Shelf-to-Basin Palaeocene Palaeogeography and Depositional Sequences, Western Pyrenees, North Spain
- Henry W. Posamentier3,
- Colin P. Summerhayes4,
- Bilal U. Haq5 and
- George P. Allen6
Published Online: 15 APR 2009
Copyright © 1993 The International Association of Sedimentologists
Sequence Stratigraphy and Facies Associations
How to Cite
Pujalte, V., Robles, S., Robador, A., Baceta, J. I. and Orue-Etxebarria, X. (1993) Shelf-to-Basin Palaeocene Palaeogeography and Depositional Sequences, Western Pyrenees, North Spain, in Sequence Stratigraphy and Facies Associations (eds H. W. Posamentier, C. P. Summerhayes, B. U. Haq and G. P. Allen), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304015.ch19
Plano, Texas, USA
Washington, DC, USA
St Remy les Chevreuses, France
- Published Online: 15 APR 2009
- Published Print: 17 NOV 1993
Print ISBN: 9780632035489
Online ISBN: 9781444304015
- shelf-to-basin Palaeocene palaeogeography and depositional sequences, western Pyrenees, north Spain;
- Palaeocene system outcrops in Aquitaine Basin;
- Upper Cretaceous-Lower Eocene successions of sectors of study area;
- major Palaeocene sedimentary systems of western Pyrenees;
- Iberian Palaeocene basinal deposits - of carbonates;
- North Iberian shelf (carbonate-platform system);
- North Pyrenean basinal system (deep-sea channel system);
- sedimentation main controls
Palaeocene depositional sequences and their constituent systems tracts (ST) have been recognized and studied in the deep-water interplate Basque basin and in the adjacent north Iberian shelf (western Pyrenees, north Spain). In addition, re-examination of the Palaeocene of the north Pyrenean basin strongly suggests that a similar set of sequences also exists there.
The age of shelfal sequences is established with benthic foraminifera, whereas in basinal settings they are accurately dated with planktonic foraminifera. In the north Iberian shelf sequences are dominated by the transgressive ST (mostly sandy grainstones) and the highstand ST (reefal limestones), which grades landwards to lagoonal and continental red shales and dolomites. In addition, the shallow (proximal) part of the lowstand prograding complexes of two sequences is preserved in the outer platform margin.
The bulk of basinal deposits occur within the lowstand ST; the transgressive ST and highstand ST are either thin or even absent in the deep-water setting. Basinal sequences from southern (Iberian) sources are entirely made up of carbonates and were accumulated in a base-of-slope carbonate apron. They are usually composed of a lower slope fan complex (resedimented breccias, calcidebrites and thick-bedded carbonate turbidites) and an upper lowstand prograding complex (thick- and thin-bedded carbonate turbidites and pelagic limestones). Sequences from western (north Pyrenean) sources have a mixed carbonate–siliciclastic nature and include: basin-floor fan complexes (thick-bedded, massive siliciclastic turbidites; not present in all sequences); slope-fan complexes (resedimented breccias, thick-bedded carbonate turbidites and marls); and lowstand prograding complexes (hemipelagic limestones or alternations of hemipelagic limestone and marls). The coarse-grained deposits of these basinal complexes infill a deep-sea channel system.
The succession was deposited during an early phase of the Pyrenean convergence, the change from extension to compression being recorded in the area by a strong reduction of siliciclastic influx and sedimentation rates, denoting sediment-starved conditions. In spite of the changing tectonics and low sediment supply, predictions of the Exxon Group's models are reasonably met, most notably: (i) the number and age of depositional sequences can be matched with third-order sea-level cycles of the 1988 version of the sea-level chart; (ii) relative magnitudes of global sea-level changes are also recorded, since the major sequence boundary of the succession can be chronostratigraphically tied to the 58.5 Ma eustatic fall, one of the more significant Palaeocene events; (iii) good agreement with current sequence-stratigraphic models is observed that relate stratal geometries and eustasy, regardless of whether carbonate or siliciclastic sediments are involved.