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1981
Conodont Biostratigraphy and Thermal Color Alteration Indices of the Upper St. Charles and Lower Garden City Formations, Bear River Range, Northern Utah and Southeastern Idaho
United States Geological Survey
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Recommended Citation United States Geological Survey, "Conodont Biostratigraphy and Thermal Color Alteration Indices of the Upper St. Charles and Lower Garden City Formations, Bear River Range, Northern Utah and Southeastern Idaho" (1981). All U.S. Government Documents (Utah Regional Depository). Paper 26. https://digitalcommons.usu.edu/govdocs/26
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GEOLOGICAL SURVEY CONODONT BIOSTRATIGRAPHY AND THERMAL COLOR ALTERATION IND[CES OF THE UPPER ST. CHARLES AND LOWER GARDEN C[TY FORMATIONS,
NORTHERN UTAH AND SOUTHEASTERN !DAIlO
by 1 CONODONT BIOSTRATIGRAPHY AND THERMAL COLOR ALTERATION IND[CES Ed Landing ABSTRACT OF THE UPPER ST. CHARLES AND LOWER GARDEN CITY FORMATIONS,
BEAR RIVER RANCE, NORTHERN UTAH AND SOUTHEASTERN !DAIlO The contact betlJeen the St. Charles and Garden City Formatlons In the Bear River Range, Bannock thrust sheet In
northern Utah and southeastern Idaho. Is 8 diachronous by
Ed Landing dlsconformlty within the Lower Ordovician. Middle or, poss lbly, upper Cordylodu8 proavu8 Zone (Clavohamulu8 elongatuB to,
poss1bly. £:.. hlntzel Subzones) conodonts indicate that lowermost
Open-FUe Report 81-740 Canadian Series (Lower Ordovician In North American usage) strata
1981 equ! valent to the Mls81squoia Zone and, pt)8s1bly. lower Symphysurina Zone (trilobites) are present In the upper part of
the St . Charles Formation. The boundary between the T'rempealeslJ;I \
Stage and Canadian Series (Cambrian-ordovlcian boundary) is
located within the upper part of the St. Charles Formation. Basal
beds of the Garden City Formation contain conodonts representing
Fauna B (upper part) in two Idaho sections and Fauna C at two Utah
localities . At least 12 m (40 feet) of erosional relief was
Ipresent address: New York State Geological Survey, State
Education Tl!:.partment I Albany. New York 12230 developed on the dolos t ones of the St. Cha rles Forma tto n prlo r to HictrUe Ordo vician fAunRl corre l a tions 1n the No r th Ame rtcan Faunal deposition of the Ga rden City Fo rmation. TrUoblte Zone A of Ross Province. Shelly fa unAS ha ve not he en recorded from the uppermost from the lower part of the Carden City Fomatio n correlates wt th pa r t o f the St. Charles Format to n, a nd t here has been no a vatlable the upper part of the Symphysurina Zone (.!.. bulbosa Subzone ) and ma c rofossIl evtdence to suppor: c l a t ms that the Ca rden City corres ponds in its lower and upper parts, respectlvely , with uppe r Formation conformably (Ross , 1949, 1951) or disconfo rruably
Fauna " and Fauna C (conodonts) . Conodont Fauna C occurs with (Willia ms, 1948; Richardson, 1913) overlles the St. Charles trilobites of upper Zone A through Zone C of Ross. Conodont Fauna Pormat t o n . n a nd trilobite Zone D have a lowest occurrence a t approximately The :> r esent study wa s i nitiated t o provide a conodont the same s tratigraphic level, although the lower pa r t of trilobite zonation fo r the upper part of the St. Cha rles Formation and lower
Zone D of Ross lles within the upper part of conodont Pauna C. part of the Carde n City Formation and to evaluate the conodont
Conodont elements from the lower part of the Carden City evidence for the possiblity t hat the contact between the
Formation have a color alterotion index ( CAl) of low 4, whereas format tons represents a hiatus . The conodont zonation also the strongly corroded specimens throughout the St . Charles provIdes a partial basis for compa ris on of Ross' (1949, 1951) dolos tones have a n apparent CAl of 6.5, although associated rarer trllobite Zone A through lowest Zone D with other known conodont elements ha ve a CAI-4(low) . The color alteration index de veloped a nd trilobite sequences. Th e uppe r 60-75 m (200- 250 feet) of the
for conodonts from limestones may not apply to samples from St . Chsrles and the lower 50 .. (165 feet) of the Carden City dolostones that have had their primary organic matter reduced by FormatIons were sampled for conodonts a l: f our localities in the leaching during dolomitization . western limb of the Logan Pea k syncline of the Bannock thrust
INTRODUCTION sheet (Richards a nd Mansfield, 1912 ; Williams. 1948), Bear River
The contact be tween the St . Charles and Carden City Range. northern Utah a nd southeastern Idaho (fig . 1) . These
Formations i n the Bear River Range of northern Utah and sections a re at or near Ross' (1949, 1951) localit1es a t Franklin
southeastern Idaho ls a striking lithologic break in a 'Rasln and HIllyard Canyon, Franklin County, Idaho , a nd Blacksmith ralogeosynclinal carbonate plat form sequence. Massive dolostones Fork Canyon a nd Creen Canyon, Cache County, Utah . Associated of the St . Charles Formation are succeeded by llmestones of the trilobites, petrograrhic features, and regiona l str atigraphy are
Carden City Formation (Richardson, 1913) containing a trilobite presently under study by H. E. Taylor a nd J . E. Repetsk1. The
and brachiopod sequence (Ross, 1949, 1951, 1953, 1968) that has results reported here apply to the central portion of the Bear
come to be regarded as a comparative standard for Early and early River Range, Utah-Idaho, and mayor may not be applIcable to the lowest beds of the Carden City Formatton in other 10calLtLes Ln CONODONT BIOSTRATtGRAPIIY the northern Creat Ba BLn and central Ro cky r·founta Ln regions. Remarks.--When present conodonts a re sparsely represented 1n
The contact between the St . Ch a rles and Garden City the upper part of the St. Charles Formation (commonly less than
Forll"3tlons t a an abrupt change frolll massively weathering, element s per kllogr am) a nd provlde a satisfactorIly resolved cliff- formIng, locally sucrosLc dolostones below, into thin- to correlation only for the uppermost m (20 feet) of the medium-hedded 1 Lmestones above. An interval of thin-bedded, formatIon. DLverse and ahl1ndant conodont faunas (greater than 500 cross- bec1ded, fIne-grained, brownish-grey dolostone wt th elements per kilogram) c ha r acterize the lowermost dolostone and dolomitized inl ~ aclast8 a nd sparse quartz sanc1 is eeneratly lower limestones of the Ca rden City Formation. The observed present above the massive dolostones. This thin-bedded dolostone faunal sequence and the local range zones of selected conodont untt is dlssltdlar to do lOB tones in the St. Charles Formation and taxa are recorded in f Lgures 2-5 . wss aBsie-ned to the Carden City Formation in the course of field !!... Charles Formation.--Clavohamulus elongatus Hiller, 1969 work. The thin-hedded dolostone unit in the basal Carden City (_£. elongatus and .£.. primittvus Miller, 1969), with Cordylodus
Porm.tlon 1. O . l~ m (0.5 feet) thlck and 6.15 m (20. 5 feet) thlck. prodvus Haller, 1959, ~ formo i!.. !..), Eoconodontus respectively, 1n the well-exposed Franklin Basin anli Blacksmith notchpeakensis (Hiller, L969), and Teridontus nakamurai (Nogami,
Fork sections . This dolostone untt is 14.8 m (49.) feet) thick at 1967) occur in the uppermost St . Charles Formation at Franklin
Hillyard Canyon but 1s partially repeated by a small fault along Rasin (upper 7.8 m; 26 feet) and at Rillyarc1 Canyon (upper 3 .3 m; the measured traverse. Some fault-related dolomitization may have 11 feet) in association with Cordylodus intermedius Furnish, 1938, taken place in the lowermost Garden Clty Formation at Hillyard s. f. This assemhlage indicates correlation with the uppermost
Canyon, but thin-bedded dolostone at Franklin Basin a nd Blacksmith Notch Peak Formation, Ibex area, west-central Utah (Miller, 1969,
Pork Canyon is not associated wlth faulting and may be of early 1978, 1980; Rintze and others, 1980) . A comparable fauna is diagenetic orlgin . Finally, considerable tectonic shearing has present in sample 03l8S-CO from at least 10 . 8 m (36 feet) below taken place in the upper St. Charles Formation in the Creen Canyon the top of the St . Charles POnDation at Green Canyon. section and appears to be related to an easterly dipping fault A highly resolved biostratigraphic correlation of conodont zone. However, at least 2.77 m (9.25 fel'!t ) of thin-bedded faunas from the uppermost part of the St. Charles .·ormation is not dolostone is present at the base of the Carden City Formation at possible, although an interval in the upper part of the Cordylodu8
Green Canyon. proavus Zone (Clavohamulua elongatus through, possibly, ~. hlntzei
Subzonea) is indicated for these Early Ordovician (Canadian) faunas . t:lavohsmulus elongatll8 has been r epo rted t o be restricted section is lowest Cansdian . Ilnd there is no evidence fo r or to the .£.. e l ongatus Suhzone (middle Co rdylodus proBvus Zo ne) in against a tentative correlation with the middle Cordylodus proavus the Ibex area , wh e r eas Cordylodus inte rmedius .! .. ~ . fLrst a ppear s Zone . in the s uperjacent IUrs utodontus simplex Subzone in that a r ea Co nodont-based correlation of lower beds in the upper St.
(Miller, 1978, 19RO; Hi ntze and ochers. 1980) . However , Miller Ch a rles Formation a r e much more probl ematical . The local range
( 19 69) has also noted chat the local range zone of f .. elongatus zones of primitive cordylodans extends 13.5 m (45 feet) (sample overlaps that of .£. hintzei, the eponymous species of the D3 102-CO ) a nd 18 m (60 Eeet) (salUpl e D3182-CO) below the top oE uppermost s ubzone of the Cordy loduB proavus Zone , whereas f.. the St . Ch a rles at Blacksmlth Fork and Gr een Canyons, i"termed ius ..! .. .!.. r a nges lower in the Cordylodu9 proavus Zo ne . rcspect l.ve l y, and indicate that these po r tions of the section
The biostratigraphic corre l a tion of the uppermost part of the represent the Cordyl odus proavus Zone of the uppermost
St . Charles Formation at Creen Canyon, Hillyard Canyon, and Trempealeauan Stage and lowest Canadian Series . Eoconodontus
Franklin Basin w1th the Cl a vohalDulus elongatus Subzone(?) is notchpeakensis in samples D3101-CO and D3 179-CO Er olU 45. 6 m (152 proposed in this r e port because conodonts s uch 8S Utahconus spp., feet) and approximately 66 m (220 feet) , res pectively, be l ow t he
JU r sutodontus simplex. Clavohamulus hintzel, a nd Monocostodus top of the St. Charles Formation at Blacksmith Fork and Green sevierensis (Miller, 1969), which first appear in the upper pa rt Canyons indicate t hat these porti ons of the sections r epresent of the Co r dylodus proavus Zone, are not present in the rich strata no ol der than the middle Trempealeauan Sa uklella junia collec tions (more than 1, 000 e lements ) f rom this interval. This Subzone of the Saukia Zone (middle Pr oconodontus Zone) , a lthough a adm ittedly negative evidence does not rule out the possibility correlation wi th any port ton o f the lower and middle Cordylodus that C. elongatus Subzone(?) of the uppermost part of the St. proavu8 Zone cannot be ruled out on the basis of the sparse
Charles 'Formation may actually include upper pa rts of the faunas . The Trempealeauan-Canadian (Cambria n-Ordovic ian) boundary
Cordylodus proavus Zone. 1s within the lower portion of the doc .1men ted cordylodan local
Samples from the uppermost St. Charles Formation at range zones In these four sections or may be somewhat lower.
Rlacksmith Fork Canyon yielded f.. intermedius .!:.!.' In the absence Hinor normal faults and problematical covered intervals 1n the of Clavohamulus elongatus. 'nle uppermost St. Charles at this Franklin 8asin and lUllyard Canyon sect lons that probably conta ln
faults are apparently responsible for the extended local range
zones of cordylodans and EoconodontuB at these two localitles. lacks 01.storlus sp. (-olstorlifonn element of TrLsngulodts? n. sp. Eoconodontl1s , Teridontu8, and the cordylodans are the A), LoxoduB branso'l{ Furnish, 1938, ClavohamuluB densu8 Furnish euryto plc and geographically widespread components of the conodont 1938, "Paltorlus" spuriu8 Ethlngton and Clark, 1964, Chosonodina faunas from the upper part of the St . Charles Formation . These herfurthi MOller, 1964, and Drepanodu8 spp • .!.:l.. These conodonts forms are knovn from North American peritidal carbonate platform appear higher in the Gartlen Cit y Formation where they are sequences, deeper water limestones and shelf ca r bonates , And associated with most of the forms first appearing tn the lower continental slope deposits (I.aodinz and others , 1980). part of the formatton. This lowes t fauna of the Garden City lacks lit rsutodontus, Semlacontlodus. and Clavohamulus, whic h dominate a complete component of s pecies comprising Fauna C in its original samples from the upper part of the St. Charles Formation, are best formulation, and this distinctiveness Ls here emphasized by its known from carbonate platform sequences in North Amertca (HilLer, rleslgnatton 89 "upper Pauna 8". Hiller's (1977) definition of the 1969, 1978, 1980) and Slberla (Abalmova, 19n; Ahaimova and base of an "upper Fauna B" based on the lowest occurrence of Harkov, 11)77), And are considered here to be characteristic of Cordylodus angulatus Pander, 1856, .!. ..!. . (-..2,., angulatus s •.!. . + £. shallow marine fAcies deposlteti under highly variable rotundatus Pander, 1856 , .!:.!..) Is not appropr i ate to the Garden e nvironmentAl conditions. Protoconodonts and paraconodont8 are City Fonaation because this fom appear s only immediately below or not present in the upper St . Charles Formation, a lthough they may within the stratigraphic interval with conodont Fauna C. comprlse more than half of the conodont elements from coeval 'Mte key condonts comprising upper conodont Fauna 8 are fonns deeper water limestones and slope deposits (E . Landing , 1982). not present in the uppermost St. Charles and include (1) Fauna !. (~.E!!!.) .--Conodonts from the lowest part of the Semiacontlodus iowensis (Furnish, 1938) [- acontiodiform vsriants Garden City Fo rmation at Franklin Basin and Hillyard Canyon are termed ACOQtiodus iowensis s.f. A. proplnquus Furnish , 1938, considerably younger than those from the underlying uppermost St. !:.!." anei an element resembling hut not comparable to~. staufferi Charles formation and are somewhat older than the lowest Ca rden Furnish, 1Q38, .!.'.!... plus an unnamed asymmetrical element} i (2) City faunas at Blacksmith Fork and Green Canyons . This oldest "Oistodus" triangularis Furnish, 1938, ! ...!:; (3) multielement fauna of the Garden City is comprised of Bome of the Acanthodus unclnatus Furnish, 1938, .!. ..!..; (4) Utahconus? bassleri characteristic conodonts reported from conodont Fauna C of Furnish , 1938 [-Acodus oneotensls Furnish, 1938, .!.'!.. t !: ~ P.thington and Clark (1971 ) , although it must be designated as .!:.!.., !.. varlabills Furnish I 1938, .!. •.!.. f Scolopodus sulcatus upper Fauna B. Conodont Fauna C was originally defined (Ethington Furnish, 1938, .!..!.:. !: warendensls Druce and Jones, 1971, .!.. •.! : and Clark, 1971, fig . 2) by the association of thirteen form (in part) ] ; (5) rare "Acanthodus" ~ (Furnish, 1938) !.-!.; species . The lowest conodont fauna from the Garden City Formation
10 9 associated 1n the l ower Carden C.lty Pomation . Upper conodont and (6) Dr epanoistodus? n. sp. A. A dominant compo ne nt of this Fauna B is prescnt i n the lower 4 . 5 m (15 feet) of the Carden Clty fauna is r epresented by the s t r i ated and nons t r i Ated e l ements , Fo rmation at Franklin Ras l n , wh ereas trilobite Zone A of Ross 1s respectively, of Utahconus t e nut s Miller , 1980, a nd New genus A. known to occur f rom 0 . 6 m (2 . 0 feet) t o a t least 5.7 m (19 feet) Cordylodan fom s pec ies persist f r om the upper pa rt of the St. above t he base of the Garden City Formation 1n thls sect lon (R. ,J. Charles and include develorlUenta l variants with secondary basal Ross) Jr. an-:i H. '::. Taylor, u"pub. data) . The correlat Lon of tips [- "Cordylodus lindstrom!" Druce a nd Jones, 19711 in the trllobLte Zone A of Ross has long been problematLcal . Wing ton anrl lower Ga rden City Formation . Co rdrlodus angula tus Pander, 1856, Nicholls (1967) compared triloblte Zone A with the ir concept of .!... l " including~. r o tundatus Pander, 1856, ! ..!. . 3S an t he Mlsstsquola Zone 1n the Llano area of Te xas , whe r eas Norfo rd 8symmetrlcal varia nt, appears 1n t he upper part of uppe r Fauna (1 (69) com pared it with both the Hlss1squola and Symphysurlna B. Ra r e elements of =Iew genus B appear through uppe r Fauna 8 of Zones of Winston and Nicholls (1967). Stitt (1977) proposed a the lower part of the Carden City Formation. New genus A a nd B somewhat younger equivalency w1th the SymphY8urlna Zone of Stitt are 31so known from lower Fauna B of the Green Point Croup, (197t) . Conodont data from the present study indicate that strata we s tern NC'o Upper conodont Fauna B was recovered from 18 terally e quivalent dolostones and llmestoneA at Hillyard Canyon and Franklin Basin, respectively , and is not strongly llthofaclally 12 11 lower part of conorlont F-.una R of the House r~tme sto ne of the are indistingtlishahle variants of .£.. intermedius .!.:.!.. with an Pogonip Group west-central Utah, are not present Ln the Bear River anteriorly c.onvex basal cavity. Drepanodus ~ (Branson and Range , Utah-Idaho . :'!ehl, 1933) and Sco1opodus rex Lindstr8m, 1955 , ~ strLcto Fauna .£..--The base of Fauna C of Ethington and Clark (1971) appear 1n the upper: part of Fauna C but a r e rare . is recognLzed herein at the lowest occurrence o f Trianeu1odus? n. Conodont Fauna C occurs with upper: trllobite Zone A and Zone SP a A Ln the Carden City Formation. Triangulodus? n. ap. A was B of Ross at franklin Basln and Blacksmith Fork a nd Zones Band C descended from Utahconus tenuls and d lffers primarily by the at 1I111yard Canyon. Conodont Fauna C unde rgoes little change presence of an oistodifortn element r-<>istodus SP a of Ethington and through thts interval. Clark, 19711; it has been Lllustrated in Iran as OLstodus Conodont Fauna C appears in abundantly fossiliferous parallelus .!..!... and Acodus oneotensis .!.o!... by Halter (1973) , and lLmestones 4.5 m (15 fe~t) above the base of the Garden City Formatton at Franklin Basin, and only 0.6 m (2.0 feet) above the in Queensland as.2... lanceolatua .!. •.!: and~ . oneotens1s by Druce and Jones (1971) . Representatives of most of the taxa fror.! the base of the formation at Blacksmith Porle. Canyon In c ross-bedded, upper part of Fauna 8 persist into conodont Founa C of the Carden IlnguloLd-bearing dotostones . These data support three City Formation. "Acnnthodus" lineatua (Furnish, 1938) a.f. is concillsions : (1) conodont Fauna C Is not strongly lithofaclally extremely abundant in Fauna C, whereas rare spec imens of Loxodus controlled tn the Garden City Formation and occur s in laterally bransoni Furnish, 1938 , .!. ..!.. and common specLmens of "~" equivalent dolostoncs and limestones; (2) unless all of upper conodont Fauna B 8S represented at the Franklin BasIn and Hillyard spurius EthLngton and Clark , 1964, .!. •.!. . occur above 0[' at the lowest occurrence of !:? n . sp. A at Franklin Basin and Hillyard Canyon sections ts contlenserl into 0.6 m (2 . 0 feet) at Blacksmith Canyon, respectively. Protopanderodus asymmetricus (Druce and Po rk Canyon, the bAse of the Carden City at the l a tter sectlon is Jones , 1971), presently descrLbed only from the upper Ninmar oo younge[' than in the northern sections; and (3) trilobites from Formation, Queenslantl, AustraliA, and Walliserodus n . SP a A are Zone A of Ross at Rlacksmith Fork Canyon occur with conodont Fauna abundant in conodont Fauna C Ln the Garden City Formation . C and are younger than lower Zone A at Franklin Bssin, which Cordylodans are s parsely represented in the upper part of conodont contains uppe r Fauna B conodonts. Conclusion pro·... ides some Fauna C. Where abundant, they display a wide r a nge of morphologic information about the relief of the erosional surface developed on variability, and separation of form species becomes subjective in the St . Charles Formation prior to deposition of the Garden City the large collections. Rare Cordylodus proavus .!..!.. elements in Formation in the Bear River Range. The 4 . 5 m (15 feet) of section Pauna C either represent the perSistence of this form species or with upper conodont Pauna B at Pranklin 8asin is not present at 13 14 Rlacksmith Pork Canyon. Upper Fauna 8 Is present at least through .!:!... , .!: robustns Ethington and Clark, 1964, .!.._!.:, Acontlodus the lower 11. 7 m ( 39 feet) of the Garden City at Hillyard stauffer! Furnish, 1938, .!:.!.., and ~: trlpllcatu8 Ethington and Canyon. Although boundary beds of the St . Charles and Garden CIty Clark, 1964, .!!.. •.!.. . J first appear In lower Fauna D. Lower Fauna 0 Formations are not exposed at Green Canyon, conodont Fauna C conodonts are also present In the lower Fillmore Fomation of the occurs 3.9 Ill. (13 feet) above the highest outcrop of St. Charles Pogonlp Group, west-central Utah (Ethington and Clark, 1971; Formation. A Bub-Garden City Formation surface wIth approximately EthIngton, 1979), In the lower part of the El Paso Group , west 12 m (40 feet) of relief I s present in the Bear River Range, Utah Texas (Repetski, 1975), and in upper "conodont complex II" through Idaho. The surface Is a diachronous dlsconfomlty wIth older "conodont complex IV " In central SIberia (Abairaov8, 1975) . units present at the base of the Carden City In the northern The base of conodont Pauna D may lie slightly above the base sections. of trilobite Zone D of Ross. Conodonts tentatively referred to Conodont FaunB D. --The distinctive conodont assemblage upper Fauna C are associated with trilobites of Zone D of Ross In representIng Pauna 0 of Et hington and Clark (1971) ftrst appears the basal bed of the Highgate Formation of Landing (1979) in at approxImately the same level as the baae of the range zone of northweste rn VCI1Dont. trilobite Zone D of Ross at Franklin Basin, Hillyard Canyon, and COLOR ALTERATION INDICES Rlacksmith Fork Canyon. "Acanthodus" lineatus (Furnish) ..!:!. .. J~o Conodont elements from the base of the Garden CIty Formation unc inatus Furnish ..!.o,!" , Scolopodus? parallelus (Branson and Hehl) , at BlacksmIth Fork and Hillyard Canyons and Franklin Basin have 8 ..!. ~ Lindau'8m, and Drepanodu8 concavus (Branson and Hehl) are color alteration index (CAl; see Epstein and others, 1977) among the few euconodonts to persist from Fauna C. Acanthodus corresponding to low 4. ThIs index has been associated with the unc'l.nat us persists into the lowest part of conodont Fauna D at upper thermal limit for dry gas production (Epstein and others I Franklin Basin, whereas .. ~.. ~ ..!. '.!.. persists into the lower 1977, p . 24) , and can be attributed to a norraal thermal gradient 66 m (200 feet) of conodont Fauna 0 in the Carden City at the base of known overburden [Lower Ordovician through Formation. Abundant elements of multielement Scolopodus fllosus Pennsylvanian, 4, 920 m (16,400 feet)J in the Bannock overthrust Ething t on and Clark, 1964, a nd Scalpellodu8 n . sp. A { (Mansfield, 1927). Protopanderodus1 n. sp. 1 snd !-. 1 n. sp. 2 of Repetski (l975)}, Conodont elements from the underlying St. Charles Formation mark the base of Fauna 0 in the Carden City Formatlon. Rare at Blacksmith Fork and Hillyard Canyons and Fr anklin Basin include elements of Scolopodus gracilis Ethington and Clark, 1964 [-.!' rare speciMens with a comparable CAl of low 4. However, most gracilis .!:.!: and.!. trlangularis Ethington and Clark, 1964, .!:.!:} elements from all samples from the s tratigraphic interval and.!. 9uadraplicatus Branson and Mehl 1933 (-.!' quadrapllcatus 16 15 inves tigated seem to have an anomalously high index of 6.5. and An anomalously high index of 5.5 Is present In conodont are a n opaque greylsh-whlte. This greyish-white color Is elements from the upper pa rt of the St. Charles Formation and tentatively consldeced to be due to a leaching of organic matter lowest Gaecten CIty Formation at Green Canyon. These specimens from most conodont elements durtng the dolomitization of the St. come from the eastward-dipping s hear zone In the bleachetl Charles. If the interstitial fluids responsible for fiolostones of the uppe r St . Charles And adjacent becls of the dolomit1zation can reduce the proportion of organic matter in Gluden City . F.levaterl GAl anti bleachin8 1n this section coulct be conodont elements after bur1a l and prior to heat1ng, then the exp181n~d by the passage of hot ftuttls Along the fault 7.one. color alteration index determined for conodont elements from Ilmestones (Epstein and others, 1977) may not be applicable to ACKNOWLE OGlfENTS spec imens f rom some dolostone!. Such spec imens may not become This study was undertaken during the tenure of a U.S. opaquely black. (CAI-4 ) at e levated t em peratures because of the Geolog iea I Survey-Na t 10na 1 Resea rch C:ounc 11 Pos tdoc toral rertuction in or1glnal oreani c material. Similarly, the Associateship in 1979-1980, and is part of a multidiscIpli.nary volatllizat1on of fixed carbon would produce grey and opaquely study of the paleontology. stratigraphy, and fDagnetostrR.ttgraphy white specimens (CAI- 6 and 7) at some ..... hat lower temperatures I)f Cambrian-ordovician boundary beds in the Western United States and/or over shorter per10ds o f heating than those required for a being conducted by S. L. Gillett, J . E. Repe tski, and H. E . comparable color altera tlon of conodonts from Ilmestones that did Taylor. not undergo leach1ng. A thesis by J. L. liason {1975, Conodont bIostratigraphy of Conodont elements from the upper St. Charles Formatton have the lower Garden City Formation (Lower Ordovtcian) of northern inte nsely corroded surfaces , and denticles and cusps a r e Utah: Salt Lake City, Univ. of Utah, unpub!. M. S . thesis] occasionally deeply pi tted and seconda rily reduced 1n size. contributed to the early stages of this stuay. Unpublished data Specimens from the thin-bedded dolostone forming the lowest part of Lower Ordovician conodont sequences of the El Paso Group we st of the Carden City Formation are weakly corroded by comparison, Texas, by J. E. Repetakt, 3nd at the Pogonip Group, west-central and have a color Index that Is fully comparable to that of Utah, by R. L. Ethington a nd D. L. Clark were raade available to specimens from the overlying limestones . These differences are the author in the course of this study . regarded a8 circulU8tantial evidence that corrosion and leaching of the St. Charles conodont elements are unrelated to and temporally antecedent to diagenesis of the Garden City Formation . 17 18 REFERENCES CITED Ethington, R. L., and Clark, D. L., 1971, Lower Ordovician Abalmov8, G. P., 1975, Ranneordovlkskle konodonty sredncgo conodonts of North America, l!!. Sweet, W. C. , and BergstrB", techentya r. T.eny: Trudy 51blrskogo Nauchno S. M., eds. t Symposium on conodont biostratigraphy: lssledovatel ' skogo Instltut Geologle, Geoflzlkle Geological Society of America Memoir 127, p . 21-61. Hlne Abalmova, G. P., and Markov, ye. P o, 1977, Pervye nakhodkl Cambrian-ordovlcian boundary in western rlewfoundland, in konortontov nlzhneordovlkskoy zony Cordylodu9 proavus ns yuge Rassett, H. and Dean, E. (eds.), The Cambrian-Ordovician Slbtrskoy Platformy: .!.!!.. Sokolov , V. S., and Kanygln, A. v., boundary: sections, foss'll distributions and correlation: eds., Problemy stratigrafIl Ordovika 1 Stlura Siblri: Trudy National Mu s eum of Wales (Cardiff), Geological Series 4, p. Instltut Geologie 1 Ceoflzlkle, Akademle Nauk SSSR, 98-134. Slblrlskoy Otdelenle, Novosibirsk, v. 372, p. 86-94. Hintze, L. F . , Hliler, J. F. , and Taylor, M. E., 1980, Upper Druce, E. C" and Jones, P. J . , 1971, Cambro-ordovlclan conodonts Cambrian-LOWer Ordovician Notch Peak Formation in western from the Burke River structural belt , Queensland: Australian Utah: U.S . Geological Survey Open-File Report 80-776, 67 p. Bureau of Hineral Resources Bulletin 110, 167 p. Landing, F.., 1979, Studies In Late Cambrian-Early Ordovician Epstein, A. C., Epstein, J . B • • and Harris, L. 0., 1977, Conodont conodont biostratigraphy and paleoecology, northern color alteration-- An index to organiC metamorphism: U.S . Appalachian region: University of Michigan, Ann Arbor, Ph.D. Geological Survey Professional Paper 995, 27 p . dissertation, 309 p . Ethington, R. L., 1979, Conodonts from the pre-Eureka Ordovician Landing , E., 19R2, Highgate Gorge: Upper Cambrian and Lower of the Great Basin, .!.!!. Sandberg, C. A., and Clark, D. L., Ordovician biostratigraphy and continental slope depOSition, northwestern Vermont: Journal of Paleontology, in press . eds ' t Conodont biostratigraphy of the Creat Basin and Rocky Mounta tns: Brigham Young University Geological Studies, v. Landing, E. and Barnes, C. R., 1981, Conodonts from the Cape Clay 26 , p. l-S. Formation (Lower Ordovician), southern Devon Island, Canadian Ethington, R. L., and Clark, D. L., 1964, Conodonts from the El Archipelago: Canadian Journal of Earth Sciences, v. 19, p. Paso Formation (Ordovician) of Texas and Arizona: Journal of 1181-119S. Paleontology, v. 38, p. 68S-704. 19 20 Landing, e., Ludvigsen, R., and von Bitter, P . H., 1980, Upper Nowlan, G. S . , 1976, Late Cambrian to late Ordovic i an conodont Cal!lhrian-Lower Ordovician conodont biostratigraphy and evolution and biostratigraphy of the Fr.anklinian hiofacies, Rahbitkettle Pomation, District of Mackenzie : miogeosyncline , eastern Canadia n Arc tic Islands : Univers ity Royal Ontario Museum Life Science Contribution 126, 44 p . of Waterloo. Waterloo. Ontario, Ph.D. dissertation, 591 p. Mansfield, G. R., 1927, Geography , geology, and mineral resources Repetski, J. e., 1975, Conodonts from the El Paso Group (Lower of part of southeastern Idaho: U.S. Geological Survey Ordovician) of west Texas: University of Missouri, Professional Paper 152, 453 p. Coloumhts . Missouri, Ph. O. thesis, 245 p . Miller, J . F . , 1969, Conodont fauna of the Notch Peak Limestone Richards, R. W., and Ha nsfielrl, G. R., lQ12, The Rannock (Cambro-ordovician). House Range, Utah: Journal of overthrust--A major fautt in southeastern Idaho a nd Paleontology, v. 43, p. 413-439 northwestern Utah: Journal of Geology. v . 20, p. 681-707. ___lQ77. Conodont biostratigraphy a nd inte rnational correlation RLchardson, G. 'lo. 1913. Paleozoic sect Lon tn northern Utah: acr oss the Cambrian-ordovician boundary: International Amer.ican Journal of Science, 4th Series, v . 36. p. 406-411;. Geological Congress, 25th, Sydney. Ab stract s , v . 1, p. 274. Ross, ~. J •• Jr.. 1949. Stratigraphy and trilobite faunal 1.:ones of ___197~, Upper Cambrian and lowest Ordovic ian conodont faunas the Garden Ci ty Formation, northwestern Utah: American of the House Range, Utah, .!!!. Hiller. J. F .• ed •• Upper Jour nal of Science, v. 247. p. 472- 491. Cambrian to Middle Ordovician conodont faunas of western ___ 1951, Stratigraphy of the Ga rden City Formation in Utah: Southwest ~is8ouri State University Geoscience Series, northeastern Utah , and its trUobite faunas: Yale no . 5, p. 1-33 . University, Peabody ~useum of Natural History Bulletin 6, ___1980, Taxonomic r evisions of some Upper Cambrian and Lower 155 p. Ordovic ian conodonts with revisions on their e volution: ___1953, Additional Garden City (Early Ordovician) University of Kansas Paleontologica l Contributions, Paper 99, trilobites: Journal of Paleontology, v. 27 , n. 5. p. 633-646. 39 p . ___1968, Brachiopods from the upper part of the Garden City Muller, K. J •• 1973, Late Cambrian and Early Ordovician conodonts Formation (Ordovician), north-central Utah: U. S . Geological from northern Iran: Geological Survey of Iran Report 3, Survey Professional Paper 593-n, 13 p •• 4 pls. 76 p. Stitt, J. H. , 1971, Cambrian-ordovician trilobites, weste rn Norford, H. S., 1969, The Early Canadian (Tremadocian) trilobites Arbuckle Mountains: Oklahoma Geological Survey Bulletin 110, Clelandia . Jujuyaspis from the southern Rocky Mountains of 83 p. Canada: Ceo10gica1 Survey of Canada Bullettn 182, p . 1- 15. 11 22 Figure Captions Stitt, J . H., 1977 , Late Cambrian a nd earliest OrdovicIan trilobites, Wichita lIountalns area , Oklahoma: Oklahoma Geologi cal Survey Bulletin 124, 79 p. Figure 1. Index map of northern Utah and southeastern Idaho Wi lliams , J . S., 1948, Geology of the Paleozoic r ocks, Logan showing location of strat l graphic sections, sampled for Quadrangle, Utah: Geological Society of America Bulletin, v. conodonts . 59, p . 1121-1164. Figure 2 . Correlation ..tnd local range zones of selected Winston, 0 . , and Nicholls, H., 1967, Late Cambrian and Early euconodonts from the upper St. Charles and lower Garden City Ordovician faunas from the '''''ilberos Formation of central Formations at Franklin Basin, Fr anklin County, Idaho. Figure 3. Corr elation and local range zones of selected Texas: Journal of Paleontology , v. 41, jJ. 66-96. euconodonts from the upper St. Charles and lower Garden City Formations at Hillyard Canyon, Fr anklin County, Idaho. Figure 4. Correlation and local range zones of selected euconodonts from the upper St. Charles and lower Garden City Formations at Green Canyon, Logan County, Utah. Figure 5. Co rrelation and local range zones of selected euconodonts from the upper St. Charl es and lower Carden City formations at Blacksmith Fork Canyon, Logan County, Utah . 23 Figure 111· t.:TAH ' Ibex 1 o 30 ItII.OMET1:115 1 __'------J 1 I 1 I Franklln Basin !~ IDAHO 1- ---,.L------~~/ HIllyard UTAH I> Canyon .3 • /Grten Canyon I - Logan / ~k~ lS I lJI>pet C... bolan 11*11 I lo_ OodoVOWl IPllII SYSl£M I C.oI ..... 11*11 : ~IPIIII SERIES I T'"",pelleau.n 11*11 I STAGE 51. c.n.1e. Fotmauon IPIIII G.tden Crty Fotm IOfI IPllII FORMATIOfII CONODONT COfdylodu, FlUna 0 -f. Ploavu. =IJ fluna C I ZONES CONODONT C C~=""• I". . ZONES 0 0 0 0 0 00000 00000 0 0 0 0 0 00 0 2 :'I ~ ~ i z ! ~ j ~... ~ SAMPlE NO. n ~ n ;; n n nnl'iw ~.~ nnnn~!' n n ;; l ~ l ~ ~. 0 0 0 0 0 0 00000 0000 0 0 0 0 0 0 0 00 0 c...... ,,.,..,.. ... ~ •I "". ,.,"' . -...... 0"".,..,., .... , I I c"'~ .t .ft ...... '" •• O-fol..-bd ...... , I COfCf.,t04-w-. o'WtoM"".... t I c- o "...,. .1 i C,, ·J~INI Pf'MfJIW' It I , , , , I ' .... o~h' . "'6Ieh"..-" ,., ., , I , r. ttdIcM, w " ~ eMWI''' I I A,.,.. ., ... 'v• I Cl~ OrJf04.,.. · '~ • m •• I en AceftflwHl. .. .t , , , -_ t 0 S. ""1'04". PI"""" I ." H •• I ;---- n , 0 IA ."" I ~ UfMc:""' ..-UIHI I 8 , ,-- I , ~ Pot,.., ' . I H .... A en "tW . "V r m P""_4• ..., •• .".Mf',rtrttl I , n I in SrMIDC.,.,bd." '" ~ en Ur ...."...... I .. - , , , , , ,--",d.o J ,. to A I , I W"thOdw. " . p A . o.~ ... co~ --l $c_ rt .. A $(010,04.,,' .610 .". • t I I w ;;: ..Oil ..IS .. 0 .. S i :i i a ~ s ~ S .. :!II SCALE 0 w ~ ... I!: .. • i ~I Lower Ordu FaunA 0 ; i; :::;:::'':;'' .!. ~J I, I " ~/ ' ~ •• .., .. , I , t------.....-----or---- ....------1 ... ., J,s.-. l"tL.-.-.... " 1------______...... ,_/ ~.J,.. 70 1------" ~I . , .. . ".,....". . ' OJ r .. _ _ t ...... - ~ ...... , ..... :::J LC t'D U'l _ ...... 1 9.., n 0 ·,.a . It . rI~ . · .,,- - . :J __ ,.. w·l.I 1------' I 0 - . ~. " ... ~ • ...J ...... ~&l-~-•• -.-.------!,...---.....-- ...... ------; I : (L- 0 I ::J .. ., ,-..,-. ..., ------....---'---+------.... ("1- I, .. '1 "/-#". , ~ ¥ " I ~! ---~--~-----~--~ . '4 .,,..,J, • .. !." '" I' {f'\ I .;;;,-,.__ 4 ,...... , -r------ -0 # "!u.J.~" ••,._ (1) ~ ... ~...... ,., '" n '~~.. . ·I.I •• .,. ID .~ .,..,I... ·~, ... .. t ... - 11I - ....'l] \.Q C 1'1 (1) W Upper Cambrian (part) I Lower Ordovician (pilI) SYSTEM I C'oixan (parI) I Canadian (part! SERIES I Trempe eauan (parI) I STAGE I ,Garden City Formation 51 . Chatl Formalion (part) FORMATION , (parI) , F...... C CONOOONT PtllCDt>OdwlIU. , Cotrlylodu. /lI""'''' I It~ trow. p ... ' ZONES I I ClrIoIwnuIu. CONOOONT I r ~II' SU8Z0NES !! ..s !! !! S s !! SS S SAMPLE NO. ~ i B S B ft ft I a Bft ft I I ~'~UI ,• I • I ".""_,11. '''"'I I I COIrIy"',d'" *,guletll' , I. I I II I I Cotrly/odul inl"'".....,. , I. , I II I I Cotrlylodu, o.-..nSd ,,. ! , I II I , Cotrlylodu, /lI1OII 11. I ! I , , I Cotrlylodu. /liM-II' s.J. r I I I , , , Eo CONODONt C,.. d~.j"du~ raunl c rlUn. 0 Prfttonodon'uJ '''()f10UJ ZONES , , Ii , , , , 0 0 0 000 0 0 0 0 0 o w w www w w ... w SAMPLE w w ...~ N 0 0 0 NO. § ... w ~ i n• n En ... n n n n n ~~~ n o 0 0 0 000 0 0 0 0 0 C",d~d". ongulol .., 1.1 . ~ I Cn,d~d, ..... ",m' Tmngulodu. 7 n: 11). A t I I ~ (I) W",. erod... n. "~ . A I I '\J I mn in I ~ (I) I I ~ I 0 "'l I "Smlnpod'''' !1m fit. .... I "S<''''''pnd"o- quod,oplkolUI I 10 c: I I t1 , I ro I I U1 I I ... Col N ~ ... g (I) ~ § II' ~