IBERIAN CHAIN SEPTEMBER, 20-23 ^ 1966 ———- N N

PUBLICACIONES DEL SEMINARIO DE PALEONTOLOGIA DE ZARAGOZA

ZARAGOZA — IBERIAN CHAIN SEPTEMBER, 20-23 ^ 1966 ———- n n

Vol.2 1990 G. Melendez (ed.) 1st. Oxfordian Meeting, Zaragoza, 1988 PUBL. SEPAZ, 2, 1990, 33-83

FIELD TRIP ON THE UPPER JURASSIC OF THE IBERIAN CHAIN (SOUTHERN MARGIN OF EBRO BASIN)

Guillermo Melendez, Marc Aurell and Alfonso Melendez

Depto. Geologia, Facultad de Ciencias, Universidad, 50009-Zaragoza, Spain

ABSTRACT

A general view of the Middle-Upper Jurassic boundary and of the Upper Jurassic Stratigraphy and ammonite successions throughout the NE Iberian Chain, southern margin of the Ebro Basin, E. Spain, was offered during a three days excursion, as the main activity of the first field Meeting of the Oxfordian Working Group (ISSJ) (Zaragoza, September 20-23, 1988).

The excursion was leaded by the authors and offered a detailed revision of some relevant problems concerning Upper Jurassic Stratigraphy and Palaeogeography.

Middle to Upper Oxfordian ammonite Biostratigraphy was revised and revisited in detail in most of the classical localities studied in the doctoral Thesis of G.Melendez (1984): Ricla, Aguilon, Arino, Calanda. The question of the Callovian-Oxfordian boundary and the associated stratigraphic gap was reviewed in all these localities under the light of Sequence Stratigraphy and taphonomic analysis, and taking into account the eustatic, tectonic and paleogeographic changes of the platform. The main exposures for that problems were those of Ricla, where a set of successive irregular cavities at this level, enclosing reworked moulds of fossils, were interpreted as karstic in origin, developped under subaerial conditions, and Moneva, where a thick Fe- ooids level enclosing numerous reworked inner moulds of Callovian ammonites was interpreted as formed during a later interval (possibly Upper Callovian to Lower Oxfordian) during this shallowing event on the platform (Lowstand Systems Tract) involving the remotion of Lower and Middle Callovian sediments and reworking of fossils. Evidence for subaerial exposition of the platform is not so strong here as it could be in Ricla. However, the important development of the Fe-oolites level (up to 1 m. thick) in the "Arcos Plateau" (Moneva-Arino), involving non-sorted pisolites and oolites associated to clay minerals such as kaolinite suggests continental influence with a near elevated, emerged area southwards (the "Ejulve-Calanda high"). In Calanda, a sharp erosional surface separates the Lower Callovian, Macro- cephalus Zone beds from the Middle Oxfordian, Transversarium Zone layers.

33 Middle Oxfordian ammonite Biostratigraphy is revised in all these classical localities, where a detailed succession of representatives of subfamilies Perisphinctinae. Passendorferiinae and Ataxioceratinae may be followed from Middle Transversarium up to Lower Planula Zone. Special attention is paid to the presence of a "Rotoides interval" (=Rotoides Subzone, in CARIOU & MELENDEZ. this volume) at the top of Transversarium Zone.

Kimmeridgian to Tithonian successions in marine, carbonate platform facies, are also reviewed in most of these localities and the changes of facies are followed through a long-section accross the platform, from the proximal, northwestern part (Ricla, Aguilon) to the more external (distal) southeastern edge (Calanda, Gallipuen, Molinos). Sediments of the Kimmeridgian sequence (Loriguilla Formation) form a thick marl and limestone interbedding, and are interpreted as typical of an homogeneous ramp, or "extensional lagoon" facies, showing an open, distal area at the East (Alacon, Calanda, Molinos), where a Kimmeridgian succession with ammonites is found. The Tithonian-Berriasian sequence (=Higueruelas Formation), forms the last, regressive stage of the Jurassic megasequence and shows a great variety of facies: lagoonal to continental facies are viewed in Ricla; oncolitic and Coral reef formations are shown at Mezalocha and Aguilon. In Ventas de Muniesa, a final episode with spelaeotemic sequences is studied. In some localities of the eastern part of the platform, (Alacon, Molinos), the oncolitic and the bioclastic and biocontructed facies reach a remarkable thickness.

Continental Lower Cretaceous sediments (Weald facies) overlie unconformably the Jurassic succession in most of the studied area.

34 Zaragoza

fig.l General road map of the field trip.Numbers indicate the succesive main stops. FIELD TRIP ON THE UPPER JURASSIC OF NE IBERIAN CHAIN (SOUTHERN MARGIN OF EBRO BASIN) (FIB.1)

SEPTEMBER 21-23 1988

PROGRAM

September 21 st. Wednesday

Stop 1.1 CORAL AND SHALLOWING UPWARDS SEQUENCES IN UPPER HIGUERUELAS FORMATION (UPPERMOST JURASSIC) The Mezalocha outcrop, in a small old quarry, near the village of Mezalocha displays a good example of coralligenous sequences developped at the upper part of Higueruelas Formation, the upermost carbonate unit of Iberian Jurassic. Upper Jurassic sediments crop out in this region, southwards from Zaragoza, forming a paleorelief fossilized by Miocene sediments.

A whole of six levels, bounded by ferruginous surfaces, may be distinguished (Fig.2), displaying a general shallowing upwards sequence which marks the final evolutive stage of this formation. These six levels may be correlated with three general evolutive stages:

I. (level 1): Inicial stage. Oncolites and bioclasts wackestone to floadstone. Coral fragments still imbedded in micrite suggest a low and still initial colonization.

II. (levels 2,3,4,): A general type-sequence may be distinguished within each level (Fig.2):

a) (lower) oncolites and bioclasts floadstone. Corals still scarce and abundant micrite matrix.

b) (upper) coral boundstone, grading laterally into bioclastic grainstones (flank facies). The presence of abundant corals (branching and other morphologies) generally in life position, suggests an intense colonization of sea-floor.

III. (levels 5,6) (Fig.3.5): Oolitic grainstone showing cross-bedding structures and low-angle planar, cross lamination. This would represent the upper element of the shallowing upwards sequence, forming a set of oolitic coastal bars. Sediment shows a typical "beach-rock" cementation and texture.

36 h * © J2C & I" V

4 if

i» 5- p

fe ®V *v \ \

3 *

N © lL i * ii, © * »J o j

m 0 0 LEYENDA

Wackestone

PT1! Packstone

| j j Grainstone

[~|~E1 Floadstone

11 i | Rudstone

Boundstone

tf Fragmentos de cord

^^ Corales ramosos

Corales masivos

ana Corales planarns v Bioclastos r- o- Bivalvos m

ft !rquln i.dos

a> t'oraminifcros

Pelloides

8 Bioturbaci6n

0? Oncol itos

O Oolitos

-»_ Lam. cruzada

... Encostramienbos CO CO

fig. 3 Interpretative sketch showing the genesis of the different kinds of shallowing upwards sequences, studied at Mezalocha quarry, (from AURELL y MELENDEZ, 1987). A) Complex sequence showing all the terms represented in the profile of the fig. 2.1.. B) More simple sequence, comprising only the terms 4 and 5 of those represented in the profile of the fig. 2.1. (i.e.: coral boundstone and oolitic grainstone). tl».4. Biostratigraphy of the Middle-Upper Oxfordian of Aguilon (outcrops AG-4 and AG-5).(from MELENDEZ,G. 1984) The transition to level 6 is marked by the gradual change from oolitic grainstones to a regular interbedding of white marly limestones and thin oolitic limestones (packstone to grainstone). Calcareous crusts, broken laminations, and probable evidence of mud-cracks are observed at the top. These beds would represent the final term of this sequence with supratidal, emersion stages.

Stop 1.2 THE JURASSIC OF AGUILON (S. OF ZARAGOZA)

Outcrop AG.4: From this point a good view of some of the Middle and Upper Jurassic lithostratigraphic units may be observed. Jurassic sediments form a general E-W faulted anticline showing the Upper Toarcian marly levels (Turmiel Formation) in the nucleus. Middle Jurassic, well-bedded limestones (Chelva Formation) form the most of the southern flank of the anticline.

Middle to Upper Oxfordian materials (Bifurcatus to lower Bimammatum Zone) may be followed in a small outcrop (the "Aguilon-4"; AG-4 outcrop), at the side of the road (Fig. 4) (grey-greenish sponge limestones and marls). The Bifurcatus-Bimammatum boundary is localized within the level AG.4/37, where the first specimens of Epipeltoceras of the semimammatum (QUENSTEDT) and berrense (FAURE) groups have been collected.

Middle and Upper Jurassic units are followed all along the roadside on a short walk through outcrop AG.l.

Stop 1.3 AGUILON. Outcrop AG.l. AG.2

Callovian to ?Tithonian of the Aguilon-Tosos area are characterized by their remarkable thickness, the good outcrop conditions and the completeness of the sequences. At the left side of the road (some 500 m. from the village of Aguil6n) the Callovian materials are exposed in a classical outcrop, and have been studied since 1979 by Sequeiros. 20 to 22 m. of grey-reddish limestones interbedded with shaley marls have yielded a quite complete ammonite succession ranquing from Upper Bathonian to lower Lamberti zone (levels 1 to 143).

40 0 X F 0 R D I E N S E MEDIO SUPERIOR TRAN SVERSARIUM BIFURCATUS BIMAMMATUM ZONA PUT iUKM. WAR T A E SCHIllI STEHOCYCLOI. GROSSQUVRt 1 HY PSELUM SUBZONA SCHIllI B If URC. HORIZONTE TRAMO ESCALA NIVEL EDBBBTO o

Holcophylloc«ras m33 % ? Och. lautlingense FRAD. -# Sowtrb. tortisulcatum (D'ORBJ >•o Trimarg. stenorhynchus {OPP. |

Och. carvaliculatuni( BUCH.j- hispidum (OPP) o Och. ex gr. raixensc-basseat o FRADIN. t~ • Glochiceras (Gl.) subclasum (OPP) c Gl ex gr.crenatum (OPP) — cornutum ZIEG. s z • Proscaphites sp. > # Pass (En.) n. sp. atf czenstocho<*iensis (SIEH.) I > Pass. (En.) birmtnsdorfensis (MOESCH ) C3 • Pass. (Pas5.) liegleri (BR.-LEW.) m % Sequeircsia (Seq.) brochwicii (SEQ.) < • • • • Seq. (Gemm.) trichoplocus (GEMM.) z O Scq. (Gemm.) n. sp. A o X > n Prososph. mairei (LORIOL) r~ O 0 Kranaosph. n. sp. A m 73 Per. (?)n. sp. aft. b«rner>sis LOR. ui o m Per (Otosph.) pseudocrotalinus KILIAN u> z P (0 ) montfalconensis LOR. TJ V) m P (0.) nectobrigeruis nov. o m • # P (0.) vermicularis LEE Per. (Dichtes) wartae 9UK. | » • P (0. ) sor linensn LORIOL # 0 Per. (Oichtes) luciaeformis ENAY. I I a> -« Per. (Oichccras) bifureatoidas ENAY > c Per. {Arisph.) helcnae OE RIAZ. • P. ID.) bifurcatus (QU.) 3 I 2 F P { A.) sp- ind. (gran talla) O O • P. ( D ] crassus ENAY z • Per. (Per.) cf. marteUi (OPP.) • P. (OJ grossouvrci SIEM. # P ( P. ) aguilon en ss nov. • PIP) malinowska* BR.-LEW. Larchcriacxgr. lubchilli {LEEI stnsu ENAY 1966 L. jchilli(OPP) • Euasptdoccras oegtr (OPP.) > Mircuph. bukowskii (CHOFF.) Q Mirosph. sp. ind b Euasp-hypcclum (OPP.)

.5. Biostratigraphy of the Middle-Upper Oxfordian at Aguilon (outcrop AG-2). (from MELENDEZ,G. 84).

41 Callovian-Oxfordian boundary

Within level 143, in an irregular, ferruginous, somewhat oolitic limestone bed, 10 to 25 cm. thick, a mixed assemblage of ammonites from Athleta and Lamberti Zones have been found. Prososphinctes claromontanus BUKOWSKI, and other Lower Oxfordian elements, have been collected as well here inside; these last ones showing Fe-oolitic infillment.lt is not excluded that Upper Callovian ammonites were in fact reworked moulds from the underlying, pre-oolitic sequence.

Middle Oxfordian

From levels 144 to 160 the typical Middle to Upper Oxfordian sediments in sponge-limestone facies may be observed.(Yatova Member of Chelva Carbonate Formation). Sedimentation begins above a hard, irregular perforated surface, representing a stratigraphic gap (?Antecedens to Middle Transversarium Zone).

Two lithologic terms may be easily distinguished within the Yatova Member: A lower term, exposed in Outcrop AG.l, formed by sponge limestones in massive, decimetric irregular banks. A typical ammonite assemblage from the middle Transversarium Zone, Wartae Subzone (=Luciaeformis Subzone, according to CARIOU & MELENDEZ, this volume), has been collected here (Fig. 5).

An upper term, formed by grey, sponge limestones with grey to greenish marly interbedding appears partly covered in outcrop AG.l, being much better exposed in outcrop AG.2, at the right side of the road. Here, above the Wartae, massive beds, (levels 12 to 24), Schilli Subzone levels (beds 24 to 30) appear well exposed. Bifurcatus Zone levels are also well exposed from beds 32 to 50. An irregular, ferruginous surface marks a small discontinuity affecting partly the uppermost horizon of Schilli Subzone and the lowermost horizon of Stenocycloides Subzone.

Upper Jurassic Units

a) Sot de Chera Formation: (c. 40 m.) It may be observed, although partly covered, at the side of the road. Grey-blueish massive and laminated marls and marly limestones. Ferruginous (limonitized) rests of fossils (ammonites, corals, bivalvs, gasteropods) plants, and bioturbation traces are typical of this unit. A Planula to lower Platynota Zone age for this formation is presumed according to the regional data.

Transition to the overlying formation (Loriguilla Fm.) is normally gradual, marked by the predominance of limestone banks in relation to marls.

42 fig. 6. General profile of Upper Jurassic lithostratigraphic units at Aguilon. (from MELEN- DEZ A. & AURELL, 1986).

43 to Loriguilla Formation ("c.60 m.) Within this unit in this locality, two independent lithological terms are easily distinguished.(Fig. 6): A lower term, up to level 20: A typical light grey limestones and shaley marls interbedding ("Ritmita" facies), and an upper term (from level 21 onwards), showing a progressive enrichment in carbonates. Several thickening upwards sequences are observed within a predominantly micritic series, meaning a probable progressive shallowing of the platform.

c) Higueruelas Formation (c.50 m.) A highly bioturbated ferruginous level marks the boundary between Loriguilla and Higueruelas Formations. Oolitic to oncolitic limestones, as well as biohermal coralligenous constructions, are the typical facies of this unit

Several oolitic to oncolitic, lenticular-shaped bodies may be observed in the lower part, prograding laterally over the underlying Loriguilla Formation. Upper members are mainly formed by oolitic shoals and coral reef patches (bioherms).

A high-energy, subtidal carbonate platform is probably the typical sedimentary environment for this unit. At the top of the last oolitic bars (litoral to sublitoral environment), several banks with ostracods, bivalvs, gastropods, etc.would mean the moment of maximum restriction, within a coastal, lagoon environment.

Stop 1.4

THE UPPER JURASSIC OF RICLA

Jurassic sediments of Ricla crop out along several, roughly parallel band westwards from the village. A very complete Oxfordian section is found some 500 m. along the road leading from the village to the railroad trench, at the right side of the road.lFIG.7)

Callovian materials appear abnormally thick in this region, over 90 m. of a monotonous marl and limestone interbedding. The last meters, a succession of black, thick, well-bedded limestones, contain ammonites of Athleta Zone, Trezeense Subzone. They are excavated by an irregular, erosional (?karstic) surface digging well deep into the last limestone banks and depicting a set of irregular cavities or "pockets". Within this first generation of "pockets" an admixture of ammonites of Athleta, Lamberti, and Claromontanus Zones (Lower Oxfordian) has been recorded. All these elements are found under the shape of reworked, inner moulds, appearing normally as incomplete specimens, and even as limonitised and/or phosphatic fragments.(FIG.8)

After a second, irregular surface, a black micritic bank contains indeterminable nuclei of Perisphinctes sp. This bank is capped by a flat, encrusted, irregular ferruginous and perforated surface. Above this surface (meaning an important sedimentary discontinuity), Middle to Upper Oxfordian sediments (10 to 12 meters of black, sponge limestones) are deposited.

As in Aguilon, a lower term, formed by 3 to 4 m. of thick, massive banks, (up to level 30) may be distinguished. Massive banks, represent the middle Transversarium, Wartae (=Luciaeformis, see above) Subzone. The lower part, however (up to level 20) could correspond to lower Transversarium and even upper Plicatilis Zone (see Fig. 9).

Schilli levels spread from bed 30 to 38, the representatives of genus Larcheria being highly abundant. The interval from bed 40 to 48 could, most probably correspond to the Rotoides Subzone (Cariou & Melendez, this volume), according to the recently accepted position of Per. rotoides RONCHADZE.

Bifurcatus Zone ranges from level 48 to c.65-70, a good succession of the different species of Per.(Dichotomoceras) having been recognized, which permits the characterization of several successive biohorizons.

Bimammatum Zone spreads approximately from beds 72 to 90. All classical subzones and horizons distinguished within have been identified here. The last levels (88-90) probably represent a condensation of Hauffianum Subzone and the lower part of Planula Subzone. This last level is capped by an irregular, ferruginous encrusted and perforated surface. Above it, the materials of Sot de Chera Formation, c.60 m. of black to dark blue shally marls with marly limestone interbeddings, are developped, appearing partly covered here. Ammonites found in the lower 10 m. comprise some forms of Orthosphinctes (Orth.) close to polygyratus group (REINECKE), as well as Taramelliceras of the litocerum-falculae and wenzeli groups WEGELE, suggesting Planula to Galar Subzone age. Overlying materials from Loriguilla Formation have yielded no ammonites. Some scarce references to "Ataxioceras" (s.l.) are found in the literature.

Sedimentary environment (Fig.8)

Both the morphology Of the "cavities" and the taphonomic analysis of fossils at the basal irregular level suggest a subaerial, ? karstic, erosional environment. Materials of Yatova Member were deposited on a subtidal platform, on an intensely colonized sea floor. The normally inverted position

46 r-

fij>. H. Interpretative sketch showing the successive processes of (subaerial) erosion and (subacuatic) infilling leading to the development of irregular {'! karstic) cavities between the Upper Callovian and lower Middle Oxfordian at Ricla (from FONTANA, 1990). The generation of irregular, erosional surfaces and taphonomic reworking of fossils takes place during long periods of subaerial exposition of the platform, punctuated by short intervals of marine flooding, involving the arrival of drifted ammonite shells. oo of sponges suggests a moderate energy and an active "baffle effect" of sponges.

The Upper Lithological units (Fig. 10)

Above the sponge limestones of Yatova Member, several lithological units, ranging from Uppermost Oxfordian to ? Tithonian age, have been recently identified (Aurell & Nieva, 1988). A good outcrop is exposed at the side of the road, outside the village.

a) Sot de Chera Formation. 45 m., black, shaley, massive marls, showing several bioclastic limestone interbeddings at the base, and a progressive enrichment in siliciclastics towards the top. Two main types of facies, i.e.(l) bioclastic wackestones, and (2) sandy marls, are recognized within.

The age of this unit presumably ranges from Uppermost Oxfordian (? Galar Subzone) to Platynota Zone. This would be supported by the finding of Orthosphinctes (Ardescia) at the lower part of the overlying formation.

b) Loriguilla Formation. 31 m. Typically "rithmic" interbedding of limestones and shally marly limestones. A high content in siliciclastics appears as the distinctive feature for this unit at this part of the Iberian Chain, unlike more eastern regions.

Scarce references to Ataxioceras (s.l.), Progeronia, etc. in the literature (Bulard 1972), as well as regional correlation, suggest a general, ? Lower Kimmeridgian age for the lower part of this unit. Two main groups of facies may be distinguished: (1) calcareous sandstones, and (2) sandy wackestones.

c) Ricla informal unit (Nieva 1986). This unit, first erected by this author as "Ricla sands and limestones Unit", proposed as equivalent of the upper part of Loriguilla Formation (Aurell, 1990), in base of its sedimentological and paleontological (mainly foraminifera) contents, comprises a some 38 m. thick succession of sands and limestones.(FIG.11)

A lower term, mainly formed by sandstones and oolitic limestones, interpreted as subtidal channel system to litoral oolitic bars deposits, and an upper term, mainly formed by micrites to silty micrites, and coral wackestones and interpretated as mostly lagoonal deposited, have been distinguished.

The precise age of this unit appears difficult to assess, since no determinative fossils have been found. Regional correlation suggests an Upper Kimmeridgian to Lower Tithonian age.

49 t 23( CI it * LEYENDA 1 1.marga 2.muds tone(arenoso) 3.wack.es tone 4. grains tone (mi crocongl.)

L 1 i. r imarga arenosa

Imarga J< u as

— superf.encostrada OS estrat. cruzada en surco 50- m. ys i^g o barras acrecion lateral * ripples de oscilacion oe »"*• ripples de corriente R*—^ A a hummocky a. estrat. lenticular 6 3 « bioturbacion i D en v bioclastos •« intraclastos e oolitos «—1••* iv O • oncolitos fT u ostreidos 1-4 S pectinidos --. 6 ' CO * foram.bentonicos < 0 crinoides so « O corales solitarios 3 V corales coloniales / restos vegetales 0 cantos blandos J< g serpulidos J M K algas 3 U A equlnidos »-C£( s

s g H O 11 tn fig. 10 General stratigraphic profil of the Upper Jurassic lithostratigraphic units at Ricla. (from AURELL & NIEVA, 1988).

50 NV SE

I77T / \ O.J 0 FM. SOT DE CHER* FH. LORIGUILLA

B NW

/ / \e \T aJSf•

c V- 0 N ft 1 H UNIDAO DC RICLA FH. KIGUERUELAS fig. 11 Sedimentary pattern and facies distribution of Lower (A) to Upper (B) sedimentary cycles of the Upper Jurassic at Ricla. (from AURELL & NIEVA, 1988).

fig.12. A: Field diagrammatic sketch of the studied shallowing upwards sequences at Ventas de Muniesa (SANCHO et al, 1988). Detailed scheme of a type sequence showing the spelaeotemic facies at the bottom, the breccia facies at the middle part and the laminate facies at the top.

51 Farther Northwest from Ricla, towards the region of Vera de Moncayo and Talamantes, the typical coralline facies of Torrecilla Formation appears dominant (see Text-Fig.2).

Conclusions: A main sedimentary cycle may be recognised throughout these last Upper Jurassic units:

1) A transgressive set: Sot de Chera and Loriguilla Formations (Upper Oxfordian-Lower Kimmeridgian): A carbonate, extended, somewhat restricted platform, showing an increasing influence of siliciclastic supply.

2) A regressive set: Ricla Unit (Upper Kimmeridgian to Lower Tithonian): Deposited mainly on an inner carbonate platform (lagoonal and similar deposits) with sporadic influence of storms and progradation of oolitic bars and shoals.

September 22, Thursday

Stop 2.1: VENTAS DE MUNIESA

SHALLOWING UPWARDS AND EMERSION SEQUENCES AT UPPER PART OF HIGIJERUELAS FORMATION fFIG.12-13^)

At the Eastern side of the new road which links the localities of Lecera and Muniesa, near the houses of Ventas de Muniesa, the uppermost terms of Higueruelas Formation crop out showing a succession of shallowing upwards sequences.

1) Lower Sequence (levels 1-2) A bank 1 to 3 m. thick of light brown oolitic grainstones representing a system of subtidal bars in a very shallow, high-energy environment. Breccia levels, of probably secondary karstic origin, are also observed.

Level 2 comprises a set of thick, irregular laminations showing a typically vadose cementation (spelaeotemic facies), interpreted also as karstic in origin.

2) Upper sequence (levels 3-4) Level 3 is formed again by a bank 1 m. thick of oolitic grainstones, similar to level 1. Level 4 would mean the final stage of this shallowing cycle, being mainly 52 -S "5 4 Llanura mareal § J i (tapices algales, caliches) 3) 3 Litoral 2 "*• A (facies oollticas)

>o • ©OA^lift o0o0 o x va w^ftQ 3) , O _i LEY END A 2 o « Rampa interna c ® rr Niveles de caliches (facies oncollticas con patches de corales) Estratif. cruzada •Ia Su Corales ramosos Corales masivos a> JS c/5 o Corales solitarios •I a 0 Crinoides n in * Alqas © Oncolitos /"i H v Rampa externa (facies micriticas con mud mounds) o Oolitos V Bioclastos 1 2 Serpulidos •§3 Bioturbaci<5n I * /> Gaster6podos tDo -g SV Br iozoos > 3 & Foraminiferos <3 £ A Espiculas 8> v- A t* Peloides J3 e _2

st 5 1= UH formed by calcareous crusts ("caliche"), developped under supratidal conditions. Three main types of facies are distinguished:

a) Spelaeotemic facies: (similar to those of level 2)

b) Breccia facies: Centimetric pebbles, showing irregular, laminated coatings and embedded in a micritic matrix with traces of plant roots

c) Laminated facies: Parallel, presumably of algal origin, laminations. They correspond to a general tidal flat environment, probably ranging from intertidal to supratidal conditions. The disposition of these facies describes a typical shallowing upwards to emersion sequence.

Stop 2.2 , . THECALLOVTAN-OXFORDTANOFMONEVA (FIQS-14-15)

The road going from Ventas de Muniesa to Moneva crosses through the Upper and Middle Jurassic sediments in a general E-W direction. A good section of Callovian to Kimmeridgian sediments is found at the Barranco de la Vega outcrop (Fig. 14). Above a 2-3 m. thick massive, grey limestones interval, a reddish 12 to 15 m. thick series of limestones and marls and limestones interbedding is observed. Several successive terms are distinguished inside:

1) (levels 1 to 6b): Yellow-red limestones. 3-4 m. of micritic (wackestone of bioclasts and fossils) limestones, stratified in regular banks. They contain ammonites from Bathonian to Lower Callovian age. Bank 6b ends with a sharp, uneven surface showing a dense concentration of fossils, mainly truncated moulds.

2) (Levels 7 to 10): 1.5 m. Red to yellow, Fe-oolites limestone, stratified in regular banks, separated by discontinuous, locally encrusted, limonitic surfaces. Most important surfaces are found on top of levels 9 and 10.

Levels 7 to 9 contain numerous ammonites, mainly incomplete inner moulds, of Lower and Middle Callovian age, showing evidence of reworking, and representing, partly, the horizons I to X of Cariou (1984). Above a hard, ferruginous surface, level 10 contains mixed elements of Lower and Middle Oxfordian (Claromontanus to Paturattensis Subzones).

3) (Levels 11 to 16): 1.5 to 1.7 m. Red to yellowish sponge limestones stratified in thick, decimetric, massive, highly bioturbated beds. These correspond well to the lower term recognized elsewhere within the Yatova Member. Ammonites collected characterize the middle part of Transversarium

54 CAUXV CKTCKMSSS E.NKD.-S.SIC- Call-in' ttcf.mf. S-EPISO SLixxxitr.-Retrocost.

<25 z op o'

(W-i FCGILES » -aar yc«rites Sp. 0. oppeli £1*1 0. discus (SOW.) sr 0. subcostarius (OPPEL) fl> Strungia voultensis LISSAJOUS n Hecticoceras sp. H.(Chanasia)pseudochanaziense (IEK0INE) o" H.(Ziet«nic«f»s) bituberculatja (TSYT.) < H.(2.) cf. zicteni (TSYT.) H.(Lunuleceras)sp. H.(Rossiensiceras) sp. H.(fi.)ro$si«nse teisseyrei (ZEISS) H.(R.)cf aetoaphalua aetoaphalua (BON.) * H.(Putealiceras) sp. n H. (P.) krakoviense (NEUK.) M H.(P.) cf. trilieneatu* (WAAG.) O H.(Orbffnyceras) ?x H.(Orbignyccras) paulovi (TSTOV.) H.(Bonarellites) aaillardi £L«I §• Cadoaitcs sp. S Proceritcs sp. s P.(Si«airadzkia) sp. P.(S.)aasticon«nsis (USS.) Wagn«ric«ras sp. o V. cf. susptnstia (BUCKM«) 3 Hoteoplanulitas sp.

55 Zone, Wartae Subzone. Per. aguilonensis MELENDEZ; Per.(Otosph.) nectobrigensis MELENDEZ and Passendotferia spp. are usual forms in these beds.

4) (Levels 17 to 20): 0.9 m. Red to yellowish sponge, fossiliferous limestones with regular red marls interbeddings. Ammonites of the genus Larcheria are commonly found up to level 19, allowing the characterization of Schilli Subzone. The boundary between Wartae and Schilli Subzones could, probably, be placed at level 16, or even below.

Level 20 shows a thin, yellow, ferruginous bed on top, containing abundant fossils, mainly under the shape of truncated moulds, and evidencing a sedimentary discontinuity. This boundary discontinuity between Transversarium and Bifurcatus Zones may be easily traceable throughout the studied area and Central Iberian Chain. Beds 19 and 20 have yielded some interesting ammonites, identical to Per. rotoides RONCHADZE, 1917 (type specimen). Both the microconch and its presumable macroconch may be identified among the studied material, giving further support to the recognition of a Rotoides Subzone (see Cariou & Melendez, this volume).

5) (Levels 21 to 32): 3 to 3.2 m. A regular interbedding of yellow-red, bioturbated, sponge limestones and red, bioturbated, fossiliferous marls. Ammonites recorded throughout this interval allow the characterization of Bifurcatus Zone (Stenocycloides and Grossouvrei Subzones) and Bimammatum Zone. First specimens of Ochetoceras of the basseae FRADIN to marantianum d'ORBIGNY groups together with some primitive Orthosphinctes, still showing typical Passendotferia-like inner whorls, are found from level 26 onwards. Epipeltoceras berrense FAVRE has been collected at levels 29-30. Typical representatives of Orthosphinctes (m. & M), including some large-sized elements commonly assigned to subgenera O. (Pseudorthosphinctes) and O.(Lithacosphinctes) have been collected on top beds (levels 31-32, probably meaning a partial condensation of Bimammatum and Hauffianum Subzones. Bed 32 is capped by a ferruginous, irregular surface, showing traces of borings and cemented ostreiids.

6) (From level 33 onwards): Marly interval (Sot de Chera Formation). Up to 10-15 m. of soft, massive grey to light beige marls. Some scarce compact, interbedding banks of marly limestones, have yielded few ammonites, close to Orthosphinctes (Orth.) polygyratus, morf. pseudopolyplocoides GEYER, suggesting a probable Galar Subzone to lower Platynota Zone age

Above this interval, the first levels of the typical "rithmic" interbedding of micritic limestone beds and shaley marls, characteristic of Loriguilla Formation, are observed.

56 XO TJ. 1 O U1 e CL LuoiHeloriH^ j Schilli ) Rotoides SUBZGNA COR TRANSVERSAR1UM Bll-URCATUS BIO/ONA CAIL I»M lllf Oxlordiense medio SUBPISO CALLOV OXFORDIENSE PI.SO 2 o — Tnmarginites stenorhynchus OPPEL ^ D - Trimarginites arolicus OPPEL S rt< Ochetocerascanaliculatum (v. BUCH.) s 95 Kranaosphinctes n. sp. A MELENDEZ 5 o Per. (Otospli.) neclobrigensis MELENDEZ e _ Per. (Dichtes.) Uiciae DE R1AZ o . Passendorferia (Enay.) birmensdorfensis MOESCH o _ Taramelliceras (Proscaphites) sp. •o • Pass. (Enay.) aft. birmensdorfensis MOESCH s Sequeirosia cf. brochwiczi(SEQUEIROS) O . Sequeirosia trichoplocus (GEMMEL.L.ARO) . . Larchena schilli (OPPEL) . . Larcheria cf. ibcrica sp. nov. . . Per. (Dichtes.) aft', wartae BUKOWSKI 3 • Per. (Otospli.) vermicularis LEE 5 , Glochiceras subclaiisum (OPPEL) •n . Glochiceras bruckneri (OI'PEl.l C • Neocampylitcs sp. 25 • Larchenasubschilli (LEE) STOP 2.3. THE UPPER JURASSIC UNITS AT ALACON

1.-(Optional). A brief stop may be made on the road to Alacon to have a panoramic view of the landscape of Upper Jurassic units of this region, near the Barranco del Mortero. Biohermal constructions and other carbonate sedimentary bodies belonging to Higueruelas Formation overlie the classical carbonate interbedding series of Loriguilla Formation, and the white, massive, "chalky" limestones of Alacon Member, at the upper part of this unit.

2.- The Upper Jurassic (Kimmeridgian -? Tithonian) of Alacon (Barranco del Mortero section) (fig. 16)

Some 3 km. northwards from the village of Alacon, following the road to the prehistoric painting caves, the Upper Jurassic materials crop out along the hillsides of the Barranco del Mortero. Above the massive, light-grey marls of Sot de Chera Formation, which form the floor of the valley, the white-yellow limestones and marly limestones interbedding of Loriguilla Formation may be studied in detail.

Level 0: At the side of the road, a first set of beds (c.lm thickness) show a strongly irregular, ferruginous surface at the top (Surface di). The last level has yielded a specimen of Orthosphinctes (Orth.) polygyratus, morf. pseudopolyplocoides GEYER, showing possible traces of primitive Ardescia (cf. Atrops, 1982) and indicating a lower Platynota Zone age.

Level la: Above the surface di, a series of 4 to 4.5 m. of regular white, fine-grained limestones with shaley marl interbeddings is topped by a hard, irregular limestone bank, 0,4 m. thick, cut by a second irregular, ferruginous surface (Surface d.2).

Specimens of Orthosphinctes (Lithacosphinctes) and O.(Ardescia), indicating a lower to middle Platynota Zone age are found throughout these levels.

Level lb: Above the surface a series of up to 6 to 6.5 m. of hard, thick bedded yellow limestones (Mudstone to wackestone with fossils) (in banks 0'6 to 1 m. thick) with thin marly interbeddings, is observed. Banks showing concentration of fossils (ammonites, brachiopods, bivalvs). A harder, more important surface (Surface d3) ends this thick interval. Specimens of Orthosphinctes (Lithacospinctes) spp. have been collected at

58 COLUMN A UNIOAOES

I < —4 < 1 ] 1 — .1 a. o z o a* uj o £ Q. ass 1 - S^K - 11 S - i

a. 4, 4, » ^ ». te ^ a i o x jj < a. « ^ o ® * I < «««s 1 I U U t TJ * -J < « XI r O ^ : o. a. o - — E < •= ^t. r = , -a O •MK Oa ^ a » -S

•D o <

o fig 16 Stratigraphic succession and biostratigraphy of the Upper Jurassic of Alacon (Prov. Teruel).

59 the lower part of this interval.

Some 2m. above the base, an involute specimen of Orth.(Ardescia) with parabolic nodes, and showing underdevelopped double bifurcation might indicate Uppermost Platynota to lower Hypselocyclum Zone age.

Lgvgl lg: Above the surface d3 a 1,6 m. thick interbedding, soft interval of brown-yellow regular, 20 to 30 cm. limestone beds and shaley marls is topped by a new, important discontinuity involving sharp facies changing, from bedded to massive limestones. Scarce specimens of Aspidoceras have been found inside, suggesting a possible equivalence of this interval with the so-called "Acanthicum marls" in the Calanda region.

Level 2: A thick series of massive, white to yellow limestone bancks overlies the surface d4. Several intervals (2a to 2d) may be distinguished inside.

2a: 3,7 m. Beige-yellow limestones in thick banks, bivalvs appear common.

2b: 1,2 m. A single, individualised thick limestone bank. A specimen close to Discosphinctoides praenuntians (FONTANNES) has been found, in a fallen block, at the upper part

2c: 2,7m. Massive, poorly stratified limestones.Some specimens of Progeronia sp. have been collected at the upper part.

2d: 5,5 to 6 m. of similar, massive limestones. A thick, o'6 m. regular bank is distinguished at the base. A fragmentary specimen, close to Discosph. praenuntians (FONT.) has been collected in this bed, suggesting upper Acanticum to lower Eudoxus Zone age. The uppermost banks have yielded, up to the present, no ammonites.

Level 3.(Alacon Member) 15 to 20 m. of homogeneous massive, white chalk limestones (pelloid and microoncolites packstones to grainstones). This massive unit has been formally defined as an upper Member of Loriguilla Formation for this region, under the name of "Alacdn Member" (Melendez et al. 1988). It can be easily identified by its white colour, massive aspect and bioclastic texture, and is regarded as a shallow, energetic environment facies developped at the inner side of the "Andorra height". The micritization process undergone by the limestone ("chalking") suggests sporadic subaerial exposition. Numerous fossils (resedimented shells) of brachiopods, bivals, echinoids, crinoids, gastropods, foraminifera etc, and bioclastic rills can be observed within. 60 Level 4: (Higueruelas Formation). Chalky limestones of Alac6n Member are capped on top by a very irregular "hard ground", red surface, evidencing a sharp sedimentary discontinuity. This surface is overlain by a 2 m. thick interval of red irregular, marls and marly limestones. Above it, a 2 m thick bank of beige-brown bioclastic limestones(fossils wackestone), which can be identified as Higueruelas Formation may be observed. A progressive decrease in thickness of this unit towards the Southeast may be remarked here. This may be due, either to non-deposition (as an effect of the "Andorra height") or to post-Jurassic erosion, since Lower Cretaceous sediment overlie unconformably the Jurassic units.

THE "ARCOS PLATEAU"

From the village of Alacon a panoramic view of the so-called "Arcos plateau", extending from the region of Muniesa-Belchite at the west, to the River Martin (Arino-Oliete line) may be observed. As remarked by Bulard (1972), Mesozoic sediments forming the Plateau deep gently to the south, which allows the Lower and Middle Jurassic materials to crop out at the Massif of Penisquera (to the north). On the contrary at the southern part, towards Alacon and the river Martin, Upper Jurassic materials disappear progressively under Lower Cretaceous, appearing only deeply cut at the valley of the river Martin. At Arino, only the lower part of Sot de Chera Formation is preserved below the Cretaceous series, the overlying Jurassic units having been presumably eroded.

Stop 2.4

THE CALLOVIAN-OXFORDIAN OF ARINO CVENTAS DE SAN PEDRO SECTION)

The farm of Ventas de San Pedro is located at the western side of the River Martin, halfway between the villages of Oliete and Arino. A small pathway links the road from Albalate del Arzobispo to Cortes, (Km. 23), with the farm. This pathway is located roughly in front of the small local road going to Alloza and Andorra. At the right bank of the river the Upper Jurassic-Lower Cretaceous beds dip gently to the south.

Stratigraphy (Fig. 17)

A 2-3 m. thick series of grey-orange coloured limestones stratified in regular banks (levels 100 to 107) contain ammonites from Bathonian to Lower Callovian age (Gracilis Zone). Level 107 is a c. 50 cm. thick, massive, irregular bank showing an extremely dense concentration in ammonites

61 (mainly inner moulds showing various evidences of reworking). The top of this bed is marked by a sharp denudation surface which may be correlated with level 6b of Moneva, and suppossed to have the same meaning, as the most important, Callovian-Oxfordian discontinuity.

Depositional sequence J3.0 (= Fe-oolite bed; ? Upper Callovian to Middle Oxfordian) shows a remarkable development here and is composed of levels 108 and 109.

- Level 108 is a 40 cm. thick bed of glauconitic yellow to grey limestone with small-sized, sparse Fe-olites, containing Lower (up to Gracilis Zone) and Middle Callovian ammonites (reworked inner moulds).

- A sharp ferruginous surface caps this bed and separates it from level 109, a some 0.60 m. interval of yellow to orange, Fe-oolites limestone. Fe oolites are large-sized (0.5 to over 2 mm.) and very abundant. Numerous limonitic surfaces and/or ferruginous crusts, normally discontinuous, may permit to distinguish locally several irregular beds within this level (109-A, B, etc).

Ammonite associations found inside this level show a very different state of preservation. Reworked elements predominate at the base. Among them, a classical Lower Oxfordian (Claromontanus Zone has been collected, including Prososphinctes claromontanus (BUK.), Prososphinctes consociatus (BUK), Per.(Otosphinctes) of the moeschi-picteti groups, DE LORIOL; Neocampylites delmontanus (OPPEL), etc. A second association, also at the lower part of the bank 109 comprises resedimented and/or accumulated elements (i.e., non-reworked, and hence, coeval with the embedding rock), characterizing the Paturattensis Subzone: Per (Otosphinctes) of the paturattensis - montfalconensis groups DE LORIOL; Per.(Arisphinctes) sp.; Kranaosphinctes kranaus BUCKMAN, etc. Higher up, within the same level 109, a further association, mainly composed of resedimented and/or accumulated elements, comprises some ammonites characteristic of Lower to Middle Transversarium Zone, namely: Perisphinctes of the parandieri - martelli groups DE LORIOL; Per.(Dichtes) close to elisabethae DE RIAZ and luciaeformis ENAY groups; Per. aguilonensis MELENDEZ, etc.

A further irregular surface caps this oolitic succession and marks the end of this first Upper Jurassic sequence. Above it, the beds of Y&tova Member spread as a well-bedded, thick (up to 10-11 m.), highly bioturbated and fossiliferous limestones. Sponges appear, however, much less abundant than usual for this unit. Three to four lithologic intervals may be distinguished within this succession:

1) A first interval, 1.8 m. thick (levels 110 to 117), formed by grey-reddish

massive, irregular sponge limestones, contains ammonites ranging from top Wartae to top Schilli Subzone. Representatives of Larcheria are commonly found in levels 115 to 117.

2) A second interval, 2.5 to 2.6 m. thick (levels 118 to 128) is formed by irregular, bioturbated brownish glauconitic limestones. Bivalvs (Pholadomyids, Limids) are abundant, whereas sponges appear much less common. Ammonite association from this interval, the classical species succession of P.(Dichotomoceras) allows characterizing the main subdivisions of Bifurcatus Zone. Stenocycloides Subzone appears partly condensed at the base. Bed 128 shows a net hard-ground locally ferruginous surface on top.

3) The third interval (levels 129 to 139), 2 to 2,2 m. thick, begins with an irregular, bioturbated Thalassinoides bank. The overlying beds, irregular, bioturbated, brown glauconitic limestones, have yielded numerous specimens of Passendorferia and primitive Orthosphinctes. The finding of Euaspidoceras hypselum (OPPEL) and Epipeltoceras of the semimammatum (QUENSTEDT) and berrense (FAVRE) groups permits characterizing different horizons within the Hypselum Subzone.

4) The last interval (levels 141 to 155) comprises some 3 to 3.2 m. of brown, glauconitic, well-bedded fossiliferous limestones with marly interbeddings. It ends with a further irregular, ferruginous surface (hard-ground) showing local development of limonitic crusts, traces of borings, and cemented ostreiids. Ammonites of the genus Orthosphinctes (M & m), Passendorferia, Subnebrodites, Taramelliceras, and Ochetoceras, of the marantianum (D'ORBIGNY) - semifalcatum (OPPEL) groups are common. Epipeltoceras bimammatum (QUENSTEDT) has been found in levels 141 to 144. Successive associations allow the precise characterization of Bimammatum to Planula Subzones. Specimens of Subnebrodites close to planula group (HEHL) are found in top level, 155.

REMARKS

Taphonomic and biostratigraphic analyses may permit an increasingly precise knowledge of sedimentary history of Oxfordian materials for this region.

1) A first sedimentary event took place, probably, somewhere between Upper Callovian and Lowermost Oxfordian. It incorporated numerous Lower and lower Middle Callovian ammonites as reworked elements (level 108).

64 2) From Claromontanus (= Lower Cordatum) to Transversarium Zone, several sedimentary events took place (level 109). Production of iron oolites was intense and sedimentation was slow and discontinuous, leading to several discontinuities and lacunes, and resulting in a highly reduced and condensed sequence, up to Middle Transversarium Zone. Production of Fe-oolites continued well up to Waftae Subzone.

3) A further discontinuity and a small stratigraphic lacune is detected between Transversarium and Bifurcatus Zones, partly affecting the top horizon of Schilli Subzone (Rotoides Horizon).

4)The irregular surface capping this limestones series (i.e. level 155), represents a further discontinuity involving a small lacune, which affects, partly, the Planula and perhaps the Galar Subzone.

Above the last level of Yatova Member Limestones (bed 155), some 10 m. of light-grey marls are observed. They have yielded no ammonites (Only some common Ostracods, Foraminifera and plant traces are found) They could, however, represent the uppermost, Galar Subzone,.

Lower Cretaceous (Barremian to Aptian) continental sandy marls and limestones, overlie this last Jurassic units in this point, by means of an erosional surface.

Stop 2.5

A brief review of Middle and Upper Jurasic in Andorra. Facies control and thickness reduction.

In the vicinities of Andorra, on the road to Calanda, a poor outcrop of Jurassic materials, at the left side of the road, may be observed, showing a strong reduction in thickness of Middle and Upper Jurassic units, as a consequence of the effects of the so-called "Andorra Height".

Above a 3-4 m. visible interval of grey marls of Toarcian age (Turmiel Formation), Dogger materials form a carbonate succession of no more than 5 m. thickness. This succession is capped by a bank, 1.5 m. thick of grey-red sponge limestone containing Macrocephalites and other Lower Callovian ammonites.

The series appears partly covered above this bank. However, traces of the Fe-oolitic level are found on the hillside. Less than 5 meters above, the white limestones of lower Loriguilla Formation, under its typical Calanda Member facies, are found again.

65 September 23rd. Friday

Stop 3.1

OXFORDIAN BIOSTRATIGR APHY OF THE CALANDA-MAS DE LAS MATAS REGTON (OUTCROP CA.3)

Mesozoic sediments in the Calanda region (NE Teruel Province) show an intense tectonic deformation. Several repeated thrusts of a general W-E direction, merging northwards, are crossed along the road going from Calanda to Mas de las Matas. Good exposures of Middle and Upper Jurassic are quite common, (fig-13)

the outcrop CA-3 is located at the right side of the local road leading from the Calanda-Mas de las Matas road to Foz Calanda. The Callovian-Oxfordian beds, pink-sed nodular limestones, crop out at the southern margin of a small thrust. Jurassic limestones form a natural wall used for the construction of the dam of Calanda reservoir.

Oxfordian sediments form a 6.5 to 7 m. succession of red coloured, highly fossiliferous sponge limestones, stratified in decimetric, irregular intensely bioturbated banks. They are capped by a dark red coloured, weathered lenticular layer of clay, 0.5 to 2m. maximum thick.

The lower part of the section appears partly covered. However, a detailed ammonite level-by-level collection has allowed the characterization of most of the Middle and Upper Oxfordian zones and subzones (Fig. 19).

1) The Fe-oolitic bank, 20-25 cm. thick has yielded some scarce specimens of Macrocephalites SPP.. from Lower Callovian, up to Gracilis Zone.

2) Lower limestone beds (levels 2 to 12) have yielded only some middle to large size specimens of evolute, crassicostate Per.(Otosphinctes) and Per. (Dichotomosphinctes), suggesting lower Transversarium Zone age. From beds 12 to 18 some specimens of Per.(Otosphinctes) of the nectobrigensis MELENDEZ and vermicularis LEE groups could characterize the middle Transversarium, Wartae Subzone (=Luciaeformis Subzone, CARIOU & MELENDEZ, see above).

Schilli Subzone extends from level 18 to 40. Representatives of the genus Larcheria are abundant throughout this interval. L.schilli (OPPEL) has been collected mostly in levels 18 to 22. Upper levels (24-40) probably correspond to the Subschilli Horizon (cfr. Melendez 1984). The species Larcheria

66 fig. 18 Geographic situation of the Oxfordian-Kimmeridgian outcrops around Calanda (from ATROPS & MELENDEZ 1985). CVP (1,2) Val de la Piedra; CA (1,2) Calanda; GP (1-4) Gallipuen; ER (1,2) Ermita Virgen de la Peiia; CE El Cerro (Molinos); LP Loma del Pinar.

67 subschilli (LEE) has been collected at level CA-3/30. The interval from this bank up to level 40 could represent the Rotoides Subzone, (see CARIOU & MELENDEZ, this volume).

Representatives of subgenus Per.(Dichotomoceras) are collected from levels 40 to 68. Per (Dichotomoceras) of the stenocycloides SIEMIRADZKI and duongi MELENDEZ groups have been found up to level 48, allowing to characterize the Stenocycloides Subzone and the Duongi horizon, and suggestinz the possibility of a partial lacune affecting the lowermost, Bifurcatoides Horizon (Melendez, 1984).

Bimammatum Zone is well characterized from level 60 onwards. Hypselum Subzone is identified up to level 66-68 by the presence of Euaspidoceras hypselum (OPPEL), Passendorferia (Enayites) of the rozaki MELENDEZ and gygii (BROCHWICZ-LEWINSKI) groups, and some representatives of Epipeltoceras of the berrense (FAVRE) group. The last beds, up to level 80 contain some scarce representatives of genera Orthosphinctes, Subnebrodites, Ochetoceras (= %x.marantianum D'ORBIGNY), etc., suggesting partial condensation of Bimammatum to Planula Subzones.

No ammonites have been found above level 80, in the red clay, lenticular interval. Further upwards, above this level, outcrop conditions appear no longer suitable.

Stop 3.2

OXFORDIAN-KIMMERIDGIAN OF THE MACIZO DEL MORRON. DETAILED SECTIONS AT THE MINING AREA OF FOZ CALANDA

The "Macizo del Morron" (Morron Massif) is another linear W-E relief resulting from a further mesozoic thrust parallel to that of outcrop CA-3 and placed some 8 to 10 km. southwards. Upper Jurassic, up to Lower Tithonian materials, crop out forming a distinct relief band, tunnelled by the road at Km, 10. This band gently descends down to the Calanda reservoir, offering, in times of low-level waters, a good section.

Many detailed sections of Oxfordian to Lower Tithonian have been studied since 1983 by Atrops and Melendez. First results were summarized in 1984 (Erlangen Symposium) and are exposed in Fig. 20. It corresponds to the type-section for this region, in the "Val de la Piedra valley", on the hillside of the Macizo del Morron. More accesible outcrops are found in the recently excavated near areas, owing to the mining works of the Foz Calanda lignite mines. 68 COLUMNA DEL OXFORDIENSE EN CALANDA (AFLORAMIENTOS CA2YCA-3)

CTl

fig.19 Biostratigraphy of the Middle-Upper Oxfordian of Calanda (Outcrops CA.2&CA.3). From MELENDEZ G. 1984 The Oxfordian-Kimmeridgian succession

A well exposed succession of Middle to Upper Jurassic is observed at the garage of the mine. Oxfordian succession is, in every point, similar to that exposed in Fig.19 for outcrop CA.2. In relation to outcrop CA-3 and other classical areas, some features are specially noteworthy:

1) The reduction in thickness of sponge limestones -Yatova Member- (=4 to 4.5 m.), and of Sot de Chera marls, which do not overpass 1.5 to 2 m.

2) The markedly glauconitic character of limestones and the remarkably high content in ammonites.

3) The strongly condensed character of the sequence, resulting from taphonomic condensation processes (i.e. reworking processes and mixing of these, older fossils with recent shells, coeval with the sediment).

Middle Transvesarium, Wartae Subzone beds appear difficult to identify. Basal levels, above the Fe-oolite bed, could already be assigned to Schilli Subzone. Thick, large size specimens of Larcheria found just above, might be assigned to the group of L.subschilli (LEE), and represent a higher biohorizon within Schilli Subzone. From level 12 onwards (in outcrop CA-2) representatives of subgenus Dichotomoceras, are abundant; associated with Gregoryceras of the fouquei group (BERTRAND & KILIAN), thus allowing to characterise the Bifurcatus Zone.

The fact that only small to middle size, crassicostate specimens of Dichotomoceras, close to stenocycloides-crassus groups have been found in these level, suggests the existence of a fairly extended lacune affecting the lower part of Stenocycloides Subzone.

Lower Bimammatum Zone beds are characterized by the presence of Euaspidoceras hypselum, and by the first representatives of genera Orthosphinctes and Epipeltoceras. It is also typical the progressive replacement of Ochetoceras of the basseae-raixense groups FRADIN, by those of marantianum group (D'ORBIGNY), and the total absence of representatives of Per .(Dichotomoceras). In outcrop CA-2 no specimens of this subgenus have been found above level 20.

Top beds of this unit (levels 46 to 50) show a dense concentration of ammonites (mainly incomplete, reworked inner moulds) of the general Taramelliceras, Glochiceras, Subnebrodites, Orthosphinctes, Subdiscosphinctes. Sutneria galar (OPPEL) has been collected at the top of

70 ATROPS & MELENDEZ, 1985).

71 level 50. This would suggest a condensation of Planula and Galar Subzones in these levels. Orthosphinctes polygyratus, morf. pseudopolyplocoides GEYER, has been collected within the overlying marls (Sot de Chera Formation), which would indicate a lowermost Platynota Zone age for this unit.The oxfordian-Kimmeridgian boundary is, therefore, placed at the top of level 50.

T nwe.r Kimmeridgian

Kimmeridgian materials, up to Acanthicum Zone, throughout the Cerro del Morron area (Calanda), are formed by a 20 to 30 m. thick carbonate series of white-yellow limestones (fossils-bearing wackestone) and white marls. This assemblage has recently been recognized as a lower member of Loriguilla Formation, and formally defined as Calanda Member (Melendez et al. 1988).

Two distinct terms may be distinguished within the Calanda Member: A lower one formed by white-yellow limestones with shalley marls interbeddings, and an upper one, formed by white soft marls with scarce, thin limestone banks (= "Acanthicum Marls"). At the outcrop of the garage of the mine the lower term (white-yellow limestones), appears well exposed, comprising some 10 to 12 m. of well-bedded limestones with marly interbeddings, and a succession ot ammonites identical to that recognised at the Val de la Piedra section (Fig 20). Platynota Zone materials show a total thickness of some 9 to 10 m. Orthosphinctes Subzone is represented within the underlying, Sot de Chera marls. Within the limestones, successive species of Orthosphinctes (Ardescia) allow the characterization of Desmoides and Guilherandense Subzones.

Hypselocyclum Zone is developped, apparently incomplete, at the upper part with a thickness less than 1 m; the representatives of genus Ataxioceras being quite common. Lothari Subzone has been identified by its nominal species, Ataxioceras lothari (OPPEL).

Divisum Zone seems to be condensed in a single, irregular limestone bank which caps the succession and contains numerous ammonites, among which representatives of the genera Crussoliceras and Garnierisphinctes are quite common. Ammonites appear mainly as incomplete inner moulds, showing evidence of reworking. A net, irregular ferruginous surface showing encrusted fossils and traces of borings caps this bed.

Acanthicum Zone is well represented in the overlying marly interval, (12 to 15 m thick) where a rich collection of Aspidoceras acanthicum (OPPEL) and Progeronia of the lictor (FONTANNES) and breviceps (QUENSTEDT) groups has been found. This marly interval is widely developped throughout 72 the whole Calanda area and may be easily followed at the outcrops of Val de la Piedra and in the cliffs surrounding the reservoir.

Stop 3.3

PANORAMIC VIEW OF THE JURASSIC OF CALANDA

From the old road of Calanda, which at present is sporadically covered by the waters of the Guadalope reservoir, a nice panoramic view of the Jurassic units of Calanda may be obtained. The Jurassic band forming the distinct relief of the Cerro del Morron, right at the north of the mine, is cut by the new road along two small tunnels. The first one (N) is excavated through the Toarcian (Turmiel Formation) and Dogger (Chelva Formation) sediments. Callovian to Oxfordian beds (thin-bedded limestones) crop out, partly covered, at the side of the road, between the two tunnels. The second one, at the south, is excavated through the Kimmeridgian limestones of the classical Loriguilla Formation. Sediments of the lower Calanda Member (marls and limestones) are clearly visible at the border of the tunnel and at the lower part of the cliff. They have been studied in detail at the water side, and may periodically be covered by the water.

Upper Kimmeridgian to Lower Tithonian limestones form the main part of the steep cliff extending throughout the Morron Massif. They appear strongly tectonized and form a distinct bar gently dipping to the water side, where the uppermost terms may be studied in detail.

This uppermost Jurassic series, 50 to 60 m. of micritic, well-bedded brown to yellow limestones, (poorly fossiliferous mudstones), may be easily correlated and compared with the thick, upper term of Loriguilla Formation, as studied in the western part of the platform. The main difference with it would be the constant, though very scarce presence of ammonites (mainly dryted shells), which has allowed characterizing the Upper Kimmeridgian, Eudoxus and Beckeri Zones, and the Lower Tithonian,Hibonotum Zone.

Sedimentary Environment

The inferred sedimentary environment for this upper unit, compared with the one of the underlying sediments of Calanda Member is probably a much more restricted, enviroment though the restriction was notdue to the action of a definite barrier, but to the combined effect of infilling and shallowing of the platform, which would lead to the development of extensional lagoon facies.

73 Several points appear specially noteworthy within this interval:

1) Lower Tithonian Hibonotum Zone levels, with Lithacocer&s and Subplanites.

2) Sponge limestone levels, already studied by Geyer & Pelleduhn (1981).

3) Some sporadic levels of bioclastic and oolitic grainstone, interpreted as resulting from occassional progradations of Alacon Member towards the distal areas, and the presence of several ferruginous irregular surfaces, which might bear evidence of emersion.

Stop 3.4

THF. KIMMERIDGIAN OF ALCORISA REGION THF. SECTION OF THE PANTANO DF. GALLIPUEN.

The Gallipuen Reservoir, built on the Guadalopillo river is located some 4 to 5 km. southwards from the village of Alcorisa. Upper Jurassic sediments crop out at both sides of the dam. Kimmeridgian ammonite-bearing beds were first quoted by Bulard (1972), who recognized a 15 m. thick Lower kimmeridgian. Moliner & Oloriz (1985) have carried out a detailed biostratigraphic study of Platynota Zone. Atrops & Melendez (1985) have carried out a detailed study of Lower Kimmeridgian (up to Acanthicum Zone) in several sections.

The Oxfordian-Kimmeridgian transition is well exposed in Section GP-1, at the right bank of Guadalopillo river: typical sponge limestones of Middle-Upper Oxfordian are covered by a bed 0.5 m. thick of brown nodular, oolitic limestone, with highly uneven upper surface. It is covered by a soft 1.75 m. thick marly interval, (Sot de Chera Formation). At the top there have been recorded: Orthosphinctes (Orth.) polygyratus (REINECKE), Orthosphinctes (Orth.) polygyratus, morf. pseudopolyplocoides GEYER, Nebrodites hospes (NEUMAYR), i.e. a typical lower Platynota Zone (Orthosphinctes Subzone) association. This interval is followed by a 15 m. thick calcareous sequence containing a rich ammonite assemblage, typical of Desmoides Subzone: Sutneria platynota (REINECKE), Aspidoceras (Phys.) circumspinosum (QUENSTEDT), Orthosphinctes (Ardescia) desmoides quenstedti ATROPS, very common, Orth. (Ardescia) enayi ATROPS, Orth. (Ardescia) proinconditus (WEGELE), Orth. (Lithacosphinctes)pseudoachdles (WEGELE).

On the left bank of the river the section may be followed as well: Above the Desmoides Zone levels, a thick limestone series with a scarce contents in 74 ammonites is capped by a massive bank, ending by a distinct hard-ground containing: Crussoliceras divisum (QUENSTEDT). Just below this level, in the limestone beds of nodular aspect and irregular joints, the last representatives of Orth.(Ardescia) inconditus (FONTANNES), from Hypselocyclum Zone, have been collected. Above the hard-ground, a new soft marly interval 12 m. thick is covered transgressively by terrigenous sediments belonging to Lower Cretaceous. In the lower part, a 0.85 m. thick limestone bank, again with a distinct hardground in its upper surface, contains still a typical ammonite assemblage from the Divisum Zone: Crussoliceras aceroides GEYER, Crussoliceras crussoliense (FONTANNES), as well as few Nautilus and numerous bivalvs and brachiopods. In its upper part there have been collected: Progeronia (Hugueningsphinctes) breviceps (QUENSTEDT) Progeronia (Progeronia) progeron (AMMON), Glochiceras nimbatum (OPPEL), characterizing the Acanthicum Zone.

It may, therefore, be concluded that in the Gallipuen region, the Upper Kimmeridgian appears incomplete, the Lower Kimmeridgian being much thicker, (particularly Desmoides Subzone) than in Val de la Piedra section. The Guilherandense Subzone has not yet been clearly identified. The Hypselocyclum Zone, although probably present, has yielded only very few ammonites.

Stop 3.5

THE UPPER JURASSIC OF MOLINOS (FIG.21)

In the surroundings of the village of Molinos, Upper Jurassic sediments crop out across wide areas, from the Ermita de la Virgen de la Pena (between Berge and Molinos), to the area of El Cerro and Loma del Pinar, (southwest from Molinos). Studies carried out by Atrops & Melendez (loc.cit.) remark the incomplete character of Kimmeridgian series, which appear partly eroded (at the level of the "Acanthicum marls") and covered by Lower Cretaceous sediments.

However, an exception to that rule is found at the side of the road leading from the village to the Cueva del Cristal. Here, Upper Jurassic beds, from Sot de Chera to Higueruelas Formations, appear intensely tectonized, affected by a small thrust It is specially remarkable the strong reduction in thickness shown by these sediments.

Marly sediments from the Sot de Chera Formation are here, 3 to 4 m. thick. They have yielded, in the upper part, some fragmentary specimens of Orthosphinctes (Orth.) polygyratus (REINECKE). Above them, white to yellowish limestones of the Calanda Member (a bioclasts, ammonite-bearing

75 wackestone), 4 to 5 m. thick, comprise several irregular banks capped by ferruginous, perforated uneven surfaces. Some scarce representatives of the Subfamily Ataxioceratinae are found throughout this interval.

A somewhat tender, partly covered, 5 to 6 m. thick marly interval, probably equivalent to the "Acanthicum marls", forms the upper part of this lower section (= Calanda Member). Some specimens of Aspidoceras acanthicum (OPPEL) have been found within. Furthermore, a single specimen oildoceras cf. balderum (OPPEL) has been collected in a hard, irregular bank at the top, showing a truncated, ferruginous (hard-ground) surface.

A poorly visible, faulted interval, where the series appear partly repeated, separates the beds of Calanda Member from the upper term. Some 15 meters of micritic, well bedded limestones, (mudstone to wackestone) have been measured. They presumably correspond to the upper, micritic term of Loriguilla Formation. No determinative ammonites, though, have been found within. At the upper part of this unit several irregular, red bioturbated beds mark the end of this depositional sequence. A final, highly bioturbated bank with Thalassinoides marks the sharp discontinuity separating the Kimmeridgian from the Tithonian-Berriasian depositional sequence (=Higueruelas Formation).

Above the Thalassinoides bank a last, 10 to 12 m. thick massive limestone series is observed. It corresponds quite well to the classical lithology of Higueruelas Formation, under bioclastic, bioconstructed, and oncolitic facies. Two main lithological terms may be distinguished:

1) Bioclastic and bioconstructed (corals and sponges) limestones: 6 m. of dark grey to brown massive bioclastic limestones (wackestone to floadstone).

2) Oncolitic limestones: 4 to 5 m. of thick bedded dark brown oncolitic, compact limestones. They display the typical thick-bedded aspect of the limestones of Higueruelas Formation.

This last unit shows sharp variation in thickness, disappearing quickly both toward the north and the south below the Lower Cretaceous series (see above).

76 fig. 21 Stratigraphic succession of Upper Jurassic sediments at Molinos (Prov. Teruel).

77 Final Paleopeographic Synthesis

1) Depositional sequence J3-1: Lowstand Systems Tract (Fe-oolites: Lower Oxfordian-).

On an extended, extremely shallow and relatively uniform platform, emerged areas suffer intense reworking and denudation processes, which affect the underlying Callovian materials. Fe-oolites are formed at the vicinities of the emerged areas and deposited on shallow areas nearby.

2) Depositional sequence J3-1: Transgressive to Highstand Systems Tracts (TST-HST~) (Sponge limestones: Yatova Member. Middle-Upper Oxfordian").

On a subtidal, open, uniform and intensely colonized carbonate platform, sponge limestones are deposited under a low rate of sedimentation. An increase of sedimentation rate and a higher influence of siliciclastic input is detected at the proximal areas, from Bifurcatus Zone onwards,during the deposition of the Transgressive Systems Tract.

3) Depositional sequence J3-2 (Sot de Chera-Loriguilla Formations. Upper Oxfordian-Lower Tithonian)

a) Sot de Chera Marls: On a subtidal, confined, uniform carbonate platform takes place the deposition of Sot de Chera Formation marls. An increase of siliciclastic supply from emerged massifs at West is responsible for the formation of marls, the distal position of the areas acting as the only "filter" for marly material.

b) Loriguilla Formation interbedding: A relative rise of sea level causes the progradation of carbonate sediments of Loriguilla Formation on the Sot de Chera Formation marls. Several paleogeographic heights ("Andorra Height") will prevent the arrival of pelagic elements (ammonites, etc) to the inner part of the shelf.

The sedimentary environment for the upper term of Loriguilla Formation would correspond to an extensional lagoon environment facies, on a shallow, uniform progressively sediment-filled platform. Bioclastic and oncolitic facies of the Alac6n Member on may locally develop some shoal, high energy areas.

78 4) Depositional sequence J3-3 (Higueruelas Formation; Tithonian-Berriasian).

After an important sedimentary discontinuity, an extremely complex inner platform develops, involving very different types of facies, from oolitic grainstone to coral bioherms, and ending with supratidal, shallowing upwards and emersion sequences.

After an intense, Lowermost Cretaceous phase of erosion, Lower Cretaceous continental or transitional sediments cover the Jurassic paleorelief.

Acknowledgements

The authors wish to express their special thanks to M- Pilar Villar and to M- Dolores Lardies for their valuable help in correcting the English text and typing the manuscript.

This Guide and the preparation of the Meeting have been possible thanks to the generous financial support from:

- International Subcommission on Jurassic Stratigraphy. - Instituto de Estudios Turolenses CSIC. - The Volkswagen Stiftung Werke and a sharing research Project in collaboration with University of Stuttgart. - The Vicerrectorado de Investigacion, Univ. Zaragoza. - The Caja de Ahorros de Zaragoza, Aragon y Rioja (CAZAR).

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