Whole-rock mineralogy of the lower Pliensbachian Santiurde section (Basque-Cantabrian basin, northern Spain)

Resumo

We present whole rock mineralogy from the lowermost Pliensbachian organic-rich hemipelagic Santiurde section (Basque-Cantabrian basin, north Iberian palaeomargin, Spain). The Santiurde section studied herein is exposed at exit 144 of motorway A67 (UTM X411431.091 Y4769002.593), approximately 50 km south-west of Santander city. The expanded hemiplegic succession offered a potentially valuable orbitally paced stratigraphic record. An integrated multiproxy study was performed in the 19 beds found between 12.4 and 15.95 m of the lower Pliensbachian succession in order to disentangle what sedimentary processes and environmental factors influenced the formation of the hemipelagic rhytmites. Sampling was mainly carried out in 2019. One sample from the central part of each bed was studied for their mineralogical content, their organic geochemistry, and their elemental composition. Whole-rock mineralogy was obtained by analysing randomly oriented rock powder samples by X-ray diffraction (XRD), using a Philips PW1710 diffractometer (Malvern Panalytical, Malvern, UK) at the University of the Basque Country (UPV/EHU).