Portuguese contourite depositional systems derived from Natural Gamma Ray records analysed during IODP Exp339, supplement to: Lofi, Johanna; Voelker, Antje H L; Ducassou, Emmanuelle; Hernandéz-Molina, Francisco Javier; Sierro, Francisco Javier; Bahr, André; Galvani, Aurélie; Lourens, Lucas Joost; Pardo-Igúzquiza, E; Pezard, Philippe A; Rodríguez-Tovar, F J; Williams, Trevor (2016): Quaternary chronostratigraphic framework and sedimentary processes for the Gulf of Cadiz and Portuguese Contourite Depositional Systems derived from Natural Gamma Ray records. Marine Geology, 377, 40-57

DOI

The Contourite Depositional Systems (CDS) in the Gulf of Cádiz and on the West Iberian margin preserve a unique archive of Mediterranean Outflow Water (MOW) variability over the past 5.3 Ma. These CDS have been recently drilled in several places during the IODP Expedition 339. These drill sites now offer a new window to the internal Pliocene and Quaternary architecture of the CDS. In this study, we use downhole and core Gamma Ray (GR) data acquired from 5 sites drilled in the CDS along the middle slope and 1 site drilled in the deeper setting of the lower slope, out of the MOW path. The GR data primarily tracks the clay content in the sediment and is the expression of sediment supply and, for sites drilled in the CDS, of the bottom current processes. Both appear astronomically controlled as shown by spectral analysis performed on the GR data. Results also reveal that the GR log patterns correlate well across the sites over the last 1.4 My. Several GR horizons corresponding to drops in GR values were identified, most of which fit with coarse-grained deposits observed in cores and interpreted as contourite beds. The GR horizons are interpreted as isochronous horizons, providing a regional scale chronostratigraphic framework for the CDS depositional records with an accuracy of ~ 20 ky. We further assess the spatial and temporal variability of the CDS hiatuses at the regional scale.

Identifier
DOI http://dx.doi.org/doi:10.1594/PANGAEA.870926
Metadata Access http://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite3&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.870926
Provenance
Creator Voelker, Antje H L;Hernandéz-Molina, Francisco Javier;Lourens, Lucas Joost;Lofi, Johanna;Pardo-Igúzquiza, E;Williams, Trevor;Rodríguez-Tovar, F J;Bahr, André;Galvani, Aurélie;Pezard, Philippe A;Sierro, Francisco Javier;Ducassou, Emmanuelle
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported (CC-BY)
Representation
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Coverage
Discipline Earth System Research
Spatial Coverage (36N-38N,10W-7 W)
Temporal Point 2011-11-25T11:59:59Z