N295 Structure and Evolution of a Passive Margin: Implications for Hydrocarbon Exploration (Western Alps, France)

Course Facts

Course Code:
N295
Duration:
6 days
Type:
Field
Physical Demand:
High
CEU:
4.8 Continuing Education Units
PDH:
48 Professional Development Hours
Certificate:
Certificate Issued Upon Completion

Summary

This course traces the evolution of the passive margin of the Western Alps from the external zones with the (failed) rifted margin, via the collapsed outer high (‘Brianconnais’), the exhumed mantle of the internal Alps, terminating with the development of the Alpine foreland basin. The Digne Thrust system illustrates Mesozoic basin evolution with its implications for: hydrocarbons, allochthonous salt, phased evolution of the thrust system and the geometry of the mountain front. 

Duration and Training Method

A six-day field course, comprising field demonstration augmented by seismic data including ION’s "Span" data which image to 40 km depth. Seismic interpretation exercises, discussion and consolidation meetings in the evenings. The proportion of field to classroom time is around 80:20.

Participants will learn to:

  1. Appraise the structural development of a classic Tethyan passive margin and apply this knowledge to other passive margins worldwide.
  2. Characterise the transformation of a passive margin to an orogenic belt and foreland basin.
  3. Reconstruct the evolution of passive margin systems from regional seismic data.
  4. Evaluate the evolution of a foreland basin associated with collision orogeny and document the change from deepwater ‘flysch’ to shallow water or terrestrial ‘molasse’.
  5. Appraise the role of salt in both extensional and compressional environments and examine field examples of structures which are normally visible only in seismic data.
  6. Assess the interaction of sedimentation with developing tectonic and halokinetic structures.
  7. Predict play-fairways both locally and in basins remote from areas of outcrop using knowledge gained from outcrop studies.

The week should enhance the participants’ appreciation of the following:

  • Tectonics
  • Rifting and passive margin evolution in the light of new ideas
  • Salt tectonics
  • Basin Analysis

Proposed Itinerary (subject to modification according to weather)

Day 0

  • Arrive Lyon, overnight at the airport hotel.
  • Introductory talks.
     

Day 1

  • The Alpine mountain front of the Chartreuse.
  • Seismic scale outcrops of Jurassic half graben at Lacs de L’Affray. Taillefer tilted fault block. Col d’Ornon.
  • Side trip to Villard-Raymond. Spectacular views of Lower Jurassic strata onlapping faulted crystalline basement.
  • Descend to Bourg d’Oisans and drive to La Grave.
  • Walk (an hour or so) on the Plateau d’Emparis for views of the more deformed parts of the external zone.

Overnight at La Grave.

 

Day 2

  • am: Drive to Briançon via the Col de Lautaret. Side trip to Col du Galibier for views and analysis of the more internal thrust sheets and the Briançonnais.
  • pm: The reduced section of the Briançonnais ‘outer high’ in the Champcella nappe (one of  the thrust sheets of the Briançonnais) near Champcella. Triassic carbonates and Liassic palaeo-karst associated with  the Tethyan rifting phase pass up into starved Middle and Upper Jurassic ‘drift’ sequence (radiolarian cherts or ‘Ammonitico Rosso’ depending on location). This is a classic rift-drift sequence in a highly reduced section.

Overnight at Briançon.

Day 3

  • The unroofed sub-continental mantle, radiolarites, ophicalcites calc-schists and ophiolites (oceanic crust) of the Ligurian Tethys. Spend the day in a hike around the Chenaillet mountain.

Overnight at Briancon.

Day 4

  • am: Dormillouse valley (or nearby). Deepwater ‘flysch’  of the first, deepwater foreland basin megasequence. European crystalline basement overlain by turbiditic sandstones of the Gres sde Champsaur.
  • pm: Drive to Seynes via exposures of the highest Alpine Units – the Embrunnais Flysch klippen. Drive and hike to the outcrops which develop the story of the foreland basin evolution. Pelagic Upper Cretaceous limestones, an unconformity and the trangressive Eocene and Oligocene deepwater turbidites foreland basin megasequence. View to the Embrunnais flysch nappes – a sequence deposited on the Apulian (Italian) margin of the Ligurian Tethys which has been thrust over the entire Alpine edifice.

Overnight at Seyne.

Day 5

  • am: The Gorges du Barles and Verdaches. Basal Triassic sandstones unconformably on Carboniferous coal measures. Evaporites and cargneule at Barles, reduced stratigraphy on top of a Liassic salt swell. Geometry of the Digne thrust and structures at which suggest an  allochthonous salt canopy and a salt ‘flap’.
  • Hike up to the top of Le Serres, Vieille Esclangon - a candidate for the best geological viewpoint in the world. Interactions of topography and thrusting. Multi-phase evolution of a thrust system.
  • Overnight at Digne

Day 6

  • Digne to Mirabeau – well site and panorama over the Digne Thrust system. Drive via Moustiers-Sainte-Marie to Lac de St Croix - spectacular views of the mountain front and evidence of its complex evolution. Drive a short distance into the Gorges de Verdon for views of the Provencal Jurassic carbonate platform.

Drive to Marseille – overnight airport hotel.

Day 7

  • All depart from Marseille

Who should attend

The course is intended to be relevant across a range of experience. It is equally useful to both geoscientists with limited experience of fieldwork and structural geology, and more senior geoscientists and managers who may need reminding as to the enormous insights to be gained from reconnecting with fundamental field geology.

Prerequisites and linking courses

No prerequisites, but familiarity with the basic concepts of structural geology and seismic interpretation are useful, as is basic understanding of sequence stratigraphy, sedimentology and basin analysis.  If participants have none of the above experience, prior attendance on Nautilus structural geology and seismic interpretation courses such as N085, N160, or N240, N142, N016 or N116 is recommended and would be beneficial. Please see the website at www.nautilusworld.com for up to date details of all our courses.

The physical demand for this course is HIGH according to the Nautilus field course grading system. There are several mountain walks, the shortest of which is a 6 km steep walk and the longest of which can be 11 km and may include >500 m ascent above 2000 m; many of the other field stops are also at altitudes between 1000 and 2000 m. Participants need to be prepared for hot and sunny weather, with occasional storms and be physically fit for long hikes and steep walks. Long days in the field are necessary.


Learn how RPS manages safety

Click on a name to learn more about the instructor

Rod Graham

James Pindell

The integration of the seismic lines in the evening was extremely valuable.