Bollettino della Società Paleontologica Italiana 37 (1), 1998 ISSN 0375-7633 3-39 5 pls. Modena, Luglio 1998
Toarcian stratigraphy of the Colle d'Orlando section (Umbria, Centrai Italy, northern Apennine)
Guido PARISI Angela BALDANZA Luca BENEDETTI Emanuela MATTIOLI Federico VENTURI Dipartimento di Scienze della Terra, Università di Perugia Stefano CRESTA Servizio Geologico d'Italia Roma
KEY WORDS - Biostratigraphy, Lithostratigraphy, Ammonites, Calcareous Nannofossils, Early-Middle jurassic, Northern Apennines, !taly.
ABSTRACT - A detailed biostratigraphic study based on ammonites and calcareous nannofossils was carried out in the Colle d'Orlando section (Centra! ltaly). This succession is characterized by a regular alternance o/ marly and limestone levels, Toarcian in age. Fifty seven Ammonite assemblages belonging to seven biozones, seven subzones and one biohorizon were recognized. They comprise all the Toarcian Standard Ammonite Zones with the exception o/the Bonarellii Zone. The ammonite assemblages exhibit a Mediterranean affinity. Severa! calcareous nannofossil events are recognized in the Late Domerian to Early Bajocian o/the Colle d'Orlando section and some con- siderations regarding the assemblaf{.e composition and preservation state are presented here. The continuous and relatively abundant record o/ ammonites and calcareous nannojossils allows far an integrated biostratigraphy and a precise correlation o/ calcareous nannofossil events to ammonite biohorizons.
RIASSUNTO- [Stratigrafia della sezione Toarciana di Colle d'Orlando (Appennino Umbro-Marchigiano, Italia Centrale)] - Nel pre- sente lavoro viene analizzata la successione giurassica di Colle d'Orlando ubicata nel Bacino Umbro-Marchigiano nel massiccio del Monte Cucco. La successione è costituita da un'alternanza di calcari e marne e da sedimenti argillosi nella sua parte inferiore. Si succedono con continuità dal basso verso l'alto tutte le unità giurassiche tipiche del bacino Umbro-Marchigiano: l'unità calcareo silicea della Corniola (Sinemuriano- Pliensbachiano), la Formazione marnoso-argillosa delle Marne di Monte Serrone (Toarciano inferiore e medio) all'interno della quale sono riconoscibili livelli pelitici scuri finemente laminati ("black shales" del Toarciano inferiore), l'unità calcareo nodulare del Rosso Ammonitico (Toarciano medio -Aaleniano inferiore) ed infine l'unità calcarea dei Calcari a Posidonia (Aaleniano-Bajociano). Questa sezione è caratterizzata da un elevato spessore, circa 90 m di sedimenti del Toarciano e dalla presenza di frequenti livelli detritici; per qi1:esti caratteri può essere classificata come sequenza di tipo esteso (tipo 1 sensu Colacicchi et al., 1988). E stato effettuato uno studio biostratigrafico di dettaglio della sezione basato sulle faune ad ammoniti e sui nannofossili calcarei. Dallo stu- dio di 59 livelli fossiliferi ad ammoniti sono stati selezionati 17 biorizzonti che hanno permesso il riconoscimento di tutte le zone standard nelle quali si articola il Toarciano, con la sola esclusione della Zona a Bonarellii. Le associazioni ad Ammoniti hanno carattere mediterraneo. Lo studio dei Nannofossili calcarei, tramite il riconoscimento di numerosi eventi, ha permesso una analisi biostratigrafica di dettaglio ed una precisa calibrazione con la biostratigrafia ad ammoniti. Gli eventi a Nannofossili risultano coincidenti con quanto ritrovato sia in coeve sezioni del bacino Umbro-Marchigiano sia in altre aree tetidee. La successione delle unità litologiche, i caratteri delle macrofaune e microfaune hanno permesso di individuare un caratteristico trend depo- sizionale comune ad altre aree del bacino Umbro-Marchigiano. Inoltre sono stati riconosciuti caratteristici eventi faunistici e litologici correla- bili, sia a livello regionale che tetideo, a fenomeni tettano-eustatici del Toarciano. La deposizione di sedimenti argillosi inizia al limite Domeriano/Toarciano e segna il limite litostratigrafico fta Corniola e Marne di Monte Serrone. Sono stati individuati livelli pelitici, scuri, finemente laminati, con un discreto spessore, all'interno d'ella Zona a Polymorphum. L'arrivo dei sedimenti argillosi nel Toarciano inferiore viene messo in relazione con la fase trasgressiva riconosciuta a scala globale. Nella parte alta del Toarciano inferiore, è stata osservata la comparsa di calcari nodulari passanti superiormente alla litofacies del Rosso Ammonitico Umbro- March!tf.ano nel Toarciano medio (Zona a Bifrons). L'inizio delle unità calcareo-nodulari, associato alla progressiva diminuzione della compo- nente jzllosilicatica, può essere invece messo in relazione con un trend regressivo. Il limite fta Rosso Ammonitico Umbro-Marchigiano e Calcari a Posidonia cade appena sopra il limite Toarciano/Aaleniano e coincide con la ricomparsa della selce. Un tipico episodio detritico legato a sedimenti tipo pebbly mudstone si ritrova nell'Aaleniano medio. Per quanto riguarda le microfaune a foraminiferi all'interno dei litotipi pelitici scuri laminati, delle Marne di Monte Serrone è stata riconosciuta un'associazione oligotipica {associazione E di Bartolini et al., 1992 e Nocchi, 1992) costituita/revalentemente da Paralingulina gr. tenera; questo taxon scompare al tetto dei "black-shales''. La comparsa di Conicospirillina si registra ne Toarciano medio così come quella di Lenticulina d'orbignyi. La comparsa di Lenticuline abrase, si registra intorno al limite Toarciano medio/Toarciano superiore. Un incremento di lamellibranchi è stato riconosciuto nel Toarciano medio, Zona a Bifrons, e nel Toarciano superiore si rinvengono dei li- velli di lumache/le a bivalvi ("winnowed beds" di Monaco, 1994).
INTRODUCTION iments outcropping in the Colle d'Orlando section, in the Cucco Mountain area (northeastern Umbria, The present work deals with a !ithologic and bio- Central Italy, Northern Apennine). This section rep- stratigraphic study of the Lower-Middle Jurassic sed- resents a good stratigraphic reference for the Lower to 4 G. PARISI et alii
Middle Jurassic because of its exposure, continuity depressed area from che Early to Late Jurassic. and the abundant and diversifìed fossil content. The During the Early and Middle Jurassic in che Jurassic sediments examined here consist of different Umbria-Marche Basin, che shallow-water sediments lithologies belonging to the Corniola Unit, the of the Calcare Massiccio were replaced by pelagic Marne di Monte Serrane Formation, the Rosso units that have been described in detail by Cresta et Ammonitico Umbro-Marchigiano and the Calcari a al. (1988) and Cresta et al. (1989b). We referto these Posidonia Units. The studied time interval ranges authors for further sedimentary and lithostratigraph- from the Late Domerian to the Early Bajocian. ical information. The Colle d'Orlando section represents an extended section, of type 1 (sensu Colacicchi et al., STUDYAREA 1988). A comparison with other Jurassic sections of (L. Benedetti & G. Parisi) the Umbria-Marche area aims at recognizing some peculiar depositional trends in the Cucco Mountain The Cucco Mountain area has been widely stud- area, relateci to palaeoenvironmental modifìcations. ied in the fast for its distinctive geologica! and pale- The Colle d'Orlando section provides an abun- ontologica records ( Marchetti & Ramaccioni, 1933; dant record of ammonites that has allowed for a Giannini 1960; Colacicchi & Pialli, 1967; Passeri, detailed biostratigraphic and chronostratigraphic res- 1971; Ramaccioni, 1936, 1939; Nicosia & Pallini, olution of the Toarcian. Standard ammonite bio- 1977). The tectonic structure of Cucco M. is a peri- stratigraphies, both European and Tethyan, have been anticline with a box-fold shape, asymmetric (N 160° taken into consideration to the present study and axis inclination) with a regular western limb and a compared with the Colle d'Orlando record. A signif- deformed eastern limb affected by elision of some icant and continuous record of calcareous nannofos- lithologic units. The study area is composed of two sils has allowed us to carry out an integrateci bio- main sectors divided by an articulated subvertical stratigraphic study. Correlations between the two fos- thrust system which follows two main orientations: si! groups allowed for a good resolution of the stud- SW-NE (with directions from N 40° to N 60°) and ied time interval and for the specifìcation of some E-W (with directions variable from N 90° to N°l lO) bio-litho and chronostratigraphic boundaries. (Text-fìg. 1) . 1) The Jurassic successions of extended and inter- GEOLOGICAL SETTING mediate type outcrop in che northern-central sector. The extended sections, characterized by a remarkable The studied area is locateci in an anticline in che thickness of the Corniola Unir and the Marne di northern portion of che Umbria-Marche Apennines. Monte Serrane Fm., constitute a large and continu- The Umbria-Marche Apennines form a well defìned ous belt aligned with a N-S direction. The strati- tectonic unir belonging to the Northern Apennine. le graphic position of the extended sequence is homo- was formed during the sedimentary cover deforma- geneous and undisturbed by tectonic activity. On the tion, because of the intense compressive tectonics of north-west slope of the Colle d'Orlando area the che Tertiary. The Apennine belt consists of two ridges thicknesses are the highest. The section sampled and formed by an alignment of second order tangential studied in detail outcrops in this area. periclines. Each anticline has a box-fold shape with a In the centra! portion, che different lithostrati- gendy dipping western limb and a steep eastern limb, graphic units rapidly decrease in thickness and near sometimes overturned and affected by thrust faults Fonte Acqua Passera che outcropping successions are (Lavecchia & Pialli, 1980; Barchi et al., 1989; thinner; the thinning of the Units is evident especial- La vecchia, 19 81). ly in corrispondence of the E-W thrust (south of The genesis of the Umbria-Marche basin is con- Fonte Acqua Passera). trolled by rifting relateci to che opening of che west- 2) The southern sector is fully represented by a ern Tethys in che Early Jurassic that caused the break great core of cyclothemic Calcare Massiccio with SW up of a large carbonate platform locateci along che dipping strata. Near the thrust the Calcare Massiccio passive African margin (Colacicchi & Bigozzi, 1995, is deeply crushed. The Jurassic sequences characteris- 1996). The basins were therefore characterized by an tic of the southern sector are generally of condensed irregular physiography with some uplifted areas type with hiatuses. (structural highs). The successions deposited on the structural highs are condensed and discontinuous, THE COLLE D'ORLANDO SECTION while in the depressed areas che successions are con- tinuous and resedimentation episodes are common. The Colle d'Orlando section is locateci in che cen- Marly calcareous and/or siliceous sediments, rep- tral-northern sector (Text-fìg. l); geologie map 116 resented by the lithostratigraphic units such as Gubbio, II SW, geographic coordinates: latitude Corniola, Marne di Monte Serrane, Rosso 43°23'01" N and longitude 0°17'01" E. The section Ammonitico Umbro-Marchigiano, Calcari e Marne a outcrops along a gorge that cuts che NE flank of Posidonia, Calcari Diasprini, were deposited in the Colle d'Orlando. The Jurassic !ithostratigraphic units TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 5
100 200 300 400 """"..S;;;;;;;;;;;i=,,,...... _. m
Text-fìg. 1 - Geologica! map of the study area and location of the Colle d'Orlando section. 1) Calcare Massiccio unit; 2) Corniola unir; 3) Marne di Monte Serrane Formation; 4) Rosso Ammonitico Umbro-Marchigiano unit; 5) Calcari a Posidonia unir; 6) Calcari Oiasprigni O NUCERA f UMBR A unir; 7) Calcari ad Aprici e Saccocoma unir; 8) Maiolica unir; [[WJ 9) Quaternary conti- 30)_..a) llb) 11 nental deposits; 1O) I I I 2 faults; 11 a), b) bed- 12 ding attitude; 12) loca- I I I 3 tion of the studied sec- tion. outcrop continuously from the Calcare Massiccio Corniola Unit, Upper Domerian (Hettangian) to the base of the Maiolica (Late Tithonian). lnterval from 170.00 m to 180.00 m (Texr-fig. The studied units are: rhe uppermost portion of 3), (PI. 1, figs.1-4). the Corniola Unir, the Marne di Monte Serrone Grey limestones with chert inrerbedded with grey- Formation, rhe Rosso Ammonitico Umbro- brown, rarely pink deeply bioturbated decimetrical Marchigiano and rhe lowermost porrion of the limestones. Calcareous detritic grey levels are fre- Calcari a Posidonia; rhe stratigraphic interval spans quent and their thickness reaches 50 cm; the derriric from Upper Domerian to Lower Bajocian. Below the levels show sharp base and millimetrical planar-par- studied section there are 170 metres of the Corniola allel laminations. Low angle cross laminations, simi- Unir rhat are nor analyzed here. lar to the hummocky cross stratification (Monaco, 1992), with wave length exceeding one meter are LITHOSTRATIGRAPHY present. Convolute laminarions are less frequent. The main microfacies is mudstone and wacke- The following litho - and biofacies (from bottom stone with bioclasts, ammonite embrions, calcareous to top) have been recognized (Texr-figs. 2 - 5): sponge spicules, rare to common radiolaria, rare 6 G. PARISI et a/ii
fringes (fìrst or second order) which overlap rhe orig- ::m: m - stratification KEY Well-bedded inai test wall of Schizosphaerella spp. :diii dm - stratification limestone :e;;: cm - stratification 111111 Marly limestone Marne di Monte Serrone Formation (Pialli, 1969), m;;; mm - stratification Lower-Middle Toarcian plane-parallel larnination Ncxlular Iimestone convolute laminations hummocky cross- c--=i Marl and clay This Formation can be subdivided imo three stratification Black shales intervals on rhe basis of different lithological charac- -o- bioturbation ters. chert [:==J Detrital leve! .l carbon remain - Pebbly mudstone 1" interval from 180.00 to 217.00 m (Text-fìgs. pyrite L_J = ncxlular structures 3-4), (PI. 1, fìgs. 5-15; PI. 2, fìgs. 1-2). bivalve shells Gy = grey Y e = yellow The fìrst marly leve! in the section (180.00 m) stylolite BI = black Gn = green marks the base of the Marne di Monte Serrone V e varicoloured Re red i:i gypsum = = Formation. The lower portion of the Marne di Monte L First occurrence 9 Last occurrence - Presence Serrone is characterized by the presence of detritic calcareous grey levels with plane-parallel laminations Texr-fìg. 2 - Key of rhe strarigraphic logs. and a thickness variable between 1O and 120 cm. The microfacies consist of wackestone and packstone and rarer microclastites. Grey or black chert, in nodules ostracods, echinoids and crinoids, rare hyaline and and beds is present only inside the detritic levels. porcellaneous foraminifers. Sometimes the calcareous detritic levels are affected The microfacies of the detritic levels are wacke- by intense silicization. Marly and shaly marls prevail stone and packstone sometimes directly graded with upward. The colour varies from yellow-brown to peloids, echinoid and crinoid fragments, rare hyaline, dark-grey to black. arenaceous and porcellaneous foraminifers. From The shaly-marls are thinly bedded, with millimet- 178.00 m upward pyrite is present. Ultrastructural ric or centimetric laminas, with abundant pyrite and analyses of the Corniola mudstones showed that the without bioturbations. These sediments have been "lncertae sediS' Schizosphaerella spp. (PI. 1, fìg. 3) is an previously referred to as black shale facies (Banolini et important constituent of the micrite, as already evi- al., 1992; Parisi et al., 1996). A regular alternati on of denced by Bombardiere (1993) and Stoico & black and yellow-brown levels forms couplets with an Baldanza (1995) in other Umbria-Marche sections. average thickness of 40 cm. The CaC03 content in In these lithotypes calcareous nannofossils are affect- this interval is very low and ranges from 5% to 30%. ed by overgrowth, as evidenced by neomorphyc Analyses of Tota! Organic Carbon (TOC) were per-
EXPLANATION OF PLATE 1
Fig. 1 - Corniola unir, Upper Oomerian. Wackesrone wirh ammonire embrions, ostracods, echinoids and radiolarians, (CO 178.20), xl2. Fig. 2 - Corniola unir, Upper Oomerian. Wackesrone wirh a rhick ostracod carapace (transversal section), (CO 173.50), x 23. Fig. 3 Corniola unir, Upper Oomerian. Particular of micrite ultrasrrucrure wirh a large recrysrallized specimens of Schizosphaerella, (CO 172.50), X 300. Fig. 4 - Corniola unir, Upper Oomerian. Wackesrone wirh Stomiosphaera, (CO 179.75), x 100. Fig. 5 Marne di Monte Serrone Formation, Lower Toarcian. Fine grained packsrone wirh echinoid fragments and Stomiosphaera, (CO 189.40), X 23. Fig. 6 - Marne di Monte Serrone Formation, Lower Toarcian. Radiolarian packsrone with clear evidences of silicization, (CO 190.60), X 12. Fig. 7 - Marne di Monte Serrone Formarion, Lower Toarcian. Packsrone wirh echinoid fragments, peloids and foraminifera, (CO 190.80), X 32. Fig. 8 - Marne di Monte Serrone Formation, Lower Toarcian. Packsrone with echinoid fragments and agglurinated foraminifera (Planiinvoluta ?), (CO 192.30), x 32. Fig. 9 - Marne di Monte Serrone Formarion, Lower Toarcian. Packsrone with Verneulinidae, (CO 192.30), x 23. Fig. 10 - Marne di Monte Serrone Formation, Lower Toarcian. Packsrone wirh echinoid fragments, peloids and hyaline foraminifera, (CO 193.20), X 32. Fig. 11 - Marne di Monte Serrone Formarion, Lower Toarcian. Agerina sp., (CO 192.30), x 100. Fig. 12 - Marne di Monte Serrone Formation, Lower Toarcian. Wackestone with radiolarians, (CO 190.10), x 23. Fig. 13 - Marne di Monte Serrone Formarion, Lower Toarcian. Packsrone with peloids, oxides and Agerina sp., (CO 202.90), x 32. Fig. 14 - Marne di Monte Serrone Formation, LowerToarcian. Wackesrone with radiolarians, echinoid fragments and Lagenidae, (CO 211.75), X 32. Fig. 15 - Marne di Monte Serrone Formation, Lower Toarcian. Planar bedded and densely packed echinoderm and peloidal calcaren- ite with radiolarians, pyrite, sponge spicules and hyaline foraminifera, (CO 213.15), x 12. G. PARISI et alii, TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION PI. 1 8 G. PARJSI et a/ii
rl ------a COU..E O'ORLANOO 1 e - -5 - [·- .li AMMONITES, e N SECTION CALCAREOUS i !l ------· % T.O.C. NANNOFOSSILS ] i :i 11Jl a E rl 51 Llthology & e & ;i= i " sedlmentary Il FORAMINIFERA structures lì :i i EVENTS "'i < RCA
IO
L. velatus (208.20)
w w
205 Mitrolithu.r /enticularis (205.00) o ,( "'lol ;::;; o 100 i!lz 5 o C. superbus, B. priruii ... =o :l: (198.60) ;::;; a 8. leufuensis (198.00) >.... >
195
. poulnabronei (192.90) .J'L. crucicentra/is (192.20) ..1' L. sigillatus, C. cavu.s Texr-fìg. 3 - Lirhosrrarigra- (191.90) phy, sedimenrary srructures, rexrures, w 90 - CaCO, % (calcium carbonare percenr- ages), Tota! Organic Carbon percenrages (TO.C.), ammo- 186.60 Gy p nire levels (CO n) 185.60 and biosrrarigraphic 85 184.70 evenrs of rhe lower 184.20 portion of rhe Colle 183.70 183.30 p d'Orlando secrion. 182.90 In rhe Ammonite Zones column the 181.10 dashed zone indi- sp. (! p Calyculu.s 80.20) ca tes uncerrain age CO 3 _t Dactylloceras 80 due to the lack of (Eodactylites) simplex 78.80 ammonire indices. 178.20 Biostratigraphic events: ammonites - 176.60 (bold), calcareous • w 175.80 nannofossils (italic), 175.20 p benthic foramini- fera ( italic under- lined;; foraminiferal CO 2 Emaciaticeras emacia and radiolarian se- L. barozii (173.5) mi quantitative 1's. grande (172.5) :.am:: p abundances: A = COI abundant, c = com- w mon, R = rare; see .[______,______Text-fìg. 2 for sym- bols. TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 9
- - rl COLLE---- D'ORLANDOi 2 AMMONI'IE, • SECTION .Il CALCAREOUS ---·-··-- -- T.O.C. e ... ll E g .caeo3 1.111 NANNOFOSSIL I .! ] !3 Whology & and < • ::;-i " _g sedlmentary FORAMINIFERA !I Ji".J:l < Ili:" Merlait.. clausu.s -- Collina oommulllria ' Hildoceras u 2 Ili: ....o ....i:.i Q Q rJ) 45 = '!' H. anguslislphonatum iii"" Conicosoirillina (243.90) -· 241.75 Hlldoceras lusltanlcwn 241.35 240- HUJ 238.90 238.00 W. colacicchii (237.55) .. z 237.00 o 236.40 Ve - - Ili: - Clii Hlldaltes -·- 292.90 ...... _, w -1' W. britannica (291) w M. elegans (288. l 0) 58 Ancolioceras opalinoides 57 Erycites f alHfax '1-T. patulu.s, C. cavu.s (286.00) w -1 B.fmchii (284.05) C.margerelii, H. maghareruis AAL J W. contracta (280.50) 56 - Pleydellia aalemls p Catulloceras :1'1-1-at.znaueria sp. I (277.10) - • (0.07) _y Retecapsa incompta m (275.30) w O 54 -- Dumortieria meneghinii Calyculus spp. (269. IO) -o -i, M.jansae (268.45) CO m p o 265- cc: _:} Gec-.iyceras perplanum Geczyceras porcarellense B. depravatum (259.40) L. d'orbìgnyi 1' M. altlcarinatus D. criotus (257.45) .)._------'--·------Texr-fìg. 5 - Conrinuarion ofTexr-fìg. 3 TOARCIAN STRAT!GRAPHY OF THE COLLE D'ORLANDO SECT!ON 11 formed only in the marly and shaly levels. The TOC stone with foraminifers, brachiopods, gastropods and reaches a maximum at 204.2 m and 209.75 m with ostracods; radiolaria abundance drastically decreases. 2.69% and 2.27%, respectively (Text-fìg. 3). Parisi et Densely packed bivalve shell deposits occur up to 247 al. (1996) reported importane results of che geo- m; thin and curved bivalve shells, although always chemical analysis carried out on che day minerai asso- present, are very rare upward. ciations, trace elements and rare-earth elements and The calcareous detritic levels, with a thickness on che organic matter. Isotopie analyses were per- variable from 1O to 80 cm, show a sharp planar base forme? by Benedetti et al., (1995) on che ò '3C carb. and plane-parallel to crossed laminations. The micro- excurs1on. facies are packstone and wackestone with peloids and Calcareous detritic levels are interbedded with bioclascs with grain size ranging from arenite to siltite marls and shales; they generally show sharp bases, (medium to fine sand). millimetric lamination, cross laminations and planar- parallel laminations which can be referred to as hum- Rosso Ammonitico Umbro-Marchigiano Unit, Middle mocky cross stratifìcation. Between 206 m and 208 Toarcian-Lower Aalenian m many calcisiltitic levels are present with a lenticu- lar shape, probably due to press-loading phenomena. lnterval from 248.5 m to 281.6 m (Texc-fìgs. 4- The microfacies generally consist of packstone and 5) , (PI. 2, fìgs. 4-15). wackestone with peloids, echinoid fragments, The lithologic boundary between che Marne di crinoids, ostracods, rare bivalves, radiolaria and pyri- Monte Serrone and che Rosso Ammonitico Umbro- tized gastropod prodissoconches. Hyaline and porcel- Marchigiano is placed in concomitance with the laneous foraminifera are present while agglutinateci increase of nodularity and dominance of the red spec1mens are rare. colour. The main lithology is represented by nodular limestones and nodular calcareous-marly levels, 2"d interval from 217.0 m to 236.0 m (Text-fìg. 4), deeply affecced by bioturbation interbedded with red (PI. 2, fìg. 3). marly levels. This interval is characterized by a sequence of The nodular limestones are wackestones with marly-limestones and calcareous-marls with interbed- ammonite embrions, bivalve shells, ostracods, echi- ded calcareous detritic levels. The bioturbation is rare noids, gastropods, foraminifers, rare crinoid frag- and becomes common from 227 m upward. ments and small brachiopods. The radiolaria increase Between 218 m and 224 m an alternance of cal- in the upper portion of che interval. careous-marly levels and calcareous detritic levels is The upper portion of the interval is characcerized represented by severa! couplets with a thickness vari- by the presence of detritic levels, red in colour, with a able between 20 and 30 cm; the calcareous-marls are thickness between 50 cm and 100 cm; their cextures grey passing to grey-green. are wackestone and packstone wich peloids, ostra- In the upper portion of the interval, fìrst nodular- cods, echinoids and common to abundant bivalves. ity appears in some calcareous bioturbated levels. An The foraminifers are represented by hyaline, porcella- increase in CaC03 contene is recorded in respect with neous and agglutinated specimens. Bivalve shells are che interval below: che CaC03 contene varies frequent and densely packed with evidence of isoori- between 50 and 80%. TOC values are very low. The entacion and shelter porosity structure (referable to a calcareous-marly levels are generally wackestone and "shelter porosity type" of Monaco, 1992). mudstone with rare bivalves (referable to the genera Lentilla humilis and Bositra buchi), abundant echi- Calcari a Posidonia Unit, Lower Aalenian - Lower noid spines and rare ostracods with smooth and orna- Bajocian mented carapaces; hyaline foraminifera and radiolar- ia are continuously present . lnterval from 281.6 m to 293.0 m (Text-fìg. 5), The detritic levels consist of deeply bioturbated (PI. 2, fìg. 16). packstone and wackestone. The biofacies is charac- The transition from che Rosso Ammonicico to che terized by echinoid fragments, calcareous sponge Calcari a Posidonia is graduai: che nodularity tends to spicules, ostracods, crinoids and rare radiolaria. disappear, che bioturbation decreases and che lime- stones become white-pink in colour. At 286.0 m red 3'd interval from 236.0 m to 248.5 m (Text-fìg. 4). and white chert occurs; this event is considered as a The interval is represented by grey-green biotur- marker to identify che base of the Calcari a Posidonia bated calcareous-marly and marly levels interbedded unit. Limestones are represented by wackestone with with laminateci calcareous detritic levels. From the bivalve shells (Lentilla and Bositra), hyaline base to che top of che interval che colour gradually foraminifers, small brachiopods, gascropods, ammo- becomes red-purple in stains and flames. In this nites and ostracods. Radiolaria become common to interval the ammonite horizons become more abun- abundant in this interval. dant and che nodularity more evident. The laminateci calcareous detritic levels are com- The main microfacies are mudstone and wacke- mon; their microfacies are packstone with peloids 12 G. PARISJ et a/ii s STANDARD The detritic level at 286. 70 m is a heterogeneous AGE AMMONITE Ammonite F'O pebbly mudstone (Colacicchi & Baldanza, 1986) :;:: .... 7,0NES with subrounded alloclasts without sorting. The allo- Lai< CONCAVUM clasts are wackestone and packstone with radiolaria, I.iz Middlt MURCHlSONAE 286-40 - 17 A 11 EXPLANATION OF PLATE 2 Fig. 1 - Marne di Monte Serrone Formarion, Lower Toarcian. Wackesrone wirh organic maner and foram inifera (Paralingulina tenera, rransversal secrion), (CO 217), x 32. Fig. 2 - Marne di Monte Serrone Formarion, Lower Toarcian. Paralingulina tenera tenera, (CO 217), x 32. Fig. 3 - Marne di Monte Serrone Formarion, Lower Toarcian . Radiolarian packsrone, (CO 222.90), x 12. Fig. 4 - Rosso Ammonirico Umbro-Marchigiano unir, Middle Toarcian. Wackesrone wi rh small gastropods, osuacods, small bra- chiopods, ammonire nuclei and bivalve remains, (CO 248.50), x 23. Fig. 5 - Rosso Ammonirico Umbro-Marchigiano unir, Middle Toarcian. Wackesrone containing ammonire embrions, bivalve shells, small gasrropods, apricus, omacods and rare echinoid fragments, (CO 254.85), x12. Fig. 6 - Rosso Ammonirico Umbro-Marchigiano unir, Middle Toarcian. Wackesrone containing bivalve shells, (CO 259.30), x 12. Figs. 7, 8 Rosso Ammonirico Umbro-Marchigiano unir, Upper Toarcian. Densely packed flar bivalve shell deposirs, (CO 262.90), x12. Figs. 9, 10 - Rosso Ammonirico Umbro-Marchigiano unir, Upper Toarcian. Packsrone containing bivalve shells, echinoid fragments and foraminifera: 9) (Planiinvoluta ?), 10) Valvulinidae, (CO 260.60), x 32. Fig. 11 - Rosso Ammonirico Umbro-Marchigiano unir, Middle Toarcian. Densely packed echinoderm and peloidal calcarenire, (CO 256.50), X 23. Fig. 12 - Rosso Ammonirico Umbro-Marchigiano unir, Upper Toarcian. Densely packed flar bivalve shell deposirs wirh hyaline foraminifera (Lenticulina sp. and Nodosaridae). Geoperal fabrics (shelrer porosiry) are co mmon below convex embedded shells, (CO 262.90), x 12. Fig. 13 - Rosso Ammonirico Umbro-Marchigiano unir, Up per Toarcian. Densely packed flar bivalve shell deposirs, (CO 273. 70), x 12. Fig. 14 - Rosso Ammonirico Umbro-Marchigiano unir, Upper Toarcian. Wackesrone wirh radiolarians, bivalve shells, small gas- rropods and osrracods, (CO 273.90), x 12. Fig. 15 - Rosso Ammonirico Umbro-Marchigiano unir, Upper Toarcian. Panicular of rhe micrire ulrrasrrucrure wirh large recrys- rallized specimens of Schizosphaerella sp., (CO 273.90), x130. Fig. 16 - Calcari a Posidonia unir, Lower Aalenian (?). Deeply biorurbared wackesrone wirh radiolarians and bivalve shells, (CO 281.80), X 12. G. PARISI et alii, TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION PI. 2 14 G. PARISI et alii the Ammonite Zones column of Text-fìgs. 4 and 5 Remarks - The assemblage found in these two lev- the dashed zones indicate uncertain age due to the els was described from the Apennines by Ferretti Jack of ammonite indices. (1970, 1972, 1975), Farinacci et al. (1978), and The markers have been reported in Plate 3 and for Kalin & Ureta (1988) and relateci to the Spinatum many of these the coi! sections and sutures have been Zone; Cecca et al. (1990), refer this assemblage to drawn with the aim of evidencing the taxonomic dif- the Emaciatum Zone (sensu Braga, 1983). ferences among specimens wirh similar side views (Text-fìgs. 7 and 8). Lower Toarcian (PI. 3, fìgs. 15, 17; Text-fìg. 7:11,17) Upper Pliensbachian To this interval we refer 57 metres of the section Only the upper four metres of the succession of (from 180.20 to 237.20); there are 14 fossiliferous this stage were sampled. The assemblages found are levels and 105 ammonites were found. Despite the consistent with the Spinatum Zone of Late Domerian discontinuity of fossi! documentation, the bad preser- age. vation of the specimens and the re-elaboration of sev- Spinatum Zone - The fìrst 8 metres of the sec- era! ammonites found in detritic levels, it was possi- tion are attributed to this zone; the sampled ble to recognize the two Biozones of the substage. ammonites (7 specimens) come from two fossilifer- Polymorphum Zone - The lower limit is identi- ous levels at 171.9 m and 173.9 m, respectively. fìed by the fìrst occurrence (FO) of D.(E.) simplex:, some species were used as an index by Goy & CO. l - (171.90) - limestone- Emaciaticeras sp. (1) C0.2 - (173.90) - limestone - Emaciaticeras emaciatum Martinez (1990) in the lberian Cordillera. To this (Catullo) (1), Canavaria reversiplicata (Fucini) (1), Canavaria sp. unir we refer 41.9 metres of the section with 9 fossil- (1), Paltarpites sp. (1), Distefania festiva Fucini (2) iferous levels and 69 ammonite specimens. The fau- \ \ I o[) I I o I o 1o I \1\J o 11 " CJ1 2 C 1 J3 ) o o 7cm Text-fìg. 7 - Coi! sections of the ammonite specimens illustrateci in Plate 3, Colle d'Orlando section. Scale bar= 1 cm. 1) Pseudomercaticeras cf. ftantzi, CO 33 - (252.20m); 2) Hildoceras sublevisoni, CO 20 - (240.80m); 3) Hildoceras angustisiphonatum, CO 30 - (249.70m); 4) Hildoceras lusitanicum, CO 23 - (243.45m); 5) Merlaites clausus, CO 35 - (253.30m); 6) Harpoceras sp., CO 14 - (234.90m); 7) Pseudomercaticeras sp., CO 32 - (250.90m); 8) Mercaticeras thyrrenicum, CO 25 - (245.70m); 9) Mercaticeras mercatii, CO 30 - (249.70m); 10) Mercaticeras dilatum, CO 30 - (249.70m); 11) Dactylioceras (Eodactylites) simplex, CO 3 - (180.20m); 12) Paroniceras sternale, CO 42 - (255.00m); 13) Erycites (Praerycites) civitellensis, CO 37 - (253.70m); 14) Collina gemma, CO 30 - (249.70m); 15) Collina nummularia, CO 33 - (252.20m); 16) Hildaites pseudolevisoni, CO 15 - (235.40m); 17) Praepolyplectus sp., CO 11 - (222.lOm); 18) Pseudogrammoceras subregale, CO 46 - (257.45m). TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 15 A I 2 lfrt 3 U : ': . · 2 ·.; . 4 A L 11 o 7cm Texr-fìg. 8 - Sutures of some ammonites illustrated in Plate 3, Colle d'Orlando secrion. Scale bar=l cm. 1) Hildaites pseudolevisoni, CO 15 - (235.40m); 2) Pseudomercaticeras cf. frantzi, CO 34 - (252.55m); 3) Merlaites clausus, CO 35 - (253.30m); 4) Mercaticeras thyrrenicum, CO 25 - (245.70m); 5) Mercaticeras mercatii, CO 30 - (249.70m); 6) Pseudomercaticeras cf. frantzi, CO 33 - (252.20m); 7) Mercaticeras dilatum, CO 33 - (252.20m); 8) Hildoceras angustisiphonatum, CO 30 - (249.70m); 9) Hildoceras sublevisoni, CO 20 - (240.80m); 10) Harpoceras sp., CO 14 - (234.90m); li) Paroniceras sternale, CO 42 - (255.00m); 12) Collina nummularia, CO 33 - (252.20m); 13) Collina gemma, CO 30 - (249.70m). nal spectrum is the following: Dacrylioceratidae 37% CO .1 O - (22 L 90) - calcareous marl - Neolioceratoides sp. (1), (25 specimens), Hildoceratidae 63% (43 specimens). Paltarpites sp. (1). CO, 11 -(222.1 O) - calcareous marl - Neolioceratoides sp. (6), Praepolyplectus sp. (11), Paltarpites sp. (1). C0.3 - (180.20) - limesrone - Dactylioceras (Eodactylites) simplex Fucini (6), D.(E.) pseudocommune Fucini (2), Paltarpites sp. (2). Remarks - These nine fossiliferous levels have C0.4 - (214.90) - calcareous detritic leve! wirh re-elaborated already been described by Ferretti (1970, 1972, ammonites - Praepo!yplectus sp. (3), Paltarpites sp. (1), 1975), Farinacci et al. (1978), Venturi (1981), and C0.5 - (216.40) - marl - Paltarpites sp. (1), Praepolyplectus Kalin & Ureta (1988), from the Apennines. In the sp. (2). whole Polymorphum Zone there are elements of C0.6 - (216.85) - marl - Dactylioceras (E) pseudocommune Fucini (2), Paltarpites sp. (3), Lytoceras sp. (1). Domerian affìniry such as Paltarpites, Neolioceratoides C0.7 - (218.20) - calcareous detritic leve! with re-elaborated and Distefania. The continuous presence of ammonires - Dactylinceras (E.) pseudocommune Fucini (12), Paltarpites from the base of the Polymorphum Zone Neolioceratoides sp. (6), Maconiceras sp. (1), Nodicoeloceras sp. permits to confìrm the presence of the lower portion (3), Praepolyplectus sp. (2). C0.8 - (219.40) - calcareous marl - Distefaniafestiva Fucini of the Lower Toarcian, in agreement with Elmi et al. (1). (1994) that report the Paltarpites Horizon at the base C0.9 - (219.65) - calcareous marl - Praepolyplectus sp. (1). of the Lower Toarcian in the Mediterranean Province. 16 G. PARISI et alii Levisoni Zone - The lower limit was placed, using Bifrons Zone - The lower limit is identifìed by the FO of Hildaites-, to this zone we refer 9.5 metres the FO of Hildoceras sublevisoni and we refer 15 of the section. Five fossiliferous levels with 36 speci- metres of the sequence to this zone; 16 fossiliferous mens were sampled. The assemblage consists of: levels yielded 455 ammonite specimens. The assem- Phylloceratidae 39% (14 specimens), Lytoceratidae blage diversifìcation permits the subdivision of this 11 o/o (4), Dactylioceratidae 8% (3), Hildoceratidae Biozone into four Subzones. 42% (15); six taxa fìrst appear in this Zone. Hildoceras sublevisoni Subzone - Its lower limit C0.12 - (227.70) - marly limestone - Hildaites sp. (1). coincides with the base of rhe H. bifrons Zone; we C0.13 - (231.55) - mari - Hildaites exilis Venturi (1), refer 4.55 metres of the sequence to this subzone, Hildaites sp. (2), Rakusites sp. (1), Lytoceras sp. (1), Phylloceras sp. (1), Calliphylloceras sp. (1). with 4 fossiliferous levels and 50 ammonite speci- C0.14 - (234.90) - marly limestone - Hildaites exilis Venturi mens. (1), Harpoceras mediterraneum Pinna (2), Harpoceras sp. (3), This assemblage characteristically yields speci- Praepolyplectus forzanensis Venturi (2), Phylloceras sp.(6), mens with spaced ribs in the adult stage belonging ro Cal!iphylloceras sp.(6), Lytoceras sp.(3). C0.15 - (235.40) - marly limestone - Hildaites pseudolevisoni the genus Hildoceras (H. sublevisoni, H. gr. graecum - Venturi (1), Praemercaticeras sp. (1). acarnanicum, H. laticosta ); we also report the FO of C0.16 - (236.50) - marly limestone - Harpoceras sp.(l), Mercaticeras mercatii. The assemblage is characterized Nodicoeloceras sp. (2). by the dominance of Hildoceratidae (70%), Dactyloceratidae (21 %), Phylloceratidae (3%) and Remarks - The assemblage observed in these fìve Lytoceratidae (6%); seven new taxa appear in rhis fossiliferous levels has been described by Venturi Subzone. (1981) withour any proposed locai index. Cecca et al. (1990) propose, for the assemblage with Hildaites C0.17 - (237.20) - nodular marly limestone - Hildoceras sampled in the Monte Nerone area, the adoption of sublevisoni Fucini (3), Hildoceras laticosta Bellini (11), H. striatus as the zonal index. Hildoceras gr. graecum-acarnanicum Renz (3), Harpoceras mediter- raneum Pinna (1), Nodicoeloceras baconicum (Gèczy) (3), Nodicoeloceras sp. (1). Middle Toarcian C0.18 - (237.40) - calcareous mari - Hildoceras sublevisoni Fucini (6), Lytoceras sp. (1). (Pl. 3, fìgs. 1-14,16; Text-fìg. 7: 1-10, 12-16, 18; C0.19 - (239.10) - mari - Hildoceras sublevisoni Fucini (3), Text-fìg. 8: 1-13) Phymatoceras elegans (Merla) (1), Mercaticeras mercatii (Hauer) (2), Mesodactylites broilii (M itzopoulos) (1), Nodicoeloceras To this interval we refer 22.1 O metres of the angelonii (Ramaccioni) (4), Ca!liphylloceras sp. (1). C0.20 - (240.80) - nodular mari - Hildoceras sublevisoni sequence (from 237.20 m to 259.30 m). There are 34 Fucini (2), H gr. graecum-acarnanicum Renz (6), Harpoceratoides fossiliferous levels and 645 ammonites were collected; serotinum (sensu Gallitelli-Wendt, 1969) (1), Nodicoeloceras the data on the Ammonitina collected in the interval baconicum (Gèczy) (1), Audaxlytoceras sp.(l), Lytoceras sp. (1). spanning the two fossiliferous levels C0.17 and C0.49 are reported in the distribution chart of Tab. Hildoceras lusitanicum Subzone - The lower limit 1. The good ammonite documentation allows for the is identifìed by the FO of H. lusitanicum; we refer identifìcation of the two Biozones of the Substage. 2.15 metres of the sequence to this subzone, with 3 EXPLANATION OF PLATE 3 Fig. 1 - HildocerassublevisoniFucini, 1919, CO 20- (240.80 m). Fig. 2 - Paroniceras sternale (von Buch, 1832) CO 42 - (255.00 m). Fig. 3 - Erycites (Praerycites) civitellensis (Venturi, 1981) CO 37 - (253.70 m). Fig. 4 Merlaites clausus (Merla, 1932) CO 35 - (253.30 m). Fig. 5 - Pseudomercaticeras frantzi Merla, 1932, CO 33 - (252.20 m). Fig. 6 - Hildoceras angustisiphonatum Prinz 1904, CO 30 - (249.70 m). Fig. 7 - Pseudomercaticeras sp., CO 32 - (250.90 m). Fig. 8 - Collina gemma Bonarelli, 1899, CO 30 - (249.70 m). Fig. 9 Collina nummularia Ramaccioni, 1939, CO 33 - (252.20 m). Fig. 10 - Harpoceras sp., CO 14 - (234.90 m). Fig. 11 - Psedogrammoceras subregale Pinna, 1967, CO 46 - (257.45 m). Fig. 12 - Mercaticeras mercatii (Hauer, 1856) CO 30 - (249.70 m). Fig. 13 - Hildoceras lusitanicum Meisrer, 1914, C:O 23 - (243.45 m). Fig. 14 - Hildaites pseudolevisoniVenturi, 1981, CO 15 - (235.40 m). Fig. 15 - Praepolyplectus sp., CO 11 - (222.10 m). Fig. 16 - Mercaticeras thyrrenicum (Fucini, 1919) CO 25 - (245.70 m). Fig. 17 - Dactylioceras (Eodactylites) simplex Fucini, 1899, CO 3 - (180.20 m). [Ali specimens are lifesize] G. PARISI et alii, TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION PI. 3 18 G. PARISI et alii sampled fossiliferous levels and 128 ammonite speci- CoLLina gemma Subzone - The lower limit is mens. The subzone is characterized by the presence of defined by the FO of CoLLina gemma; we refer 2.5 H. lusitanicum and by the diversification of the genus metres of the sequence to this subzone, 3 fossiliferous Mercaticeras (M mercatii, M rursicostatum, M umbiLi- horizons with 111 ammonites collected. The levels catum, M. thyrrenicum). The assemblage is represent- are characterized by C. gemma, C. linae and by H. ed by: Hildoceratidae (76%), Dactylioceratidae angustisiphonatum; Mercaticeras and Pseudomercaticeras (6%), Phylloceratidae (13%), Lytoceratidae (5%). are frequent in the assemblages. Eight species appear in this subzone. The FO of Praerycites (the first genus representa- tive of Hammatoceratidae) was observed. The assem- C0.21 - (241.75) - mari - Hildoceras lusitanicum Meister blage is represented by: Hildoceratidae (63%), (9), Hildoceras sp. (!), Hildoceras tethysi Gèczy (2), Nodicoeloceras Dacrylioceratidae (19%), Hammatoceratidae (1 %), sp. (nucleus) (!), Nodicoeloceras chojfati Renz (!), Harpoceras subexaratum Bonarelli (!), "Harpoceratoides"sp. (!), Mercaticeras Phymatoceratidae (2%), Phylloceratidae (11 %) and sp. (!), Mercaticeras mercatii (Hauer) (!), Mercaticeras rursicosta- Lytoceratidae (4%). Thirreen species first appear in tum Merla (3), Mercaticeras umbilicatum Buckman (!), this subzone. Mercaticeras thyrrenicum (Fucini) (2), Pseudomercaticeras venzoi Pinna (!), Lytoceras sp. (2), Audaxlytoceras sp. (I), Phylloceras sp. C0.30 - (249.70) - nodular calcareous mari - Collina gemma (4), Calliphylloceras sp. (4). C0.22 - (242.55) - marly limestone - Hildoceras lusitanicum Bonarelli (4), Paroniceras sp. (!), Collina linae Parish & Viale(!), Meister (34), Transicoeloceras viallii (Venzo) (!), Nodicoeloceras Hildoceras angustisiphonatum Prinz (13), Hildoceras sp. (2), H. (Bruguière) (!), (Hauer) (12), sp. (!), Audaxlytoceras sp. (1). bifrons Mercaticeras mercatii M. C0.23 - (243.45) - calcareous mari - Hildoceras lusitanicum dilatum (Meneghini) (!), M. thyrrenicum (Fucini) (4), sp. (2), Pinna (3), Meisrer (35), Hildoceras sp. (4), Polyplectus pluricostatus (Haas) Pseudomercaticeras Pseudomercaticeras venzoi sp. (!), (Buckman) (2), (1 ), Nodicoeloceras sp. (2), Nodicoeloceras renzi (Pinna) (2), Furloceras Nodicoeloceras verticosum N (Ramaccioni) (3), sp. (1), Phylloceras sp. (3), Calliphylloceras sp. (6), Lytoceras sp. (!), angelonii Transicoeloceras Maconiceras Audaxlytoceras sp. (!). sp. (!), Harpoceras subexaratum Bonarelli (5), Harpoceras mediter- raneum Pinna (!), Polyplectus pluricostatus (Haas) (3), Atractites sp. (2), Phylloceras sp.(3), Calliphylloceras sp.(3), Audaxlytoceras Hildoceras angustisiphonatum Subzone - The sp.(2). lower limit was placed at the FO of H. angusti- C0.31 - (250.35) - nodular marly limestone - Erycites siphonatum; we refer 5.8 metres of the studied (Praerycites) civitellensis (Venturi) (1), Maconiceras sp. (!), Mercaticeras mercatii (Hauer) (2), Mesodactylites mediterraneus sequence to this subzone with 6 fossiliferous levels (Meister) (!), Pseudomercaticeras venzoi Pinna (I), Nodicoeloceras and 161 ammonites collected. The levels are charac- sp. (I), Calliphylloceras sp.(2). terized by H. angustisiphonatum and by the presence C0.32 - (250.90) - nodular marly limestone - Hildoceras of H. lusitanicum, very abundant in rhe basai leve!. angustisiphonatum Prinz (13), Hildoceras cf. bifrons (Bruguière) The assemblage is made up of Hildoceratidae (77%), (!), Paroniceras sp. (!), Collina linae Parish & Viale (2), Collina sp. (I), Pseudomercaticeras sp. (I), Pseudomercaticeras venzoi Pinna Phymatoceratidae (2%), Dactylioceratidae (7%), (!), Transicoeloceras angustum (Venzo) (!), Transicoeloceras viallii Phylloceratidae (7%), Lytoceratidae (7%). Six new (Venzo) (2), Phymatoceras robustum Hyatt (!), Transicoeloceras sp. taxa appear in this subzone. (2), Phylloceras sp. (2), Calliphylloceras sp. (2), Lytoceras sp. (2), Audaxlytoceras sp. (!). C0.24 - (243.90) - shaly mari - H. angustisiphonatum Prinz (4), Hildoceras lusitanicum Meister (43), Mesodactylites sapphicus Remarks-As shown in Tab. 1, in the Bifrons Zone (Renz) (!), Maconiceras sp. (!), Lytoceras sp. (2), Audaxlytoceras the first occurrences of ali the species ot the genus sp. (!), Calliphylloceras sp. (2). C0.25 - (245.70) - marly limestone - Hildoceras Hildoceras are documented in succession, from the angustisiphonatum Prinz (!), Nodicoeloceras sp. (2), Mercaticeras first one H. sublevisoni to the last one H. umbilicatum Buckman (2), M. thyrrenicum (Fucini) (2), angustisiphonatum. This succession is quite consistent Mesodactylites sapphicus (Renz) (I), Phylloceras sp. (2), and more complete than that reporred by Gallitelli Calliphylloceras sp. (I), Lytoceras sp. (I), Audaxlytoceras sp. (I). C0.26 - (248.20) - nodular marly limestone - Hildoceras Wendt (1969), Elmi (1981 a and b), Monaco et al angustisiphonatum Prinz (6), Harpoceras mediterraneum Pinna (1994) and Cresta et al (1989a). In this Zone rhe (2), Mercaticeras umbilicatum Buckman (!), Mercaticeras mercatii increase in abundance of the species of the genus (Hauer) (!), Mercaticeras thyrrenicum (Fucini) (2). Nodicoeloceras was noticed. At the top of this Zone C0.27 - (248.50) - nodular calcareous mari- Hildoceras many specimens of the genus Paroniceras appear; they angustisiphonatum Prinz (18), Hildoceras bifrons (Bruguière) (2), Harpoceras mediterraneum Pinna (!), Mesodactylites ghinii could not be identified as Paroniceras sternale and are (Mitzopoulos) (3), Mesodactylites broilii (Mitzopoulos) (!), reporred as Paroniceras sp. • Pseudomercaticeras sp. (I), Phylloceras sp. (I), Lytoceras sp. (I), We consider the C. gemma Subzone as stili belong- Audaxlytoceras sp. (!). ing to the H. bifrons Zone, because the ammonite C0.28 - (248.95) - nodular calcareous mari - Hildoceras angusti- siphonatum Prinz (4), Mesodactylites ghinii (Mitzopoulos) (!). assemblage in this Subzone is dominated by species of C0.29 - (249.15) - nodular calcareous mari - Hildoceras the genus Hildoceras. angustisiphonatum Prinz (10), Hildoceras biftons (Bruguière) (!), H. lusitanicum Meister (9), Hildoceras sp. (IO), Nodicoelocerassp. Gradata Zone - The lower limit is identified by (2), N renzi Pinna(!), Frechiella subcarinata (Young & Bird) (!), Furloceras fa.baie (Buckman) (2), Mercaticeras mercatii (Hauer) rhe FO of CoLLina nummularia; we refer 7.8 metres of (3), Maconiceras sp. (!), Phylloceras sp. (2), Lytoceras sp. (2), the section to this unit with 19 fossiliferous levels and Calliphylloceras sp. (3), Audaxlytoceras sp. (!). 190 ammonites collected. The assemblage diversifica- TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 19 --·----·------·------·----·------AGE M I O O LE T O A R CI AN AMMONITE ZONF.S ···--· GRADA_T._A_·------< FOSSIL LEVEL 17 18 19 20 21 22 23 24 2S 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 HiKUx,erw lalicosta 11 1:1. gr. graecum-acarnatncum 3 Hildoceras sut>levisoni 6 Harpoceras mwilerraneum 1 1 .. uu.icoeuxeras vacomcum 3 Noaicoeloeerru sp. Lircx:eras sp. cvvu.icoetoceras angelOmi ,Mesoaactylilfll!s t>roiii1 1ML"rcaticeras mercalii 3 12 3 3 Auaaxiy1oceras sp. [HarpoceraJ,f..JWLS cl . .Jerotinum IPhylloceras sp. ---- _____ 3 3 111arpoceras suotxaralum 1 • Harpoceratau:tes sp. 1rmaoceras sp. 4 IO lHi1(.wcera.s tusitarricum 34 35 43 NiKUJ<.erasteurysi MercaJiceras sp. Mercalicera.J n.1rsicosta1um 3 Mercahceras umbllìcalUm Mercal1ceras thyrrenu:um "'seuaomercaticeras venzoi 3• 1 viaHii 1vuu.icoetoceras renr.1 roiyplectus pluricosrarus Mesvuuc.tyllle.1 sappnu:us Hùaoceras angusti.fipl&ona/um 18 4 IO 13 13 n-1aCOtriceraJ &p. Mesoaactyllles glrin11 PseU(lQ111ercaziceras sp. Hiiauçeras Piporu ,Furloceras Jaoale 1EVlX.11.Coeloceraswracnressp.-- vertì-·-----cosum 11 ransicoeJoceras sp. 1<..:oltina gemma 1,_ o/lina linae IMercaziceras a11a.mm iraronzcera..s sp. lt.ryciies ( t'raerycites) civll:eltensis MesodactyliJes medile"aneus ·- 1n1ymatoceras rOOiìstum 1c.omna sp. Il ransicoetoceras angustum T ransicoeloceras ramaccionii ouina rwmmulana erbaense -.'ff:Uaomerca11ceras sp. ___ _ reronoceras sp. Porpocera.s sp. MerlaileSClall.Su.t MerlaileJ sp. t'eronoceras voru.x Peronoceras tubcrcula/u,n Cra.uiceras taZum .Noaicoeloceras ack.ermanm apenmmcus it'eronocenu acutearum l.IWutaius gr(J{Ji(UUS 1reronocerru suoarmatum 1..... rasstceras canavan1 µwertmres mattoni ll'urloceras venustulum IParo11tceras sternale -- irseuc,wgrammoceras '"""''80Je IPseudogrammocer& sub/auaci.osum irseuaogrammoceras sp. ICieczyceras sp. 1uspertioceras t . Tab. 1 - Distriburion charr of ammonire specimens from rhe Biftons ro Gradata Zones, Colle d'Orlando secrion. See Texr-fìgs. 4-5 for posirion of fossi! levels. 20 G. PARISI et alii rion allows for che subdivision of rhis Biozone mto Merlaites clausus Subzone - The lower limit is four Subzones. idenrifìed by the FO of M. clausus; we refer 2.95 metres of che sequence to this subzone with 1O fossil- Collina nummularia Subzone - The lower limit iferous levels and 75 ammonites collected. The is defìned as that of the Gradata Zone; we refer 1.1 O assemblage is characterized by M clausus, Crassiceras merres of che sequence to this subzone with 2 fossil- latum and by various species of the genus Peronoceras iferous horizons and 60 ammonites collecred. The (P. tuberculatum, P. aculeatum, P. subarrnatum). At rhe assemblage is characterized by Pseudomercaticeras base of che subzone, a level with Peronoceras vortex frantzi and by C. nummularia, C. gemma, was observed. The assemblage is composed of: Phymatoceras erbaense, the last specimens of Hildoceratidae (32%), Dactylioceratidae (21 %), Hildoceras and Mercaticeras. Six taxa fìrst occur in Hammatoceratidae (1 %), Phymatoceratidae (21 %), rhis subzone. Phylloceratidae (4%), Lytoceratidae (21 %). Thirteen taxa fìrst occur in rhis subzone. C0.33 - (252.20) - nodular marly limesrone - Collina num- mularia Ramaccioni (5), Phymatoceras erbaense (Hauer) (1), C0.35 - (253.30) - nodular marly limesrone - Merlaites Hildoceras bifrons (Bruguière) (2), Hildoceras angustisiphonatum clausu.s (Merla) (6), Merlaites sp. (1), Peronoceras vortex Simpson Prinz (3), Hi!doceras sp. (1), Harpoceras subexaratum Bonarelli (2), Peronoceras tuberculatum Pinna (2), Transicoeloceras angustum (2), Collina gemma Bonarelli (1), Collina sp. (1), Mesodactylites (Venzo) (1), Crassiceras latum Merla (1), Nodicoeloceras acker- sapphicus (Renz) (1), Nodicoeloceras verticosum (Buckman) (1), manni Pinna (I), Phymatoceras erbaense (Hauer) (1), Polyplectus Transicoeloceras ramaccionii (Venzo) (1), Transicoeloceras viallii apenninicus (Haas) (1). (Venzo) (1), Pseudomercaticeras sp. (1), Pseudomercaticeras venzoi C0.36 - (253.60) - nodular marly limesrone - Phymatoceras Pinna ( 1), Pseudomercaticeras frantzi Merla ( 1), Mercaticeras dila- erbaense (Hauer) (I), Phymatoceras iserense (Oppel) (2) , tum (Meneghini) (1), Mercaticeras mercatii (Hauer) (3), Peronoceras sp. (1), Peronoceras vortex Simpson (I). Mercaticeras sp. (1), Calliphylloceras sp. (1), Audaxlytoceras sp. C0.37 - (253.70) - nodular marly limesrone - Merlaites (1 ). clausus (Merla) (1), Peronoceras vortex Simpson (1 ), Peronoceras C0.34 - (252.55) - nodular marly limesrone - Collina gemma aculeatum Parish & Viale (2), Erycites (Praerycites) civitellensis Bonarelli (9), Collina sp. (2), C. nummularia Ramaccioni (7), (Venturi) (I). Pseudomercaticeras frantzi Merla (2), Pseudomercaticeras sp. (2), C0.38 - (253.85) - nodular marly limesrone - Harpoceras Mercaticeras thyrrenicum (Fucini) (2), Mercaticeras mercatii subexaratum Bonarelli (1), Collina gemma Bonarelfi (1), (Hauer) (3), Transicoeloceras angustum (Venzo) (1), Porpoceras sp. Polyplectus apenninicus (Haas) (2), Merlaites gradatus (Merla) (1), (1), Harpoceras subexaratum Bonarelli (1), Furloceras sp. (1). Peronoceras subarmatum (Yung & Bird) (1), Peronoceras sp. (1), Lytoceras sp. (1). Remarks - This subzone is here considered as the C0.39 - (254.00) - nodular marly limesrone - Crassiceras lowermost one of the Gradata Zone because in this canavarii Merla (1), Merlaites gradatus (Merla) (1), Merlaites mo/toni (Venzo) (!), Phymatoceras iserense (Oppel) (I). inrerval we observed a great faunal renewal leading to C0.40 - (254.25) - nodular marly limesrone - Crassiceras the disappearance of che genus Hildoceras. Ir is worrh latum Merla (1), Nodicoeloceras sp. (!), Phymatoceras iserense mentioning that in the expanded Colle d'Orlando sec- (Oppel) (1), Furloceras venustulum (Merla) (1), Furloceras fabale tion che FO of C gemma precedes che appearance of (Buckman) (2), Furloceras sp. (!), Polyplectus apenninicus (Haas) (1) , Phylloceras sp.(l), Calliphylloceras sp.(2), Lytoceras sp.(2), C nummularia as it was noticed in che Valdorbia sec- Audaxlytoceras sp. (3). tion (Monaco et al., 1994). The scaling of rhese rwo C0.41 - (254.90) - nodular marly limesrone - Audaxlytoceras evenrs was nor observed in che condensed sections. sp.(2), Phymatoceras sp. (1). EXPLANATION OF PLATE 4 Fig. 1 - Schizosphaerella sp., half valve deeply affected by recrystallization (a large fringe of neomorphic overgrowth cemenr is evidenr); crossed nicols, magnifìcarion x 3250, Corniola unir, (CO 173.50). Fig. 2 - Crepidolithus crassus, specimens deeply affected by recrystallization (yellow-orange birifrangence colour); proximal view, crossed nicols, x 3400, Corniola unir, (CO 173.50). Fig. 3 - Mitrolithus jansae, enlarged size specimens affected by recrysrallization; side view, crossed nicols, x 5000, Corniola unir, (CO 173.90). Figs. 4, 5 - Tubirhabdus patulus, dista! views, crossed nicols, x 5000, Marne di Monre Serrane Fm., (CO 192.60). Fig. 6 Parhabdolithus sp., (specimen without spine, probably dissolved); side view, crossed nicols, x 4200, Marne di Monre Serrane Fm., (CO 198.60). Fig. 7 - Biscutumfinchii, proximal view, crossed nicols, x 6000, Marne di Monte Serrane Fm., (CO 201.6). Fig. 8 Biscutum depravatus, dista! view, crossed nico!s, x 5300, Rosso Ammonitico Umbro-Marchigiano unir, (CO 261.40). Figs. 9, 12, 13 - Lotharingius crucicentralis, dista! views, crossed nicols, x 4400, Marne di Monte Serrane Fm., (CO 219.50 , CO 237.40 , CO 248.20 , respectively). Figs. 10, 11 - Carinolithus superbus, side views, crossed nicols, (fìg. l O - x 2500; fìg. 11 - x 2750), Marne di Monte Serrane Fm., (CO 238.90). Fig. 14 - Lotharingius frodai, dista! view, crossed nicols, x 4400, Marne di Monte Serrane Fm., (CO 199.20). Figs. 15, 16 Tubirhabdus patulus, proximal views, crossed and parallel nicols respectively, x 5000, Marne di Monte Serrane Fm., (CO 202.60). Fig. 17 - Bussonius prinsii, distai view, crossed nicols, x 3800, Marne di Monte Serrane Fm., (CO 199. 20). Fig. 18 Carinolithus superbus, S.E.M. microphoros, x 3650, Marne di Monre Serrane Fm., (CO 241.75). G. PARISI et alii, TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION PI. 4 22 G. PARISI et alii C0.42 - (255.00) - nodular marly limestone - Paroniceras Aalenian. This is the reason for the undetermined sternale (von Buch) (4), Harpoceras subexaratum Bonarelli (1), interval (dashed zone) reported in the stratigraphic Phymatoceras sp. (3), Peronoceras sp. (1), Lytoceras sp.(2). C0.43 - (255.90) - nodular limestone - Phymatoceras log (Text-fìg. 5). erbaense (Hauer) (2). The biostratigraphic record is very discontinuous C0.44 - (256.15) - nodular limestone - Lytoceras sp. (5), as far as the lower portion of the sequence is con- Audaxlytoceras sp.(l). cerned; the ammonites collected permits the identifì- cation of only three of the four Biozoncs of the Pseudogrammoceras subregale Subzone - The lower Substage. In fact, in the sequence of Colle d'Orlando, limit is placed at the FO of P subregale; we refer 1.9 the identifìcation of the Bonarellii Zone is prevented metres of the sequence to this subzone with 4 fossil- by the absence of bioevents or characteristic assem- iferous horizons and 28 ammonites collected. In this blages. interval severa! species of the genus Pseudogram- moceras (P subregale, P fallaciosum, P subfallaciosum) Geczyceras speciosum Zone - We refer 10.25 metres dominate the assemblage (64% of the total number). of the sequence to this zone with the base coinciding In the fossiliferous leve! C0.48 the FO of with the FO of Geczyceras porcarellense (Bonarelli). Osperlioceras was observed. In this subzone six taxa This interval contains 2 fossiliferous levels and 11 fìrst appear. ammonites collected. The limited number of speci- mens prevents any consideration of the assemblage C0.45 - (256.25) - nodular marly limestone - Pseudogrammoceras subregale Pinna (1). composition. C0.46 - (257.45) - nodular mari - Paroniceras sternale (Buch) (!), Pseudogrammoceras subregale Pinna (9), Pseudogrammoceras C0.52 - (260.00) - nodular limestone - Geczyceras porcarel- Jallaciosum (Bayle) (2), Pseudogrammoceras sp. (1), Harpoceras lense (Bonarelli) (!), Geczyceras sp. (4), Osperlioceras sp. (!), subexaratum Bonarelli (I), Phylloceras sp. (1), Audaxlytoceras Furloceras caro li (Merla) (I), Polyplectus apenninicus (Haas) (I), sp.(3). Praerycites (nucleus) sp. (I), Pseudolioceras sp. (I), Harpoceras C0.47 - (257.80) - nodular limestone - Paroniceras sternale subexaratum Bonarelli (1), Calliphylloceras sp. (I). (Buch) (1), Audaxlytoceras sp.(I), Pseudogrammoceras sp. (1). C0.53 - (261.40) - nodular limestone - Geczyceras perplanum C0.48 - (257.95) - nodular marly limestone - Geczyceras sp. (Prinz) (I). (4), Osperlioceras sp. (1), Phylloceras sp. (1). Remarks - The fauna! renewal which occurred in Merlaites alticarinatus Subzone - The lower limit the Upper Toarcian is represented by the first occur- coincides with the FO of M. alticarinatus, we refer rence of the genus Geczyceras, with G. porcarellense as 1.9 metres of the sequence to this subzone with 3 fos- the first species of the genus to appear. We use the FO siliferous horizons and 27 ammonites collected. The of G. porcarellense as the index for the base of the G. Phymatoceratidae represent 74% of the entire assem- speciosum Zone because of the lack of specimens of G. blage; two taxa fìrst occur in this subzone. speciosum in the Mediterranean Tethys (see Elmi et al., 1997). C0.49 - (258.15) - nodular limestone - M alticarinatus (Merla) (2), Merlaites gradatus (Merla) (2), Merlaites sp. (2), Dumortieria meneghinii Zone - The lower limit is Osperlioceras sp. (1), Pseudogrammoceras sp.(l), Furloceras sp. (1), Phylloceras sp. (1). idenrifìed by the FO of Dumortieria meneghinii. We C0.50 - (258.50) - nodular limestone - Phymatoceras elegans refer 9.55 metres of the sequence to this zone with 2 (Merla) (!), Phymatoceras erbaense (Hauer) (!), Merlaites gradatus fossiliferous levels and 13 ammonites collected. (Merla) (6), Merlaites sp. (2), Phylloceras sp. (2), Audaxlytoceras sp. (!). C0.54 - (270.25) - nodular marly limestone - Dumortieria C0.51 - (259.30) - nodular marly limestone - Furloceras ca- meneghinii Haug in Zitte!(!), Dumortieria incerta (Ramaccioni) ro/i (Merla) (2), Furloceras sp. (1), Harpoceras subexaratum (!), D. pannonica Gèczy (!), D. latumbilicata Gèczy (!), Bonarelli (1). Catulloceras sp. (1), Erycites elaphus Merla (2), Phylloceras sp. (3), Lytoceras sp. (I), Audaxlytoceras sp. (I). Remarks- The Gradata Zone yields the successive C0.55 - (278.00) - nodular marly limestone - Catulloceras fìrst occurrences of the species of the genus Merlaites, sp. (!). the fìrst occurrence of M. clausus precedes the first occurrence of M. alticarinatus, and the FO of M. Aalensis Zone - A single fossiliferous leve! charac- clausus precedes the FO of Paroniceras sternale (Tab. terized by Pleydellia aalensis can be attribured to this 1). zone. C0.56 - (279.80) - nodular marly limestone - Pleydellia Upper Toarcian aalensis (Zieten) (1), Planammatoceras cf. tipperi Seyed-Emami (!), Lytoceras sp. (!). We refer 21.20 metres of the sequence (from 259.30 m to 280.50 m) to this substage with 5 fos- Aalenian siliferous levels and 27 ammonites collected. The thickness of the interval is unknown because of the No fossiliferous levels were found for the charac- lack of fossiliferous horizons referable to the Lower terization of the Leioceras opalinum Zone. The first TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 23 fossiliferous leve! is belonging ro che Middle Aalenian. V A more than 5 specimens in l view A i to 5 specimensln-"lview__ _ Murchisonae Zone - The lower limit coincides e l specimen in 2-10 views with che FO of Ancolioceras opalinoides. We refer 1.8 ----p--·--·--·- ______mecres of che sequence to chis zone with 3 fossilifer- R ous levels and 27 ammonites collecced. The zone is 1 specimen in 31-100 views VR 1-2 specimens area ( 10 mm2) characterized by Erycites fàllifax in associacion wich '------·------·------In the- -- Tmetoceras scissum, Abbasitoides modestus and -T.A.: TOTAL ABUNDANCE Planammatoceras tenuinsigne. In che Cordillera Becica, Linares & Sandoval f----VÀ. more than 10 specimens in eadi-vlew (1994) formally adopted chis zone, although ics scraci- A 10 to 15 specimens in 1 view graphic excension exceedes che lower limit of che L. >------e---- l to 10 specimens in l vie\-v---1 murchisonae Standard Zone. Cresta ( 1996) and F O, 1 to 1 specimens in 1 view Cresca et al. (1995) proposed che use of che Murchisonae Zone in che Apennine sequences as an interval spanning che upper porcion of che Opalinum (Scissum Zone, Scissum Beds, Comptum Subzone, Auctt.) and che Murchisonae Standard Zones. · SPECIES DIVERSITY L from 1 to 10 species in the assemblage C0.57 - (286.40) - nodular limestone - Ancolioceras opali- from 10 to 20 species in the assemblage noides (Mayer) (1), Erycites fallifax Arkell (1), qtoceras sp. (2), Tmetoceras sp. (1), Ludwigia haugi (Douville) (1 ), Holcophyl- -=-"-----· loceras ultramontanum (Zirrel) (1 ), Coeloceras sp. (sensu Vacek, 1886) (1). C0.58 - (286.80) - nodular limestone - Abbasitoides modes- -PRESERVATION tus (Vacek) (4), Lytoceras sp. (2), P!anammatoceras sp. (1), Erycites sp. (1). C0.59 - (288.20) - nodular limestone - Tmetoceras scissum (Benecke) (1), Abbasitoides modestus (Vacek) (2), Lytoceras sp. (1), § Alocolytoceras ophioneum (Benecke) (1), Planammatoceras tenuin- --· G ______.____ _ signe (Vacek) (3), Erycites fallifax Arkell (3). Text-fìg. 9 - Tota!, relative abundance, species diversiry and Remarks - The assemblage of chese 3 fossiliferous preservation values of calcareous nannofossils used for rhe compilation ofTables 2-6. levels was reported from che Umbria-Marche Apennines and named "Erycites fallifax Beds" by Zitte! (1869), and Bonarelli (1893), and recendy by Cresta (1988, 1996), Kalin & Ureta (1988), and Zone); and (3) che introduccion of che C. nummula- Cecca et al. (1990). ria Subzone as the first subzone of the Gradata Zone. Ali che Toarcian-Aalenian standard Zones used in che FINAL REMARKS Medicerranean Province (Elmi et al., 1994) were rec- ognized in che Colle d'Orlando section except che Concerning che Levisonii Zone, we could nor Bonarellii Zone in che Toarcian and che Opalinum recover enough ammonite horizons ro be able to doc- and Concavum Zones in che Aalenian (Texc-fìg.6). ument satisfactorily boch che base and che top of che Zone as well as its Subzones. As far as che Bonarellii CALCAREOUS NANNOFOSSILS Zone is concerned, the 2 m chick sequence between (E. Mattioli & A. Baldanza) che Merlaites alticarinatus and Geczyceras porcarellense bioevencs (indices of che Alticarinatus Subzone and of Macerials and methods che Speciosum Zone, respectively) are apparendy bar- ren in ammonites. We do not exclude chac a furcher The continuous and well exposed section of Colle sampling of che incerval may provide materiai co d'Orlando represencs a good reference for che study cover this chronoscracigraphic gap, also because che of calcareous nannofossils in che northern-cencral stracigraphic index Geczyceras bonarellii is quite fre- Apennines. A total of 234 samples were studied, col- quenc in ocher Apennine sequences. lected from che differenc lichocypes. Sampling was The presene work incroduces many differences variably spaced, from 1 O cm co 50 cm. Smear slide wich respect to che zona! scheme proposed by Elmi et preparacion was as simple as possible to retain che al. (1994) with the exception of (1) che subdivision of origina! nannofossil assemblage composition, using che Gradata Zone into two subzones; (2) che use of the standard techniques. che C. gemma Subzone as che lasc subzone of che A semiquantitative study of tota! and relative species Bifrons Zone (not che firsc subzone of che Gradata abundances was performed under a lighc microscope at 24 G. PARISI et alii a magnifìcarion of X 1000 using che classes of abun- Colle d'Orlando ci. Il dance reporred in Texr-fìg. 9. Visual esrimares of over- 1" " all preservation led co che recognirion of fìve classes of :§ -- 8 2 E preservation on che basis of dissolution/overgrowth fac- ·a:i g l .... §] .... < ;l t tors (Text-fìg. 9). The stratigraphical distribution is Q. ! 8 '"" ]'& r.!:: tlg 2) The second interval (191.9 m - 193.8 m) con- 3) The transition to the overlying interval (198.0 tains a more abundant and better diversified nanno- m - 205.0 m) is characterized by the highest values of fossi l assemblages, the values of total abundance tota! abundance (ranging from common to very being between few and common, and species diversi- abundant) and species diversity (varying from medi- ty be!ng moderate. Preservation also improves, vary- um to high). Preservation is also generally good. ing from poor to medium. Biscutaceae are constantly Schizosphaerella spp. is always abundant and M present even though scarce in abundance. The assem- jansae is rare to common. The presence of blage, although more diversified, is stili dominated by Watznaueriaceae becomes consistent in this interval Schizosphaerella spp., M. jansae and L. hauffii. as do the Biscutaceae, which reach the highest values lmbr1cated placoliths with more complex centra! area of the whole succession. Calyculus spp. is commonly structures appear in this interval (Text-fig. 3). The found in the assemblage. Bussonius leufoensis and B. preservation, better than in the previous interval, could prinsii are always rare but significant in Toarcian be related to the inception of a mainly argillaceous sed- assemblages. The excellent record of calcareous nan- imentation, resulting in a higher species diversity. nofossils in this interval could be linked to the good r · jll i!' ·ì: .., g .. I :i I "' .s .., "' § ì2 ., :; :§ ] .a eEi - (Il e ti o a ;:: ;.: i;:s ;;.. ].nt::3 ;;.. (,,1 c:s t3 %: r:= i.. - '...i ::I ·e: :::! ::s ] 'l < "' "" "' R . R . R . R 216.2 VAP M VAR R . R R R F . P R R. A R R . R R R . R. R 215.8 A PMH VAR R R . F R R F . C F R . A F R . R R R R. RRR 215.6 CA P M A R R R R . R F R . ARFRRRRRR . R . R 215.4 FC P M CA . R . R R . R . R R . C R R . R . R . R . 215.2 FC P M CA . R . F R . R . R R R . F R R . R . R . R . 41 215.0 A P M C R R . F R R F . R F F . A R R . R R R . R . RRR Cl 214.8 F VP M R R . R R R R. R F R . A R R . R R . R . O 214.6 VR . L VR . R . :z i. 214.4 C P M A R . F . F R R R . C R R . R R R. < i. 214.2 R P L F R . R . F. R . 41 213.8 FC VP M C R . F R . R . R R R . C R R . R R . R . Cfl 213.6 A P M R R R R . F F F F F F AFFRRFRR. RRR 213.4 A P M VA. R R. C F R R. R R R . C RRRRF. R. R . 213.2 A PMM VA . R. F . R . R R R . C R R . R . R . :;;, 41 213.0 A P M VA . R . F R . R . R R R . c. R R . ::e: ... 212.8 A P M A R . F R . R . R R R . A R R . RR R . Cl 212.6 B ci.: O 212.2 FC P M C R . F R R R . R R . C . R . R . R . R . e ::; 212.0 R VP L R R R . R . f . R . 211.8 C P M CA . R R R R . R R . R R . C R R . R . ;.... 211.6 VR . L VR . ·- 209.4 B e '1' 209.2 VR . L VR . 209.0 VR . L VR . R . " 208.6 RPLR RR. RR . R . F R. R . 208.4 B Cl 208.2 FCMLFC . A . RR . FRRR . F R . R . i. 208.0 c MGM c R. A. RR . C RRRRFRRR . R . "' 207.8 FCML C A . R . R . R . RR . ::; 21Y7.6 B 21Y7.5 ll 21Y7.3 VR . L R 21Y7 .1 VR . L R 206.9 VR . L R Tab. 4 - Distribution charr of calcareous nanno- 206.7 c VP M FC . A R R . R . R . R . e R R . F . fo ssils from samr,le 206.50 to sample 206.65 FC VP M FC . c . R . R R . R R . c . R R R R R . R . R . 216.60. Colle d Orlando section. See 206.5 CA VP M FC . A R R R . R R R R R R C R R R R F R . R . Text-fìg. 9 for symbols explanation. preservationa!Jotential of the investigateci !ithotypes, 5) In the rest of the Marne di Monte Serrone Fm. but as argue in Mattioli (l 995a) and Bucefalo (212.8 m - 248.2 m), the assemblage composition is Palliani et al. (in press), a primary productivity event almost stable, the abundance shows fluctuations from can also be recognized as a nannoplankton bloom. common to abundant and species diversity from 4) A sharp drop in calcareous nannofossil abun- medium to high. Preservation also fluctuares from dance and diversity is recorded in the overlying inter- poor to medium according to the different lithotypes. val (205.2 m - 212.6 m). Nannofossils are very rare Watznaueriaceae show some high values, in particular and some samples are barren; preservation is poor, L. hauffii. Biscutaceae, usually rare in Toarcian assem- with the exception of few samples. The dominating blages, here range from few to common. Schizo- taxon is M jansae instead of Schizosphaerella spp. sphaerella spp. stil! dominates, while M. jansae records This impoverishment in the assemblage composition a net decline anticipating its disappearance. From could be linked to preservational facrors. In fact, in 230 m upwards e superbus becomes common to this interval the highest values of TOC were record- abundant and is a characteristic component of rhe ed, indicating the presence of aggressive waters in the assemblage. diagenetic environment, due to the catabolic breack- down of the organic matter (Mattioli, 1993, l 995a; Rosso Ammonitico Umbro-Marchigiano Unit Bucefalo Palliani et al., in press). However, the deple- tion in calcareous nannofossils with the dominance of In this interval there is a gradua! but signifìcant usually rare species (i.e., M. jansae) can also be regard- turnover in the assemblage composition. The taxa ed as a biologica! crisis of the phyroplankton, as with a Lower Jurassic affìnity, such as Crepidolithus already shown by Mattioli (l 995a) and Bucefalo spp. and Mitrolithus spp., tend ro decrease both in Palliani et al. (in press). abundance and in number of species. The species TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 27 '-- _ tll .S IC V "' :É· E § ] !l § c., § t: J:; c., lo') c., ·e c., e · ; 't) 15 ::: ::s E ·- E 3 ·- .s ·- ::: - S1 ::: :t i: "ti ;:: 2 a= ..., e; e "" t:s t:s .2 § \) ...(:) '-.l ;;,. ::: :s: :s '"- r...i ·ac ::: ::: I ti...;:: ;:: i: C ::: ·- g < '------r/)_ ,.. Vl à: "'- u u u -,.J,\,> '.'.='"" t,,! :::.9 253.70 VA M M A X R F . R . R R . A F R R X . F . A R F R F R . 3 253.60 C M M F . X . X . R X . F F R X . R . R R R F F R . : 253.30 R L P F . X . X . X X . ! 252.55 C L P A . R. R X X . R . XXR . X. ! 252.20 A M MGA X . R . R . X X R X. F R X. R . FFRRRX? .___ 250.90 F L P F . X . R. R. F. RRRX? z 250.35 C M P A . R . X . R . F R . R. R . RXR. RR . < i:.: 249.70 C M P A X . X . R X. R R X . X . R . RRRX. ... _ _ 249.15 CA M P A . R . X . R X . C. R. C. RXR . u 248.20 A M P A . R . R R . C R R. R. C. RRF .? = 245.50 A M P A . X . XC R X . R. C. RRR . < 243.90 CA M P C X . X . R . XRR . ARR. X . R. AXRRPX. o 243.45 CA M P A X . X . XRRR. C R . X. R. FXRRR. E-- 242.55 A M PM C . X R X X . RFR . ARX. R . R. AXR . R . 241.75 A M MG A X . R . X . RXR . C RR . X . CX R . F . <> 241.55 F L P C . R. C. F. R. = 241.35 FC l. PM C . R . F. C. F R F . o 240.80 FC M PM C . R . R R . P . X R . F . X R R F . .... i. 239.50 P L P C . X . X . C. R.R . R . X. i. 239.10 C L PM A X . X . A. R. XX. RXX . G.> 238.90 C M PM A . R . XR . A X . R. C. RXRX Cll 238.30 FC L P F . X . C. X. R . X . XR. 237.55 C L PM R . R . X. A . A . RRRX. G.> 237.40 F L P R . R. C. R . RX. XX. .,. 237.20 FC L P F R . F . R . F . .____.__ _, = 235.40 C M P A . X. R R . CX. C. R. C FXF. o 234.90 R L IVP e . R . R . R . C F. c. ::i!: 231.55 R L .yp C . R. R . 231.50 FC L P F . F . R . R . F. F C. F F. F. z ·• 229.20 A M PM A . F C . F F . C. XXCF. CA. RR CF. R . < "!:! 227.20 F L PM F RR . C. C. X . X. 225.00 F M P C . R X . X. XXRR X R . RRR . G.> 224.20 F 1. P F . F . R R . F . R . R F R R . = 223.95 F M M F . R F . F R X. F. X. F XC . i. 223.50 F L M F . R F . F R X. F. F R C. OI 222.20 c M M c . R F . F . FF RR C. F R . RFRRF. ::i!: 221.20 F 1. P F . RF . R C R . F. R. 220.40 F M P F . R R . F F F . F P . R R R . F. C. 219.50 FC M IP F . X R X . RRFXFCF . FRRR . R XC. 219.00 F M P F X R X . RRFXRCF. RRR. R . Tab. 5 - Distriburion charr of calcareous 218.45 F M P F . X R R . RRX . CRXXRX. X. nannofossils from sample 216.85 217.90 R L P R . R . R . X . XFX. XX to sample 253.70. Colle d'Or- 217.50 F L PM F . X . R X. F R X. X. lando section. See Texr-fig. 9 for 216.85 e G e . R F X R R . F R X . X A F _:_F_;F:.__:_F_;X:.:.' _:_Ro_·:.__:_Ro_·:.___c __;o_ -'--'--'-...L...- - L--' symbols explanarion. belonging to che genus Lotharingius (in particular L. dance. AH che typical constituents of the Lower haujfiz) gradually decrease and are substituted by che Jurassic assemblages are severely depleted, including Watznaueria group. Carinolithus superbus is common Schizosphaerella spp., Lotharingius spp. and Biscutum as well as some of che Biscucaceae (i.e., D. ignotus and spp. Conversely, Watznaueriaceae, C. superbus and D. D. striatus). Total abundance and species diversity are striatus dominate the assemblage. The disappearances quite high and preservacion is variable according to exceed the first occurrences. the lithology. The turnover also regards the species wichin the assemblage, because several events are Correlation of the nannoevents recorded in this interval, both fìrst and last occur- rences (Text-fìgs. 4-5). The nannofossil events recorded in che Colle d'Orlando section in che Upper Domerian-Lower Calcari a Posidonia Unit Bajocian interval are summarized in che stratigraphic logs (Text-figs. 3-5). The main events related to Preservation is very scarce in che merely calcareous Standard ammonite Zones are discussed here and lithocypes of this unit. The assemblage composition compared to previous reports in order to test their shows limited diversification and low total abun- biostratigraphic reliability (Text-fig. 1O). 28 G. PARISI et alii 291.70 F L 291.00 FIC M OI 288.20 F L P A . F F R. 288.10 RR L P X X . X . R. MURCHISON. :i 286.80 R M VP F R X . R. R . FFR. RX . XXX. 286.40 R L P F R R . R . OI 286.00 F L P C . R . C R . R . R . F R R . ·e 285.40 RR L VP X B 285.10 FIC L p F R . CR. RRR . F R. R. li 284.65 RIF M P c. R . X X . R . RRRRRR. R . XR . ...., 284.05 F L P c. X. X . X . R. R F F R R. 283.90 F M P F X X. RRR FRRRFC. R . 281.80 RIF L P c. X . FR. RFFR. RR . X. _ 281.75 B 280.50 A H p A . R F R . A A R X. R. AFAFFX . X. XRRXR. 279.80 F L p C. F R . R . RF CC. AALENSIS 279.10 F L P C . X . X. R. R. XXFR. F X . 278.90 e M M C. X. RR . R . XX. FFFRC. XR . X. 218.00 e H p A . RXX . X. XFF R R . X . X . FR C RR CX. R . 277.10 FIC M P A . X . R X. XRRFRFX . X . 275.80 R L P R . X. 275.30 A M P C. X X . A A C. R. R. R . AFARRF X . 275.20 R L P C. R . R . R . R X X. 274.90 F M VP C. X X R . R . RRRRXF X . 274.20 F M VP C.XR. R R. F R R R F F F 0 273.90 F L P C. R . X . RFRRCF 213 .10 e L M A. R R R. FRRFFC. " 273.20 e M M A R . R . R X. FF FRCF. R. ·- 2n.10 e L p IA R. RRFR . C. _ 211.90 e MMA . XX. X . RRR . R . RR. R . C RR . RC . 271.60 F L P C . X . X . X . R . RXRRR . ·- 270.25 F M P A . R X . R . X . R . FRRCR . >---·--·- e 269.10 F L P F . R X. X X . RR. R . RXRRRF 268.45 e M PIM C. R . R . R R . R . R . F C RCXF . o 267.45 F M P e. R . R . X . X. RRRRRC . E 267.10 F M p C . F R R . X . R. R . R . RRXF 266.75 F L G C. X X. XRRRR. E 262.90 FIR L p C. X. R . X. X. 261.40 A M p A . R . X . RXXRR. RX. F. C RFXXF R . < 260.60 R L P F X. X . R . X. 259.90 F M PIMF R . X. R . XAF R. R . R . XRR. 259.60 e M PIM A . X R. RXFFR . X . XR . R . C R F R R X . o 259.45 F M P C. R. XRRR. X. R. A. R . "' 259.40 e M M A. X . X . R R R . X. X. R . F. XX. R . X . 259.30 F M PIM C . X X X. ?XFRR.X. X . R . RRRRX. "' 259.00 F L VP A . R. X . X. R . R . O 258.50 F/C M P A . X . X. X . R . R . C. R . RXX . CIC 2.57 .85 e M P A . R. R X. F . X . R . RRRRXR . 257.45 A HMA . RRFR X . e e e. XRXXFXF . ARCRRRR . 257.20 F L p F . F F X. C RRFFX . 256.50 R L P R . R . R . RRR . R . 256.30 C M PAX F X . F R. X . R ?CRRR RF 256.15 FIC M P A . R . R X R R . R X . X R . F R R R X F ? 255.85 FIC M M/G F F FRFFRR . 255.70 F M IP A . X R X . R. RXX . FXRRRX ? 254.90 CIA M P A . F R F RR. X. XF ARFR. C. 254.50 FiC M P A . R . X. X R R . FR. R. C. RRRR . 254.28 F M G F XR. FRF X. 254.25 A M G A X . X. X X R R . CRXR. XF. CRRFRF 253.85 VA lv!__ - x_ ._x_...... :....:...... : __R _ X ..:.....:...... f..._R_ . _._._._ R_ R_ F_._.C,R'-'CR...._ . Tab. 6 - Distribution chart of calcareous nannofoss ils from sample 253.85 to sample 292.90. Colle d'Orlando section. See Text-fig. 9 for symbols explanation. TOARCIAN STRA TIGRAPHY OF THE COLLE D'ORLANDO SECTION 29 recorded in the uppermost Domerian (Erba & CHRONOSTRATIGRAPHY CakareotM NaHDofossH Events Cobianchi, 1989; Cobianchi, 1990, 1992; Bartolini Stagrs Standard :; Ammonite Zones et al., 1992) or in the lowermost Toarcian (Reale et z L41e CONCAVUM al., 1991). Studi es from Portugal and the Bo real < MJddle MURClllSONAE 286-80 - LO Milrolitlius elmgans domain show no agreement in the literature (for an 286.00 - LO Tubirhabdus patubu . Crtpidolilhus cat.us overview, see Mattioli, 1995b). < Early OPALINUM 284 05 - U) Biscuuon fa11.:hii '280.50 - FO Wat1'!11lUt:ria contra.eta. Haalithus magharensis AALENSIS C)(: lagelosphaero marguelii FO of Carinolithus poulnabronei Mattioli, 1996 MENEGlllNII m .IO - FO Wazwaueria sp. 1 The species appears in the basal Toarcian 27530 - FO Retecapso-incompta (Polymorphum Zone), as in other ltalian sections. 3 SPECIOSUM 269. 1O - LO Làlyculus spp. 268.45 - LO Mitrolithus jansae Mattioli (1996) considers this species as a transition- z BONARELLll 259.40 - FO Biscutum depravaxum al form between the genera Calyculus and < 257.45 - FO Discorhabdus criotus Carinolithus. GRADATA 256.30 - FO Parhabdolilhus liasicus u '.!! li! BIFRONS 237.40 - FO Waunaueria colacicchii "< FO of Lotharingius crucicentralis (Medd, 1971) Gri.in LE VISONI 232.55 - FO Wa.l1!1aUeria sp. l & Zweili, 1980 o 229.20 - LO Carinolit.hus poulnelJrounei ... This event has been registered in the present study 219.00- FO DiscorllabdusstriaJus 213.60 - FO Discorhabdus igrwtus in agreement with previous records for the ltalian sec- 208.20 - FO LOlhanngius Yek:itus 205.00 - LO Milroli1Jws len1i cularis tions, in the Lower Toarcian Mirabile Zone (Erba & i POLYMORPHUM 198.60 - FO Carinolil/ws superbus, &sson.i.us pri.Juìi "' 198.00 - FO Bussonius Cobianchi, 1989; Cobianchi, 1990, 1992; Bartolini 192.90 - FO Carinolilhus poulnebrounei 192.20 - FO Lotharingius cru cicentrolis et al., 1992; Reale et al., 1991; Mattioli, 1993, 191 90 - FO Lolharingius sigillaJus, Crf:pidolilhus cavus l 995b; Bucefalo Palliani & Mattioli, 1994). 180 20 - FO Ca/yculus sp. i. 173.90. FOSollasues spp ..i i SPINATUM FO of Carinolithus superbus (Deflandre, 1954) Prins ::i _, 173 50 FO Lotharingius barozii Q, 172 50 - FO Biscutum grande inGriin eta!., 1974 Carinolithus superbus first appears shordy after the Text-fìg. 1O - Stratigraphic correlation of main calcareous nan- FO of L. crucicentralis, in the Lower Toarcian nofossil events (metre levels are from the Colle Polymorphum Zone, in this section as well as in other d'Orlando section; FO = fìrst occurrence; LO = last occurrence). Umbria-Marche sections (Reale et al., 1991; Baldanza & Mattioli, l 992a, l 992b; Bartolini et al., 1992; Mattioli, 1993, l 995b; Bucefalo Palliani & Mattioli, 1994). lts occurrence in the Lombardy basin (Erba & FO of Biscutum grande Bown, 1987 Cobianchi, 1989; Cobianchi, 1990, 1992) and in This species, characteristic of Lower Toarcian North European areas (Medd, 1982; Crux, 1984, assemblages, was recorded in the Upper Domerian 1987b; Bown, 1987; Bown et al., 1988; Bown & Spinatum Zone of the Colle d'Orlando section. This Cooper, 1989) is slightly younger (Serpentinus record is qui te consistent with that reported by Bown Zone). (1987) and Mattioli (1993, 1995b) for the Boreal and Tethyan domains, with the exception of Portugal, FO of Lotharingius velatus Bown & Cooper, 1989 where Bown (1987) noticed this event in the Lower This event is found in the Lower Toarcian Carixian, and in Lombardy, where Cobianchi (1992) Polymorphum Zone, in this section as well as in other reports this event in the Upper Carixian . Umbria-Marche sections (Mattioli, 1995b). Other records both in Umbria-Marche and in Lombardy FO of Lotharingius barozii Noel, 1973 confìrm this Lower Toarcian occurrence (Erba & The FO of L. barozii was recorded in the Cobianchi, 1989; Reale et al., 1991; Cobianchi, Spinatum Zone in this section as well as in other 1990, 1992; Baldanza & Mattioli, 1992b; Bartolini et Umbria-Marche sections (for an overview, see al., 1992; Mattioli, 1993). On the contrary, in Boreal Mattioli, l 995b). The same distribution has been areas, Bown & Cooper (1989) noticed this event in reported in the Lombardy basin (Cobianchi, 1992), the Middle Aalenian. while in Portugal, Bown (1987) has placed this event in the Middle Carixian. In Nonhern Europe this FO of Discorhabdus ignotus (Gorka, 1957) Perch- occurrence has been noticed in the Lower Toarcian Nielsen, 1968 (Noel, 1973; Gri.in et al., 1974; Goy, 1979, 1981). This event falls in the Polymorphum Zone. The record is consistent with that found in other Umbria- FO of Calyculus spp. Marche sections (Bucefalo Palliani & Mattioli, 1994; The entry of the genus Cafyculus occurs at the Mattioli, 1995a), while some discrepancies emerge base of the Polymorphum Zone (lowermost Toarcian). from the literature (see Mattioli, 1995b, for an This datum is fairly consistent with the literature overview). from ltalian sections in which Calyculus spp. has been 30 G. PARIS! et a/ii FO of Discorhabdus striatus Moshkovitz & Ehrlich, fax (basal Aalenian). The simultaneous appearance of 1976 three species (H. magharensis, Cyclagelosphaera marge- This event has been found in the upper part of the relii and Watznaueria contracta) is anomalous, as they Polymorphum Zone at Colle d'Orlando and it is con- are usually subsequent to each other. This may sug- sistent with other Umbria-Marche sections. gest the presence of a sedimentary gap. Many authors Sciunnach & Erba (1994) recorded D. striatus in only have reported this event as occurring in the Lower one sample dated as Bajocian-Bathonian in the Aalenian (Reale et al., 1991; Baldanza & Mattioli, Ticino area (Southern Switzerland). In Portugal and 1992a,b; Cobianchi, 1992). On the other hand, Morocco (Tethyan Domain) De Kaenel & Bergen Baldanza et al. (1990) and Erba (1990) recorded the (1993) report this event from the Tenuicostatum FO of H. magharensis in the Concavum Zone (Upper Zone; Bown et al. (1988) in northern Europe (Boreal Aalenian). Although rare, this species is, however, sig- Domain) this species from the upper portion nifìcant for dating the Early Aalenian. of the Falcijerum Zone. FO of Watznaueria contracta (Bown & Cooper, FO of Watznaueria sp. 1 1989) Cobianchi et al., 1992 The entry of the genus Watznaueria is in the In the ltalian sections this event characterizes the Lower Toarcian Serpentinus Zone in the Colle Lower Aalenian both in the Lombardy and Umbria- d'Orlando section. This record is consistent with the Marche areas (Co bianchi et al., 1992; Mattioli, 1994, Lombardy basin (Erba & Cobianchi, 1989; l 995b; Barro lini et al., 1995). In Northern Europe, Cobianchi, 1990, 1992). On the contrary, in other Bown & Cooper (1989) report a Middle Aalenian Umbria-Marche sections the FO of W sp. 1 (report- age for this event. In the south-west Germany ed as W barnesae) was previously placed in the Middle (Wittnau Borehole, Oberrhein area) Baldanza & Toarcian (Baldanza & Mattioli, 1992b; Nini et al. , Mattioli (1996) report an Early Aalenian age for this 1995) or in the Up per Toarcian (Reale et al. , 1991). event. FO of Discorhabdus criotus Bown, 1987 FO of Cyclagelosphaera margerelii Noel, 1965 The FO of D . criotus was found in this section as This species at Colle d'Orlando, fìrst appears in an well as in another section of the Umbria-Marche area interval overlying the last horizon with Toarcian (Fiuminata) in the ammonite biohorizons indicating ammonites (P. aalensis) and underlying the fìrst the Erbaense Zone, therefore its distribution is consist- ammonite levels of the Aalenian. ent with that given by Bown (1987). In the Lombardy Some discrepancies exist in che liceracure concern- basin this event is recorded in the uppermost ing che age of chis event, as discussed in Erba (1990). Toarcian (Cobianchi, 1992). Different taxonomic concepts may account for such discrepancies. Many recent papers concerning ltalian FO of Biscutum depravatum Bown, 1987 seccions report chis event in the Middle Aalenian This event was recorded in the Upper Toarcian by (Reale et al., 1991; Baldanza & Mattioli, l 992b; Bown (1987) in Portugal sections and in the Aalenian Co bianchi, 1992; Bartolini et al. , 1995). in the Digne area by Erba (1990). In the present sec- tion as well as in the Fiuminata area (Mattioli, 1994) FO of Watz naueria britannica (Stradner, 1963) this event occurs in the upper part of the Middle Reinhardc, 1964 Toarcian. rare, this form is therefore con- This event has been recorded in che uppermosc sidered as identitying a Middle - Upper Toarcian Aalenian (Erba & Cobianchi, 1989; Erba, 1990; assemblage. Cobianchi, 1992; Bartolini et al., 1995) or in the basai Bajocian (Baldanza et al., 1990; Reale et al., FO of Retecapsa incompta Bown & Cooper, 1989 1991) ofltalian seccions. le can, cherefore, be conside- Although very rare and discontinuous in distribu- red as a good marker for placing che Aalenian/ tion, this species can be considered as indicating a Bajocian boundary in che Colle d'Orlando section, Late Toarcian age. In fact, it apfears to be concomi- devoid of ammonites in this interval. tant with ammonite horizons o the Meneghinii Zone in the Colle d'Orlando section and this record is con- MICROFAUNA AND OTHER 0RGANISMS sistent with those given in the literature both for Tethyan and Boreal Realms (Bown & Cooper, 1989; Foraminifers Mattioli, 1994, 1995b) The benthic foraminifers are present overall in the studied sequence wich variable abundances as reporc- FO of Hexalithus magharensis Moshkovitz & Ehrlich, ed in Text-fìgs. 3-5; the main biostratigraphic events 1976 of chis group are also reporced. The microfaunal This event, as well as the two discussed below, analyses allow us to recognize some typical and char- occurs after the horizon of the Aalensis Zone (upper- acceristic Assemblage Uni es in che Toarcian according most Toarcian) and before the horizon of the E. falli- to: Barrolini et al. (1992), Nocchi (1992) , Monaco et G. PARISI et alii, TOARCIAN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION PI. 5 EXPLANATION OF PLATE 5 Fig. 1 - Discorhabdus criotus, distai view, crossed nicols, x 5000, Rosso Ammonitico Umbro-Marchigiano unir, (CO 237.70). Figs. 2, 5 - Discorhabdus striatus, distai views, crossed and parallel nicols respectively, x 5400, Rosso Ammonitico Umbro-Marchigiano unir, (CO 237.70). Fig. 3 - Hexalithus magharensis, basai flate, crossed nicols, x 5250, Calcari a Posidonia unir, (CO 291.00). Fig. 4 Watznaueria colacicchii, dista view, crossed nicols, x 5000, Calcari a Posidonia unir, (CO 284.05). Fig. 6 - Carinolithus poulnabronei, side view, crossed nicols, x 3650, Marne di Monte Serrone Fm., (CO 193.80). Fig. 7 Watznaueria sp., specimen affecred by recrystallization, (yellow-orange colour), crossed nicols, x 5800, Calcari a Posidonia unir, (CO 281.80). Fig. 8 - Watznaueria contracta, distai view, crossed nicols, x 4800, Calcari a Posidonia unir, (CO 286.00). Figs. 9, 10 - Retecapsa incompta, proximal and distai views respectively, crossed nicols, x 4800, Rosso Ammonitico Umbro-Marchigiano unir, (CO 280.50). 32 G. PARISI et alii al. (1994), Nini et al. (1997) and Pettinelli et al. been found in the Umbria-Marche area and in the (1995). Ionian Basin sequences associated with black shale- From the base to the top of the Colle d'Orlando like lithotypes (Pettinelli et al., 1995). section the Assemblage Units are: In the Middle and Upper Toarcian, radiolarians - in the Lower Toarcian, Assemblage Unir D are few or absent but they increase in abundance, (Euguttulina Unit) is characterized by common becoming common to abundant in proximity to the Lagenina with mainly Euguttulina and Prodentalina, Toarcian/Aalenian boundary. small Astacolus and small Lagenina showing a Pliensbachian affinity. Bivalves - Assemblage Unit E is characteristic of a disaero- Bivalve shells, that can be related ro ch e genera bic environment, represented by common Lagenina, Lenti/la and Bositra (Conti & Monari, 1992), are with frequent and characteristic Paralingulina gr. te- common throughout the Toarcian and Aalenian in nera, and always abundant Euguttulina and the Colle d'Orlando section. In rhe Lower Toarcian Prodentalina. During rhe Early Toarcian, in the mid- they are rare and represented by flattened and elon- dle-upper portion of the dark laminated-shales, a gated valve sections. Their abundance increases in rhe bloom of Paralingulina gr. tenera is evident in a cal- Middle Toarcian and rhe base of rhe Rosso cisiltitic leve! (217 m, wackestone with Paralingulina, Ammonirico Umbro-Marchigiano is characrerized PI. 2, figs. 1-2) that marks the end of black shale by densely packed bivalve deposits (PI. 2, fìgs. facies. 7,8,12,13). The bivalve shells, known in rhe past as - At the boundary between the Lower Toarcian «jìlaments », are commonly found in rhe Toarcian and and Middle Toarcian, Assemblage Unir F, character- Aalenian of Umbria-Marche and in orher Terhyan ized by an increase in size of Polymorphinidae and areas as well. common lenticulinas, was recovered. - In the Middle Toarcian, concomitant with the In comparison with the intervals below, rhe Rosso base of rhe Rosso Ammonitico Umbro-Marchigiano Ammonitico Umbro-Marchigiano is characterized by unir, there is an increase in abundance of the genus a higher abundance of organisms such as microgas- Lenticulina, and Spirillina and Conicospirillina tropods, echinoderms, microbrachiopods and holo- become common in rhe assemblage. Large and abrad- turian sclerites, and ammonite embrions have been ed lenticulinas are present and the percentage of spec- observed. imens larger than 150 µm increases. Bioturbation is common throughout the section, Here Bullopora, Falsopalmula jurensis, Falso- except for the black shale interval. In rhe Rosso palmula tenuistriata and Lenticulina d'orbignyi fìrst Ammonitico Umbro-Marchigiano, bioturbation appear. The listed characters define the Assemblage reaches the highest values with a maximum in pene- Units G and F. tration depth and in burrow diameters (Monaco, The first occurrences of Conicospirillina spp. and 1992, 1994; Monaco et al., 1994). Lenticulina d'orbignyi are important events and the second one in particular can identify the stratigraph- CONCLUSIONS ic boundary between the Middle and UpperToarcian. The FO of L. d'orbignyi is coeva! in different Tethyan We have recognized some signifìcanr evenrs, areas (Ruget, 1985; Nicollin & Ruget, 1988; turnovers and characteristic depositional trends in the Monaco et al., 1994; Pettinelli et al., 1995). Colle d'Orlando section (Texr-fìg. 11), which can be related to regional and global changes that have Ostracods occurred in the Tethyan Jurassic. A preliminary study of the ostracod fauna has been carried out on rhe Polymorphum Zone samples UPPER PLIENSBACHIAN-LOWER TOARCIAN by Arias (1993). The assemblage recovered is repre- sented by Ektyphocytere, Acrocytere, Metacytheropteron, In the Colle d'Orlando section the Pliens- Pseudomacrocypris and Isobythocypris. The study evi- bachian/Toarcian boundary is marked by a sharp denced that the assemblage compositions are similar change in sedimentation passing from the limesrones to those known for coeva! sediments of other Tethyan with chert of the Corniola Unir to the marls and areas and south-western Germany. argillaceous marls of the Marne di Monte Serrane Formation. Turbidites and gravity flow deposits are Radiolarians frequent in the uppermost Corniola up to the basa! The radiolarians are always present in highly vari- portion of the Marne di Monte Serrane Formation able frequencies (see Text-fìgs. 3-5) but with a char- with a mean of 75% of the tota! thickness. acteristic trend. The distribution trend shows high Afterwards, in the lower and middle portion of the frequency in the Lower Toarcian, and culminates Polymorphum Zone, the detrital levels gradually with a typical radiolarian packstone at the top of the decrease to a ratio of 30% of rhe thickness. The chert dark laminated shales (PI. 2, fig. 3). This event has disappears at the top of the Corniola unir and is ...l gi w i::: gi -;; .... < <-- QO i:>:;;.-w .... u ,., z "'w ...."' ...l a:i SEA-LEVEL CURVE STRATIGRAPHJC ..,.. ..."' c.:> <-w ;i f:J i:>: : (Hallam, 1988) EVENTS ;iz :i:: ;i o < N o :i:: Q :20 :i:: o u a:i 05 50 7- 100 t: < .... o z b ...l Transgression Regressi on ::; I ·, l } _J l nw I R C5 A " .. + ...i-oz MURCHISONAE Limesrones with cheti, 178 disappcarance of nod\llarity . "".. ca lcareous turbidites and RcCOl'e1y of cherty ·;::: pcbbly mudstone dcposits I------limestonc sediments ::i Anunort.ite decrease. Turbidites and gravil)' flow EARLY OPAUNUM "; d abundanl bivalve she1ls, deposits development 179 AALEN. U 'Hll r.1\..- radiolarian increase '------..._ I------ AALENSIS Nodular limestoues. decrease of nodularity. calcareous 180 turbidi tes and '"innowed Vi beds z o < t:: :::i MENEGHINIJ .:!! 181 u .;!! Q( .i:: !:: Abw1dant ammonites, < Nodular limestones and ,·ecy 4° Nectonic and benthonic very abundant bivalve shells, " fcw nodular marly-liwestonc ------fauna! tlUTIO\'Cf o foraminiferal a.ssemblagcs F -·- .... SPECIOSUM Jevels, calcareous turbìdites E and G. increase ofradiolaria, 182 and winnowed beds 3° Nectonic w 5 reworked for.uninifers in the faunal tumover ;i detrital levels .... o < ttj ...l 183 BONARELLll ·= .. s e < Limestones and marlv- Abundant anunonites, I- ---- o limestones, increase gastropods and brachiopods. " ti 184 i:>: nodularity , calcareous foramiruferal assemblage F, cj turbiditcs with densely packed reworked foraminifers in tbe Nannoplankton tumorer .e z echinodenns detrital levels GRAD.4TA l "' ...lU ® 185 I- ---- 2° Nectonic sei faunal turno\'Cr o ::;-o .... 248.50m BIFRONS Cì § Recovery of aerobìc cond.itions 186 Mari es and maliy·limestones. Ammonite increase. :::i t caJcareous turbidites, peloidal for.am.iniferal asserublage F, "'J!J calcarcnites witb dcnsely abw1danl echinoid f ragments .. 1-EVISONI = pack.ed cchinodenn " o 1° Nectonic and benthoWc 187 iu - fauna) tumover Q. <:::<; '6 217 m Marles and clays.black shales. Radiolana packst .. Pan.ilingulina gr. Anoxic evcnt " HCS.calctu'COUS turbfdites en(!ro bl:oom . foram . assembla,ge E of Domenan o PO/,YMORPHUM E affinity fauna .... ,l\farl)•-limestones, cale. amalgamated Rare aromonites cchinodenn Narmq>lanklon diversificatioo lrurbidites. HCS. clay increase Oay occWTence 188 f ragments. ostracods, t LA TE I I :; 180 ml Limestones with cherts, ,·ery foraminiferal assemblage D Turb:idites and gravity Oow SPIN.1TUM Corniola abundant detrital le"els deposits de\'elopment LIENSB. 170 m Il n Text-fìg. 11 - Comparative scheme between lithofacies, biofacies, main Toarcian - Aalenian events and relationship with che Hallam (1988) eustatic curve. \.>.) \.>.) 34 G. PARJS! et alii always absent in the Toarcian units. In this interval a MIDDLE TOARCIAN-UPPER TOARCIAN nannoplankton diversifìcation and the extinction of ammonite fauna of Domerian affìnity also occur. In this interval the nodularity and rhe bioturba- A similar sharp lithological change at the tion increased, reaching the highest values in the Pliensbachian/Toarcian boundary occurs in other upper part of the Bifrons Zone. The base of che Rosso areas of the Mediterranean Tethys and in South-west- Ammonitico Umbro-Marchigiano Unir falls in the ern Europe, with an increase in marly and shaly sedi- Bifrons Zone. The base of rhis red and nodular lirho- ments (Walzebuck, 1982; Cubaynes & Fauré, 1984; facies is diachronous (Colacicchi et al. , 1988; Cresta Baudin & Lachkar, 1990; Baudin et al., 1990; Sadki, et al., 1989b); the diachroneity can be relateci to the 1992; Graciansky et al., 1993; Braga et al., 1981; high variability of the basin palaeomorphology dur- Braga et al., 1988; Oschmann, 1995; Pettinelli et al., ing the Toarcian. 1995; Morettini et al., 1996). This lithological The deposition of these lithotypes can be relateci change could be interpreted as a global phenomenon to several paleoenvironmental facrors such as better relateci to the transgression which occurred at the circulation and oxygenation of the water masses, a Pliensbachian/Toarcian boundary (Hallam, 1988; lower sedimentation rate and to rhe high acrivity of Haq et al., 1987). Colacicchi & Bigozzi (1996) bioturbants. Such palaeoenvironmental conditions noriced in the Early Toarcian a period of high energy induced a proliferarion of benthic fauna. The litho- carbonate sedimentation on the Latium-Abruzzi plat- logical characters of che Rosso Ammonirico indicate a form and they relateci both the basinal marly deposi- regressive trend which began in rhe Middle Toarcian: tion and the high energy sedimentation on the plat- the benthic foraminiferal assemblages indicate a shal- form to a relative sea leve! rise. lowing trend, similar to rhat found in the Valdorbia In the middle-upper portion of the Polymorphum and Pozzale sections (Monaco et al, 1994; ini et al., Zone, in the studied section, dark shales with a vari- 1997). able amount of preserved organic matter occurred, Red nodular limestones are common in the deposited in low-oxygen paleoenvironmental condi- Mediterranean Tethys (Cecca et al., 1992), in Greece tions. The "black-shale facies" are characterized by an (Karakitsios, 1995; Pettinelli et al., 1995), in important positive geochemical anomaly in trace ele- Marocco and Algeria (Sadki, 1992; Elmi, 1996), in ments and rare-earth elements; the day mineral asso- Turkey (Altiner et al., 1991, cum bibl.) and in Spain ciations showed the greatest abundance of kaolinite (Braga et al., 1981; Braga, 1983). In these areas the and a considerable decrease in smectite (Parisi et al., red nodular limestone units always begin after the 1996). marly-shaly sediments of the Lower and Middlc On the basis of sedimentologica!, geochemical Toarcian; the onset of nodular limestones, however, is and organic (dinoflagellates and nannoplankton) heterochronous, as it is in the Umbria-Marche basin. data, Bucefalo Palliani et al. (in press) have recognized In the Gradata Zone both nectonic fauna and a maximum flooding event in this section in the mid- nannoplankton experienced a turnover. During the dle portion of the Marne di Monte Serrane Late Toarcian no variation is evident in rhe lithology. Formation. The maximum flooding event goes from Other turnover events occur at the base of the the FO of Carinolithus superbus to the FO of Speciosum Zone in the necton and in the Meneghinii Discorhabdus ignotus and this datum is in agreement Zone in the nectonic and benthic faunas, respectively. with other data originateci from different sections of the Umbria-Marche basin (Bucefalo Palliani & AALENIAN Matti oli, 1994; Bucefalo Palliani et al., in press). The isotopie data on the a 13 C carb. showed a neg- In the Lower Aalenian the Calcari a Posidonia ative value in the black-shale facies of the middle- Unir represents an evident change in the sedimenta- upper portion of the Polymorphum Zone followed by tion with the reappearance of cherty limestones. The a positive value in the uppermost portion of the detritic levels again increase reaching 45% of the tota! Polymorphum Zone and in the Levisoni Zone. The sediment. In the Middle Aalenian, a pebbly mud- isotopie trend mirrors the sea-level variation stone deposit is present in the Colle d'Orlando area (Benedetti et al., 1995; Morettini et al., 1996). and it is clearly correlatable to some other coeva! The anoxic event occurred synchronously in all episodes found in the Umbria-Marche area the studied sections of the Umbria-Marche basin (Centamore eta!., 1971; Elmi, 1981a, b; Cecca eta!., (Bucefalo Palliani & Mattioli, 1994; Benedetti et al., 1990; Monaco et al., 1994; Nini et al., 1997). 1995; Stoico & Baldanza, 1995; Nini et al., 1995, The depositional trend recognized in the Colle 1997; Parisi et al., 1996) and can be relateci to the d'Orlando section and documented by a succession global Early Toarcian anoxic event (Jenkyns, 1988; of biological and sedimentologica! events, has already Jenkyns & Clayton, 1986,1997). been recognized in other sections of the Umbria- In the upper portion of the Lower Toarcian a nec- Marche basin (Monaco et al., 1994; Morettini et al., tonic and benthic faunal turnover is evident. 1996; Nini et al., 1997) and in other Tethyan areas (Altiner et al., 1991; Cubaynes et al., 1991; TOARC!AN STRATIGRAPHY OF THE COLLE D'ORLANDO SECTION 35 Graciansky et al., 1993; Braga et al., 1988; Subfamily HILDOCERAT!NAE Hyatt, 1867 Oschmann, 1995; Pettinelli et al., 1995) and is there- Hildaites pseudolevisoni Venturi, 1981 Hildaites cf. exilis Venturi, 1975 fore of regional importance. Hildoceras sublevisoni Fucini, 1919 Hildoceras laticosta Bellini, 1900 Hildoceras graecum Renz, l 906 ACKNOWLEDGMENTS Hildoceras tethysi Geczy, 1967 Hildoceras acarnanicum Mitzopoulos, 1930 We are very grateful to Prof. M. Nocchi for his comments on Hildoceras biftons (Bruguiére, 1874) the foraminiferal assemblages. Our warmest thanks ro Prof. R. Hildoceras angustisiphonatum Prinz, 1904 Colacicchi and Dr. P. Monaco for their constructive criticisms. Hildoceras lusitanicum Meister, 1914 We are also indebted to A. Barrolucci and G. Tosti of the Mercaticeras mercatii (Hauer, 1856) Department of Earrh Science of Perugia for their technical assis- Mercaticeras umbilicatum Buckman, 1913 tance. Finally, our thanks to W. Benedetti for his assistance and Mercaticeras dilatum (Meneghini, l 885) patience during the sampling of the ammonite fauna. This work Mercaticeras thyrrenicum (Fucini, 1919) was supporred by 40% and 60% MURST to Prof. Colacicchi Mercaticeras rursicostatum Merla, 1932 and by 40% MURST to Prof. Parisi. Subfamily GRAMMOCERAT!NAE Buckman, 1905 Pseudogrammoceras subregale Pinna, 1967 Pseudogrammoceras fallaciosum Bayle, 1885 lNDEX OF AMMONITE SPECIES Pseudogrammoceras subfallaciosum Pinna, 1967 Dumortieria meneghinii (Zitte!, 1887) Order AMMONOIDEA Zitte!, 1884 Dumortieria pannonica Geczy, 1967 Suborder PHYLLOCERAT!NA Arkell, l 950 Dumortieria latumbilicata Geczy, 1967 Family PHYLLOCERATIDAE Zitte!, 1884 Dumortieria incerta (Ramaccioni, 1939) Subfamily CALLJPHYLLOCERATINAE Spath, 1927 Pleydellia aalensis (Zieten, 1830) Holcophylloceras ultramontanum (Zitte!, 1869) Suborder LYTOCERATINA Hyatt, 1889 Subfamily BOULEICERAT!NAE Arkell, 1950 & Family LYTOCERATIDAE Neumayr, 1875 Frechiella subcarinata (Young Bird, 1882) Subfamily ALOCOLYTOCERATINAE Spath, 1927 Paroniceras sternale (van Buch, 1832) Alocolytoceras ophioneum (Benecke, 1865) Subfamily TMETOCERATINAE Spath, 1936 Suborder AMMONITINA Hyatt, 1889 Tmetoceras scissum (Benecke, 1865) Superfamily EODEROCERATACEAE Spath, 1929 Family DACTYLIOCERATIDAE Hyatt, 1867 Family PHYMATOCERATIDAE Hyatt,1867 Dactylioceras (Eodactylites) pseudocommune Fucini, 1899 Subfamily PHYMATOCERAT!NAE Hyatt, 1867 Dactylioceras (Eodactylites) simplex Fucini, 1899 Phymatoceras robustum Hyatt, 1867 Nodicoeloceras angelonii (Ramaccioni, 1939) Phymatoceras erbaense (Hauer, 1856) Nodicoeloceras baconicum (Geczy, 1967) Phymatoceras elegans (Merla, 1932) Nodicoeloceras chojfàti Renz, 1912 Phymatoceras iserense (Oppel, 1856) Nodicoeloceras renzi Pinna, 1971 Pseudomercaticeras ftantzi Merla, 1932 Nodicoeloceras spicatum Buckman, 1928 Pseudomercaticeras venzoi Pinna, 1963 Nodicoeloceras ackermanni Pinna, 1971 Crassiceras latum Merla, 1932 Nodicoeloceras verticosum (Buckman, 1914) Crassiceras canavarii (Merla, 1932) Mesodactylites broilii (Mitzopoulos, l 930) Merlaites alticarinatus (Merla, 1932) Mesodactylites sapphicus (Renz, 1912) Merlaites gradatus (Merla, 1932) Mesodactylites mediterraneus (Meister, 1913) Merlaites dausus (Merla, 1932) Mesodactylites ghinii (Mitzopoulos, 1930) Merlaites mo/toni (Venzo, 1952) Transicoeloceras angustum (Venzo, 1952) emend. Pinna, 1966 Furloceras fa baie (Buckman, 1921) Transicoeloceras viallii (Venzo, 1952) emend. Pinna, 1966 Furloceras venustulum (Merla, 1932) Transicoeloceras ramaccionii (Venzo, 1952) Furloceras caro/i (Merla, 1932) Peronoceras tuberculatum Pinna, 1966 Peronoceras aculeatum Parish & Viale, 1906 Family GRAPHOCERATIDAE Buckman, 1905 Peronoceras subarmatum (Yung & Bird, 1822) Subfamily LEIOCERAT!NAE Spath, 1936 Peronoceras vortexSimpson, 1855 Ancolioceras opalinoides (Mayer, 1864) Collina gemma Bonarelli, 1899 Collina nummularia Ramaccioni, 1939 Subfamily GRAPHOCERATINAE Buckman, 1905 Collina linae Parish & Viale, 1906 Ludwigia haugi Douvillé, 1885 Superfamily H!LDOCERATACEAE Hyatt, 1867 Superfamily HAMMATOCERATACEAE Schindewolf, 1963 Family HILDOCERATIDAE Hyatt, 1867 Family HAMMATOCERATIDAE Buckman, 1887 Subfamily HARPOCERAT!NAE Neumayr, 1875 Subfamily HAMMATOCERATINAE Buckman, 1887 Neolioceratoides schopeni (Gemmellaro, 1885) Geczyceras perplanum (Prinz, 1904) Harpoceras mediterraneum Pinna, 1967 Geczyceras porcarellense (Bonarelli, 1899) Harpoceras subexaratum Bonarelli, 1899 "Planammatoceras" tipperi Seyed-Emam i, 1971 Praepolyplectus jòrzanensis Venturi, 1981 Planammatoceras tenuinsigne (Vacek, 1886) Polyplectus apenninicus (Haas, 1913) Polyplectus pluricostatus (Haas, 1913) Subfamily ERYC!T!NAE Spath, 1928 Erycites (Praerycites) civitellensis (Venturi, 1981) Subfamily ARIETICERAT!NAE Howarrh, 1955 Abbasitoides modestus (Vacek, 1886) Emaciaticeras emaciatum (Catullo, 1853) Erycites elaphus Merla, 1933 Distefania festiva Fucini, 1930 Erycites fallifax Arkell, 1957 36 G. PARISI et a/ii !NDEX OF CALCAREOUS NANNOFOSSIL SPECIES Family SCHIZOSPHAERELLACEAE Oeflandre, 1959 Oivision PRYMNESIOPHYTA Hibberd, 1976 Genus Schizosphaerella Deflandre & Dangeard, 1938 Class PRYMNESIOPHYCEAE Hibberd, 1976 Schizosphaerella punctulata Deflandre & Dangeard, 1938 Order EIFFELLITHALES Rood, Hay & Barnard, 1971 lNCERTAE SED IS Family ZYGODISCACEAE Hay & Mohler, 1967 Genus Hexalithus Gardet, 1955 Hexalithus magharensis Moshkovitz & Ehrlich, 1976 Crepidolithus cavus Rood, Hay & Barnard, 1973 Crepidolithus crassus (Deflandre, 1954) Noel, 1965 Crepidolithus granulatus Bown, 1987b REFERENCES Tubirhabdus patulus Reinhardt, 1965 ALTINER, 0., KOCYIGIT, A., FARINACCI, A., NICOSIA, U. & Family PARHABDOLITHACEAE Bown, 1987b CONTI, M.A., 1991, Jurassic-Lower Cretaceous Stratigraphy and paleogeographic evolution of the southern pan of Mitrolithus jansae (Wiegand, 1984) Bown & Young in Young et North-Western Anatolia (Turkey). In Farinacci, A., Ager, al., 1986 O.V. & Nicosia, U. (eds.), Geology and Paleontology of Mitrolithus elegans Deflandre, 1954 Western Pontides Turkey: Geologica Romana, 27: 13-80. Parhabdolithus liasicus Deflandre, 1952 ARIAS, C.F., 1993, Upper Domerian and Lower Toarcian Family RETECAPSACEAE Griin in Griin & Allemann, 1975 Ostracoda from the Umbria-Marche Basin, Centrai Italy: Boli. Soc. Paleont. Ttal., 32 (3): 367-383. Retecapsa incompta Bown & Cooper, 1989 BALDANZA, A., CRESTA, S. & MATTIOLI, E., 1990, Bajocian cal- careous nannofossils from Umbro-Marchean Apennines Order PODORHABDHALES Rood, Hay & Barnard, 1971 (Monte Nerone Area). In Cresta, S. & Pavia, G. (eds.), Proc. Family BI SCUTACEAE (BLACK, 1971) Bown, 1987b "Meeting on Bajocian stratigraphy": Mem. Descr. Carta Subfamily BISCUTOIDEAE Hoffman, 1970 Geo!. ltal., 40: 225-236. & MATTIOLI, E., l 992a, Biostratigraphical synthesis of Biscutum cruciulum (De Kaenel & Bergen, 1993) emend. Nannofossils in the Early-Middle Jurassic of Southern Biscutum depravatum Bown, I 987b Tethys: Knihovnicka, ZPN, 14a (1): 111-141. Biscutum dubium (Noel, 1965) Griin in Griin eta!., 1974 Biscutum jìnchii (Crux, 1984) Bown, 1987 & -, I 992b, Biozonazione a Nannofossili calcarei del Biscutum grande Bown, 1987b Giurassico inferiore-medio della Provincia mediterranea Biscutum novum (Gay, 1979) Bown, 1987b (Dominio tetideo): revisione ed ampliamento: Paleopelagos, Discorhabdus criotus Bown, 1987b 2: 69-77, C.S.A. Università "La Sapienza" Roma. Discorhabdus ignotus (Gorka, 1957) Perch-Nielsen, 1968 - &-, 1996, The Calcareous Nannofossils in the Wittnau KB Discorhabdus striatus Moshkovitz & Ehrlich 1976a borehole: Aalenews- Toarcian and Aalenian working groups meeting, Fuentelsaz and Freiburg 20-26 september 1996, 6: Subfamily SOLLASITOIDEAE (Rood eta/., 1971) Bown, 1987b 21-27. Sollasites lowei (Bukry, 1969) Rood et al., 1971 BARCHI, M., LAVECCH!A, G. & MINELLI, G., 1989, Sezione geo- logica bilanciata attraverso il sistema a pieghe Umbro- Family CALYCULACEAE Noel, 1973 Marchigiano: 2 - La sezione Scheggia-Serra S.Abbondio: Calyculus sp. indet. Boli. Soc. Geo!. ltal., 108: 69-81. Carinolithus poulnabronei Martioli, 1996 Carinolithus superbus (Deflandre, 1954) Prins in Griin et al., BARTOLI I A., NOCCHI, M., BALDANZA, A. & PARISI, G., 1992, 1974 Benthic !ife during the early Toarcian anoxic event in the southwestern Tethyan Umbria-Marche Basin, Centrai Iraly: Order WATZNAUE RIALESALES Bown, 1987b Studies in Benthic Foraminifera, Benthos'90, Sendai, Japan, Family WATZNAU ERJACEAE (Rood et a/., 1971) Bown, l 987b Tokai Univ. Press : 323-338. -, BAUMGARTNER, P.0., & MATTIOLI, E., 1995, Midclle and Bussonius prinsii (Noel, 1973) Goy, 1979 Late Jurassic Radiolarians Biostratigraphy of the Colle Bussonius leufuensis Bown & Kielbowicz, 1987 in Bown, I 987b Benone and Terminilleno sections (Umbria-Marche-Sabina Lotharingius barozii Noel, 1973 Apennines, Centrai Italy): an integrateci strarigraphical Lotharingius crucicentralis (Medd, 1971) Griin & Zweili, 1980 approach. In Baumgartner P.O., et al., (eds.), Middle Lotharingius frodoi Mattioli, 1996 Jurassic to Lower Creraceous Radiolaria of Tethys: occur- Lotharingius hauffìi Griin & Zweili in Griin et al., 1974 rences, sistematics, biochronology: Mém. Géol. Lausanne, Lotharingius sigillatus (Stradner, 1961) Prins in Griin et al., 1974 23 : 817-831. Lotharingius velatus Bown & Cooper, 1989 BAUDIN, F. & LACHKAR, G., 1990, Géochimie organique et paly- Watznaueria barnesae (Black in Black & Barnes, 1959) Perch- nologie du Lias supérieur en zone ionienne (Grèce). Nielsen, 1968 Exemple d'une sédimentation anoxique conservée dans un Watznaueria britannica (Stradner, 1963) Reinhardt, 1964 paléo-marge en distension: B.S.G.F., 8 (6), n° 1: 123-132. Watznaueria colacicchii Mattioli, 1996 Watznaueria contracta (Bown & Cooper, 1989) Cobianchi, Erba -, H ERBIN, J., BASSOU LLET,]., DERCOU RT T, ]., LACHKAR, G., & Pirini Radrizzani, 1992 MANIVlT, H. & RENARD, M., 1990, Distribution of organ- Watznaueria manivitae Bukry, 1973 ic marter during the Toarcian in the Mediterranean Tethys Watznaueria aff. W manivitae Cobianchi, Erba & Pirini and Middle East. In Huc, A.Y (ed.), Deposirion of organic Radrizzani, 1992 facies: AAPG, Srudies in Geology, 30: 73-91. 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