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THE SUCCESSION OF VERTEBRATES AND PLANTS ACROSS THE - TERTIARY BOUNDARY IN THE FORMATION, AGER VALLEY (SOUTH-CENTRAL PYRENEES, ) NIEVES LOPEZ-MARTINEZ, M A TERESA FERN~/DEZ - MARRON & MARIA F. VALLE

LOPEZ-MARTINEZ N., FERN~NDEZ-MARRON M.T. & VALLE M.F. 1999. The succession of Vertebrates and Plants across the Cretaceous-Tertiary boundary in the , Ager valley (South-central Pyrenees, Spain). [La succession de vert6br~s et de plantes ~ travers la limite Cr~tac~-Tertiaire dans la Formation Tremp, vall6e d'Ager (Pyr6n~es sud-centrales, Espagne)]. GEOBIOS, 32, 4: 617-627. Villeurbanne, le 31.08.1999.

Manuscrit d~pos~ le 11.03.1998; accept~ dgfinitivement le 25.05.1998.

ABSTRACT - The Tremp Formation red beds in the Ager valley (Fontllonga section, , Spain) have yielded plants (macrorests, palynomorphs) and vertebrates (teeth, bones, eggshells and footprints) at different levels from Early to Early Palaeocene. A decrease in diversity affected both, plants and vertebrates, but not syn- chronously. Plant diversity decreases early in the Maastrichtian, while the change in vertebrate assemblages (sud- den extinction of the ) occurs later on, at the Cretaceous-Tertiary (K/T) boundary. This pattern agrees with the record of France and China, but contrasts with that of North American Western Interim; where both changes coincide with the K/T boundary. KEYWORDS: CRETACEOUS-TERTIARYBOUNDARY, PALAEOBOTANY,VERTEBRATES, TREMP FM., PYRENEES.

RI~SUMI~ - Les d6p6ts continentaux de la Formation Tremp dans la vallge d'Ager (coupe de Fontllonga, Lleida, Spain) ont fourni des fossiles de plantes (palynomorphes et macrorestes) et de vertebras (ossements, dents, oeufs et traces) dates du Maastrichtien infgrieur-PalSoc~ne inf~rieur. Les deux groupes montrent une r~duction de la diver- sitg mais celle-ci n'est pas synchrone: la crise floraie a eu lieu pendant le Maastrichtien, et celle des vertebras ter- restres s'est passSe plus tard, ~ la limite K/T. Ceci est en accord avec les donn~es de la France et de la Chine, mais contraste avec celles du Western Interior de l'Am~rique du Nord of1 les deux changements coYncident avec Ia limite Crgtac~-Tertiaire. MOTS-CLI~S: LIMITE CRI~TACE-TERTIAIRE, PALEOBOTANIQUE, VERTEBRES, FORMATION TREMP~ PYRENI~ES.

INTRODUCTION and the fossil content from presumably reworked channel-fill sediments, seriously flaw the inter- The Tremp Formation in the south-central pretations of the palaeoenvironmental crisis. Also Pyrenees (Lleida, Spain), dated from Early in other areas of the world (Southern France, Maastrichtian to Late Palaeocene, is one of the China), the K/T boundary in continental forma- rare areas in the world preserving the geological tions cannot yet be unambiguously situated record across the Cretaceous/Tertiary (K/T) boun- (Jaeger & Westphal 1989; Zao et al. 1991; Stets et dary in continental environments. Its study is al. 1996). The study of new sections in continental relevant in order to assess the conditions, extent formations is thus necessary for collecting high and intensity of the K/T boundary crisis far from resolution geological data. the area of the extraterrestrial impact. The Tremp Fro. has the suitable conditions in The lack of sedimentary continuity in continental thickness, and continuity for enabling the palaeoenvironments often produces ambiguous study of the palaeoenvironmental changes during results when studying palaeoenvironmental this critical period. Its red beds are rich in fossil changes. This is the case in US Western Interior, remains from shallow marine, coastal and the only continental area in the world were the non- marine environments: , benthic foramini- K/T boundary crisis has been intensively docu- fera, , plants, , dinosaurs and . mented (Tschudy et al. 1984; Lerbekmo et al. On the basis of palaeomagnetic and biostratigra- 1986; Smit et al. 1987; Sheenan et al. 1991; phic data, the I%'T boundary can be accurately pla- Archibald 1996). The abundant erosive episodes ced in the Ager valley (Lleida, Spain), where the 618

Fontllonga section contains an almost complete the oblique collision between the Iberian and sequence from the Early Maastrichtian to the Early European plates. The compressive tectonics res- . (Llompart & Krauss 1982; Feist & Colombo ponsible for the Pyrenean orogeny has divided the 1983; M~dus et al. 1988, 1992; Galbrun et al. 1993; basin into several tectonic units by a progressive Alvarez-Sierra et al. 1994; L6pez Martinez et al. series of thrusts. 1998 a; Vianey-Liaud & LSpez-Martinez 1997). The Tremp Formation represents the last filling In our present study, we compare the vertebrate episode of the Pyrenean foredeep basin. It is and the new plant fossil records around the K/T underlain and intercalated with the near-shore boundary in the Fontllonga section and in the sur- marine Ar~n (Late Campanian-Early rounding Ager valley, which allow us to interpret Maastrichtian), and overlain by the Ilerdian the pattern of changes of the terrestrial biota in transgressive Alveolina and the area during the K/T transition. (Late Palaeocene-Early , Fig. 1) (Mey et al. 1968; Diaz Molina 1987; Krauss 1990). GEOLOGICAL SETTING The Tremp Formation crops out in the central and The Pyrenean foredeep basin was formed subse- western part of the Southern Pyrenees, reaching quently to the opening of the Bay of Biscay during about 900 m at the depocenter near the type locali- the . It constitutes the first stage ty (Tremp, Lleida province, Spain). Fossil verte- of the history of the Pyrenean orogeny, caused by brates and plants from this area have been studied

~hv~ s

4"" ._m unit 3

0

unit 2

3 Map of the Tremp & Ager basins

- F6 ~ Paleogeneconglomerates tracks C~) eggshells I~ Ilerdian Tremp Fro. £;:=3 bones ~ TrempFormation plant I--'--] Ar~n Sandstone macrorests # palynomorphs ~ Upper Cretaceous and older unit 1 oysters "~ Fossil sites rudists ~) oncolithes ~ Though cross-stratification ~ Sigmoidal cross-str. O-Ut Serres Lst. Fontllonga section

FIGURE 1 - Geological map of the Tremp-Ager area, and stratigraphic column of the Fontllonga section with the situation of the main fossil localities. Palaeomagnetic data from Galbrun et al., 1993; stratigraphic data from L. Arddvol, in L6pez-Martinez et al. (1998a). Carte gdologique de la rdgion de Tremp-Ager, et colonne stratigraphique de la coupe de Fontllonga avecla situation des principales localitds fossilif~res. Donndes paldomagndtiques d'apr~s Galbrun et al, 1993; donndes stratigraphiques d'apr~s L. Arddvol, in Ldpez- Martfnez et al. (1998a). 619 by Casanovas et al. (1987), De Porta et al. (1985), Maastrichtian to the Danian in stratigraphical Ashraf & Erben (1986), M6dus et al. (1988, 1992) superposition correlated with the geomagnetic and Barr6n & Di6guez (1992). South of this area, time scale (L6pez-Martinez et al. 1996a, 1998a). the Montsec thrust separates two large, asymme- Two Early Maastrichtian sites contain large sau- tric synclines oriented W-E, the Tremp syncline in ropod footprints, situated about 150 m below the the North from the Ager valley in the South (Fig. 1). K/T boundary interval at the top of Unit 1. La The Tremp Formation in the Ager valley, where Massana site, in the Fontllonga section is an the Fontllonga section is located, reaches about extend dinoturbated surface with hundreds of 700 m in thickness and has been divided into four round- shaped dinosaur footprints bimodal in size units: Unit 1 consists of limestones and marls up (40 and 60 cm in diameter; L6pez- Martinez et al. to 70 m thick with minor intercalations of sand- 1998b). Peralba site, 10 km east from Fontllonga, stones. It has a diverse fossil content with shows several large footprints similar to those remains of oysters, Girvanella, charophytes, from La Massana. plants, benthic foraminifers, and dino- The Fontllonga-6 site is situated about 100 m saurs footprints near the top of the unit. Unit 2 below the K/T boundary interval, near the base of consists of up to 150 m thick reddish the chron C31r (Early Maastrichtian). It has yiel- and with minor intercalations of ded remains of fish (scales from bony , teeth limestones and . It contains plant, ostra- from the rays indicus and Rhornbodus cod, gastropod and vertebrate remains• Unit 3 and sp.), , , , and 4 consist of up to 400 m thick limestones, mud- dinosaurs (dromeosaurs, titanosaurian sauro- stones and sandstones with minor intercalations pods, ankylosaurs and seven types of eggshells} of gypsum. Its main fossil content is Microcodium (Alvarez- Sierra et al. 1994; Soler- Gij6n & De la in the lower part, gastropods and large benthic Pe~a 1995; Vianey-Liaud & LSpez-Martinez 1997; in the upper part. Soler Gij6n & L6pez-Martinez 1998}. Scattered Detailed studies of the stratigraphy, sedimentology, bones and eggshell remains of dinosaurs are docu- paleontology and isotopic content of the Tremp For- mented as well along this section, reaching up to about 70 m below the K/T boundary interval mation in the Ager syncline can be found in Ldpez- Martinez et al. (1998 a) and references therein. (Galbrun et al. 1993). Additionally, a mandible of a large hadrosaur has been reported from the The Chron C29r containing the K/T boundary is Fontllonga section, about 60 m below the K/T located in a 24 m thick succession of sandstone boundary interval (Le Loeuff, verbal com. 1996). and deposits from estuarine environ- This record has been interpreted by Galbrun ments in the upper part of this unit (Galbrun et al. (1997) as evidence of a diachronous extinction of 1993). The K/T boundary interval can be situated the dinosaurs, which would disappear in Europe in a 3 m thick silt level near the top of the section before than in . On the contrary, correlated to the upper part of chron C29r. This the record of dinosaur footprints near the end of interval separates the last record of dinosaurs • . 13 . . the Cretaceous in the Ager valley provides new from a strong excurslon m C isotoplc content of evidence supporting a synchronous extinction of carbonates (Ldpez-Martinez et al. 1996b, 1998a). dinosaurs in both continents. The thickness and uniformity of the deposits in this section during the K/T boundary interval sug- Closer to the VJI~ boundary, three localities i~om gest a relative continuity of the sedimentary the Ager basin have yielded abundant and diver- conditions. The main change occurs after the K/T sifted dinosaur footprints. The Mas de Sauri site boundary, upward in the section where limestones, shows eight footprints from a track attributed to evaporites and dominate. a large ornithischian (Llompart, 1979; L6pez- Martinez et al. 1998 a). It is situated about 25 m VERTEBRATES below the K/T boundary interval, correlated to the base of chron C29r (L6pez- Martinez et al. 1998a). Unit 2 of the Tremp Fm. at Fontllonga section The Mas Morull and Sta. Maria de Mei~ sites contains two rich vertebrate assemblages, Font- have the youngest dinosaur footprints, situated llonga- 6 (F6) in the Early Maastrichtian and Font- about 8 m below the end of chron C29r. This stra- llonga-3 (F3) in the Early Danian (Fig. 1). Some tigraphic interval may represent 200-350 thou- scattered samples have been collected from other sand according to the estimated sedimenta- levels. Additionally, five other sites from the Ager ry rate (L6pez-Martinez et al. 1998a), thus the syncline correlated with the Fontllonga section site corresponds approximately to the chronologi- have a rich record of dinosaur tracks. They allow us cal position of the K/T boundary assuming no to document a vertebrate fossil sequence across the major breaks in the sedimentary process. The K/T boundary with eleven sites from the Early Mas Morull site (near Figuerola, Fig. 1) shows 620

FIGURE 2 - Dinosaur megatracksite south of Sta M a de Mei~. The pic- ture shows a part of the dinotur- bated surface close to the Creta- ceous-Tertiary boundary, contai- ning rounded footprints attributed to a herd of probably quadrupedal, small sauropod dinosaurs. Gisement de grandes traces de dinosaures au sud de Sta M a de Meid. L'image montre une partie d'une surface dinotarbde proehe de la limite Crdtacd-Tertiaire, qui contient des traces arrondies attri- buges d un troupeau de dino- saures, probablement des petits sauropodes quadrup~des.

thirty footprints from at least two types of dino- ked fossils from dinosaurs have been recorded in saurs, a large sauropod and a small type. The Sta. sandstone levels above the K/T boundary (Smit el Maria de Mei~ megatracksite holds a large dino- al. 1987; Argast et al. 1987). turbated surface, about one thousand square meters in area, showing hundreds of evenly spa- FLORAL ASSEMBLAGES ced rounded footprints, attributed to a herd of small sauropods (Fig. 2). Two rich palynological samples have been studied in the Fontllonga section: sample #32 is located 14 The localities Fontllonga 3 and Figuerola are cor- m below the K/T boundary interval, and sample related to the top of chron C29r (Earliest Danian). #36, 2.5 m above it, at the vertebrate site They are situated approximately 3 m above the Fontllonga-3 (Fig. 1). The age of both samples can surface containing dinosaur footprints at Mas be accurately dated, respectively at the middle Morull and Sta. Maria de Mei/~. An exhaustive part and near the top of chron C29r. In addition, a sampling of these marly levels has yielded a large macrofossil plant assemblage has been recovered number of bones and teeth from fish (aft. one m above the level of palynological sample #36, Lepisosteiformes, , cf. close to the top of chron C29r. This assemblage laurenti, Stephanodus sp., Siluriformes), frag- yielded fragmentary leaf and scarce fruit remains. ments of carapaces, remains and Among these remains, about 50 specimens show tiny bird eggshells, as well as some teeth from better preservation, allowing us to identify 13 mammals, but no dinosaur remains. The fish spe- taxa. This is the first reference to a Danian plant cies Coelodus cf. laurenti is in age (De macrofossil assemblage in Europe. la Pefia & Soler Gijdn 1996). The best represented In our palynological samples the spores predomi- corresponds to the multituberculate nate over the gymnosperm or the angiosperm pol- genus , also known from the Lower len, both below and above the K/T boundary (Fig. Paleocene site Hainin (Belgium). 3). They reach 72 % in the Late Cretaceous Other scattered vertebrate remains from Unit 2 sample, and 48 % in the Danian one. They are upper sandstones, correlated to chron C29n and composed of Anthocerotaceae (Phaeocerosporites C28r (Danian), correspond to remains of turtles. fsp.) Lycopodiaceae (Hamulatisporites fsp.) Selagi- Up to now, neither dinosaur eggshells nor bone nellaceae (Echinatisporis fsp., Gabonisporis fsp., remains have been reported in the Palaeocene Ceratosporites fsp), ferns including Schizaeaceae part of the Tremp Formation, not even as rewor- (Schizaeoisporites fsp., Cicatricosisporites fsp., Tri- ked fossils. This contrasts with the situation in lobosporites fsp. and several forms of Leiotriletes), the Western Interior basin, were putative rewor- Polypodiaceae (Laevigatosporites fsp., Converru- 621

FIGURE 3 - Relative abundance of the three main plant groups repre- sented in palynological samples from the Fontllonga section situa- ted just below and above the K/T boundary (see fig. 1). Frdquenee Danian i Angiosperms I relative des trois groupes princi- # 36 -~ paux de pIantes reprdsentds dans la Gymnosperms coupe de Fontllonga dans les deux dchantillons palynologiques situds juste au-dessous et au-dessus de la Spores limite Crdtacd-Tertiaire (voir fig. 1).

Maastrichtian # 32 ......

1'0 2~0 30~ 40~ 5; 60~ 70, 80 cosisporites fsp.), GIeichenidaceae (Gleicheniidites laceaepollenites), Tiliaceae (Intratriporopollenites, fsp., Toroisporis fsp.), Granulatisporis fsp., Tripo- very scarce in #36, doubtfully in #32) and Norma- roletes fsp., etc. The spores dominate in some other polles form-genus incertae sedis (PEcapollis, Maastrichtian Pyrenean assemblages, but a Semioculipollis, Nudopollis, Longanulipollis). fern- spike at the K/T boundary has not yet been found in the Pyrenees (De Porta et al. 1985; M6dus The Danian sample #36 yielded the Nor- et al. 1988). However, the K/T boundary palynolo- mapolles taxon Pseudoromeinipollenites paleoce- gical event has been reported near the Maas- nicus KEDVES, 1982, similar to that described from trichtian type section, marked by an unusual Menat (Late Palaeocene, France). This taxon is abundance of bryophyte spores (Brinkhuis & absent in the Late Cretaceous sample #32. The Visscher 1994). morphogenus Pseudoromeinipollenites sensu Le- The gymnosperms are slightly more abundant goux is however reported by M6dus (1986) and relative to angiosperms in the Cretaceous sample M6dus et al. (1992) as a typical Cretaceous taxa than in the Palaeocene one (29% against 23% along the complete Fontllonga section and other from the total of flowering plants, fig. 3). They are European localities. mainly represented by Inaperturopollenites fsp. The Danian macrorest assemblage from Font- (Cupressaceae-Taxodiaceae, Glyptostrobus being llonga contains Juglandaceae (Juglandophyllum also present in the plant macrofossil assemblage); sp. and Carya sp.), Fagaceae (Eotrigonobalanus Cycadaceae pollen and very rare Pinaceae (Pityosporites) are also present. We do not observe furcinervis [RossM.] Walter & Kvacek) and an increase in the Pinaceae frequency from Late Myricaceae (Myrica sp.). Also Salicaceae (Populus Cretaceous to Early Tertiary in this section, aff. leuce [RossM.] Ung. and P. cf. zaddachii HEER) contrary to that assessed by M6dus et al. (1992). and Proteaceae (Dryandroides quercinea VEL.) are identified. Less frequent are Magnoliaceae (cf. Monocots are very scarce in all Fontllonga samples Magnolia dianae UNG.), Lauraceae (Daphnogene of both palynological and macroremain assem- sp.), Myrtaceae (Rhodomyrtophyltum reticulosum blages. Only a few monocolpate can be [ROSSM.] Knobloch & Kvacek and c£ Myrtos- attributed to Palmaceae. This contrasts with the permun cooperi CHANDLER) and Ebenaceae (Dios- neighbouring palaeobotanical assemblages from pyros brachysepala AL.BR.). Isona (Early Maastrichtian of the Tremp basin), where Palmae are very frequent or dominant, both Microphyll leaves dominate this foliar assembla- in palynological and macroremain assemblages ge, which can indicate either a subtropical seaso- (De Porta et al. 1985; Barrdn & Di6guez 1992). nally dry climate or a warm- temperate moist cli- Dicots, mainly Hamamelidae, are dominant mate. The abundance of mesotherm taxa and the among angiosperms as both pollen and foliar presence of evergreen angiosperms (Mag~oliaceae remains. The pollen assemblage contains Juglan- and Lauraceae) indicate a subtropical climate. daceae (Subtriporopollenites and Platycarya- Entire- margined leaves constitute approximately pollenites ), Fagaceae (Tricolporopollenites ), Myri- half of the sample, typical for subtropical forests caceae ( Triatriopollenites and Labraferoidaepolle- (Wolfe 1971). Therefore we infer a subtropical sea- nites), Betnlaceae (Triporopollenites), Ulmaceae sonally dry climate for the Earliest Palaeocene in (Rugulitriporites ), Clethraceae-Cyritlaceae (Cyril- the Tremp Formation. 622

DISCUSSION The diversity of Danian foliar remains from The record of vertebrates shows an abrupt pat- Fontllonga decreases in relation to Late tern of change across the Cretaceous-Tertiary Cretaceous Central Spain assemblages (GSmez boundary in the Tremp Formation, dinosaur and Porter 1983). We pass from 52 taxa (2,6 remains ray remains disappearing at the top of unit 2. per species) in the Late Campanian-Early Vertebrate diversity decreases from Late Creta- Maastrichtian assemblages from Central Spain to ceous to Earliest Tertiary mainly due to the dra- 13 taxa (4 remains per species) in the Danian matic change from associations rich in dinosaurs assemblage from Fontllonga. These figures coinci- to associations with no dinosaurs. The absence of de with those of the foliar assemblages from the rays in Tertiary levels may be attributed to more Western Interior, showing also a strong decrease freshwater palaeoenvironmental conditions, since in plant diversity from Cretaceous to Tertiary: the the estuarine sandstones organized in thickening average number of taxa passes from 42 taxa in and coarsening sequence indicate a regressive nine Cretaceous sites to 8 taxa in seven Early trend of the unit 2 of the Tremp Formation. Sedi- Palaeocene sites (Wolfe & Upchurch 1986). mentary conditions are similar in both Creta- A decrease in plant diversity in the Western ceous and Tertiary parts of the unit 2, thus the Interior is detected in palynological taxa at the absence of dinosaur remains in the top of the unit K/T boundary, passing from 200 taxa in Late does not seem to be linked to taphonomy. The Ager Maastrichtian to 135 taxa in the Palaeocene tracksites prove the presence of abundant and (Nichols et al. 1990). In contrast, the diversity loss diverse dinosaurs living in the area just before in palynological assemblages in the Pyrenees the ~T boundary, while no dinosaur remains occurs during the Maastrichtian, before the K/T have yet been recorded above it. The modest boundary. We go from 103 taxa in the Late increase in the mammalian abundance in the Campanian-Early Maastrichtian from Central Early Tertiary does not balance the diversity loss Spain, and 83 taxa in the Early Maastrichtian due to dinosaur extinction. from Isona (Alvarez Ramis et al. 1994, 1996; De The abrupt disappearance of dinosaurs in the Porta et al. 1985), to 40 taxa in the Late Maas- Tremp Formation at the upper part of the chron trichtian and 44 taxa in the Early Danian from C29r close to a 13C isotopic excursion coincides with Fontllonga. The same case occurs in the Nanxiong the K/T boundary position, located in marine sec- basin (China), where Stets et al. (1996) document tions about 250 000 years before the end of chron a strong decrease in palynological diversity, from C29r around a 13C isotopic excursion. This coinci- 34 to 11 taxa, located 90 m below the last dinosaur dence suggests that global palaeoenvironmental record. They propose to consider this floral event catastrophic processes were responsible for mass as the K/T boundary, and the youngest dinosaurs extinction in both marine and non-marine realms. as Tertiary in age, but Zhao et al. (1990) dated the floral crisis as Late Maastrichtian, near the base In spite of the catastrophe which could affect the of chron C29r. Therefore in Spain and China the terrestrial environments, a smooth transition plant diversity crisis would occur during the from Late Cretaceous to Palaeocene palynological Maastrichtian, while in North America it appa- assemblages has been described in the Old World rently occurs later on, at the K/T boundary. (M~dus et al., 1988; M~on 1990, 1991). In the case of the European plant macrofossil assemblages, a In the Coll de Narg5 area (south-central Pyrenees, gradual transition across the K/T boundary seems Spain) and the Aix basin (Provence, France), also to be the case (see Knobloch et al., 1993). In Ashraf & Erben (1986) have reported a decrease in our Danian macroremain assemblage, six out of palynological diversity from 8 to 3 taxa (mainly thirteen taxa (Dryandroides quercinea, Rhodo- Pinacea; palynozones B/C boundary) situated myrtophyllum reticulosum, Populus leuce, Myrica below several levels with dinosaur eggshells. sp., Diospyros brachysepala and Glyptostrobus These authors as well as M~dus et al. (1988) consi- sp.) are shared with Late Cretaceous assemblages dered this modest palynological change to be the from other regions. However the extinct Chei- K/T boundary, but Cojan (1989) instead situated it rolepidaceae, common in the Late Cretaceous in the transition from Early to Late Maastri- from Central Spain and Pyrenees (Isona) are chtian, although with no positive dating. Another, absent in the Latest Maastrichtian and Danian older palynological change is reported by Ashraf & assemblages from the Tremp Formation. A turno- Erben (1986) between their palynozones A and B ver in plant composition thus occurs during the in the Coll de Narg5 section. However the samples Maastrichtian, before the K/T boundary. below and above this change contain 19 taxa, most

FIGURE 4 - 1. Spiniferites fsp. Fontllonga #32. x 900. 2. Cicatricosisporites fsp. Fontllonga #36. x 900. 3. Granulatisporites fsp. Fontllonga #32. x 900.4. Triporoletes fsp. Fontllonga #32. x 900.5. Converrucosisporites fsp. Fontllonga #32. x 900.6. Ceratosporites fsp. Fontllonga #36. x 900.7. Leiotriletes fsp. Fontllonga #32. x 400.8. Echinatisporis fsp. Fontllonga #36. x 900. 623

5 ¸ 6

8 624

6

FIGURE 5 - 1. Inaperturopollenites fsp. Fontllonga #36. x 900.2. Pseudoromeinipollenites paleocenicus KEDWS.Fontllonga #36. x 900.3. Rugulitriporites fsp. Fontllonga #36. x 900.4. Nudopollis fsp. Fontllonga #36. x 900.5. Longanulipollis fsp. Fontllonga #32. x 900.6. Polycolpites fsp. Fontllonga #36. x 900.7. Tricolporopollenites fsp. Fontllonga #36. x 900.8. Populus aff. leuce (RossM.) Ung. Fontllonga #36. x 1.9. Juglandophyllum sp. Fontllonga #36. x 1.10. Rhodomyrtophyllum reticulosum (RosSM.) Knobloch & Kvacek. Fontllonga #36. x 1.11. Eotrigonobalanus furcinervis (RossM.) Walter & Kvacek. Fontllonga # 36. x 1.12. Diospyros brachisepala A1 Br. Fontllonga #36. x 1. 13. Dryandroides quercinea Vel. Fontllonga #36. x 1. The palynomorph slides are stored in the Department of Geology (Paleontology). University of Salamanca and the foliar remains in the Department of Paleontology, CSIC-Universidad Complutense, Madrid (Spain). Les lames des palynomorphes sont dOposges dans le D~parternent de Ggologie (Paldontologie) de l'Universitd de Salamanca et les restes foliaires dans le Ddpartement de Pal~ontologie du CSIC-Universidad Complutense, Madrid (Espagne). of them in common and not significantly different gical assemblages is the progressive loss of from those of Fontllonga #32 and #36. Therefore, Normapolles taxa replaced by modern angio- data from Ashraf & Erben (1986) are not conclusi- sperms (Herngreen et al. 1986). Normapolles ve for dating the vegetation crises in the Pyre- constitute about 70-76% of pollen taxa (spores nean-Provence region. A chronological trend clear- excluded) in the Gulpen Formation (Netherlands) ly observed in the Cretaceous-Paleocene palynolo- and the Rognac at Bachasson (France); 625 then 57-60 % in the Maastricht Formation (Ne- nic pattern of change in terrestrial ecosystems therlands) and Central Spain; they decrease to from the Old World contrasts with the synchro- only 25-29% at La Posa and Fontllonga #32-#36 nous change in plants and vertebrates at the K/T (Spain), and to only 16% in the Rognac Limestone boundary described in North America. at Rognac, France (data from De Porta et al. 1985; The abrupt pattern of dinosaur extinction in the Kedves et al. 1980; Herngreen et al. 1986; M~dus Ager basin, approximately coinciding with that of et al. 1992; Alvarez-Ramis et al. 1994, 1996, and the marine realm at the Cretaceous-Tertiary this paper). A decrease of Normapolles thus boundary, is indicative of a global palaeoenviron- occurs during the Maastrichtian, although it may mental catastrophe although the whole assem- not be strictly synchronous in different regions. blages of plants were not affected by this event. The diversity loss in plants during the Maas- The data from the Pyrenees confirm a global cli- trichtian in Spain is mainly due to a lower num- matic deterioration during the Maastrichtian pre- ber of taxa of gymnosperms, monocots (palms) ceding the Kf]] boundary, and reinforce the catas- and Normapolles in the Latest Maastrichtian and trophic pattern of the K/T crisis demonstrating its Danian assemblages by comparison with the Late selective effects. Campanian and Early Maastrichtian assem- Acknowledgements - We thanks our colleagues L. Ardevol blages. This diversity loss does not change the (Tremp), M.E. Arribas (Madrid), J. Civis, A. GSnzalez- Delgado overall composition of the flora, which continues (Salamanca) for their help in the field work. The team of the being dominated by ferns, Taxodiaceae, Hama- Institut d'Estudis Ilerden~s (Lleida), leaded by Antoni Laeasa, melidae and Magnolidae. The local ecological fac- is thanked for making available to us the plant macrofossils tors thus cannot explain by themselves the obser- from Fonttlonga and the location of many other fossil sites. Drs. ved pattern of change, towards a more modern J.L. Sanz and J.J. Moratalla (Madrid) supervised several dino- type of flora. This change suggests indeed a saur tracksites. Funds were provided by project PB95-0398 decrease in temperature from megatherm (tropi- from the DGICYT, Ministerio de EdueaciSn (Spain). cal) to mesotherm (subtropical-warm temperate) taxa, which coincides with many other indices of a REFERENCES global climatic change at the Early-Late ALVAREZ RAM!S C. • DOUBINGER J. 1994 - Contribuci6n al cono- Maastrichtian transition detected in the marine cimiento de la palinoflora cret~cica de la provincia de realm as well as on the continent (Barrera 1994; Madrid. Los Alcores, Guadalix de la Sierra. Reuista Espa- Le Loeuff et al. 1994). 5ola de Micropaleontolog[a, 26, 2: 5-22. ALVAREZ RAMIS C., KEDVES M., FERNANDEZ MARRON T. & CLEMENTE In the Pyrenees there is not indications of an BELMONTE P. 1996 - Nuevos datos pMinoldgicos sobre tas increased plu'Aosity across the K/T transition, such Angiospermas primitivas del Cretficico superior de los as described in the Western Interior by Wolfe & Alcores (Guadalix de la Sierra, Madrid). Revista Espagola Upchurch 1986 (but see Gemmill & Johnson 1997). de Micropaleontologia, 28, 3: 101-110. ALVAREZ-SIERRA M.A., ARaIBAS M.E., ARDEVOL L., CIvIS J., DAAMS R., KRAUSS S., LOPEZ-MARTiNEZ N., DE LA PE~A A., SOLER R., CONCLUSIONS VIANEY-LIAUD M., LACASA A., MARANDAT B., PEL•EZ-CAMPOMANES P., SEVILLA P. & SIGl~B. 1994 - E1 limite Cret~cico-Terciario en The K/T boundary transition on land can be docu- la seccion de Fontllonga (Cuenca de Ager, provincia de mented in the Pyrenees by the study of verte- Lfirida). H Congreso G.E.T Jaca, Comunieaciones: 23-26. brates and plants in rather continuous sections AaCHmALD J.D. 1996 - Testing extinction theories at the Creta- with well-constrained dating. The record consists ceous-Tertiary boundary using the vertebrate fossil record. of eleven localities with vertebrates and five loca- In McLEoD N. & KELLER G. (eds), Cretaceous-Tertiary mass extinctions. Biotic and environmental changes: 373-397. lities with plants. The succession shows that a cri- ARGAST S., FARLOW J.O., GABET R.M., BRINKMAN D.L. 1987 - sis affected both plants and land vertebrates, but Transport-induced abrasion of fossil reptilian teeth: impli- not synchronously. Plant diversity in the Pyrenees cations for the existence of Tertiary dinosaurs in the Hell decreases first, during the Maastrichtian; the Creek Formation, Montana. Geology, 15: 927-930. major vertebrate change, affecting specially dino- ASHRAF A.R. & ERBEN H.K. - 1986. Palynologische Untersuchun- gen an der Kreide/Terti~ir-Grenze west-mediterraneaner saurs with an apparently abrupt extinction pro- Regionen. Palaeontographica, B, 200: 111-163. cess, occurs later on during the K/T boundary. BARRERAE. 1994 - Global environmental changes preceding the Cretaceous-Tertiary boundary: Early-Late Maastrichtian Compared with other areas, a similar diachronic transition. Geology, 22: 877-880. change occurs in the Late Cretaceous of China, BARRON E. & DIEGUEZ M.C. 1992 - Palaeoecological aspects of a where plant succession changes during the new flora from the Garumnian deposits of Isona (Lerida, Maastrichtian before the change in vertebrate Spain). [V Confdrence Organisation [nternationale de succession. The plant succession change in the Paldobotanique, Paris: 17. Pyrenees and China approximately coincides with BRINKHUIS H. & VISSER H. 1994 - New evidence for terrestrial ecosystem collapse at the KT and / boun- a global climatic deterioration detected at the daries. Lunar and Planetary Institut, NASA Conference Early-Late Maastrichtian transition. The diachro- Proceedings, 07, 825, 17 p. 626

CASANOVAS M.L., SANTAF]~ J.V., SANZ J.L. & BUSCALIONI A.D. 1987 Maastrichtian dinosaur assemblages from the Corbi~res Arcosaurios (, Dinosauria) del Cret~cico (southern France). Geological Magazine, 131: 625-630. Superior de la Conca de Tremp (Lleida, Espafia). In SANZ LLOMPART C. 1979 - Yacimiento de huellas de pisadas de reptil J.L. (ed.), Geologia y Paleontologia (Arcosaurios) de los yaci- en el Cret~cico superior prepirenaico. Acta Geol6gica His- mientos cret~cicos de Galve (Teruel) y Tremp (L~rida). pdnica, 14: 333-336. Estudios Geoldgicos : 95-110. LLOMPART C. & KRAUSS S. 1982 - Restos de moluscos y dinosau- COJAN I. 1989 - Discontinuit~s majeures en milieu continental. rios en formaciones estromatoliticas garumnienses al S. del Proposition de correlation avec des 6v~nements globaux (Bas- Montsec (Prov. de L~rida). Boletfn Geol6gico y Minero, 93: sin de Provence, S. France, Passage Cr~tac~/Tertiaire). Comp- 371-378. tes Rendus de l'Acaddmie des Sciences, II, 309:1013-1018 LOPEZ-MARTfNEZN., ALVAREZ-SIERRAM.A., DAAMS R., PEL/~EZ-CAM- DE LA PEI~A A. & SOLER-GIJ6N R. 1996 - The first siluriform POMANES P. & SEVILLA P. 1996a - Vertebrate succesion from from the Cretaceous-Tertiary boundary interval of Eurasia. Late Cretaceous to Early Tertiary, South Central Pyrenees Lethaia, 29:85-86 (Lleida, Spain). In REPETSKI J.E. (ed.), VI N.A.P.C. Was- DE PORTA J., KEDVES M., SOLI~ DE PORTA N. & CIVIS J. 1985 - hington, Abstracts of papers. Paleontological Society, Special Palinologia del Maastrichtiense del Barranco de la Posa Publication, 8: 246. (L6rida, Espafia). Problem~tica regional. Revista d'Investi- LOPEZ-MARTiNEZ N., ARDEVOL L., ARRIBAS-MOcOROAM.E., CIvIs J. gacions Geologiques, 40: 5-28. & GONZ£LEZ-DELGADO J.A. 1996b - Transicion Cret~cico- DIAZ MOLINA M. 1987 - Sedimentacion sintectonica asociada a Terciario en depositos continentales de la cuenca de Tremp- una subida relativa del nivel del mar durante el Cretacico Graus: dates preliminares de isotopes estables de C y O. superior. In SANZ J.L. (ed.), Geologia y paleontologia Geogaceta, 20 (1): 62-65. (Arcosaurios) de los yacimientos cretacicos de Galve LOPEZ-MARTINEZ N., ARDEVOL L., ARRIBAS M.E., CIvm J. & GONZA- (Teruel) y Tremp (Lerida). Estudios Geol6gicos, num. ext. LEZ-DELGADO A. 1998 a - The geological record in non-mari- Tremp-Galve: 69-93. ne environments around the K/T boundary (Tremp Forma- FEIST M. & COLOMBO F. 1983 - La limite Cretac~-Tertiaire dans tion, Spain). Bulletin de la Socidtd gdologique de France, 169 le nord-est de rEspagne du point de vue des charophytes. (1): 11-20. Gdologie Mdditerrandenne, 10:303-326 LOPEz-MARTiNEZN., LACASARUIZ A. & MARTINEZ-DELCLOSX. 1998b

GALBRUN B. 1997 - Did the European dinosaurs disappear befo- - Icnites de dinosaures saurbpodes en el Cretaci superior de re the K-T event? Magnetostratigraphic evidence. Earth (la Noguera, Lleida). Ilerda "Ci~ncies" 52: 35-46. and Planetary Science letters, 148:569-579 MEDUS J. 1986 - Pal~og6ographie et systdmatique du genre GALBRUN S., FEIST M., COLOMBO F., ROCCHIA R. & TAMBAREAUY. Pseudoromeinipollenites au Cr4tacd sup~rieur. Actas de 1993 - Magnetostratigraphy and biostratigraphy of Creta- Palinolog$a: 321-325. ceous-Tertiary continental deposits, Ager basin, province of Mt~DUS J., COLOMBO F. & DURAND J.P. 1992 - Pollen and spores Lerida, Spain. , Palaeoclimatology, Palaeo- assemblages of uppermost Cretaceous continental forma- ecology, 102: 41-52. tions of South-Eastern France and North-Eastern Spain. GEMMILL C.E.C. & JOHNSON K.R. 1997 - Paleoecelogy of a Late Cretaceous Research, 13: 119-132. Paleocene (Tiffanian) megaflera from the Northern Great MEDUS J., FEIST M., ROCCHIA R., BATTEN D.J., BOCLET D., Divide basin, Wyoming. Palaios, 12: 439-448. COLOMBO F., TAMBAREAU Y. & VILLATTE J. 1988 - Prospects for G(SMEZ PORTER P. 1983 - Estudio paleobot~nico de los macror- recognition of the palynological Cretaceous/Tertiary boun- restos de dos canteras sitas en el borde Sur del embalse del dary and an anormaly in nonmarine facies of the VellSn (Guadalix de la Sierra, Madrid). Memoria de eastern Spanish Pyrenees: a preliminary report. Newslet- Licenciatura, Universidad Complutense Madrid, 115 p. ters on Stratigraphy, 18 (3): 123-138. (unpublished). MEON H. 1990 - Palynologic studies of the Cretaceous- Tertiary HERNGREEN G.F.W., FELDER W.M., KEDVES M. & MEESSEN boundary interval at E1 Kef outcrop, northwestern : J.P.M.T. 1986 - Micropaleentology of the Maestrichtian in paleogeographic implications. Review of Palaeobotany and borehole Bunde, The Netherlands. Review of Palaeobotany Palynology, 65 i 85-94. and Palynology, 48, 70 p. MI~ON H. 1991 - Etudes sporopolliniques ~ la limite Cr~tac~- JAEGER J.J. & WESTBHAL W. (eds) 1989 - La limite Cr~tac~- Tertiaire: la coupe du Kef (Tunisie Nord-Occidentale); Tertiaire dans le bassin de L'Arc (Sud-est, France). Cahiers ~tude syst~matique, stratigraphie, pal~og~ographie et ~vo- Rdserve gdologique de Haute Provence, Digne, 1, 60 p. lution climatique. Palaeontographica, B, 223: 107-168. KEDVES M. 1982 - Palynology of the layers of Menat. MEY P., NAGTECAAL P., ROBERTI K. & HARTEVELT J. 1968 - Palaeontographica, B, 182: 87-150. Lithostratigraphic subdivision of posthercynian deposits in KEDVES M. & HERNGREEN G.F.W. 1980 - Palynology of the stra- the South-Central Pyrenees, Spain. Leidse Geologische Me- retype of the Maastrichtian and the Gulpen Formation, dedelingen, 41:221-228 Enci section, Maastricht, The Netherlands. Pollen et Spores, NICHOLS D.J., FLEMING R.F. & FREDERIKSEN N.O. 1990 - 22: 483-544. Palynological evidence of effects of the terminal Cretaceous KNOBLOCH E., KVACEKZ., BUZEKC., MAI D.H. & BATTEN D.J. 1993 event on terrestrial floras in Western North America. In - Evolutionary significance of floristic changes in the KAUFFMAN E.J. & WALLISER O.H. (eds), Extinction Events in Northern Hemisphere during the Late Cretaceous and Earth History: 351- 364 Springer-Verlag. Paleogene, with particular reference to Central Europe. SHEENAN P., FASTOWSKYD., HOFFMAN G., BERGHAUS C. & GABRIEL Review of Palaeobotany and Palynology, 78: 41-54. D. 1991 - Sudden extinction of the dinosaurs: Latest Creta- KRAUSS S. 1990 - Stratigraphy and facies of the "Garumnian" - ceous, Upper Great Plains, U.S.A. Science, 254: 835-839. Late Cretaceous to Early Paleogene - in the Tremp region, SMIT J., VAN DER KAARS W.A. & RICBY J.K. Jr. 1987 - Strati- Central Southern Pyrenees. Ti~binger Geowissenchaft graphic aspects of the Cretaceous-Tertiary boundary in the Arbeiten, 11, 152 p. Bug Creek area of Eastern Montana, USA. Mdmoires de la LERBEKMO J.F. & ST.LouIs R.M. 1986 - The terminal Cretaceous Socidtd gdologique de France, N.S. 150: 53-73. iridium anomaly in the Red Deer Valley, Alberta, . SOLER-GIJON R. & DE LA PEI~A A. 1995. Fishes from the Canadian Journal of Earth Sciences, 23: 120-124. Cretaceous-Tertiary boundary interval of the Ager basin, LE LOEUFE J., BUFFETAUTE. & MARTIN M. 1994 - The last stages Lerida province (Spain). Terra Nostra, 65 Jab. PahGes. of dinosaur faunal history in Europe: a succession of Tag., Hisdesheim: 73-74. 627

SOLER-GIJ(~N R. • LOFEZ-MARTfNEZ N. 1998 - Sharks and rays WOLFE J.A. 1971 - Tertiary climates fluctuations and methods (Chondrichthyes) from the upper Cretaceous red beds of of analysis of Tertiary floras. Palaeogeography, Palaeocli- the Central Pyrenees (Lleida, Spain): indices of a - matology, Palaeoecolvgy, 9: 27-57. Eurasia connection. Palaeogeography, Palaeoclimatology, WOLFE J.A. & UPCHURCH G.R.Jr. 1986 - Vegetation, climatic and Palaeoecology, 141: 1-12. floral changes at the Cretaceous-Tertiary boundary. STETS J., ASHRAF A.-R., ERBEN H.K., HAHN G., HAMBACH U., Nature, 324: 148-152. KRUMSIEK K., THEIN J. & WURSTER P. 1996 - The Cretaceous- ZHAO Z.K., LI H.M., ZHAO Z. & YAN Z. 1991 - Extinction of the dino- Tertiary boundary in the Nanxiong basin (continental saurs across the Cretaceous-Tertiary boundary in Narmiong facies, Southern China). In McLEOD N. & KELLER G. (eds), basin, Guandong province. Vertebrata PalAsiatica, 29, 2 p. Cretaceous-Tertiary mass extinctions. Biotic and environ- mental changes. Norton: 349-371. N. L6PEZ-MARTiNEZ & M.T. FERN.a~NDEZ-MARR6N TSCHUDY R.H., PILLMORE C.L., ORTH C.J., GILMORE J.S., KNIGHT Dept.- UEI Paleontologia J.D. 1984 - Disruption of the terrestrial plant ecosystem at Universidad Complutense, CSIC the Cretaceous-Tertiary boundary, Western North America. E-28040 Madrid Science, 225: 1030-1032. VIANEY-LIAUD M. & LOPEZ-MARTiNEZN. 1997 - Late Cretaceous di- M.F. VALLE nosaur eggshells from the Tremp basin (Southern Pyrenees, Dept. Geologia, Universidad de Salamanca Lleida, Spain). Journal of Paleontology, 71 (6): 1157-1171. E-37008 Salamanca