State of the art of Triassic palynostratigraphical knowledge of the Cantabrian Mountains (N Spain)

Manuel A Juncal,José López-Gómez,José B Diez,José F Barrenechea,Raúl De La Horra,Violeta Borruel-Abadía

doi:10.5802/crgeos.12

Abstract

The present-day Cantabrian Mountains (North Spain) represent the western continuation of the Pyrenean-Cantabrian Orogen, which arose from a Cenozoic collision between the Iberian and Eurasian plates. The early Alpine sedimentary record of the Cantabrian basin is represented by the latest Carboniferous-Permian and Triassic rocks, mostly of continental origin. A lack of palaeontological data has led, until recently, to erroneous interpretations of the stratigraphic position of this sedimentary record. Within the framework of the Triassic sedimentary record in northern Spain, the precise age of six samples was determined and they were grouped into four palynological assemblages according to their taxonomic composition. The study of these assemblages includes a review of all the Triassic assemblages published to date as regards the Cantabrian Mountains, thereby optimising our Triassic palynostratigraphical knowledge of this area enabling comparisons with other Triassic assemblages of Central and SW Europe.

Highlights

Today’s Cantabrian Mountains (North Spain) run parallel to the Bay of Biscay and it is considered the western range of the Pyrenean-Cantabrian Orogen that arose when the Iberian and Eurasian plates collided during the Cenozoic [Barnolas and Pujalte, 2004, Gallastegui et al, 2002, Martín-González and Heredia, 011a,b, Pulgar et al, 1999]
Six new palynological samples were obtained from the Triassic record of the Cantabrian Mountains (Figure 3), four in the Cicera Fm (Samples Ca1, SP5, Cic11 and Cic12) and two in the Transición Fm (Figure 4)
The Cueli Beach sample (Cu-1 sample), which belongs to the Transición Fm, is attributed to the Norian-middle Rhaetian interval due to the presence of Classopollis spp. and Ovalipollis pseudoalatus (Thiergart) Schuurman 1976

Summary

Introduction

Today’s Cantabrian Mountains (North Spain) run parallel to the Bay of Biscay and it is considered the western range of the Pyrenean-Cantabrian Orogen that arose when the Iberian and Eurasian plates collided during the Cenozoic [Barnolas and Pujalte, 2004, Gallastegui et al, 2002, Martín-González and Heredia, 011a,b, Pulgar et al, 1999]. Numerous lithostratigraphic nomenclatures have been used for the same units, and these units have even been wrongly laterally correlated because they were only valid locally (e.g., Suárez-Rodríguez [1988], for the Asturias province; Gand et al [1997], Martínez-García [991a,b]; for the Cantabria and Palencia provinces) In spite of these confusing correlations, studies based on tectonosedimentary analysis made it possible to define the main fault lineaments and their post-Variscan activity [Alonso et al, 1996, Cadenas et al, 2018, Cámara, 2017, García-Espina, 1997, Julivert, 1971, MartínGonzález and Heredia, 011a,b, Merino-Tomé et al, 2009, Pulgar et al, 1999, Rodríguez-Fernández et al, 2002]

Methods

Results

Discussion

Conclusion