N232 Salt Tectonics: Global Styles, Spanish Outcrops (Basque-Cantabrian Pyrenees, Spain)

Course Facts

Course Code:
6 days
Physical Demand:
5.6 Continuing Education Units
56 Professional Development Hours
Certificate Issued Upon Completion


A combined lecture/field course covering global salt tectonics and its practical application to petroleum exploration and production. In the Basque-Cantabrian Pyrenees, both field exposures and seismic data illustrate thick- and thin-skinned salt structures, extensional and contractional diapirs, halokinetic deformation involving turbidites, and allochthonous salt, in a passive-margin setting subsequently subjected to convergent-margin tectonics.

Duration and Training Method

A six-day course to the Basque-Cantabrian region, northern Spain. The course will comprise a mixture of lectures, exercises and field excursions, classroom to field time will be approximately 50:50. Both field and seismic interpretation exercises will form part of the learning experience.

Participants will learn to:

  1. Characterise the formation and internal deformation of layered evaporite sequences.
  2. Assess the role of salt in different tectonic environments including rift basins, passive margins and convergent margins.
  3. Evaluate salt structures developed or reactivated during extension,contraction and strike-slip deformation.
  4. Appraise and interpret the stratal geometries associated with salt evacuation and passive diapirism.
  5. Predict near-diapir stratal geometries and their impact on reservoir distribution.
  6. Characterise allochthonous salt geometries on seismic data and evaluate the nature of sub-salt deformation.
  7. Evaluate the interaction between salt-related deformation and sedimentation in different depositional environments, from fluvial to deepwater.
  8. Appraise the likely influence of salt bodies and salt welds on hydrocarbon generation and migration and possible trapping geometries.

Classroom modules will address the theory of salt-related deformation, compare to field analogues from elsewhere in the world, and review subsurface data and interpretation from major petroleum basins including the North Sea, Precaspian Basin, Persian Gulf and Zagros Mountains, eastern Mediterranean, offshore West Africa, offshore Brazil, and the Gulf of Mexico. Lectures will cover: the tectonic setting of salt basins and the nature of layered evaporite sequences; the mechanics of salt movement; extensional and contractional salt tectonics; salt evacuation and diapirism; near-diapir folding and faulting; the emplacement and evolution of allochthonous salt; salt-sediment interaction, and the impact of salt on hydrocarbon maturation, migration and seal.

Field modules will focus on those Cantabrian examples where there is the widest variety of salt styles and sediments. Depositional environments include sub-aerial, shelf clastics and carbonates and deepwater turbidites. Diapirs were triggered during extension, grew passively, and show different degrees of reactivation during the Pyrenean contractional event. Field examples will be supplemented by seismic and well data over mildly reactivated diapirs offshore in the adjoining Bay of Biscay and over onshore Cantabrian salt structures where they are the focus of research programs for waste disposal and gas storage (Cantabria is one of the few areas in Spain in which oil exploration is still active).


Day 0:

Arrive in Bilbao. Group introductions and safety matters; lectures on evaporite basins and the Basque-Cantabrian Pyrenees

Day 1:

Field transect through the Cantabrian Pyrenees, from south to north, to illustrate stratigraphy and regional structure.

Day 2:

All day lectures interspersed with global seismic exercises. Topics include: fundamentals of salt tectonics (mechanics, definitions, drives); extensional salt tectonics in thin and thck-skinned settings; and contractional salt tectonics in both settings.

Day 3:

Field excursion all day to Poza de la Sal diapir – Triassic evaporites, contact with overlying strata, initiation mechanism and deformation in surrounding shallow water siliciclastics and carbonates. Includes mid-day lecture on internal deformation of layered evaporite sequences and caprock formation.

Day 4:

Morning lectures interspersed with seismic exercises. Topics include: strike-slip salt tectonics; vertical salt tectonics (salt evacuation and diapirism); and passive diapirs.

Afternoon field excursion to Villasana de Mena diapir - near diapir deformation and stratal geometries.

Day 5:

Field excursion all day to examine halokinetic deformation surrounding the Bakio diapir. Diapir interior and margins, flanking deformation of adjacent turbidites and major failure of carbonate platform margin (debrites and olistoliths), unconformities and onlap. Includes a mid-day lecture on halokinetic sequences.


Day 6:

Morning lectures – allochthonous salt, salt and the petroeleum system (trap, reservoir, hydrocarbon maturation and migration), wrap-up.

Afternoon field excursion to Sopela beach and summary of Basque-Cantabrian Pyrenees structure and salt tectonics..End of course dinner.

Day 7:

Depart from Bilbao.

Who should attend

Exploration and development geologists, geophysicists and reservoir engineers working in areas affected by salt tectonics.

Potential attendees should note that salt tectonics courses N071 and N232 have similar classroom content taught by Mark Rowan. The principal differences are:

  • N071 - US-based seismic interpretation workshop with lectures built around the exercises. Thus the content does not include some aspects of salt tectonics.
  • N232 - classroom content gives equal treatment of the fundamentals of salt-related deformation and salt tectonic styles around the world. Includes 4 days in the field in the Basque-Cantabrian fold and thrust belt with associated regional geological context and seismic exercises.

Prerequisites and linking courses

Previous experience of working salt basins and seismic interpretation is an advantage, but not necessary. A working knowledge of sedimentology, seismic interpretation and structural geology is assumed. A grounding in these subjects can be obtained through attendance on classes in the NTA Programme. Structural seismic interpretation is covered in courses N090 (US) and N160 (EU) while field courses N016 and N116 provide a broad structural geology primer, including some discussion of salt tectonics.

Subsurface staff can expand their knowledge of salt tectonics by attendance on NTA salt tectonics field classes N023 (Nova Scotia) and N163 (Paradox Basin, Utah) while seismic interpreters may wish to take the classroom-based seismic interpretation workshop in salt tectonics, N071. The Nautilus website should be consulted for full details of these courses.

The physical demands for this class are LOW according to the Nautilus Training Alliance (NTA) field course grading system. There will be several hikes up to a maximum of 3 km on easy tracks, paths or beaches. Some locations are at elevations of around 1000m but there are no strenuous activities. The field day at Bakio requires some scrambling over tidal foreshores with large, slippery boulders and ledges. Weather conditions can vary widely from hot and dry to cool and wet.


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Josep Anton Munoz

Eduard Roca

Mark Rowan

Related Subjects

Great course - I would recommend it to all experience levels in salt tectonics. Everyone can take something away from the course! I also really enjoyed the Bakio Salt Diapir with its interaction between salt and turbidites.