merate represent debris and grainflow deposits they cannot.!:>e used as evidence for sha1low water deposition. T-hey imply deposition on 'a slope rather than within a deep basin. In summary, 1itho1ogy (si1tstone with some limestone and conglo­ merate lenses), fauna (confined for the most part to dacryoconarids and

( graptolites) and structure (fine laminations) indicate that at least the lower member of the Stuart Bay Formation surrounding the blocks in eastern Bathurst Island was deposited in marine deep water environment that may have been sha11'ower than that of the basinal Bathurst Island Formation.

,

• 26

( BIOHERMAL BLOCKS

Location and General Descrjption ~ The so-ca11ed bioherms have been identified at six locations within

the Stuart Bay Fonnation on eastern Bathurst Island (see fig.2). The b1oc~s are wel1 exposed and, because they are readily seen from the a~, can be 1 used for navigation. They range in size from 1 cubic metre to several metres long and wide. T:here is no apparent pattern to this diversity and large and

small b10cks are found at a11 localities. The "biohenns" look like tors or

mega1ithic blocks such as those at Stonehenge, Avebury or Carnac. The faces , of the blocks are steep. A surficial ca1careous tufa developed on weathering

and lichen cover obscure the original textures. Some of the blocks are

surrounded by an apron of talus; many rise vertica11y from the regolith sur-

face. The number of b 1ocks per site ranges from one to over th; rty; at the ( two sites having the most blocks (Polar Bear Pass and Moses Robinson River)

they occur in rows ~arallel to bedding. The blocks have not been observed

to be in contact with the surrounding siltstone and conglomerate of the

Stuart Bay Formation but at the Cheyne River locality and at block 20 of the

Moses Robinson River 10cality the siltstone and conglomerate are separated from the b10cks by only one metre. In both occurrences the blocks are a10n9

strike from the sediments. Between sorne of the blocks are circular to

elliptical masses of limestone rubble having fossils and textures similar

to those of the blocks. These may be rermants of blockS reduced te rubble

by frost âction.

Site description s 0 Polar Bear Pass: .15045' N, 98 20' W (see fig. 2,5; plate 1 ).. ,.J

The Polar Bear Pass locality 1s the site mentioned by Kerr (1974) •

27

as section 34 and the block in his plate VI (p.32) is block 2 of the present

study. The blods occur in an area of solif1uction ,debris with the Scoresby

Hills Anticline ta ,the east, outcrops of the Stuart Bay siltstone inmediate-

1y to the west and beyond them an unnamed south-flowing river, and outcrops

of the Disappointment Bay dolomite to the north. To the south is Polar

Bear Pass.

All but one of the 26 blocks occur in two rows parallel to bedding.

about 1.3 km long and 200 m apart (70 m apart stratigraphically). To the

east is a solitary block (26) on a slight elevation. The alignment of the

northwes t 1i ne i 5 not as good as tha t of the southeas t 1; ne. Seve ra 1 of the

blocks (18, 19,23) are located slight1y off the line of the others. The

rows trend about N600 E which is para11el ta the strlke measured in siltstone ( nearby. The dip of the siltstone probably changes eastward toward the anti­ cline but no evidence was found that the strike of the fonnation changes in

the ~rea.

0 Polar Bear Pass North: 75° 50' 40" N, 98 la' 50" lai ( see fig. 2; plate 1)

A few kil ometres ta the north i s the Pola r Bea r Pass North 1 oca l ity . Here

two smal1 blocks and an e11iptical mass of rubble occur in an area of soli-

fl uction debris 'Jiess than 1 km w~st of the Cape Phi 11 ips Formation exposed

in the Scoresby Hills Anticline. No bedding attitudes were found. 0 0 Arthur's Seat: 75 51' N, 98 31' W (see fig.2; plate 2). This loca1ity

is a few km north a10ng the unnamed river that f10ws past the Polar Bear

Pass blocks. About twenty blocks in two groups overlook the river from high

ground to the west. Many of the b locks are frost-shattered. They are

surrounded by an area of finely laminated frost-heaved siltstones that dip -, -

(

, /., 1 / , , ,~ , 1 1 1 ... ' " '1'1 " o ~12 ~ 0 ,", ,,0 17. ~ l • • 20 ~. \J" 1 1 16 ...... 1 l , , , '" , , .... -, li ; / ~ ~ : , .".--'" :.~~ ~ 2l~19 t ..... _,'l - Il ._- .... ,-""" " 0 o :' .cP t4 ~ O~OI>O 020 <;J n c It 22 • • as 0 o~ . 0 25 •. IO:·,~ 'N ". o 9 7 ~o 6 Figure 5, Uap of the Polar Bear Pass locality, (Blocks to Beale). 4 Legend; '3 o ~ °1 block (;1 20~ o 50 100 150 m block number • .. ~ .... ". siltstone ...... , .. ) cp bedding attitude ~ geopetal structure attitude N ~026 .~ 00 siltstone bedding attitude "

intermittent stream ,,»

~w.-I\IO ...... _ 29

( toward the east. Some structures, probab1y soft sediment sl uft1)S, are

present. 1

Moses Robinson River: 76°5' N, 97°58' W (see fig 2,6; plate"2).

Over thi rty blocks in two, or three, rough1y l inear rows occur in a six km

long zone within an area mapped by Kerr (1974) as undifferentiated Bathurst

Island and Stuart Bay Formations on the east flank of the Queens Channel J. Anticline. These rows do not appear as straight or as parallel as those at

the Polar Bear Pass 10cality. However. shorter ~egnents of the rows are

comparable in straightness and alignment. The 1ack of precise a1ignment of

the blocks allows them to be interpreted as fonning two or three rows. The

blacks are surrounded by solif1uction debris and several intermittent streams

make parts of the area boggy. The "bioherms" are not in contact with the

surraunding rocks of the Stuart Bay Formation but an outcrop of siltstone

( i 5 found wi th; n a metre of b 1ock 20 (1 ocated in the forl<. between the two

tributaries of the Moses Robinson River at the southern end of the rows).

The block is along the strike of the siltstone. The size range of blùcks 3 3 at this locality is especia1ly great and blacks range fram l m to 3750 m 1 (block 5). Block 1 contains a high percentage of golf ba1l sized pisolites.

Cheyne Ri ver: 76°11' N. 98°7' W (see fi g. 2,7; pl ate 3). South

of the Cheyne/iver two blocks occur stratigraphically between beds of si1t~

stone and conglomerate. Beds of siltstone and conglomerate east and west

of the blocks strike into them. The "biohenns" are in an area of solifluc- \ tion debris and are not in contact with any of the outcrops although there

is only a one metre gap between them. The conglomerate consists of well

rounded pebbles of fine grained limestone and chert, and fossils (crinoids ..

brachiopods. tentaculitids. bryozoaos, favositids up ta 20 cm in diameter) in 30

(

," ..... ~ Figure é. Map of the Moses Robinson River locality. ,7 " (Blocks not to scale).

Legend: 21 F1 " ' / .' block • block number

bedding attitude 1 • geopetal structure attitude 2 • 3 • siltstone bedding attitude N

intermittent stream

stream •JO ( o 300 '00 900 m

j 1 1 t,

-- 31

(

..... 12------&;;;~ -- ~-----_.--. --- ___ J

-----~ / f \ ~---'--. ______- ,.""J

.

.... , ( , '" , , ~,-, / 1 \ , ,- ocr \ ( ... \ \ Fiqure 7. Diagram of the Cheyne River "- \ ..... - l oea1 i ty ( approximate scale). \ \ \ Leqend: ~ \

black 0 ~Ç) 1 \ ,- -i... 1 \ siltstone-conalomerate .- / / , /' beddinQ attitude 1 \ &J ,..-, 1 si lts. -conq. beddina attitude ( • \ ai -~ '., , '_1-, \

ca 50 nt j l • l 32 1t

( a silty calcareous matrix.

The base of the Stuart Bay Formation is define~ by the lowermost pebb1e bed. Only at this locality has the writer been able to verify th,at , , the blocks' are found in the lower 130 m of the formation.

Cheyne River North: 76014 1 N, 97°59 1 W {see fig 2).__ North of the Cheyne River is, one small (2 to 3 m high), block surrounded by, talus.

(

1

• J t J

J 1 1 ,..

~ - 1

1 .. r 33 - .

Obferva ti ons Dolomite Most of the blocks in the Stuart Bay Formation. are limestone • only'17 are dolomHe. The dolornHe is iron-free, finely crystallir:ae and

very hard. Fossi 1 preservation ranges from poor to good. Many fOS~ ls are preserved as molds. The dolomite ;s light grey, whitish or ochre. The

contact be'tWeen dolomite and lirœstone do es not occur within any individual • • block but dolomitic blocks may be separated from limestone blocks by on1y a few metres. Blocks near the north end of both rows at Polar Sear Pass

are dolomitic. 50 are b locks at ~e south eMd ~of the western row( s) and a11 but one of those in the eastern row at Moses Robinson River. Thare are no dolomitic b10cks at any of the other localities. In both areas the dolomite ( occurs close to the boundary of the Stuart Bay Fonnation with the overlying O;sappointrnent Bay Formation. There is no Disappointment Bay Fonnation in the vicinity of the localities lacking dolomitic blocks. Perhaps the me­ chanism of dolomitization that acted upon the Oisappointment Bay Formation also partially affected the Stuart Bay Formation blQcks . .... Limes tone texture The limestone blocks are a1so 1ight coloured but their textures

are more variable. Thin sections show that the calcite is iron-free and

contains 1 i tt1e or no argil1aceous material or pyrite. This implies , - - deposition i,n shallow, well oxygenated water. Samples from the blocks were categori zed accord; ng te the classificatioo schemè of Embry and Klovan (1972)

for carbonates that supposed1y di fferentiates ~etween reef and non~reef

ma te ri al. , The texture of the limestone in the blocks varies;, wacklStone , 1 and floatsto~ predominate but -grainstone, mudstone. packstone, rudstone

î i • 1 , .

-.KI"'"r<>F_ 4i ..

34

( and framestone are also present (see table 2). Wilson (1970. 1974) claimed that organ;c reefs* are dominated by boundstone with pockets of grainstone

and packstone. The other textures predominate in the environments surroun-

ding the reef. Howerr, Lon91Jan (1981) maintained that though boundstone

dominates his reef flmework facies that coral gal sand and other sed;rments

especially those characterized by abundant skeletal debris - often accumula­ te local1y. Thus the lack of boundstones (a "reef-specifie" texture) in the blocks need not im;>ly that they are other than r'eef fragments.

Oendreid organisms must occupy a minimum of 20% of a ~ef by volu­

me in order to ac~ as a framework according to Wilson (1974). If this is

true then at least an equal percentage of domal or laminar organisms - such

as the cora1s and stromatoporoi ds in the b10cks - would be requ; red to

form a framework. But Lon~n {198l) stated that foss;l reefs tYP1cally ( are between 10 and 70% framework with an average of about 30%. Sampling 1 may cause this framework proportion ta appear to range from 0 te 90%.

Ladd (1971) wrote that in modern reefs organisms in growth position may

account for only 10% of the total reef masse Furthenmore, Selwood (in , Readi n9, 1978) recorded that in at 1east one we11-known ancient reef - the

Permian Capitan reef - in place framebuilding organisms make up only 30%

of the total volume. Table 3 shows- the percentage of available framebuilders . , in certain blocks as measured on random lines across block surfaces. The * The problem of a definition for the term reef has been discussed by Heckel (1974) and Lon~n (1981). The wrrter follows the latter's defini­ tion of a reef as "any biologically-influenced buildup of carbonate sediment wbich affected deposition in adjacent area5 (and thus differed ta sorne . degree from surrounding sediments), anp stood topographically higher than

s'urrdundi ng sedi ments dur; ng depos ; ti on Il (p. 10).

( 1 •

35

( TABLE 2.

"

Percentage of thin sections exhibiting specifie textures. ., Texture % Wackstone Q34 F10atstane 28 Grainstone 15 Mudstone . 12 Packstone 6 Rudstone 4 Framestone 1

TABLE 3. ( , Percentage of frame bui1ders (stromatoporoids and cora1s) in blacks as measured on random 1ines drawn on b10ck surfaces.

Pol ar Bear Pass B10ck % Block % B10ck %

1 25 14 34 9 2 27 18 27 22b 33 5 37 19 16 24b 59 6 23 20 19 26 8 7 20 Arthur's Seat 6 40 ~ l Moses Robi nson Ri ver ~ "i 8 45 15 23 19 28 11 62 16 26 24 77 , 1 < LB6 ,1 f 1 • 1 .- l ( table shows that the percentage of framebuilders is variable but that it fa11s within the range specified by Longman (1981) as characterizing his reef framework facies. "The presence of fine grained sediment is not necessarily indica­ tive of deposition in quiet water (Mountjoy and Riding, 1981). Lime mud occurs within severa1 env;ronments w;th;n reefs and may account for a1most the whole volume of the bioherm (eg. Lower Carboniferous Wau1sortian facies). Ginsburg and Schroeder (1973) and James et al. (1976) have repor­ ted the occurrence of lime mud in modern reefs in highly agltated water. Mud may be deposited in a reef where currents have been baffled (Longman, 1981). Much;s also 10ca11y produced by the destructive action of boring organisms (Warme, 1977; Moore and Shedd, 1977). The mixing of coarse skeleta1 materia1 with the fine mud causes many of the typical textures ( observed in the blocks. Thus the high percentage of micrite in the blocks does not indicate that the b10cKs are not detached from reefs. Geopeta1 structures and bedding attitudes • Most of the blocKs within the Stuart Bay Formation are massive and unbedded. However, in 11 b10cks at Polar Bear Pass, 5 at Moses RObin­ son River and l at Cheyne River laminar fossils or the a1ignment of geo­ petal structures give evidence of be~ding (see fig. 5,6,7; table 4). Most of the blocks were sampled for geopetal structures. An oriented sample was taken from the block and sawed in the 1aboratory a10ng random1y determined vertical and horizontal lines (see fig. 8). Each cut surface was examined for geopetal structures using a binocular microscope. The only such structures observed were brachiopod she11s filled partly with

r • 37

( TABLE 4.

Orie~tation of bedding and geopetal structur'es of b1ocks.

• Polar Bear Pass Di p Dip direction Loca 1 si 1tstone 220 330° B10ck 3 35 315 5 60 335 j 6 75 205 11 8 315 15 18,11 315 18 78 315 19 20 45 21 30 315 2la 85 45 Feta1 8-6)22b 64 352 ( 23 20 315 25 68 335- /J~l Geopetal 10) 26 90 278 , ... ( peta1 10-1) 26 90 77 (PBP North) 45 270 • Moses Robinson River Local sil tstone 65 115 Block 6 53 25 8 , 46 45 136 46 90 20 43 90 '. (Geopeta1 16.4) 24 61 335 25 75 335 • Cheyne Ri ver , Local. sil ts tone 42 180 B10ck 1 80 270

. 1 38

-(

~ ~-"""'''

(

Figure 8. Diagram of a s~le that has been cut and PQllshed to reveal geopetal structures. The dashed lines represent the intersection of the horizontal plane derived from the spar-sediment contact with the cut surface. These lines are then plotted on a Wulff projection as in fig. 9.

. i ~ • t,

" i

~ .. j " 39

(

mud and part1y with cement. -rhe orientation of the sediment spar surfaces.- within the brachiopods was-plotted using a Wu1ff net. The orientation in space of these surfaces was presumab1y horizontal at the time of depositian of the sediment (nat of the blacks). This horizontal plane can on1y be determined if it is intersected by at least two cut surfaces that are not para1le1. Because a11 the geopetal structures within a samp1e indicate

the same horizontal plane it is not nec~ssary that the same brachiopod

be cut twice, on1y that geopeta1 structures be cut by two non-para11el surfaces. See fig. 9 for an illustration of the methad. Only four samples fulfilled these conditions and are included in the maps and diagrams of bedding attitudes.

The two maps (fig. 5,6) show that the b10cks have different1y ( oriented bedding and that these differ from the attitude of the nearby siltstone. The blocks show a \Otide range of both dips and strikes. The dip .

of the siltstone may decrease gradually as the anticlinal a~es (Scoresby Hil1s Anticline near Polar Sear Pass, Queens Channel Antic1ine near Moses Robinson River) are appraached but the strike of the siltstone is

shown by the rows of bl ocks te be cons tant.

Figure 10 is a plot of the poles ta bedding attitude for the Polar Sear Pass, Moses Robinson River and Cheyne River blocks. The points on the plot are prajected pales of bedding planes thus the poi nts close ta the centre of the circle represent bedding planes close to the horizontal - and points near the periphery of the circle represent bedding planes dipping at approximately 90°, Because a magnetic compass cou1d not be used so dose te the north magnetic pole. azimuths have been estimated fram time, 40

'(

(

Figure 9. Wulff projection of two lines fram sample 8-6 (plotted as points) showing how the original horizontal is determined from cuts through~wo geopetal structures.

, 1 1 ~1 (

• .. •• • • • o y

• • D

(

Figure 10. Wulff projection of poles to geopetal structures and bedding attitudes rotated so that the local siltstone bedding attitude becomes horizontal.

Legend attitude location bedding geopetal structure • '0 Polar Bear Pu. • C Ka.e. Robillaon River y Ch.yue liver 42

( sun position and geographic features. The poles have been rotated 50 the deformation of the local siltstone is eliminated and the siltstone beds become horizontal. Note that this is not to imply that the blacks came to rest on a horizontal surface; they were probably deposit,ed on a sea­ ward slope of a few degrees. The siltstone is rotated to horizontal for convenience of plotting and comparison. The figure shows that over 65% of the points are more than 20° away fram the centre of the circle (i.e. that planes represented by these poles are IOOre than 200 from the hor1- zontal) and that departures from the centre are not systematic. The growth layering of small reefs that are in place would differ little fram the horizontal or from the depositional surface. The range would not be

as great as that shown by the Stuart Bay blocks. Blocks that had turi>led

( down a slope would show random orientations like those in the Stuart Bay Formation. If blocks had broken in such a way that the bedding plane was the largest side of the blacks and then slid down a slope. the orièntations would cluster close ta that of the surface of deposition. Six points from Polar Bear Pass blacks are clustered about the centre of the circle in

fig. 10. These poles indicate an approxirnate bedding stri'ke of N2S o E and dip of 20° HW (before rotation) which is compatible with the lo~l silt­ stone bedding attitude at Polar Bear Pass. Therefore, the orientation of the bedding and geopetal structures delllOnstrate that the Stuart Bay Formation blocks have rotated and are moved fram the1r original site of deposition. Fauna The blocks in the Stuart Bay Formation have a rich and diverse fossi1 fauna. Fossi1s make up a significant fraction of the rock

.. ./ "

43

( (average of 30% in thin section, at least 50% in lines drawn across blocK surfaces). They are usually well-preserved except in the dolomitic blocks but the microstructure of stromatoporoids and of some corals is obscured by diagenetic textures in some specimens. The fauna appears to have been transported: brachiopods are disarticulated, crinoids are fragmented. eorals and stromatoporoids appear out of place because they grow in different directions. This is not unexpected in a reef; for example

Ladd (1971) writes that in modern reefs organisms in growth position may account for only 10% of the reef masse The most commen fossils are stromatoporoids, corals (tabulate and rugose). eehinoderms and crinolds, bryozoans and brachiopods. Gastropods. ostracods. sponge spicules. foraminifers and cephalopods are a1so present. Algae are uncommon but important fossils. this shallow water fauna con- ( \ trasts with the deep watér fauna (dacryoconarid~. graptolites and brach1o- pods) that oeeur in the siltstone,of the Stuart Bay Formation. In most of the blocks stromatoporoids are the most abundant fossils but some are dominated by favositid corals. The percentages of the other fossils fluctuate from black ta block but there is no recogni­ zable pattern. Algae The algae are of partieular interest. They are limited to only

a few of the blocks and can only be detected with a microscope. Three forms of al gae are present: Re.n.a.lc..i.6, GVr.va.n.eU4 and Spho..vwc.odi.J.an. Re.n.a.lc..i.6 has been considered a blue-green or a red alga (Machiel se. 1972; Hoffman. 1975) or a foraminifera (Riding and Braiser, 1975). It occurs as chambered, massive ,and crustase grape-like clusters or irregular masses 44

f

( which appear to be unattaèhed when sèen in two dimensions. In several

of the hand samp1es containing R~. this alga comprises up ta 50~ of the rock and the samp1es exhibit a fenestral renalcid micrite or wackestone

texture (sensu MountJoy and Jull, 1978; JJtount~oy and Riding, 1981). In this texture the so-ca11ed fenestrae are irregular pores part1y or comp1e­

te1y fi11ed with sparry calcite or internal sediment. Accordin~ to

Machie1se (1972) Renat~ is found in the organic reef facies - but not in

/' the zone of vigorous wave action - and is a minor framebùi1der. This in­ J terpretation is compattb1e with its occurrence in the blocks. According to MountJoy and Riding (1981) Renalc14 is capable of acting in a stabilizing and supporting role in "fenestral" micrite, forming grainstones or packstones, encrusting other organisms and cavities, and rarely cons- tructing small rounds a few centimetres high. The Re.na.ic..i.b in the b10cks ( fulfills the first of these roles and may also fOMII grainstones and pack- stones.

~vanella is a twisted, tubu1ar blue-green a1ga, that occurs • in intertwined tubules forming clumps or nodules. The GUt.vanell4 masses are composed of only a few strands and f10at in the matrix or they may be th; der, cOl11losed of many s trands, .more conti nuous and may encrus t s tro:" matoporoids and cora1s. Preservation ranges from excellent where the

tubules are clearly visible te poor where they are reduced te dense threads

of nncrite. According to Machie1se (1972) ~vanetta occurs within onco1ites and algal ooze, and in intermound areas or in a quiet, slight1y restricted subtidal environment.

Sph4~codium is a fan or chain-1ike tubular a19a that occurs 1nterbedded with GUt.vanel..l.4 and a foraminifer tentatively 1dêntified as 45

W:eth~edtlla. It always occurs encrusting corals or stromatoporoids. Acco'rding ta Machie1se (1972) SphaeJtOc.ocU.um is a reef-builder and binder

that stabi1izes mounds. It is syrrtliotic with GUtvaJle..Ua t "/(eega." and

the encrusting foraminifera Weth~edetta , and is a150 associated with

, These three forms of algae do not constitute a large volume of the blocks but they are nonetheless important in paleoenvironmental reconstruction. If these fonllS are 5imilar to roodern algae in their light requirements then they indicate that the blocks were fonned in the photic zone. James (1981) has come to the same conclusion with respect to the megablocks in the CoW Head breccia. If the environmental conclusions of

Machielse (1972) are correct then the presence of Renai~, ~va.netia

and Spha~c.odium implies a reef origin for the blocks in which they oceur. ( 46

Possible Qrigins

The shallow water fauna and 1ight co1our of the Stuart Bay

"bioherms ll indicate deposition in sha110w water. Vet the b10cks are surroun-

ded by deep water siltstones. Three possible origins can be ~nvisaged for

these carbonate masses: they may be erosiona1 remnants, in-place bioherms (Kerr, 1974) or allochthonous blocks (Polan and Stearn, 1981). Table 5

summaT;zes how well each explanation accounts for the properties of the blods.

Erosional remnants

The Stuart Bay "bioherms" could be the remnants of continuous beds of reefal carbonate within the siltstones that have been separated by ero- sional proeesses either recently, or immediately after théy were deposited

and before the overlying siltstone was laid down. MacQueen (1974) has des­ ( cribed blocks of similar age and form from the Prongs Creek Formation of the

Knorr Range (Yukon Territory) and postulated an erosiona1 origine The masses

are confined t0-2!,_e stratigraphie level and consist of "very pure, pelloidal grain padstones or wackestones with sparry calcite matrix in part" (p.325).

MacQueen favours the hypothesis that these bl_ocks were a continuous sheet of

limestone that was separated into rernnants by erosion immediately after de­

pas i tion and then. cdvered by deep wa ter sha 1 es tha t now 1i e bath over and between them. The attitude of the bedding in the Prongs Creek blacks is parallel to that of the enclosing shaTes. The discordance between the bedding attitudes of the Stuart Bay blacks and the surrounding siltstones precludes the hypothesis that they are remnants of once continuous sheets.

For this hypothesis,to explain the repeated occurrence of the blacks at

seteral levels in the Stu~rt Bay Formatton the area would have had to bel 47

q ( " raised into the zone of erosion after reefal growth and plunged into deep water for the deposition of the siltstone, the", raised aga,n for the

'~ growth of the second level of reefs. Such rapid oscillations of sea level seem unlikely. In the introduction the blacks were compared ta tors. According --=:::::::::- to Bloom (1978) tors are jointed bare rock masse~ that form by differen­ tial weathering along joints, at least one set of which must be subhori-

l ' zontal. They may form at depth within the/regolith by joint controlled weathering and then be exposed by differential weathering and erosion (2-cycle tors), or_ they may develop as resistant rock ledges that are exposed as the active layer of the regolith flows downhill due to soli­

fluction (l-cycle tors). -Twida1e (1976) was carefu1 to point out that ( tors do not stand out because they are formed of more resistant rèèk. They fonn because the jointing within them 1s less dense than in, 'the '; . surrounding rock. These more resistant masses remain when the ,sfm.ilar but less resistant and more jointed rock between them has been eroded away. Oavies (1969) noted that tors occur on the sùmmit of hills, at

" the break in the slope and on valley sides. The StuartJBay blocks are jointed and they do occur in an area of solifluction. They occur on hilltops, slopes and on valley sides. 1 But they also occur in val1eys and in f1at areas. There is no evidence , that they are remnants of a once continuous sheet of 1imestone that 1 formed a continuous bed. Thi's hypothesis does not explain the vari ations in bedding attitudes among blocks nor the contrast betweeJI the shallow water reefal deposits and J:he adjacent ]deep water si ltstones. \, The blocks are not erosional remnants of once ~ontinuous deposits.

/ ·' 48

In-place bioherms / , The lithology and reefa1 fauna of the b10cks in the Stuart Bay J Formation conv;nced Kerr (1974) that they were bioherms. However, the

blacks are enclosed in deep water siltstone and the bedding attitudes

of the blacks do not accord with that of , the siltstone. For these

reaso~ the carbonate masses cannot be in-place bioherms. , A1lochthonous blacks - .~--~------Polan and Stearn (1981) proposed that the Stuart Bay "biohenns"

are a110chthonous blocks. They based this conclusion on the two argu- ments given above: the "bioherms" oecur in deep water siltstone (this implies that they are out of place or that there was a rapid shallowing

and then deepening ~f the sea), and they exhibit a great range in bedding ( ':attitude (this implies that they are not in their original 'si'te of depo­ ,sition) . Several grainstone and eonglomerate beds that may be debris flows occur in the Stuart Bay Formation. The presence of these other allochtho­ nous deposits in the formation can be explained by the same mechanism that

atcounts for the origin and emplacement of the blocks. Later sections , will investigate the mechanism of emplacement and the source of the b1ocks. i Table 5 shows that the "allochthonous block theory" accounts for J f 1 most of the characteristics of the "bioherms" .. j i Because the writer does not believe th~t the b10cks are erosional ~ remants of a once continuous bed does ''flot ;~li~hat ~e present shape , and volume of the blocks are necessari1y the sa~ as when they tunbled into the basin. Arctic weathering conditions are capable of destroying the blocks. Masses of rubble interpreted as the remains of frost-shattered

• .. f \ - _1 .. 49 1

-- -.,1 TABLE 5.

Three theories to acco~nt for the presence of carbonate masses in the Stuart Bay Formation. ;\ \ \ 1/1 \ ~ 1/1 (,) +1 c:: ,...0 tG ~ ca QI .c III 0 :::s J ....co 0c:: , .... 0 tGc:: 8 :5 0 Ils .s::: ...... (,) III Q. 0 0 1 ,... s.- c:: U.I - -cC Lithology .; .J J ( Colou.r .j J J Reefal Fauna .; J Range of bedding and geopetal attitudes X X J, Mechanism of e~lacement '" Source '"J Relation to topography X J lack of topographie expression between outcrops X J .J Occurrence of similar deposits in Stuart Bay F. X X J Occurrence on bedding planes J 1 J Enclosed by deep water rocks X X J

J 111eory accounts for PropertY/Observa"tion X Theory does not account for Property/Observat10n .. Property/Observation does not apply • ~

( 50

blacks occur between some àf the "tors" (plate 2). The fact that these • fiat rubble areas with reefal fossils occur within the lines of the

blacks suggests that the debris iSI in place. Many of the blacks are

surrounded by small vol umes of tal us but other blacks have none. Thi s implies that there has been only a modest change in the shape and volume 'of)11Ost of the blocks due ta erosion. \

"

1 .

1 \

t,

. 1 51

, ' Oi>scuss i on Genesis and transport of blocks

If the carbof)ate blocks in the Stuart Bay Fannation are allochtho­ l'J nous then how were they detached fram the source reef1 What i ni thted IIIJve­

ment and what was the manner of transport and de~si tian? Any explanation

must account for the large volume of material enr;>laced during each event and

the recurring but unusual nature of the deposit. Because there is no evidence of deformation structures within the blocks they IIlJst have been cemented prior ta detachment and retained their 'shape during transport. If a reef was only partially cemented then blocks

would be expected t~ break along the boundary- between cemented and uncemented regions. Many modern and ancient reefs have been shown to be cemented ear1y in their history (Friedman et al., 1974; Ginsburg and James, 1976; Mountjoy

( and Ri ding, 1981) 1,

'.... The b 1 ocks may have been dislodged from reefs by earthquak~ shocks,

stonn waves or by gravity acting on differenti lly-cemented buildups (~

; exteod\gg over unstable unconso1fdated sedime • These agents are not

mutua11y exclusive; on the contrary. they are co~lementary. Kerr {1~77.

19B1} proposed that the Devonian history of the Aretic Islands is punctuated by'several pulses of activity in the Cornwallis Foldbelt (the Cornwallis Oisturbance). One of these pulsesoccurred immediately prior to, and another after. deposition of the Stuart Bay Fonnation. There may a1so have been , periodic minor disturbances - such as earthquakes - during Stuart Bay time. The force of an earthquake is sufficient to dislodge large fragments from reefs. Stonn waves other than tsunamis are probab1y inadequate to detach

b l ocks un 1ess the reef t}as J 1 ready been weakened. Adv.ance of the reef over 52

( - unconso 1i dated sediment woul d prav; de th; s ; ns tabil ity.

The b locks would be carri ed downs 1 ope by gravi ty once roovement had

been initiated. rt>untjoy et al. (1972) wrote that this rootion could oceur

in one step or the blocks may slowly ereep downslope with periodie shoeks

dislodging them. The Stuart Bay blocks may have been emplaced in a single

rootion or in many steps. Dott (1963) divided submarine gr.avity flow IOOvements into four gradational types: rockfal1s; slides and slumps, mass flows, and turbidity

f1ows. Most of the blocks in the Stuart Bay occur in areas with no other

rocks that could be interpreted as allochthonous nearby. These must have

been deposited by rockfall. However, at the Cheyne River locality and at

block 20 at the Moses Robinson River locality, conglomerates oceur close to ( the blocks. If the conglomerates and blocks were deposited at the same time by the same mechanism. then the mud-supported. poorly sorted clasts in the

conglomerate indicate that both blocks and conglàmerate were deposited by

a submarine massflow. As the exact contact relationships are not known the

blocks and conglo~rate may not have been deposited by the same mechanism.

The provenance of clasts in the cong1omerate - Kerr (1974) considered that

the source of the chert pebbles is the Cape Phillips Formati~n - ;ndicates

that beds of severa 1 ages were reworked.ta forro the corril; ned cong1 omera~­

block deposit. If this is so then the conglomerates were deposited first

in an unstable position at the top of the slope and then came down en masse

wi th the blocks.

Possi b 1e source reef for the b1 ocks

The source of the Stuart Bay blocks must have been a reef somewhere

east of the preJent block locations. Blocks of comparable size in the 53

( Napier and Virgin Hi1.1s Formations in the Upper Devonian Canning Basin

(Australia) are exposed fn discont1nuous outcrops up te 4 km from the marg1n of the exposed pl atfonn (P1ayford and LOWry, 1966; Moun1;j oy et a1.. 1972). Larger b10cks in the "Tamabra Formation" at Xilitla, Mexico, are thought to have travelled 3.5 km from the platform (Carrasco, 1977). In the Canning Basin the fore-reef rocks are steep1y dipping (10-3SJ) but this inclination decreases away from the reefs. In the Xilit1a area there are hundreds of metres of relief between the basin and the platform. If these two occurrences can be used as a 9uide then the Stuart Bay blocks probably travelled no faf'ther than 5 kilometres. No reefs are known within 5 km of the blocks. In fact, litt1e of the Stuart Bay Formation is exposed east of the b10cks on the Cornwallis Foldbelt. In the one section in this area the fonnation consists of shaly ( bloclastic limestone and sha~y si1tstone (Kerr, 1974). The source reefs

ha ve appa ren t 1Y been eroded away. The fo 11 awi ng seena ri 0 exp 1ai ns

the occurrence of b10cks in the Stuart Bay Formation. Reefs were developed a10ng the flank of the Cornwallis Fo1dbelt between pulses of the Cornwallis (> Disturbance and events such as earthquakes (perhaps associated with the

disburbance) periodically dis10dged fra~ts of these reefs that tunt>led into the adjacent basin where s11tstones were accumulat1ng. Because the blocks occur at 1east two stratigraphie levels within the Stuart Bay Fonnation there must have been et least two such events. Erosion of the fo.ldbelt during a later pulse of act; vitY destroyed the reefs. Kerr (1981) has determined that the western limit of erosion during Pulse II was the

ca 1edon i an River Dame (w es t of the b1 ocks ) . Pulse III was al ms t as s trong

and extensive. The blockS' occur wtthin 1 few km of the western edge of the ~ - 1 J \ '.1 j , ! (• 54

( foldbelt so this scenario is rëasonable 'see fig. 11). Accordi!ng to Kerr {1974} the folds on eastern Bathurst Island are drape folds that can be attributed to the uplift on north-trending crystalline basement blocks within-the Boothia Horst. The truncation of stratigraphie units at the base of the Stuart Bay and Disappointment Bay Formations shows that two of these folds - the Scoresby Hi11s and,Queens ~ , Channel Antielines - were fonned during Pulse II of the Cornwallis Distur- bance and were further deformed during Pulse III. If the anticli nes did develop during this time then they may have been slightly e1evated with respect to the rest of the seafloor after Pulse II and loealized the growth of reefs in shallow water. . Subsequent elevation and denudation during Pulse III would have eroded the reefs and breached the antielines. Most of the block locations ( are less than 5 km from these antielines. r

Q

( 55

......

o 0 ......

(

Fiaure 11. Schematic diaqram of part of eastern Bathurst Island durino Stuart Bay time. Reefs are develored on the western f1ank of the Cornwallis Foldbelt (C Fb) and a landmass is situated farther east. Blocks and debris dis10dqed from the reefs tumble into the basin where the siltstone of the Stuart Bay Formation is accumulatino. l.

( 56

( Other Examples of Blocks Mlistaken for Reefs

Nubrygin Formation

According to Wolf (1965 a,b) a1ga1 reef limestones deve10ped

around volcanic pedestals occur in the Lower Devonian Nubrygin Fonnation

of New South Wa1es. According to Conaghan et al. (1976) the reefs are

allochthonous b1ocks. This fonnation was deposited in the Pa1eozoic

Tasman mobile be1t which consists of several arches or volcanic archipe-

lagoes separated by sedimentary troughs. The Malong Arch is one of'these

and i s f1 anked by the Cowra Trough on the wes t and the Hi, 11 End Trough

on the east. These are filled with volcanics and f1ysch. The Nubrygin

Fonnation consists of about 400 m of interbedded mudstone, allodapic , carbonate and megabreccia with exotic blacks (according to Conaghan et al. ( 1976) or alga1 reefs (according to Wolf, 1965 a,b). The megabreccia occurs between the Molong Arch (west) and the turbidite-fi11ed Hill End

Trough (eas t) . According to Conaghan et al. (1976) 5 types of iso1ated b10cks

occur wi thi n the megabrecci a: mass ive al ga 1, s trama topo roi d .and cora 1

bounds tone ("al gal biohenns "); l imestone pebb 1! and cobb le orthobrecci as; ~ massive lime mudstone, wackestone and packstane; bedded lime mudstone;

and massive lava (andesite). The limestone blocks predominate whi1e the

vo1canics are subordinate. The following features lead Conaghan et al.

(1976) to conc1ude that the so-called reefs are al1ochthonous blocks:

1. Wide range of clast size.

2. Wide range of clast types and size in close juxtaposition.

3. Discordance between the attitude of the bedding in the

"] , b10cks and th~at of the enclosing beds. , r "

57"

( 4. Laclc of distinèti ve and regul ar facies changes within the li mes tone bodies, especi a lly nsar thei r margi ns: 5. Abrupt and random truncation of intemal fabric at block J margins. 6. Lack of an autochthonous vo1canic foundation for the reefs. 7. Anomalous lithofacies aiSOciation of massive bodies of sha1-

low water l i mes tane with enc10sing flysch. , The blocks were derived from contemporary shallow water carbona-

tes on the Mo10ng Arch. The megabreccia was transported into

the adjacent trough in debri S fi ows. The b 1ocks s 1 i d and roll ed . , down the s 1ope.

Characters (3), (5) and (7) of the "a1gal-reefs" in the Nubrygin

Formati on al so apply ta the IIbiohenns fi in the Stuart Bay Formation • • Conaghan et al. (1976) stated that "one o~ the mst important diagnostic criteria for establishing the nature of suspected megaclasts is the detection of stratigrap'hic qiscordance between them and the surrqunding strata" (p.524). This characteristic was the most important in determi­

ning the truè nature of ttte Stuart Bay blocks., Conaghan et al. (1976) f stated that the a1ga1 l imes tonès are more resistant than .the surroun- ding- sediment and stand out lilce tors.

~ Cassian Formation Acco'rdi n9 to FtJrs i ch and Wendt (1977), and Wendt and Fa rs i ch (1979) the Middle to Upper Triassic (upper Ladinian to lower Camian) cassian Formation in the Central Dolomites of the Southem Alps records

a gradua l décrease in water depth wi th time. l t was depos i ted in basins f J between carbonate buildups_and locally in the backreef. They\divided i \

.' 58

( 1 tbe environments in which the 'Cassian Formation and contemporaneous, depos1ts were laid down as fo11ows: 1. Volcanic is1ands. These were the source of volcano-clastic sandstones between reefs. Terrestrial plants and rare occurrences of amber imply that a land mass existed near the ma ri ne depos i ts . , 2. Nearshore back reef. TAis cin' be divided-into small patch

reefs whose internal st~ucture has been destroyed by dia­

genesis. inter-reef deposits, and backreefs ~haracterize.d , by cycles of supra-, inter- and subtidal sediments. 3. Carbonate platform. These carbonates are up to 1 km thick. They are usually dolomitized and characterized by early diagenetic cement. Karst phenomena indkate that they ( underwent several phases of emersion. , 4. Basin. Argillaceous-calcareous sedimentation interrupted by volcanic and carbonate-detrital turbidites characterizes this facies. These deposits are div1ded into the C1pit

boulders (FUrsich and Wendt. 1977; Wendt.and FUrsich. 1979; , \ Biddle, 1980) which were described as patch reefs by Ogilvie-Gordon (1894), shallow marginal basin deposits, '\ 1 basin slope turbi dites and finely 1aminated central basin ! clay and limestone alternating with detrita1 turbi di tes. The Cipit boulders are composed of alga1 boundstone, peloid packstone and wackestone, coral boundstone. Qioclastic packstone and

wackestone. limestone breccia and rare bioclastic gr~instones (Biddle, 1980). Algae are the mort COlJIIIQn reefbuilders, corals and stromatopo- 1 f 1 ,,..\

1 59

roi ds are genera lly rare or absènt.

The following features lead FUrsich and Wendt -(1977), and Wendt and Ftlrsich (1979) to conclude that the so-caned patch reefs are allochthonous blocks:

1. Early diagenetic ce~ntation. 2. Dolomitization slight or absent (in contrast ta the source rocks) . 3. Solution cavities eut primary textures. 4. Primary geopetal structures yield an orientation d1fferent ,fram that of the enclosing beds but secondary geapetal fills in the solution cavities have the same attitude as the surroundi ng sediments. 5. Fe-hydroxide crusts (rare, probably subaerial). ( 6. Underlying beds folded and defor~.in the vicinity of the blocks. 7. Very few blacks colanized by encrusting organisms. This implies that they were deposited in deep water, that the ,\ - blocks were rapidly covered by ~urbidites, or that the blocks sank too deeply in the surrounding soft sediment. 8. Fauna of the b.locks composed of organisms that are other­ wise restri cted to the platform. , 9. Blocks enclased by flysc~ sediments. 1 The blacks ariginated fram exposure and subaerial erosion of ca rbona te pTa tforms (5ch 1ern Dol omi te) fa 11 owed by slidin9.of the detached blacks fram the outer marg1n of the platform into the basin.

·,~--- ~-,--,---Y , 60

Characters (1), (4- bedding attitude indicated by the primary geopetal structures of the blocks does Qot confonn to that of the surroundfng sediment), (8- fauna of the b locks does not _correspond to the environment of deposition of the enclosing rocks) and (9) of the 1 1 i IIpatch reefs" in the Cassian Fonnatfon also apply to the "bioherms ll l, i in the Stuart Bay Fonnation.

o

'-

- "

'$

\ 1

/'

, -

. " . .' ! < 61 , , , . ,

/' SYSTEMATIC PALËONTOLOGY Corals ... Four genera of rugose corals and four genera of tabulate eorals were identified from the blocks in the Stuart Bay Formation. ,The population

is dQp1inated by Favollliu sp. which aecounts for' over 75% of the sanJ,lles. " Most of the other genera are represented by only Z or 3 samples. Altheu~ i 0 the Fa.vo..6UtA sp. colonies are larger than any of the other corals and JlX)st eas11y seen and identified in the field it is unlikely that their dominance of the coral fauna is due solely te samp1ing bias.

All samples weré identified us1ng Jackson ~t al. ,(1978) or Hill

(1981) except St:a.wtornaZi4Wm sp. which was i dent; fi ed from Pedder and 01 i vet: ( 1982)<, The following abbreviations are used in the discussion: PBP '. <- (Polar Bear Pass), PBPN (Polar Bear Pass North), AS (Arthur's Seat), MRR (Moses Robinson River), CR (Cheyne River) and CRN (Cheyne River North)

followed by the number of the b16cK fram whieh the sa~le comes." "-~, Rugosa • Order Cys ti phyll i da Ni cho 1son, 1889 Fami 1y Trypl asmati dae Etheridge, 1907 __ ~_ (1 Subfamily Tryplasrratinae Etheridge. 1907 1 Gen us Tryp 1asma Lons da 1e ~ 1845

TJt..ypl.u,ma. s p. Plate 4, figures 1 J 2.

" 1 Descri ption: Cora 11 um soli ta ry, cy 1 indri ca 1, wi de (diameter, up

to 4;5/IID) and long;, narrow peripheral stereozone; tabulae complete, c10sely spaeed, subhorizontal to irregular and may intersect; septa short. 1 order, -', about 80; calyx wide and deep wfth a flat to co~cave bottom. J .. 1 , 62

Remarks: Because-of the'ir large 's1ze'these s~les res.le samples of

P.6~pl.Vt.U.6. Discussion ~ith A.E. ~edder conftrmed tflat the samples are a new species of fJtypltuma. which he is deSè)ribing. Materiel and occurrence: Four sBllJl1es co~rising 10 individuals, spme silictfied: 6-3 (P8P-6)", 11-2 (PBPN), 11-4 (PBPN-2), 23-1 (MRR-8).' , Order S tauri ; da Verril h 1865

Suborder Streptelasnêtina Wedekind~ 1927 FannlY Mucophyllidae Soshk1na, 1947

·Gen!.ls Stylople~ra Merriam, 1973

SZIjlo pl.WI/l. s p • Plate 4, figures 3, 4.• Description: Corallum solitary, perhaps fas.ciculate, cy1indncal,

~lender (diameter up ta 15 l1li1); tabulae comp,lete', horrizonql, wide1y spaced, convex but become concave at wall margins; septa short, 1 order, 44.'to 48; wall shows undu1ations. Remarks: Because the corals ,are broken and in- complete the typical flar1n9 calices or oonnecting processes were not observed. lncluded in this genus is one saq)le (23-3) that exhibits the

characteristi cs of S4Jl.oplWJtQ. but ha,s close1y spaced, i rregu14r and

fn~omp1ete _ tabu~ae. It may be a second species of the same genus. Mltena1 and,occurrence: Three samples comprising over 20 individua1 r corallites: 16-6 (MRR-13a), 23-2 (MRR-7), 23-3 (MRR-6).'

Order Stalit'iida Verril1, 1~5 Suborder Ptenophyl1ina Wedekind! 1927 Fami1y Ptenophy11idae Wedekind, 1923

S ubfami l y Ptenophy 11 i nae Wedek i nd t 1923, Genus Australophyl1- um Stunm, 1949.

r r 63 1

Plate 5, figures 1, 2. . Description: Corallum cerio1d, polygonal, diameter up ta 15 mm; \ wall thick; tabu1ae irregu1ar,. short, discontinuous, conf1ned ta centre of coranite; dissepimentarium wide; dis$epiments lonsdaleo1d; sep ta separa­ ted from wall by dissepimentarium. 2 ordérs, 34, te 38 (even1y divided between the two orders). major septa long, interdigitate in tabularium, some

longer than others. Remarks: These -sa~les differ from the similar genus Xij6t:Jr.i...phyllum in their wider dissepimentarium. Material and occurrence: Two saq>les: 11-1 (PBPN-l), 23-6 (MRR-1). Order undetenni ned* Family Stauromatiidae Pedder and Oliver, 1982

Genus Stauromatidium Pedder and. Oliver, 198Z ~

s~sp. Plate 5. figures 3. 4. ( Description: Corallum cylindrical, slender (diameter: Sm>', solitary but associated with many others and may be fasciculate; tabulae closely spaced. regular, curved; septa long, may form an axial complex, larder, 19 to 20. Remarks: The samp1e was identified as S~~ sp. nov. by A.E. Pedder (oral comm., 1982). Materi.1 and occurrence: on~poorlY preserved dolomitized and part1y silicified sample cans1st1ng of fragments of over 25 coral 1 i tes:.. 15-9 (MRR-19) • Tabulata Four genera of tabulate· corals were identifted fr'Olll the Stuart Bay Forma ti on block.s.

* Pedder and Oliver (1982) assign this flew species and genus only ta the "order" RugOsa.without.specifying subdivisjons other th.n famfly. ., . 64 } 1

O~der Aulopor1da Sokolov, 1947

S~perfamily Syringoporicae de Fromentel, 1861 Fanrily Roemeriidae Poëta. 1904 Genus Roemeripora Kraicz. 1934 Plate 5, figure 5. Description: Corallum fasciculate; coral1ites cylindrical. slender, connected; peripheral stereozofte transversely wrinkled. appears fibrous;

septal spines present; tabulae thin, infundibulifonm. Materi~l and occurrence: Two poor1y preserved salJ1)les: 8-2 (PBP-24a), 23-1a (MM-a).. The fi rst 15 assoc1ated witJ1 a stromatoporoid. Order Hel101itida Frech. 1897 Suborder He1iolitina Frech, 1897 Superfanrl1y Helio1iticae LindstrOm, 1876 <. Fami1y Helio1itidae LindstrOm. 1876 Genus Heliolites Dana, 1846

HeUoZiteB sp. Plate 6, figures l, 2. Description: COrallum heliolitoid; circu1ar. closely spaced (diameter exceeds spacing between them); 12 spine­ like septa. no aurèOle around larger cora1lftesi tabulae slightly irregular, ~ not at same ~eve1 in adjacent coral li tes. Material and occurrence: One

samp1e: 5-7 (PB~-5). Order Favositida Wedekind, 1937

Suborder Favositina Wedekin~, 1937

Superfami1y fivositicae Dana, 1846 i Fami 1y Fa vos; ti dae Oanad, 1846 1 Subfamily Favositinae Dana. 1846 1 Genus Dictyofavosites Chernyshev, 1951, .- .. .. l 65 j " l Vfd:y.o't1VO.6U:u Spa Piate 0, fi gures 3, 4. Description: Cora11um ceri~Ulae of all coral1ites at same

level, horizontal or slightly curved~ 29 per cm; corallites thin-waned .. (d1ameter about 0.02 mm), slender (diameter about 0.5 nm); 1 row of IIIJral 00 pores. Material and OCCUl1"ence: One well-pr'eserved 5aqJle: 6-6 (PBP-8).

Favosiws "gothZ4ndicus" speci es group Plate 6, figures 5, 6. Description: CoralllJll cerioid, tabular to hemispheriçal; coralli­ ( tes prismatic, thin-walled (diameter 0.02 to 0.19 mm), minilJlJm diameter f- of the largest coral1ites in the spect1nens measured ranges fram 0.79 to 2.74

mm; sorne sampl~s have septal spines; tabulae complete, horizontal to subho­

nzantal. 1.5 te 5.3 per nID; IIIJral pores in 1 or 2 rows, diameter 0.09 ta 0.23 mm. Material and occurrence: see table 6. Discussion: Because the , specimens of f4v0Ute.6 are the mst numetous corals in the blocks and because they are amenable to quanti tative study they were studi'ed in detan. The followi n9 Îœasurements were made and ~Veraged for each sample: 1 1. Minimum diameter of ten of the largeSjcoral1i~S. •1. f 1 2. N...mer of tabulae per ft1II for ten of th corallites. i 1 Two addi tionel mels~re_nts, were made on se ected samples: .. ~ ., ( ,

Il fi t )

66

(

(

TABLE 6 - Surnrr.ary of data for samples of l'a.V06Lte.j Cora111 t e Wall Por e Oiameter : 1 Ellock. Group Tab/1!I1I O,ameter 1 Thl ckness Samole 1 1 .98 2-4 MRR A 3.5 - - 1 2-16 AS'- A 4.2 .79 - - XI 3-10 AS 81,82 4.6,3.4 1. 57 ,2.02 .09 ," 19. - 4-6 CR A 2.4 1.37 - - 6-1 PBP (btwn 5,6) 82 2.7 1 94 02 - 6-2 PBP tloat 81 Z 3 1. 73 115 .23 6-5 P8P 7 3.1 1. 94 - - 82 3 1 93 - XI 6-6 P8P 8 ,- 7-7 PBP 12 (2A. Z 4 1 44 - 8-4 PBP 236 A 2 6 1. 34 - - Xl 8-6 PBP 226 82.C 2 4,2 1 2.31.2 63 - .·03 -- 8-8 PBP 21 il 2.4 .96 05 - ( 10-4 PBP A Z 9 1 02 .02 Il 10-7 PBP 20 A 3 1 1.29 - - 1 1 -, .16 ,- X2 10-8 t PBP 19 A.B2.82 3.2 4.1.5 1.32.1. 98 ,1.97 ~ .. 05 .- 1 10-10 PSP 18 il 3 1.47 - - Xl 10-H PBP (near 25) A.B ,A 2.3.2 2,2.4 1.33,1.62,1.5 .09 ,.06 .- -, .20 ,- 10-15 PBP (near 25) il 3.7 1.19 -. - Xl 11-3 PBPN (btwn 1.2) A.A 3.4,4 2 .84, .86 - - - - 11-4 PBPN 2 il 4 .98 - - XI 12-2 PBP 16 B2,Bl 2.3,1.6 u l 13,1.59 -- - - \5-3 MAA 23 Po 2.1 .95 .19 - 15-8 MRR 19 A 1.1 . 1.14 - - \6-1 MRR 17 A J.J 1.17 - - XI 16-3 MAR 15 'A,A 4.1,4.4 .93,1.06 - - - - 16-6 l'IRR 13a il 3.3 1.01 .06 .14 Hi-1 MRR IZb A ( J.Z 1.04 .08 . .09 23-1 MRR 8 C 2.4 2.74 .08 - 23-2 MRR 7 A 2.4 .79 - - 23-3 MRR 6 A 2.5 1.2 - - 23-4 MRR 5 A 5.3 .88 - - 26-3 CR (btwn 8,9) B2· 2.4 2.1 - - 1 26.5 CR 10 A J 1.23 - - 26-7 CR 4 BI 2.9 1. 74 . - j 87-11 • A 2 2.38 - - 1 1 Notes' xl: Z samples A, B (i.e. J-10A, 3-10S) xl: 3 sampI es A.' 8, C (J.f. IO-SA, 10-88, ID-SC)

j Î . f 1 j 1 , il 1 67

1. Wall thickness of several ëoral1ites*. 2. Pore diameter of severa1 coral11tes. The minimum diameter of coral1ites was used sa tnat any obliquity of the cut surface ta the corallite axes would have no effect on the measurement. The largest corallites were selected because they are assumed to have reached an adult diameter. Figure 12 is a graph show1ng the corall1te diameter plptted against

the nunber of tabulae per IJIII (tabu-lar density) for-each sample. The data has been d1vided into 3 groups** based on coral1ite diameter. Group B can be subdivided as shown. Six simples from Group A, 5 fram Group Band 2 from Group C were thin sectioned. The pore diameter and wall thic'kness of cora­

llites in these samples were measured ~nd the presence of spines WBS noted. Table 7 gives the resulting data [or each group. The table shows that ( Group A is di s ti ngui shed from the others by i ts sma 11 pores and tha t Group B2

can be differentiated by it$ lack of spines. However. these conclusions are

based on a li~ted number of samples and may not be valide Figure 12 shows what could be interpreted as a random scattering of points that have been arbitrarily divided into groups. Several alterna­ tive arbitrary group1ngs are possible. * The wo1l be1:ween corallites of favcuUt6 is usually divfded in half by a longitudinal dark (or light) line. The outer wall be1:ween the colony and'the l surrounding sediment lacks this median line. This indicates that half the wall was constructed by one polyp and the oth~r half by the adjacent polyp. lhus the space between polyps i~ occupied by what could be tenned a double­ wall. Half of this, the true wall thickness, was used in this study. ** These informal groups may be species~ subspecies,ecophenotypic variants within ~ species etc.

.l 1

-1 , • 1 68 r; 1 (', TABLE 7. - Data fram thin sections.

Group A Wall thiclcness 0.02 to 0.19 (6)* .J Pore di ameter 0.09 to 0.11 (3) Spines present (4) Group Bl ,Wa 11 thi ckness 0.05 to 0.09 (3) Pore diameter 0.16 to 0.23 ' (3) Spines Present (2) Group B2 Wall thickness 0.02 to 0.05 (2) Pore diameter 0.02 (1) Spines absent (4) Group C Wall thi ckness 0.03 to 0.08 (2) Pore diameter present (1) Spines present (1 ) ,1 * The nuni>er in brackets, i 5 the nuœer of sa~ 1es tha t were used.

( TABLE 8. - S ta ti s ti ca 1 test of 3 possible groupings of points 1 n fig. )2 1; as determi ned by cora 11 i te di ameter.

Group X SX N Confidence that the populations A l.16 .32 are distinct B 1. 91 .22 15U} 99.9% C 2.69 ':08 2 2 Group A &8 1.42 .46 C 2.69, .08 4;1 99.9i 3 Group ~ A &81 1.23 .34 82 .. 2.04 .12 10~~ 99.9% 2 f C .. 2.69 .08 .1

, /

- - - ..... -.- . .- 1""""-... ~,

~

6 r; ~

5 • '" • • '"" • 4 • • • ...... ~ • ~ • 1 1 ~ • - 1 • e_ 1 • 1 :.... 3 • • •• • .1 •• '.f)- • 1 J <:: e • 1 • ..tJ e _• • -1 • ~ 1 • 1 2 • -. • • • • • • • -' ... A • B1 • B2 C i...... 1

., 1.0 1.5 2.0 2.5 3.0 Il 1 . 1 1 1 CCRALLITE DJAMETER (mm) Figure 12. Tabular density plotted against coral11te d1ameter for the Favosites samples. " 0\ 1.0

''j tS'dS lrrt~IIif""YIIiII.I"UI"i't,,"''''~''''''''''''''--'''_~'''''I. .... , .... -,"-- cc • A . -..,...... ~ 1

70

( Table 8 g;ves three of these with their statist;eal parameters. The statistical significance of the difference between the means of diametèrs of the corallites in these various groupings was tested using the T-test. As 'Table 8 shows eaeh of the divisions is equally valide The fact that any

arbitrary division results in statistical signifieanee suggests that the samples a11 belong to the same species population and that fur'ther collecting would close the morphologie gaps and eliminate the differences between the subgroups.

Table 9 shows the criteria for 12 speeies of Fa.voliLtu randomly selected from the li terature. Compari son of the ranges of measurements for

the ~escribed, species with those of the various possible groups of Stuart Bay favositids shows that no division of the Stuart Bay samples is to be ( preferred over any other. The divisions again appear to be arbitrary, indi­ cating that the samples should be eonsidered as one group. The range of coral lite diameter, tabular density, pore diameter and wall thickness for

the s,amples taken as a whole are conmonly several times the ranges that have , , been aecepted within described species. The above indicates that the samples , would be divided in}O several groups if traditional taxonomie praetiees were followed. Therefore, traditional species are too narrowly defined. Are the parameters selected in this study - corallite diameter, 1 tabu 1.ar density, wall thickness and"pore diameter - adequate to distinguish 1 '" species? Stel ,(1978) noted that the tabular density is clearly related to

enri vonment in F. ~oJtbu.i.. The tabul ar density ref' ects the growth rate of the coral. Any genetic control of this is probably masked by env;ronmental i l, effects. The Stuart Bay favositids show a 9reat range in this character

within each group. Almost ~11 samples show variation in tabular density·

r .r-: ,...... ~

---,

ï,. TABLE 9 A. - S-r:r of data for 12 ra1ldollly s-elected -species of !ta\1OÛ.tl6 de5cribed in the l1terlture. "' 1 1 Tab. CORALLITE DIAfETER (.) WALL THICICIIESS (-.) Pore SPEtlES per_ Range "'x-.in. Max/.in. linge Max-Idn. Ml~/.in. Di_let' Ref.

,f. ~~A. 1 1. 5-2.1 0.6 1.4 .18-.5 .32 2.77 .23-.3 1 ,. c.c.cu..", 1 .3- .8 0.5 2.67 - - - 0.2 2 f. ~btll' 1 .3- .7 0.4 2.33 - - - 0.1 2 f. Ua tI.LI .3- .9 ô., 3 0.2 2 ., .-.é - - - - -4l. f.~ N.laU.u 1-10 .5-1.3 0:8 2.6 -- - 0.2 2 ~ F. IID.woOÜM.u .4-1 0.7 - -- - - 0.2 2

F. hlewfD~ 3-5 .&-2.1 , .13 2.63 .7-.19 .12 2.71 t,.. .., ~ .15 3 F. V.é.eUt«lJ., 3-5 1. ~-1. 7 0.5 '~42 .09-.3 .21 3.33 .2 3 F. • kl-il!4tu6 2~ 1.5-2.2 0.7 1.47 - - - .15-.18 3 .5-1 0.5 2 , f. Ut.UtgeM. 2-3 .6-.14 0.8 2.33 .04-2 .16 5 .15 4 -' F. ObUqwu 1-7 1.4-1.9 0.5 1.36 .06-.08 .02 1.33 .14-.2 4 F. FDItbu.i. - .6-1.8 1.2 - 3 .05-.2 .15 4 ,.25 4 , \ ------....,. * IllY be" SqU4llU~4VC4.Uu ,d. " 1: D.H. Swann. 1947 2: St.- , Tyler. 1964 3: Stel. 1976 4: Stel. 1978

~

:..- lE :::!ltr"lf t "e•• ~ ...... OfZ tri -"'-. -- "...... :-'l1

"l Il ,

l f pv J l ' l y l'MU' • s f data ~I thl. dhb1 f thé DOtnt: ftl.12

\ ~ fTab. CORALLITE DI_TER (_, WAlL lHlClNESS (.) ,.... MIUI-IItn. Hax/.t" ....ge Mai-.i" MI.,_." Cr::'ter - A• 1.7-5.3 .19-1.5-. .71 1.9 .02-.189 .169 .945 .091-.11 A , 1.5-5.3 .79-2.38 1.59 3.01 .02-.189 .169 9.45 ·09\-r234 , A Il 1.6-5.3 .79-1.64 .85 2.08 .02-.115 .169 9.45 .091-.234 ~ • 1.5-4.' 1.57-2.38 .81 1.52 .024-.091 .067 3.79 .155-.234 Il 1.5-1.4 1.93-2.38 .45 1.21 .024-.054 .03 2.25 .155 1 . ~ C 2.1-2.4 2.li3-.2.7. .11 . 1.04 .028-.054 .053 2.89 - f 1 A • C 1.5-5.3 .19-2.74. 1.95 1.S .02-.• 19 .17 9.5 .09-.U

< 1 1 l' .,. 1 j\j

1:

~ '1 ~~~~~----~~~~... ~~~--~~~~~.. ~~~~~~..~~~" - '-..... ~ 1 1 73 ft

within a frw mi11imetres. lnis character is therefore useless 1n species determination in this study.

Ste1 {1978} obSff'ved bath thick walled (0.2-0.4 !lin) corallites

with spines and thin walled (O.08-0.l6 11111) cora11ites without spines in the r"-- \ same sa~le of F. hA..6.i.ngeJL.i.. This was also observed in the Stuart B~y favositids. Stel {1978} also found that F. 6oJtbu.i.. has a large range of wall thickness. In the Stuart Bay samples the ranges of wall thicknes's for 1

different groups (distinguished on the basi$ of corallite diameter) are no~

1 mutually exclusive. If such large ranges are found within single specimens or si ngle species then the wall thi ckness cannot be used ta differenti ate species. The pore size is the rnost diff~cult of the criteria t~ measure. , 1 It is also usual1y poorly documented in sp~ies descriptions a"d is therefore ( unsui table for cOnrlarison. 0 '\iY' "'Y

The diameter of favositid corallites is ea~y ta measure. But what measur,-ment should be understood as the diameter (see fig.13)? Should

the range, maximum, modal or mean diameter be used? The minimum diameter , ,of the. largest corallites was used to construct fig. 12 because few measure­ ments are needed to arrive at a meaningful result and because the largest i " .. corallites are presumably IOOst mature. But if the colony had not attained maturity or if different levels of matutity are sampled in different colonies then no comparison can be made. The previous discussion has "shawn that cora'llite diameter is insufficient to distinguish species of Fa.VOllilu. 1 Stel (1978) showed that large numbers of measurements are requi~ red ta s'how adequateTy the true ecophenotypic range within a species (he

used between 127 and 2843 me~surements p.er sa""le). He i 11 us trates a coral

r .' ~ 1 ____ JJ.::"Y_. __•. __,, ...... ,l''~..,''''.

, , i, 14

f'

., '

A·

. <- ."

c

Figure 13. Three different measuremen~s that may be considéred the diameter of a corallfte of Favosites (B waa used in this study).

' .

.. '. , "\ _ ,_""-'"'~..,..-..."" ..... >-_ ~-""""""""'''''~r~'''- ~ II!!. J5&!St ~"'"~ . ..,.... _"h,~ ... " l'~ ~ .~, ...?t ...... " .t,,,.

-' (- , .,

\ . , that clearly shows bimodal d1stribution of cora11ite size O( F. 6oJLbe4i J

but measurements of the corallite diameter do not yie1d a bimoda1 frequency .'

graph even after 1307 measuremeots ar~ p10tted. The shape of the frequency j distribution a1so depends on which measurement of coral1ite diameter is used \ J~ rI ~ (see fig: 13). -

" ~ Each group in fig. 12 appear.s to be characterized by a particular

frequency distr,ibution -(see fig. 14). In Group A there is a gradua 1 increase

in frequency with increasing size until the, modal value 1s reached and then a sharp drop. In Group B either the rrode occurs at the low diameter end of " the distribution with a gradual decrease in frequency with increasing size

or else there is a broad plateau of values. Group ,C has a birrodal, distribu~ \ ,

tion. , 'However, saDJ;)le lO .. l1a '(on the fringe of Group A) exhibits a pattern '0

characteristic; of Group Bt and the frequepcy distributi~n of sample B-6a, (00 the boundary between" Groups, Band C) approaches the pattern of Grou'p C. Despi te the 'Uncertai nty due to, the sma1l numer of measurements used to

construct the histograms, the pat~rn characteristic of'each' g~oup seems,to

be part .of a conti nuum. The boundary of groups defined by thes~ frequency distributions wou1d not match the boundaries determined by corallite diameter,

\ , 1 nor would these new boun(taries be Any rrore distinct . ... It appears that the parameters selected in this study cannot

'be u~ed to characterize species until after the species have been defined using other criteria. The published species listed in Table 9 all have narrow ranges 1 l' ! -of coral lite diametèr. tabular densi~y. pore diameter and w!ll thickness. Is this a true reflection of species characteristics or an artiJicially

'Il restrictive construct impo~ed on nature by p~leontol09ists? i J • l, t- --- i . " ~ -~~

! .., f ( i ! +. 1 ", 76 J • ) f ...... ~

'. 1

1

" . ,1 . \

"

;..

",

't __ .

\ .,

1

1 • l .; ... l J. r, ... '* 77 20 A , -/0 18 < 1, 16 ( 14 ( , , 12 10 8 -, 6 4 .2 c(Jra'lit~ dia",.t~r (mm) • 8 78 1t DI, 24 22 20

18 t~ 16 14 12 10 3-10 A 8 6 4 2 coralli~ dia. (mm)..

12 ~ 10 6-2 8 6 1'4 2 .1

16 14 ( . 12 10 6-5 8 6 4 2

28· 26'" 24 22 20 18 16 14 12 10 8 ;' ,6 4 / 2 ...... --'w--'-h.....- ___~~ , }<" " . ;,' ,

, " 79

,\ 80

('. This inabil1ty to separate ecophenotyp1c ranges wi thin species fram specifie differences between"populations is a recurring problem in paleon­ tology. Ste 1 (1978) has concluded that the current narrow de li mi tatton of

coral1ite diameter ranges w;thin so-cal1ed spectes of the genus F~V04~

is too narrow to allow for ecophenotypic· variation and that corallite diameter can only be used as a species characteristic once the ecophenotypic range 1s known, ~therwise weI can on1y test whether or not populations are

statistically separate without knowing the cause. Based on the data obtained . fram over 30 samples fram the Stuart Bay blocks the writer agrees that

current species definitions within the genus F~v04-i..t:u are too narrow and

that if the taxon~~is based on coral lite diame~er. tabular density, wall thickness and pore si ze then it is based on ina8equate cri teria. The favo- • sitids have been d~ed into an artificially high number of species. But what other characters can be used? Colony shape is usually believed ta be detennined by environment. Length or prominence of spines has been shown

to range widely within a single corallum. Diagenesis masks the origin~l microstructure and chemistry (i .e. % of Mg) of the skeleton secreted by the ·organism. Recent work. by Bondarenko (1981) on he1 io1 ; tids suggests that the pattern of change of nuœrical parameters (eg. coral 1 i te diameter. tabular \ s pa ci ng) wi th i ncreas i ng col ony ma turi ty may be a cha racteri s ti c tha t can be

used to distinguish tabulate spec;, It is nonetheless poss~ble that the genus Fav04..i.te.6 consists of fonllS that cannot be d1vided into spectes except arb1trarily. The testing of thfs hypothesis is beyond the scope of

this thesis because it would ;nvolve the measuring and statistical analysis

of several criteria in thousands of corallites 1n many sa~les of different

ages and locations. The evaluat10n of the suggestion ,that" Fa.vo.sLtu lIIily not ( l ' .. -" 81

< • c be a coral (F1Ugel.·1976) 15 1150 beyond the scope of this thesis. • •f

\

(

.... ---~------... ' 82

Strama toporo 1ds ..... Eight genera of stromatoporoids 1ncluding nineospec1es were

identified from the blocks i~ the Stuart Bay Formation. Two genera,

P.6 e.u.d.otJw.pU:.0.4tJr.oma. ana SyM.rtB0~' account for more then 50% of the samples. The other six genera are represented by fewer than fhe specimens apiece. Five of the samples are 1nfested with a coral tentatiVely iden­

tified as Sylli.rrgOPOlLeU.a. sp. al'though its tabulae are infundibu1iform rather than horizontal. The genera were identified by C.W. Stearn but were described - 1 by the ~riter. The classificttion scheme pr.oposed by Stearn (1980) was used. Class St-romatoporoidea Nicho1scm and Murie, 1879

Order Cl athrodi ctyi da Bogoyavl enskaya, 1969 <. Family Clathrodictyidae Kuhn, 19~7 Genus Cl athrodi ctyon Ni cha 15 on and Mu ri ~ 1 1879

cta.tIrJt.od.i..ct.Jjo n S p • A Plate 8, figure 1.

Description: Surf~ undulent, namelons absent. lurlnar structures

predominate; laminae simple, ~h;n to'thick, cont1nuous. moderately to widel,r spaced (8-16 in 2 l1li1), undulant; pillars confined to inter1aminar spaces, soma ar< superposed, thick, irregularly spaced (4-6 in 2 111ft), , - taPjt downward, many incomplete, cut as circular to polygonal dots in tangential sect1ôns; astrorhiz,e present. Material and occurrence: Three t' slq)les: 3-13 (AS), 5-6a (P8P-5) ,"-8-"2 (PBP-24a). l' 1 Genus Atopostroma Yang and Dong, 1979 ! Plate 8, figures 2, 3. Description: Mulelons shalloW, -not prominent; lamina-: str,..ctures predo-

o • \ t(. 1 . 1 :. 83 -

, " minate; ga11~ries longer than high; laminae composite (co~~eQ. of bundles of mi crolam;nae) plJl)derate1y thick. continuous, undula!nt' ta irregular.

~ c10sely spaced; pillars prominent. confined to inter1aminar spaces, sllper-

posed. ,thiek, irregularly spaced, eut ~s round dots with irregular outlines and spacing in tangentia1 sections; astrorhizae prominent. large, 4-6

bifureated ~rimary canals. Materia1 and occurrence: Two semples: 3-6 (AS). 11-2 (PBPN).

Genus Gerronostroma Yavorsky. 1931

?Gerronoatroma sp. A Plate 8, figùre 6. ~

Description: Laminar structures predominate; 1aminae'tlmplet thin, promi nent, persistent, maze-like ; n tangentia1 section. Mater;a1 and

occurrence: One sample: 8-4b (P8P-23b)

?Gerronostroma sp. B Plate 8, figures 4, 5. Description-: laminar structures predominate; open structure; laminae siqlle, thj.n, disco!'tinuous and anastomosing. irregular1y and widely spaced, '(' 1 - disseplments colIIII)n between laminae; pil1ars regu~~!,ly superposed. thick-rr , than l'aminae. irregu1arly spaced. long, cut as sma11, widely spaced. cir- cular or irregular dots in tangential sections. Material and occurrence:' One sall{Jle: 8-5 (P8P·23a). '

Family Ecclimad1ctyidae Steam. 1980 - Genus Actinod1ctyon Parts. 1909 ~ AdUwdi.t!tqon sp. A Plate 7-. figures l, 2. Description: Laminar structures predominate; llnrin'ie si'q>le. th1n.

irragular. discontinuous t anastamosing. cyst-lfke, closely spaced (7-8 in 2 m); pillars throughgoing. thicker than laminae, widely and irregularly

,spaced (4-5 in 2 _) .. sl1~tty. bent or irregular, long (up to 5 IIIII~,

t

~._"_ ...... -, - -,---_.--..-..--_.------84

( eut as clark dots in tangential sections; astrorhifae inéonspicuous, vary

widely spaced. Material and occurre~ce: Three samples: 6-3 (PB P-6) , 8-4a (PBP-23b), 8-6 (PBP-22b). Order Stromatoporellida Stearn, 1980 Family Hermatostrorœtidae Nestor. 1964

Genus Trupetostroma Parks, 1936 ~'e Plate 7, fi gures 3. 4.

) Description: Laminar and vertical structures equally developed; laminae siq>le, thick, thickened be10w by tissue, discontinuous, irregu1arly and wide1y spaced (9-11 in 2 m); pillars thick. superposed or continuous-, taper downward, wide1y spaced; astrorhizae large, close1y spaced, prominent.

cana 1s multi branched. Mate ri al and occurrence:

Order Stromatoporida Stearn. 1980 , Fanrlly Stromatoporidae Winche1'. 1867 Genus Pseudotrupetostroma Kha l fi na r971 ?Pse'U.à:cJ.trupetostt>oma sp. A Plate 7, figures 5. 6. Description: Mamelons variab1e- large, well-defined and closely spaced,

or inconspicuous; dense str~cture; laminar structures predominatei laminae composite, thick, continuous, undul.nt ta curved. c10sely spaced (12-14" in -., 1 2 mm); pillars inconspicuous, cut as closely spaced. sma~l dots in a labyrin­ t thine arrangement; astrorhizae prominent, canals wide • vertical columns 1

formed of uptumed inflections of the 1ami nae contain abun~ant superposed i ..; i as trorh hal canals. Material and occurrence: Sixteen sa~les: 2-5 (MRR), 1

2-6 (MRR). 3"_3 (AS), 3-4 (AS), 4-1c (PBPN). 4-5a (CRN), 4-5b (CRN). 6-6

(PBP-a), 12-2 (PBP-16) ~ 16-1 O"tR-17)~ 16-2 (MRR-16) 16-3 (MRR-15), 16-4 1 {MRR-14),.16-5 (MRR-13~), 16-6 (MRR-l~), 23-1b (MRR-8). ~. f ~ ... ", . / 85

Furily Syringostromell1dae Stearn. 1980 . , Genus Sa19irella Khalfina. 1960

~ sp. A Plate 9. figure 1. Description: Mamelons.)bsent; amalgamate .network. laminae simple. thick. discontinuous, irregular1y spaced; coenosteles promnnent, thick. regular1y spaced. form hbyrinthine arnalgamate network in tangential sections; as"trorhizae inconspicuous, canals wide : irregu1ar arrangement of galleries radiate away from astrorhizae. Materia1 and occurrence: Three samples: 4-1a (PBPN), 4-lb (PBPN), 10-7 (PBP-20). Family Syringostromatidae Lecompte. 1951 (amended by Stea"" 1980)

Genus ~yri ngos troma Ni cha 1son, 1875

Plate 9. figu~s a,~3. Description: Mamelons c1osel}' spaced, medi um diameter; dense structure penetrated by irregular pores; 1aminae composite, thiek, continuous, infl1cted upward into colUlllls in whieh the tissue thiekens; eolums up ta 10 mm long, c10sely spaced, eut in tangential, sections as large dark dots or nodes which may be surrounded by thin concentric circ1es of cut laminae, pi11ars confined to interlaminar spaces, thick, superposed. eut as dense ..,., ma~ses of ve~ smal1 dots in tangentia1 sections; astrorhizae prominent, large. Material and occurrence: Seven samples: 6-10a (PBP-10), 6-l0b

(~PdO). 7-4 (PBP-lla). 11-1a (PBP~-l), 11-1b (PBPN-l), 23-la (MRR-8), 23-4 (MRR-5).

j t B6

C'. ACKNOWLEOGEMENTS ~ .. , . ---~- - --~---~- 1 t'hank Col in Stearn for proposin'g the topic, naming the stromato~roids and for,. his constant he1p throughout the project. 1 a1so thank J. Elsoh for suggesting references, E. Mountjoy for suggest.ing references and ~~ 1 for his help, A.E.H. Pedder for confirming the genus designations~of the rugosan eorals- and for identifying the specimen of Staupomatidium sp .•

--' and T. Uyeno for provi,ding age data on the Stuart Bay Fonnation. r thank ... R. Yates and Cynthia Polan for he1p with the plates. Thanks are due to D. Smith for his able assistance in the field, to S. Islam for help, and espeeially to Gary Smith for help, adviee and encouragement that were \ of 9,reat benefit. ; am especia11y grateful to M. Arts who typ~d and my father who proofread the thesis. Thank you to mY mother and family for support and encouragement in this

1 1 1

\

r 1

1 87 , J

REFE~NCES B,iddle, K.T. '1980. The b~sinal Cipit boulders: indicators oT'M1ddle to

Upper Triassic buildup margin~, Do1omnte Alps, Triassic. R1v1sta'

ita1iana d1~Pa1eontolog1a, 86 (4). pp~ 779-794.

Bloom A.L. 1978. Geomorphology: a systematic analysis of Late Cenozoic' t .. ç;1 1andfonRS. Prentice-Ha11 Inc., Eng1ewood Cli.ffs, ~ew Jersey, 5}O pp.

Bondarenko. O.B. 1981. Numeric~l diagnosis of tabulatomorph corals. , /J ti{f Vestnlk Moskovskogo Universiteta, Geo1ogiya, 36 (2)~ pp. 46-53

tarrasco-V., B." 1977. Albian sedimentation. of submar1ne autochthonous. and allochthonous carbonates, east edge of the Valles- San L.ûis Potos; , , Platform, Mexico' f ln Deep-Water Carbonate Environments. Edited by H.E. Cook and P. Enos. Society of Economnc Paleontologists and Mineralo- , ~ gists. Special Publication no. 25, pp. 263-272. ' ~

CQnaghan, P.J .• Mountjoy, E.W., Edgecomb, D.R., Talent. J.A., and OWen,

D.E., 1976. Nubrigyn a1ga1 reefs (Devonian), Ea~tern Australia: al1och- thonous blacks and megabreccias. Geological Soçiety of America

• Bulletin, 87, pp. 515-5~.

if- Dav1es, J.l. ,1969. An introdact1on ta systematic geGlllDrpholog)', vol&llle 3, " . landforms of cold cl1nates. M.I.T. Press, Calœridge, Massachusetts, 200 pp.

. '

~' ..' - -"C~~-"""""""'''''''''''''''''''V. ____''-'-:'_OC'~,,", ___''''~i+<_' -- 4 .....-.-_-"-_Î_~ ...... _...... ,...... -' .... ~.... 8""'· _nif"",,,U.,..: ----- r

1 1, Dott •. R.H., Jr. 1963. Oynami cs of subaqueous gravi tY',cdeposi. ti anal , , processes. American Association of Petro1eum Geologists Bulletin,

47, pp. 104-128. l

Ermry, A.F., and K1ovan, J.E. 1972. A Late Devonhn ,reef tract on northeastern Banks Island, Northwes-t Territories. Bulletin of Canadian i - Petroleum Geology, 19, pp. 730-781. 1

••• and ... 1976. The Middle-Upper Devoni~n c1ast1c wedge of the . ' Frank1inian Geosyncline. Bulletin of Canadian Petroleum Geology, 24 (4). pp. 485-639.

F10gel, H. 1976. Ein Spongienmodell fur die Favositidae. Lethaia~ 9, r ~ \ pp. 407:--431. ;

( /

Fortier, Y.0., and Thors te; ns'son t R. 1953. The parry ISlands Fo1d Bel t in the Canadian Aretic Archipelago. American Journal of Science, 251, ." 00-

:::: 'V pp. 259-267. ",

~ . ... , B1ackadar, R.G. Gle.nister, B.F., Greiner, H.R., McLaren, D.J., , " McMillan, N.J., Norris, A.W., Roots, E.F., Southe~, J.G., Thorsilinsson, \ R., and Toz€r, LT. 1963. Geo1ogy of the North-central part of the- Arctic Archipelago, Northwest Territories (Operation Franklin). Geological Survey, of Canada Memoir 32q., pp. 67l.

1 l !

.1~ ri . 1 J- - -ij i6 C1sc:s:t4JZ&i !fi' U '(1 dl" al é.O. tt_~~ __ J, •• III>

1 , , -89 rl • 1 1, J

Fflrs,ch, F.T., and Wendt, J, 1977. B1ost~atinofI\Y and PalaeoecoJo~ of the ,,- , Cassia,n Fonnation (Triassic) of the Sollthern Alps. Pa1aeogeography, i 1 PaUeoclimatology, Palaeoecology; 22, pp: 257-323 • • :1 Friedrrrn, G.M., Amiel, A.J., and Schnefdermann, N. 1974. Submarine , ; " !i 1 cemerrtatiQn in reefs: an eXimp1e' fram the Red Sea. J'mal 01 Sedimentary ! ., " 1 ! Petr,pl ogy, 44, pp. 81-6-825. " 1 o ,Yi ..

, , Ginsbtlrg, R.N., and ~arnes, N.P. 1976: q,Submari~e botryo.1dal ar.agonite

in Ho 1ocene reef ri mes ~ones: Bel i ze. Geo 1ogy, 4, pp. 431-436. .. ••• and S~hroedert J .. H. 1,97Y Growth and submarine f~ssilizat10n of

à l ga 1 cup' reefs, ~ennuda. Sedi mento 1ogy, 20 t pp. 575-614. ". ,

Heckel, P.H. 1974. Carbonate bul1dl,lps in the geo10g1cal record: a '. ' review. ln Reefs in Time -and Space. Edited by L. F. Laporte. Sdciety . e '- of Eco"omic Paleonto1ogists and M1nera1ogists Special Publication no. 18. i pp. '90-154 • l· . and Witzke,' S.J. 1979. Devon1an wor1d palaeogeography detenni ned • 1 frol" distribution-of carbonates and related 1 ithic palaeoclimatic indica- f :tors. In The' Devonian System. Edited by M.R. Hauset C.T. ScrlJtton, ,i and 'M.G. Sassett.. Special Papers in Pa1aeontology no. 3. pp. 99-123. .1 ,

, . , 1 1 1 '. ," . ' 1 ! 1 • j .~~~j • : 90

( ~ - ~:oo.. Hill, -D. 1981. Coelenterata. In Treatise on lnvertebrate" Pa1eonto1o~, l' Part F, Supplement I, Rùgosa and Tabulata. Ed1ted by C. Teichert. Geologi cal Society of America, Un'4versity of Kansas, '762 pp.

\ ... Hoffmal1, H.J. 1975. Stratifonn Precarmrian stromatolites, Belcher I."lands, ) , Canada: relations between s;licified m;crofossi1s and microstructures.

American Journal of Scienc~ 275, pp. 1121-1132.

Hueber, F.M. 1971. Èarly Devonia" land plants from Bathurst Island.

District of Frank1in.1 GeolQ.gical Survey of Canada, Paper 71-28,17 pp.

Jackson, D.E., Lenz, A.C. and Pedder, A.E.H. 1978. Late Silurian and Ear1y Devon;an graptolite, brachiopod and coral faunas from northwestern ( and Arctic Canada. Geo1ogieal Association of Canada, Special Paper 17, l ,159 pp.

'James N.P. 1981. Megablocks of ea1cified algae in the Cow Head Breceia, western Newfoundl'and: vesti ges of a Carmro-Ordovician platform margi n. Geolo.gica1 Society of America Bulletin Part l, 92, pp. 799-811.

... , Ginsburg, R.N., Marsza1ek, O.S., and Choquette, P.W. 1976. Facies and fabrie specificity of early subsea cements in sha110w Belize.. (Britfsh Honduras) reefs. Journal of Sedimentary Petrology, 46, pp. 523-544·

\ \ ,

91

.. ( Jenness, J.L., 1952a. Erosive forces in the physiography of western Arctie Canada. Geographical Review, 42, pp. 238-252

... , 1952b. Problem of glaciation in the northwest islands of Aret1c " ..... Canada. Geologieal S~eiety of America B~lletin, 63, pp. 939-952.

Kerr, J. 1968. Devonian of the Franklinian Miogeosyneline and adjacent

Cèntral Stable ~egion, Arctic Canada. In Proceeèfings of the International

Symposium on the Devonian System.. Edited - by D.H. Oswald. Alberta Society of Petroleum Geologists, l, pp. 677-692 .

1974. Geo1ogy of Bathurst Island Group and Byam Martin Island,

Arctic Canada (Operation Bathurst ISland). Geo1ogiea1 Survey of Can~da", "'"",- ( Mèiroi r 378, 152 pp~

1976. Stratigraphy of central and eastern Ellesmere Island, Arctic Canada, part IlL. Upper Ordovician (Richmondian), Silurian, and Oevonian. Geological Survey of Canada Bulletin 260, 55 pp.

1977. Cornwallis Fold Belt and ;he mechanism of basement up1ift. Canadian Journal of Earth Sciences, 1~} pp. 1374-1401. ..

1981. Evolution of the Canadian Arctié Islands: a transition between the Atlantic and Arctie Oceans. In The Ocean Basins and Margins, S, Arctic Ocean. Edited by A.LM. Na;"" M. Churkin Jr., and F.G. Steh1i. Plenum Press, pp. 105-199. , "

\ 92

( ••• 1 McGregor. C.D., and McLiren, D.J. 1965: An unconfonnity batween Middle and Upper Devonian rocks of Bathurst ls1and~ with cOJllllents on ,. . .. ' Ùpper Devo.nian faunas' and microfloras of the Parry Islands. Bulletin

of Canadian Petroleum Geo1ogy, 13(3). pp."'409-431."

Ladd. H.S. 1971. Existing re~fs-geologic aspects in reef organisms

through time. North American Paleonto1ogical Convention. Chicago. 1969. Proceedi ngs J.. pp. 1273-1300.

, ....

Lenz, A.C. 1973. Q,uadrithyris mne (lower 'Devonian) near-reef brachio­ pods fram Bathurst Island, Arctic .Canada; . with a description of'a new . rhynchonell ; d brachiopod Frankl inella. ,Cana'dian ·Journal of Earth<

Sciences, 10, pp. 1403-1409~ (

Longman. M.W. 1981. ''A, process approach Ita recognizing facies of reef

comp le xes . 1n ~uropean Foss il Reef Mode 1s . Edi ted ~y O. F. Too~y. , Society of Economie Pal eontol ogists, and Mineralogists, Special Publieation , ( no. 30, pp. 9-40 .

Ludvigsen, R. 1972. Late Ear1y Devonian dacryoconar1d tentacu1ités,

northern ~ukon Territory. Canadian Journal of Earth Sciences, g; pp. 297,-

318.

J Machie1se, S. 1972. Devonian algae and their contributiqn te the

Western canadian Sedimentary Basin. Bulletin of èanadian Petroleum

Geology,20 ("2), pp. 187-237. ...

J 93

( Macqueen. R.W. 1974~ lc~er jd Middle Pal'eozoic, studies, northern Yukon Territory (106 E, Ft L). Geo1dgica', Survey of Caoada Paper 74-1, part A, pp. 323-326 .

\ Mayr,, U. 1980. Strat;'graphy and corre1 ati on of Lower Paleozoi c formations. subsurfaee• of Bathurst Island anaadjaeent sma11er is1ands, Canadian Arctic Archipe1ago. Geo1ogi'ca1 Survey of Canada Bulletin 306, 52 pp.

McGregor, D.C., and Uyeno, ToT. 1972. ~vohian spores and conodonts of

Melville and Bathurst l'slands, District of Franklin. -Geo1ogic::a1 Survey f

. of Canada Paper 71-13, 36 pp.

McLaren, D.J. 1963. In Geo10gy of the north~entral p,art

( of Ple Arctic Archipel " Northwest Terrftories (Operation Franklin).

Geo1ogiea1 Survey of Canada Memoir 320, pp. 596-620.

McNair, A.H. 1961. Relations of the Parry Islands Fo1d Belt and the

Cornwallis Fo1ds, eastern B-athurst Island, Canadiarr Archipelago. In

Geology of the )\rctic, University of Toronto Press, pp. 421-426.

Moore, C.H.,- ~nd Shedd, W.W. 1977. Effective rates of sponge bioerosion

as a function of carbonate production: Third International Coral ~e.f

Symposium Proceedings, 2 (~ology). pp. 499-505 .

,. ~4

( Mountjoy, LW., Cook, M. E., P.ray, L. C. 'and McDani el: P. N. 1972.'

Allochthonous carbonate debr~s f1ows- worldwide indicat~rs of. reef

complexes, banks or shelf margins. Twenty'fourth International Geolâgical~

Congress, Section 6, pp. 172-189. , ,

.•. , and Ju11, R.K. 1978. Fore-reef carbonate mud bioh,erms and associa­

ted reef margin, Upper Devonian, Ancient Wall reef cOfl1Jlex, Alberta. Canadian,Journa1 of'Earth Science,- 15 (8), pp. 1304-1325. 6 •

.•. , and Riding, R. 1981. F'ores1ope. stromatoporoid-renalcid bioherm with evidence of early cementation, Dev~nian Ancient Wall reef complex Rocky Mountains. 'Sedimentology, 28, pp. 299-319.

( Ogilvie-Gordon. M.M. 1894. Coral in the IDo1omites" of South Tyrol. , Geological Magazines 4, pp. 1-49.

Ormiston, A. 1967. lower and Middle Onenian tr-i lobi tes.. of the Canadian

Arctic Isldnds. Geologica1 Survey. of Canada Bull,etin '153, 189 pp.

• 0 Pedder, A.E.H., and Oliver, W.A., Jr. 1982. Stauromatidium .and Stau- ,-

romatiidae, new genus an.d fami1y of Upper Silurian and Lower Devonian

rugose eorals. Geo1ogica1 Survef of Canada Bulletin 352, 43 pp.

Playford, P.E •• and Lowry,' D.C~ 1966. Devonian-reef complexes of the ./ \ .

Canning Basin, Western Australiii'. Geological Sur~ey of Western Australi~ = Bulletin 118, 50 pp.

) • ... t 95 .,.. • , , " Polan, K.P,.~ and Stearn, C.W. 1981. Allochtho~ou~ origin of Devonian " " f, "b'iohenns" of Bathurst Island, Arctic Cànada. Geo10gical Society of America Abstracts with Program, Nor.theastem Section, p. 170. ~

, t 1 Powell, T.G. 1978. An assessment of the hYdroearbon sourcerock potent;al ,. . ,.,IJ " ... of the Canad1an Arctic Islands. Géo1og1~al Survey of Canada Paper 78-12, , . 82 pp • • ~ ~ t Reading, H.G. (editor). 1978. Sedimentary environments and facies.

Elsevier Nor\Holl.nd Ine •• Ne_ York, 557p. J'

Riding. R., and Braiser, M.D. 1~75. The earliest ca1careous foraminifera. Nature, 257. pp. 833-848.

Smith, R.E. 1974. Upper Si1ur;an and Lower De\(()n;an (Gedinnian) bio­ stratigraphy and brachiopod faünas, Bitillie-Hamilton, Prince of Wale,s , and Bathurst Islands, District of Franklin. Geo1ogica1 Survey of Canada Paper 74-1 Part At p. 120. -- i i\, ,

" 1980. Lower Devonian (Lochltovian) biostrat1graphy and brach10pod i• faunas, Canadian Aret; c Is 1 ands. Gealogi cal, Survey of Canada Bul1eti n i 308', 155 pp. f

Stearn, C.W. 1980. Classification of the Paleozo;c stromatoporoids. r \ Journal of Paleonto10gy, 54 (5), pp. 881-902. J • ! / 1, '1 1 " .... - . ~ ...... ~" ~ ~ 1 ,....~ $'- -,~-,,... ~~,,,. ~ ...... '" f','"

96

~tel, J.H. 1976. The Paleozc,.i.c °hard substrate trace fossils Helieosalpinx, . ... Chaetosalpinx and ,Torquaysalpinx. Neues Jahrbudf fÜer Geologie und Ptli - " --- ( '1109: e, It>natshefte 12, pp, 726-~44. ,

••. ,1978. ,Environment and qÛantitativè' \1llrphology of some Silurianr tabulates frorn Gotland. ,Scripta Geologiea 47, 75 pp.

StlJJlll. E.C., and Tyler, J.H. 1964. COrals of thé Traverse Group of , . "', Mithigan part XII, the small-eel1ed species of Favosites and Eh00llsia. , Contributions from the Museum Of Paleonto10gy, Universf'ty of Michigan. 1 XIX (3), pp. 23-36.

Swann, O.H. 1947. The EavQ~jtes aloenensjs l1neage in the Middle Devon.ian ( Trave,:se Group ~f ~i ehi gàr. Co~tributions from the ~ùseum of Paleon~lo9.v ~ University of Mlehlgan, vtt artn.le 9, pp. 235-318 • ~ . ,

. .) , Taylor, A•. 1956. Geographiea1 biscovery and exploration in the Queen Elizabeth Islands. Geographieal Braneh of Canada Memotr 3, 172 pp. ,

Thorsteinsson, R., and Tozer, E.T. 1970. Chapter XVII, the ~retic Archi- . \ " pelago. In Geology and Economie Minerals of Canada. Edited by R.J~W.

Douglas'. Geological Survey of Canada, Report number 1 t F1fth Edition.

, , Tw1dale, C.R. 1976. Analysis of Landfonns. John Wiley & Sons,> Australia

PtY t Sydney, 572 pp .

.'

1 i - '. '1 . .. ~, , l •

, ~" f' 97 -l

... \ ( Wa~, J.E. 1977. Carbonate borer'S" their role in r~ef ecology and preservation. American Association of Petroleum Geo1ogy Studies in

Geo 1ogy no.' 4 t pp. 261-280. (1

.. -- Wendt, J., and FUfsich, F.l.· 1979. Facies ana1.,xsis and palaegeography JI;' of the cassian For:mation, Triassic, Southern Alps. Rivista Ita1;ana

1 di Pa1eonto10gia, 86 (4), pp. 1003-1028. ',' 1" Wilson, J.L. 1970. Depositiona1 facies a'cross carbonate she1f margins. . ~ . Transactions of the Gulf Coas·t Association of Geologieal Societies, 20, J pp. 229-233 .

.••' 1974. Characteristics of carbonate platform margins. American Asso­ ciation of Petro1eum teo'og;sts Bulletin, 58, pp. ~810-824. " , "

, ~ \ Wolf, K.H. 1965a. Gradational sedimentary products of calcareous algae. Sedimentology, 5, pp. 1-37.

1965b. Li ttora 1 envi ronment î ndi Ca ted by opel1-space structures in , , al gal lime1tones. Pa laeogeography t Pal aeoclimato10gy , Palaeoeco1 ogy , 1, pp. 183-223.

l,

, . f 1 ,~ \ .,

..

,..... ~-...... -;'I,W_ 1 1, 98

PLATE CAPTIONS ., ( Plate '1. Figure 1. Aerial view ~f the two rows of blocks" trending N600E at the - , Polar Bear ~ass loCali~y. The prominent black in the rowpr . centre of the picture is PBP-2. This view shows the generally subdued topography of Bathurst Island. The white line of snow in the background delineafes an unnamed south-flowing river. North i s toward the upper ri ghthand corner of the fi gure. Figure 2. One of th~ blocks at the Polar Bear Pass North locality with C.W. Stearn as a scale.

Plate 2. ~igure 1. Aerïal view looking southward of the two groups of blocks at the Arthur' s Seat loca 1 ity hi gh above the same ri ver that ; s viSible in Plate 1. figure '1. Steeply incised river valleys provide the only appreciab1e relief on Bathurst Island.

( Figure 2. Aerial v;ew 100king approximately northward 11 the Moses Robinson River lo~ality. The black at the bottom of the picture is MRR-15. Within the dark area in the centre\;f the photograph is a 1ight coloured aval mass of rubble with trai 1;ng edges. ,This is interpreted to be a frost-reduced blaCk. -J 'plate 3. Figure 1. ., Aerial view ofrthe Cheyne River local ity showing the two blocks adjacent to an outcr?p qf sil tstone and cong1 omerate . (foreground) #0 Behi nd the b1 ocks i s another 10w area of si ltstone and conglomerate outcrop and debri s which ; s' along strike from the eastern (foreground) outcrop. North is toward the upper righthand corner of the figure. l 1 ! ï Plat~ 4. ..

l , ~ Figures 1, 2. Tryplaf1lTla sp. sample 23-1 (MRR-8), x 1.5. ~ i, Figures 3. 4. Stylopl.eura sp. sample 23-2' (MRR:"7). x 4.5: ! - "

1 -,'- 1 ...... _ ..... _ .. ~_ .,1-<..,.,.,.-,-""" .,... '" ~ _..,... ,-'_, ->._ .. _ , 99 ! . i ,

Pla'te 5·. 1 Figures 1, 2. AUBt:raZophyttUl'lf Spa samplt! 11-1 (PBPN-l), x 4.5. figures 3, 4. StQUP&matidium Spa sample 15~9 (MRR~19), x 4.5. Figure 5. Roemeripo:ra sp:- sample 8-2 (PBP-24a), x 4.5.

Plate 6. ~ Figure 1. HeUoUtes Spa sample ~BP-S), ~ 4.5 • .- ), - Figure 2. HelioLite8 SPA sample 5-7 (PBP-S), x 6. Figures 3, 4. 1Jiotyofavo8ite8 Spa sample 6-6 (PBP-8), i 10\ Figures 5, 6. Favosites "gothlandiaus" sample 6-2 (PBP), x 5.

Plate 7. Figure 1. Aotinodictyçn sp. sample 6-3(PBP-6), x 10 (a11 'stromatoporoid photographs are x 10), oblique tangential. Figure 2. Same, vertical. Ptgure 3. Tl"Ulle..tost1'oma sp. sample 8-8' (PBP-21), oblique tangential. J Figure 4. Same, vert; ca 1. Figure 5. ?Pseudot1'upetostroma sp. sample 6-6 (PBP-8), tangential. ( Figure 6. Same, vertical.

Plate 8. Figure 1- CLath1'odiotyon Spa sample 5-6a (PBP-5), vertical. 1 Figure 2. Atopost:roma Spa sample 3-6 (AS), tangential. "

Figure 3. Same, vertical. 1] \ Figure 4. ?Ger1'onost:roma sp. b sample 8-5 (PBP-23a) , tangential. j Figure 5. Same~ vertical. i Fi gure 6. ?Gerrono8t:roma Sp . a sample 8-4b (PBP-23b), oblique~

Plate 9. Figure 1.. SaLa:i.:reUa sp. sample 10-7 (PBP-20), oblique. Figure 2. Sy:ringost:roma Spa sample 6-10b~(PBP-IO), oblique tangential. Figure 3. Same, vertical.

, ~ I!F-'--'~"'.:"d~ -,'" , . •" :::·1' o Î

• 1

p Plate 2.

.... (,

/ .. .. Pl ate 3.•

( - ,

. ,

..

• f

\ ?- \ 1 \

___\-~ _~ ____'_ - fi ..

· ,

)

\ r 1a t. '" ""1 i Plate 8.

.. o Plate 9.

/

•