Volume 42rr. 1-212003

rssN 0375 7633

Bollettinodella

Societn Paleontologic aItalianaPubblicato sotto gli auspicidel Consiglio Nazionale delle Ricerche

MUCCHI MODENA

Bollenino della Societh Paleontologica ltaliana 42 (r-2),2003rssN 0375-763339-47 I pl. Modena, Giugn o 2003

Conodont biostratigraphy of the Norian-Rhaetian (

in the Northern Calabria: the Valle Corvino and G:

Adelaide MnsTANDREA Edoardo PEnRI Claudio NEzu Franco Russ<

Dipartimento di Scienze della Terra- Universith della Calabria

KEY WORDS - Conodonts, Biostratigraphy, Basin fupositt Norian, Rhaetian, Northern

ABSTRACT - The present paper deals with the bio-chronosnatigraphy of the Upper Triassi'has been carried out through thi conodont biostratigraphy of two setiloit Uille Coiiino and Gthe Triassic basinal successions Dertaining to the Verbicaro Unit Auct.

The sections yielded threeTisilnct iororypicfaunas of Norian and Rhaetian age, rePresentean.sp. C populatiSn Orchard, 1983; it has Ot:t"fo"nd in'the lou,erpart of theValle Coruino sectartorait bktftrm; it allows to refer the upper part of the Lower Unit i U;d-elaunian; b) Eyy'y Kouacs,' 1i86; it occurs through krge firt i1 tlrc Valle Coruino section, within tbe. Uppt, iSeuatiau d Misikella postherns-teini

"Kozur 6 Mock; it occurs in the lower Part of the Grisoli,

marks the base of the Rhaetian Stage.Therefore, in this sector of Nirthern Cakbria, it has been possible to date accurately the

platforms.' J The monotypic,nAture of the ft""f: o?d the preynce ofl,. slovakensis suggest that the st

innaplatfor* trough characterized by disoxic to anoxic conditions.

RASSUNTO - [Biostratigrafia a Conodonti dei depositi norico-retici della Calabria serGrisolia) - Il presente lnuoro a-'rn connibuto alln bio-moiostratigrafa dei terreni dzl Trias sup,(Uatt" Coruini e Grisolia, Cosenz,a), complessiuamente raPPresentitiie dcllz successioni bacinali'n'hanno

fornito faune a conodonti di eth nbrica e retica. Dil basso uerso l'aho si succedono: a) un inOrchaid t 983, indicatiua dellAkuniano medio, ritrouata nei depositi sia di bacino che di scarualh caratterizzato dnlk Dresenzn esclusiua di Episondolella slovfuensis, A uolte molto abbondniinteruallo con Misikella posthetnsteini, indicatiia del Retico, preceduta, in continuith snatigradatare con Drecisione le siccessioni di bacino e lz conektiue piattaforme carbonatiche di questi se

Inoltt, il carattere monotipico delle faune e k presenra di E. slovaken sis indicheiebbero,nale "stressato", piil probabilmente rapprisentato da un solco innapiattaforma che non da un m

INTRODUCTION

This paper is a contribution to bio- and chrono-stratigraphic knowledge of the Upper tiassic(Norian-Rhaetian) basinal successions cropping outin the northern sector of the Catena Costiera(=Coastal Range) of Calabria (i.e., Grisolia and ValleCorvino, Cos enza; Text-fig. I ).

A preliminary reconstruction of the geometric-stratigraphic relationships between Upper Thiassicbasiriatd ."tbonate platform deposits hit been pro-posed by Per ri et al. (in press): this proposal, based onihe analysis of several

-stratigraphic sections, partly

still undlr study, is here adoited to show the orret"ilstratigraphic setting of the rwo sections object of the

present paper (Text-fig. ?.ry9 maf or units, more or

Iess corresponding to depositional sequences, havebeen identified within the Norian-Rhaetian succes-sion of Northern Calabria:a) the Lower Unit, characterized by high-relief, pro-

grading carbonate platforlrlS, laterally gradi.g into

toe-of-slope and basin deposits through high-angle (25-30') slopes;

b) the Upper Unit, mainly consistitg of deep-waterlime mudstones and turbidites, laterally gradinginto minor shallow water back-stepping carbon-ates; it records an abrupt change in pafeogeography,as. significant sectors -of .the platform domain per:talnlng to the Lower Unit are drowned and coveredby baslnal deposits of the Upper Unit (Text-fi g. 2).

A formal lithostratigraphit^ classification fo; thedifferent carbonate depbsits involved in the abovequoted informal units ii still lacking; possibly, it willb. defined in future, in the contex"t of th. nationalproject of gelogical mapping at the scale 1150.000(CARG Project).

The studied successions are included in the majortectonic-stratigraphic unit known as Wrbicaro Unit(sensuAmodiJMorelli et al., 1976), comprising sedi-mentary deposits ranging in age from Late Thiassic toEarly Miocene. Accoiding to Authors, such unit tec-tonitally overlies the sJ-called San Donato Unit

study area

qe?

{rrrhen\af

"

" o o o ^ o

. G r i so l i a

Gr i so l i a sec t .

i _ , ^ _ , : ^ ^ , - M . C a r p i n o s o; T.E Salice

- { l: t- \' t

o

?g)a

aog)

Buonv i c i no

D iaman te

40 A. MASTANDREA et al.

(Amodio Morelli et al., 197 6; Ietto 6c Barilaro, 1993;Iannace et al., 1995), in turn constituted of phylliticmetamorphics interpreted as Mid-Ti"iassic terrigenousdeposit, and of -L,"-.arbonates and .rr"potTt., ofCarnian age. It is, however, to point out that the con-tinuiry between the Ladinian-Carnian (San DonatoUnit) and the Norian-Rhaetian (Verbicaro Unit) car-bonate deposits of Northern Calabria was previouslyhypotized-by Grandjacquet (1962) and subsequentlystated by Iannace et al. (1995).

The Upper Triassic carbonate deposits, belongingto the Verbiiaro Unit, have been formerly reported byGrandjacquet & Grandjacquet (1962) as

" Trias

Dolom:itique" and by Damiani (1970) as " Dolomie

scure" (= d"rk dolostone); moreover, they correspondto the so-called

" dolomie nere o grigie del Trias fossili-

ftro" (=black to gray Tliassic fossil-bearing dolostone)of Iett o et al. (1992) .

The uppermost part of the Thiassic succession(Verbicaro Unit) is characterized by the repeatedalternation of grey limestone and yellowish to redshale and marls" and may be referrel to the GrisoliaFormation sensu Damiani (1970).

The age of the "dolomitic"

units (mainly repre-sented by -arbonate platform deposits) has been tradi-tiondly referred to the Norian-Rhaetian interval, onthe basis of benthic fossils (megalodontids, foramini-fers such as Triasina hantheni, tI. dasycladacean Gry-phoporelln curuata) (Climaco et al., 1995; Posenato 6{letto, 1995; etc.). The Grisolia Formation was in turnreferred by Damiani (1970) to the Rhaetian-EarlyLiassic times on the basis of scattered benthic foramsincluding Triasina and some liassic taxa.

Befo"re the present work, reporting the first resultsof a research project on bio-chronostratigraphy ofUpper Thiassic deposits of Northern Calabria andLucania, only rwo papers have been published on

Text-fig I - Location-map of thestudied stratigraphicsections.

conodont stratigraphy in Calabria, based on sectionscropping out il in. tectonic windows of MonteColuzzo (Mastandrea et dl., 1997) and MonteLucerna (Mastandre a et al., 1998), south of Cosenza.Conodont assemblages from these areas, the lowerone dominated by Epigondolella slouakensis, the uppercharacterized by MisiEella /ternsteini and M. posthern-steini, indicate respectively the Norian and theRhaetian stase. The occurence of Misikella ultima inthe Fosso Pi'ntanelle section (Monte Lucerna area)also records the occurrence of Late Rhaetian deposits,suggesting the possibi l i ty to invest igate thetiassicf urassic bo undary.

DESCRIPTION OF THE STRATIGRAPHIC SECTIONS

The two studied stratigraphic sections representalmost completely the *ho'ie basin succession of theLower and Upper Units (Text-fig. 2); they crop outrespectively:a) itr the valley of Corvino river

(Text-fig. 1), near the vil lage(Cosenza);

b) near the village of Grisolia, rype-localiry of thehomonimous formation designated by Damiani(1970) (Text-fig. 1).

Both areas are affected by polyphasic tectonics,responsible for a strong deformation. However, it islocally possible to reconstruct quite continuous tractsof the itratigraphic succession, as in the case of thestudied sections. Minor tectonic disturbances havebeen omitted or, if possible, restored.

Vnlr-E ConuNo sECTIoN (Text-figs. I and 3)

It consists of toe-of-slope and basin carbonate(mainly dolomit ic) deposits, includitg dolotur-

(Valle Corvino)of Buonvicino

CONODONT BIOSTRATIGRAPHY OF NORTHERN CALABRIA 4 l

tr.gf

oostr

:c:)L

occf

5lo t l-ll

Gr i so l i a

Va l le Corv ino

tro

a-

L

o-L

oCLCt=

a:

tr=L

o'o

J

7 0F,Z

gEE t r

= €i . o='zotrl

Text-fig . 2 - Simplified sketch of the geometric-stratigraphic relationships between basin an,lia area (Northern Cdabria, Cosenza). Not to scale. Key: A) basin deposits o

:ff ff irii:1#ffi8ffi'3,;?$:*:r;:'"'#:l';,lTii?H*?ti:U':ping carbonate pladorm; G) himipelryic dep6iits (Grisolia Formation).

bidites, debrites and deep-water lime mudstone (nowdolomitized); in the higher part of the valley, it over-lies a rhauwacke body, possibly Carnian in tge,referred to the San Donato Urrit; unfortunately, witerecent covers and tectonic deformation prevent adetailed analysis of the bound ary.

The lowermost tract of the section (0-45 m) is veryrich in doloturbidites and contains layers ofbreccia/megabreccia with platform-deriving clasts. Anoverall coarsening-thickening up trend suggests that itis lateral to a prograding carbonate platform (i.e., thehigh-relief plaiform pert-ainirg to the Lower Unit).

On the contrary, the followirg tract overlyirg thewide recent cover (45-120 m), is dominated by darkdololutites with thin fine grained turbidites andsparse debrites mainly consisti.g of rerycled basindeposits. Locally, thin dark pelite layers, a few cen-timetres thick, may be intercalated within the inter-vals dominated by thin turbididites and dololutites.Also the amalgamated coarse turbidites and/ordebrites occurri.g at 160 m, 190-210 m and 340-370 m, consist to a large extent of basin-derivedgrains or clasts. The faci that most of graviry-dis-

filaced deposits consist of recycled basinal"sediments,suggests a guite ab,rupt lateral shift of the plaformmargin, ?nd possibly the partial drownirg of the pre-vious carbonate plaform system.

For this reason, we reFer the tract of the sectionabove the cover (45-120 m) to the Upper Unit (Text-fig.2), with an uncertain boundary placed within thecovered interval.

No apparent trend seems to be observable in thebasin deposits of the Upper Unit; only the tracrbetwee n 410 m and 440 m is characterized by " distinctthinning-up trend, which may record increasirg depth.

At abo w 440 m a marked increase in pelitic con-tent, the occurrence of meter-thick horizons of yellowto reddish marls and shales, the progressive replace-menr of dolomitic turbidites by cilcilutites, -aik thelower bound ary of Grisolia Formation; only the lower-most part (about 20 m) of this formation has beeninvestigated.

GzusoLI.A sECTIoN (Text-figs. I and 4)

The sampled part of the section, reported in Text-fig. 4, is representative mainly of the GrisoliaFormation, characterized by fine grained, usually thinbedded limestones alternated to yellow-red marls andshales. Debrites and slumped deposits are occasional-ly intercalated in the lower part of the formation; theupper part (about 45-50 m thick) is characrerized byreduction in pelite layers and contemporaneousincrease in fine grained' limestone, locally stronglyrecrystallized.

The lowermost part of the section (r'tp to about I 8m) is represented by a dolomite-dominated intervalwith thin fine srained turbidites alternated to dololu-tites, that *"y"b. referred to the pre-Grisolia basinaltract of the Uqrper Unit,(Text-fig. 2). V"fb{tunately,the bound ary berween the two formations is of tec-tonic nature (Text-fig. 4), although the fault deter-mined a relatively small displacement.

CONODONT ASSEMBLAGES AND BIOSTRATIGRAPHY

As previously stated, the biostratigraphy of theCorvino-Grisolia areas is mainly based on conodonts.Ammonoids and other fossils, regarded as importantstratigraphic tools, are missing. However, an isolated

42

F

z z

z

t

tU

(L

IL

f

z

tzftUJ=oJ

A. MASTANDREA, et al.

cR 17

cR 16

cR 15

cR 14

cR 13

cR 12

cR 11

cR 10

c R 9

c R 8

c R 7c R 6

c R 5

c R 4SPD 4c R 3

c R 2

c R 1

co2SPD 2

1.ec4so{goco

so

€so.g)urq

/t/

^z

\_ 11

A 1 0- 9

o - b Q^ , s e ^ a

o a b o ( l

1 51 41 31 2

%

Text-fig. 3 - Vdle Corvino section.Key: I ) coarse grained, ruditic tur-bidites, with Sasin-derived clasts;2a) coarse to medium graineddoloarenitic rurbidites; 2b\; fine-grained doloturbidites; 3) stronglyrecrystallized carbonates (mainlydolomit e); 4) lime mudstone (cd-cilutite or dololutite); 5) marl andshale; 6) slumped deposits; 7) poly-genic carbonate breccia; 8) coveredtract; 9) erosional surface; l0) plat-form clast or megaclast; I I ) slump-scar; l2) slump;11) skeletal grainsin general; 14)fault; l5) chert; 16)coirt.-crystalline dolostone; 17)dololutite; 18) marly dolostone;19) doloarenite; 20) dolorudite;2l) calcilutite; 22) calcarenire; 23)shale and ma rl; 24) alternation ofdifferent litorypes.

I

7

6

54

Eo

.C,gof,qsoq

Ociac

sg€so.9uJq

Ic o 1SPD 1

CONODONT BIOSTRATIGRAPHY OF NORTHERN CALABRIA 43

and occasional finding of a monorypic ammonoidfauna (belonging to genus Didymites Mojsisovics, F.Bizarrini, pers. comm.) has to be quoted from innerplatform sediments of the Lower Unit (Perri et al., inpress). Thtr fipdi,ng indicates an age.compatible withthe coeval basinal sediments: Didymites sp. indicates anot precisely defined lower part of the Norian stage.

Althoueh isolated conodont-bearing samples(BV41) haie been collected from the platFor- tfop.of the Lower Unit (Text-fig. 2), the biostratigraphicstudy has mainly been carried out on the basin suc-cessions: Valle Corvino and Grisolia.

Vru-m ConuNo SECTIoN

Twenry-rwo samples, each about 6 kg in weight,have been collected from the Valle Corvino section.About 2000 specimens were obtained by dissolutionin acetic acid with the standard method.

Platform elements have been found in associationwith ramiform elements, dominated by enanthio-gnatiforms, often incomplete or broken.v

The lower paft of ih. section (samples SPD 1,COl, SPD2 andcoz) (Text-fig.3), as well as an iso-lated sample from the slope of the adjacent carbonateplatform (Te*t-fig. 2), yielded a conodont fauna char-icterized by Ep&o"do'lella n.sp.C Orchard (see sys-tematics remarks) corresponding to the ColumbianusZone (Subzone I) of Middle Norian.

On the basis of the Tethyan biozonation it is pos-sible to correlate the Columbianus Zone of Canada tothe Tethya n Himauauites hogarti Zone, correspondingto the Alaun ran 2 of Krysryn (rn Zapfe, 1983).

The same association has been reported in theAlaunian 1 and 2 by Krysryn (in Gallet et al., 1992)from pelagic limestones of the Bolucektasi T.p. sec-tion (S\f Tirrkey).

Therefore, the interval including samples SPD Ito CO2 may be referred to Alaunian p.p.

Samples CRI to CR14, pertaini.g to the basindeposi,r olrh: Upper- Uli, if.ry-figl i, yielded amonospecrfic fauna^ referable to Epig6ndolella slouak-ensis (Kozur) emend. Budai & Kovacs, 1986. Inupper view the Valle Corvino specimens show all thedistinctive features of the Epigondolelk postera popu-lation of Orchard ( 1 983, pp. l Se- I 88), bnly differingin the abrupt break of the blade on the low posteriorcarina.

Budai 6{ Kovacs ( 1986) and Kovacs & N"gy( 1989) described E. slouakensis from the ReziMountains and Pilis Hegiseg respectively in theBalaton Highland, western Hungary. Accorditg tothese authors E. slouakensis ranges from the UpperAlaunian to Sevatian.

Kozur (1972; 1989) and Kozur 6c Mock (1991)consider Epigondolella slouakensis restricted toSevatian: its occurrence marks the upper part of theE. bidentata Zone and its disappearance coincidewith the base of the Misihelk hernsteini-Paruigondo-

lella andrusoui Assemblages Zone (sensu Kozur 6cMock, 1991) .

Amodeo et al. (1993) reported the presence ofthis species in the Late Sevatian of the LagonegroBasin (Southern Italy).

\7e refer the interval CRI to CRl4 to LateAlaunian-Sevatian, followitg Budai & Kovacs (1986)and taking into account thJ chronostratigraphic dis-tribution

"of the underlying EpigondolelTa ;. sp. C

population.The samples CRl5, CR16 and CR17 from the

upper part of the section, are unfortunately barren,""d therefore the bound ary between Norian andRhaetian can not be recorded in this section.

GrusoLrA sECTroN

Twenry-six samples collected from Grisolia sec-tion yielded stratigraphic"lly significant conodonts.The ir.r.r.. of tlie iulitiktlta t7*stuini (Mostler) inthe sample GR3 indicates, in absence of Misikelk post-hernsteini, a Late Norian (Suessi Zone)(Mostl er it al.,1978; Gazdzich et al., 1979; Kovacs & Kozur, 1980).

Krysryn ( 1980) and Golebiowski ( 1986; 1990)reported this species in the Lower Rhaetian(Stuerzenbaumi Subzone) of the Zamblach Marls andKossen Beds (Northern Calcareous Alpt) (in fact, itsrange partially overlaps the range of

-Misikelk post-

lternsteini).Misikella posthernsteini (Kozur & Mock, l99l )

occurs in the iample GR4 and continues up to sam-ple GI10a. This species is cosmopolitan: it has beenieported from Euiope (Kozur & Mock, 1974; l99l;Mostler et al., 1978; Gazdzicl<r, 1978; Gazdzicl<r etdl., 1979; Kovacs 6( Kozur, 1980; Krysryn, 1980;1988; Golebiowski, I 986; I 990; Gul lo, 1996;Mastandrea et dl., 1997; 1998), Japan (Isozaki 6(Matsuda, 1982), Australia (Nicoll S( Foster, 1994)and Nord America (Orchard, l99l:' 1997).

Although the base of the Rhaetian Stage has notyet been dEfined, in Europe the appearance of theMisikella postlternsteini represents an important strati-graphic datum for the Norian/Rhaetian boundary. InF".i, accordirg to Kozur 6c Mock ( l99l ), it tepre-sents the marker of the base of the Rhaetian stage.Unfortunately, this species, being rare in NordAmerica, .".rttot be th. right rt."t-igraphic tool fordefining the base of the Rhaetian stage worldwide(Orchard, 1997).

Samples from GI I I to GI 16 are barren in cono-donts.

The last 60 m of the section (samples GI I lA toGI16) are characterized by an association of

"coni-

form elements" of doubt systematic attribution.All conodonts from Valle Corvino and Grisolia

sections have thermal maturation values of CAI 5,5(Epstein et dl., 1977), indicating exposure to temper-atures no higher than 480"C. The same values of CAIare observed in the

"coniform elements" up to the

44

. G l 1 6

. G l 1 5

. G l 14

. G l 1 3

. G l 12b

. Gl 12a

. G l 1 2

. G l 1 1 b

. G l 1 1 a

. G l 1 1

. Gl 10a

. G l 1 0

. Gl 9a

. G l g

. G l g

. G l 7

. Gl 6b

. Gl 6a

. G l 6

. G l 5

. G l 4

. G l 3' G r 2

. G l 1

. G R 4

. G R 3

Text-fig. 4 - Grisolia section. Symbols as in Text-fig. 3.

sample GI15, whereas the "coniform

elements" insamples GIIS and GIl6 have a CAI 7 indicating atemperature ranse berwee n 490"-720"C. This hieherCAI values "r. g".nerally correlated with rocks "ff..t-ed by regionaf metamorphism, contact-metamor-phism, orTrydrothermal aciiviry. fu the upper part ofihe Grisolia section is apparently continous from astratigraphic point of view, *e beiieve that th.- abruptincrease ln CAI may be due to a local thermal everit.

SYSTEMATICS REMARKS

Eprco'u"?f,',T;l il;, I

o'chard

1983 Epigondohlkn. sp. C Orchard, pp.185-186, Figs.9B,C,G;10,12C,D,2; l5M,N,O.

Remarks Some specimens display e distinctlyasymmetric platform in which one -"tgitt is,later qllyexpanded at^ midlenght and an irregul"", ol'rtline du!to outgrowth of stroilg -"rginal ,to{.r. In associationwith ,[.r. elements o"thers"sho* a squat and rectan-gular platform with a bifurcate basal scar and are veryIi-il"t (homeomorph) to Epigondolelk triangukris (-E. abneptis subspecies B Orchard, 1983). However,the rypital specimens of E. triangukris usually displaya more symmetrically developed anterior part and ̂more -"rk.d bifot."tiott of the basal scar.

This fauna is comparable to that classified byOrchard ( 1983) as Epifond,olelk n. sp. C populationin the British Columbia ('Western Canada) and sub-sequently referred, in large part, ro Epigondolelk sPi-culata (Orchard, l99l ). In particular this species isthe nominal species for the E, spiculata Zone(Orchard, l99l i, corresponding to thb ColumbianusZone (Subzone I) of Middle Norian.

CONCLUSIONS

The rwo studied sections show three distinctmonorypic faunas, represented, in the stratigraphicorder, by:

A. MASTANDREA et al.

ocoEootrL

ora-.Eoo

3

:EocnEo€qoa.

=

oca

Eo€=

a

Figs I-3, 5

Figs 4,6-7

Figs 8- 10

Figs ll-14

EXPIANATION OF PIATE 1

Episondolelk n. sp. C Orchard, 1983.t,l5) lower viewi of specimens showing a bifurcate basal scar, (1) BV4l,x75, (5b; COl,BV4I, x75, (5a) COI, x75; 3) la terd v iew, BV4I, x75.

Epigondolelk shaakensis (Kozur) emend. Budai & Kovacs, 1986.4,6\ upper views, CR4, x 90 ; 7) lower view, CR8, x 90.

Misikelk hernsteini (Mostler, 1967).8) lateral view; 9) upper view; l0) lower view, CR3, x 180.

Misikelk posthernsteini Kozur & Mock, 1974.11,13) lateral views; 12) lower view; 14) upper view, GI2, x 180.

A. MASTANDREA et al., CONODONT BIOSTMTIGRAPHY OF NORTHERN CAL Pl. I

46 A. MASTANDRM et al.

a) Epigond.olella n. sp. C population Orchard, 1983;if hls been found in the Valle Corvino section, inthe basinal deposits of the Lower Unit as well as inthe upper slop^e of the adjacent carbonate platform;it alldws to t.f.t the upper part of the Lorver Unitto Mid-Alaunian;

b) Epigondolelh slouakensis (Kozur) emend. Budai 6.Kovacs, 1986; it occurs through large paft of theCorvino section, within the bisin dlposits of theUpper Unit, below the boundary with the GrisoliaFormation; followitg Budai & Kovacs (1986), irtchronostratigraphic range may be referred, in thestudied section, to the Late Alaunian-Sevatian;

c) Misikelk posthernsteini Kozur 6( Mock, from thelower pari of the Grisolia section (Text-fi g. 4); thefirst appearence of M. posthernsteini is a few metresbelow the bound ary with the Grisolia Formationand it is preced ed by M. lternsteini, occurritg in asingle sam.ple. l"_l]"wing :h: chronostratigraphicint-rpretation of Kozur & Mock (192I), M. Posth-ernsteini marks the base of the Rhaetian stage.Therefore in the Grisolia section the Norian-Rhaetian boundary falls between the samples GR3and GR4.

A similar succession of conodont faunas has beenreported bv Mastandrea et al. (1997; 1998) from ar.Ltor of

'the Catena Costiera located south of

Cosenza (Monte Cocuzzo, Monte Lucerna); also inthese areas the Upper Norian deposits are character-rzed by " monorypic E. slouahensis fauna, upward fol-lowed by M. posthernsteini; moreover, in the MonteLucerna area (Fosso Pantanelle section) the LateRhaeti an Misikella uhima Kozur & Mock also occurs,within a basin succession, roughly correlatable to theGrisolia Formation, named

"LJpper Sedimentary

Complex" by Ietto & Ietto (1998).Unfortunately, great part of the Grisolia section is

barren or characierLed 6y "coniforms"

of uncertainsystematic attribution and unknown chronostrati-graphic mean_ing; it is thus not possible to attest theoccurrence of LIte Rhaetian in the studied area.

The above reported conodont faunas also allowsome paleoecological-paleogeographical considera-tions. A great part of Norian basin to slope depositsof the Citena Costiera are marked by t monotypic,long-range E. slouakensis fauna, frequently represent-ed ltr thE samples by a very large number of speci-mens. This contrasts with the preliminary dataachieved from Lagonegro basin, *h.t. the

"Calcari

con selce" (cherry-lime-stones) yield more diversifiedconodont assemblages.

Kozur & Mock"( 1991) stated tha t E. slouakensis isrypical of restricted basins. Roghi et al. (1995) report-id, E. slouakensis from the Dolomia di Forni (Carnia,Northern Italy), deposited within an intraplatformtrough characierized by disoxic to anoxic conditions.Mosi probably, this interpretation may be suitablealso for the Norian basins of the calabrian CatenaCostiera, as it is confirmed by the biofacies of adja-

cent carbonate platform, dominated by microbialcommunities and very poor in skeletal metazoans,with the remarkable .*..ption of monorypic mound-builders sphinctozoan and serpulid faunas (Perri etal., in press.). It is to point out that the coeval car-bonate- platforms flanking the Lagonegro basin arecharacterired by ^ much itot. dive"rsifiA assemblageof frame-builders skeletal metazoan, to confirm thefully marine character of this basin (Iannace &Zamparelli, 2002).

On the contrary, the genus Misihelk has beenreferrei by Kozur & Mo.!. (199.1) lo lT op.n, pelag-lc manne setting. This paleoecological interpretationis not in contrast with the above reported considera-tions: the trend observed in the uppermost Norian toRhaetian deposits of the studied aiea is indicative ofa significant-deepeni.g, that may account for a moreopen manne envlronment.

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(manuscript receiued December 30, 2002accepted January 27, 2003)

Adelaide MRSTnNDREA

Edoardo PERRT

Claudio NEzu

Franco Russo

Dipartimento di Scienze della TerraUniversiti della Calabria

87036 Arcavacata di Rende (Cosenza), Italy

CONODONT BIOSTRATIGRAPHY OF NORTHERN ULABRIA