See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/262299869 Palynological characterization of a transgressive episode intransitional deposits in the Cretaceous Aren and Tremp formations (South-Central Pyrenees, Spain) Article in Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen · January 2012 DOI: 10.1127/0077-7749/2012/0291 CITATIONS READS 17 907 4 authors, including: Angelica Torices Maria Teresa Fernández-Marrón Universidad de La Rioja (Spain) Complutense University of Madrid 72 PUBLICATIONS 533 CITATIONS 33 PUBLICATIONS 370 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: The biota of the Upper Cretaceous site of Lo Hueco (Cuenca, Spain) View project All content following this page was uploaded by Angelica Torices on 14 May 2014. The user has requested enhancement of the downloaded file. N. Jb. Geol. Paläont. Abh. 266/2, 159–172 Article Stuttgart, November 2012 Palynological characterization of a transgressive episode in transitional deposits in the Cretaceous Aren and Tremp formations (south-central Pyrenees, Spain) Angélica Torices, María-Teresa Fernández-Marrón, Fernando Fonollá, and Nieves López-Martínez With 6 figures Nieves Lopez-MartiNez initiated this study and was its driving force up to her premature death. The co-authors dedicate this paper to her memory. torices, a., FerNáNdez-MarróN, M.-t., FoNollá, F. & López-MartíNez, N. (2012): Palynological characterization of a transgressive episode in transitional deposits in the Cretaceous Aren and Tremp formations (south-central Pyrenees, Spain). – N. Jb. Geol. Paläont. Abh., 266: 159–172; Stuttgart. Abstract: The overall marine regression leading to the infilling of the Cretaceous Pyrenean ba- sin was punctuated by transgressive episodes. These events produced a complex architecture in the interfingering deposits in the marine Aren and continental Tremp formations in south-central Pyr- enees. The Vicari section is useful for studying the lateral change between these marine-continental deposits bearing fossil vertebrates and pollen. In this section, palynological changes reveal in detail transgressive and regressive events in the lower part of the continental Tremp Formation, which could not be detected otherwise by non-correlated lithological changes. A rapid regression is documented through the contact between the lower Aren and Tremp deposits: in-situ dinosaur egg clutches and other vertebrate remains are preserved with terrestrial palynomorphs indicating warm humid pal- aeoclimatic conditions (tree ferns, cycads, etc.). Furthermore, palynological content, rich in marine phytoplankton, reveals a transgressive episode in the upper grey marls in the Tremp Formation. Key words: Upper Cretaceous, South-central Pyrenees, vertebrates, palynology, marine transgres- sion. 1. Introduction aeoenvironments along the Cretaceous-Tertiary tran- sition by means of sequence stratigraphy, biostratig- South-Pyrenean Upper Cretaceous deposits contain raphy and magnetostratigraphy on correlated marine abundant biotic (foraminifera, molluscs, vertebrates and continental formations (Salas Marls, Aren Sand- and plants) and sedimentary indicators to document stone and Tremp red beds) (déraMoNt et al. 1993; in detail the palaeoenvironment and palaeoclimatic viceNs et al. 1999, 2001, 2004; ardèvoL et al. 2000; changes registered in the ancient coastlines of the López-MartíNez et al. 2001; díaz MoLiNa et al. 2007; Pyrenean Cretaceous basin during its last infilling epi- oMs et al. 2007). sodes. These deposits allow an accurate chronologi- The South Pyrenean Central Unit is one of the larg- cal framework of environmental and climatic changes est Pyrenean tectonic structures formed by detached to be established in both marine and continental pal- cover of the Pyrenean Orogen and contains the thickest ©2012 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany www.schweizerbart.de DOI: 10.1127/0077-7749/2012/0291 0077-7749/2012/0291 $ 3.50 160 A. Torices et al. Fig. 1. Geological map of the Pyrenees and the Tremp syncline, with the location of the Vicari section and its detailed geological map: 1 – offshore marls and 2 – shoreface sandstones from the Aren Fm lower unit; 3 – transgressive calcaren- ites from the Aren Fm upper unit; 4 – Tremp Fm grey marls; 5 – Tremp Fm red lutites; 6 – covered. E – dinosaur eggs and eggshells; R – rudists belonging to the H. castroi horizon; W-C-E mark the position of the stratigraphic logs in Fig. 3. succession of transitional marine-continental depos- be clearly observed. The marine-continental transition its within the Cretaceous-Tertiary transition. On the in this area is indicated by the micro- and macrover- northern flank of the Tremp Syncline, the sedimentary tebrates preserved at several localities (BuscaLioNi et succession has been extensively studied due to its ex- al. 1986; López-MartíNez et al. 1996; torices 2003). ceptional outcrops, which enable the documentation of The objective of this paper is to present a new overall marine regression since the Late Cretaceous. palynological record from the lower part of the Tremp Several of these works outline the complex interfinger- Formation, documenting the presence of marine paly- ing relations between the two main lithostratigraphic nomorphs in these red beds. These data allow us to in- units, namely, the Aren and Tremp formations, record- fer a previously undetected transgressive episode and ing the end of the Cretaceous marine basin in this area the palaeoenvironmental and palaeoclimatic changes (NagtegaaL et al. 1983; diaz MoLiNa 1987; Mutti & that took place at the end of the marine Cretaceous sgavetti 1987; déraMoNt et al. 1993; ardèvoL et al. basin in the South-Central Pyrenees. 2000; guillauMe et al. 2008). The Vicari section, in the northern flank of the 2. Geological setting Tremp Syncline, is an east-west oriented outcrop where the interfingering architecture between marine The Tremp Syncline, where the Vicari section is locat- Aren sandstones and continental Tremp red beds can ed, is a major east-west oriented structure in the cen- Palynological characterization of a transgressive episode in transitional deposits 161 Fig. 2. Correlation chart between the uppermost Cretaceous and lowermost Tertiary marine (blue-clear)and continental (red-dull) deposits in southern Pyrenees, including the location of three main rudist horizons and the Vicari section. K/T – Cretaceous-Tertiary boundary; MPU – Mid-Paleocene unconformity; P/E – Paleocene-Eocene boundary. S1/S2 sequence boundary; data from roBador 2005; viceNs et al. 2001, 2004, and oMs et al. 2007; dating of the upper rudist horizon B. chapperi has been modified according to magnetostratigraphic data (see text; oMs & caNudo 2004; pereda-suBerBioLa et al. 2009). tral part of the South-Pyrenean Central Unit (séguret numerous existing publications and summarized in 1972; Fig. 1). The Tremp Syncline forms part of the Fig. 2. Marine Aren Fm is exclusively present in Cen- Montsec Unit and is bounded to the north by the Abel- tral Pyrenees, while continental Tremp Fm extends la-Boixols Anticline, which forms part of the Boixols along central and eastern Pyrenees. Both formations Unit (ardèvoL et al. 2000). change laterally to distal marine deposits in the west- The Vicari section is a 400 m-wide area, where a ern area of the South Pyrenean Central Unit and all N-S oriented ravine cuts across the contact between along western Pyrenees, where the Marboré Fm con- the marine Aren Formation and the non-marine Tremp stitutes a lithological unit analogous to Aren Fm (ar- Formation. These formations have been described in dèvoL et al. 2000; roBador 2005; oMs et al. 2007). 162 A. Torices et al. Fig. 3. Correlation panel along an E-W transect in the Vicari section. The location of vertebrate fossil localities and paly- nological samples is indicated in the stratigraphic logs. In south-central Pyrenees, time-transgressive clas- er, the stratigraphic correlation and dating previously tic deposits in the Aren Fm (calcarenites and hybrid proposed need to be modified on the basis of further arenites) prograde north-westwards (basinwards) over magnetostratigraphic data from the intermediate Riba- the Salas offshore marls, while the lower part of the gorzana section (oMs & caNudo 2004; pereda-suBer- Tremp Fm (grey marls limestone from unit 1 and red BioLa et al. 2009). According to these data, the age of clastics from unit 2) prograde from south and east the Vicari section also includes the Maastrichtian (Fig. (landwards) over the Aren Fm (diaz MoLiNa 1987; 2). eicheNseer 1988; ardèvoL et al. 2000; díaz MoLiNa The Vicari section represents just one of several et al. 2007). The Aren Fm ends below the Cretaceous- episodes in which Aren shoreface deposits overlie Tertiary boundary, when the upper part of the unit 2 coastal Tremp red beds as both formations prograde of the Tremp Fm to the west it changes to the ma- north-westwards (díaz MoLiNa 1987; ardèvoL et al. rine Laspún Fm (Campo section) and expands across 2000). south-central Pyrenees (López-MartíNez et al. 2006; Fig. 2). 3. Stratigraphy The age of these formations in the Vicari section was dated as Late Campanian through lateral corre- Vicari is a good example of the way the Aren and lation of rudist horizons to basinal deposits bearing Tremp formations change laterally relative to one an- planktonic foraminifera in a more north-western loca- other. In this area,