The European Alpine mountain chain was produced by the collision of Africa (and other smaller continental fragments) with the southern margin of Europe following the closing of a large ocean (Tethys) between the two continental masses. The collision began in the Cretaceous (around 80 million years ago) and carried on into the Pliocene (about 5 million years ago), and is still active. In the earlier stages collision rates and mountain-uplift rates were high and this led to the classic steep mountain gradients and deeply incised valleys that are implied by the word “ Alpine”. This gives us superb, and often three dimensional exposure of strata and structures, sometimes on huge scales (see figure 2. ).

THE GEOLOGY LEADER
Professor Donny Hutton is a professional and semi-retired university academic and active scientific researcher. His first and research degrees were from Queen’s University Belfast and he subsequently taught on the staffs of the geology departments at Trinity College Dublin, Durham University and The University of Birmingham, where he was awarded a chair in 1997. He is currently an honorary professor at Birmingham and he teaches structural geology and tectonics courses at Imperial College, London and at the University Of Bristol.
He is an international research scientist who has published more than 120 peer-reviewed scientific papers. He is a highly experienced field observational geologist who has carried out extensive fieldwork in many far-flung places including: Antarctica, China, South America, Alaska, Greenland and Africa as well as Britain, Ireland  and other European countries.
As a lecturer and field leader of more than 30 years experience he has, over the years, helped thousands of undergraduate students through their degree courses. A highly effective communicator of the geological sciences, he has a reputation for clear effective explanations in simple terms of the more complex ideas in both the theoretical and practical (field) aspects.  He is a lively, warm and interesting character.

THE HOST AND CHEF
Wiz Clift is a well known chef, having run the Talbot @ Knightwick with her sister Annie for over twenty years. Wiz also became known as the BBC hedgerow correspondent and hosted her own radio series as well as appearing on many other gardening/ cooking/ wild food shows. She has established a new base with her own gites in the “real Provence” which she runs with Philippe a passionate French gardener. Together they have established gites which provide very comfortable spacious accommodation in Northern Provence, offering mouth watering menus using their own or local produce. They are both passionate and knowledgeable about the area.

PROGRAMME
2nd June 2012
Minibuses will collect from Marseille airport and transfer guests directly to the Gites in Cruis. Depending on arrival time guests will have time to visit the village before a leisurely apéro and dinner, with a short introductory lecture to the field trip afterwards.

3rd June - 8th
After breakfast, daily field trips will depart in the mini buses between 8-8:30am returning at approximately 5pm.A light picnic lunch will be provided.
It is hoped that guests will be able to enjoy a relaxing evening after their day’s exertions/excursions either in the pool or playing some of the many games/sports available. A four course evening meal will be served at 8pm.This meal will be an opportunity to taste the wonderful range of produce Wiz and Philippe and the surrounding farmers offer as well as a time to compare notes for the day and discuss the next day’s activities.

9th June
After a leisurely breakfast the mini buses  will depart for Marseille airport.

DETAILED ITINERARY 2nd June - 9th June

Day 1 The Jabron valley and Montagne de Lure. This is close to our base and so is suitable for a slightly short day to enable recovery from the previous day’s travel. Jurassic and Cretaceous stratigraphy; large scale Pyrenean folds and thrusts. Spectacular views from the summit of Montagne de Lur.

Day 2 The Pelvoux Massif,  Montagne de Faraut and the Col du Noyer  Hercynian age basement gneisses, migmatites, amphibolites and granites. Thrust of basement over Jurassuc sediments, original unconformity between Jurassic and basement. Normal faults associated with continental extension prior to rifting. Major unconformity truncating early major folds. Base of the Tertiary succession-the Calcaires Nummulitic.

Day 3 The Champsur area and Drac Valley. The Champsur  Turbidites (deep water sediments) Marnes Bleu and Calcaire Nummulitic. Lunch on Hercynian Migmatites. Large scale folding of the turbidites. Carbonate turbidites and small scale folding and thrusting.

Day 4 Local and cultural. Days 2 and 3 are the longest of the trip so on Day 4 we do a half day of geology and a half day of local history and culture. Megabreccia of Tourache and the history of the major Durance fault.

Day 5 A traverse up the Durance valley between Ganagobie and Curbans. The Alpine deglaciation uplift terraces of the Durance valley. Les Penitents and the Tertiary Valensole Molasse basin. Large scale folding around Sisteron. Folding, thrusting and Triassic redbeds and evaporites near Curbans.

Day 6 Digne and Barreme The current Alpine thrust front and folds  at Digne. A classic Lower Jurassic Ammonite site. Triassic redbeds and evaporates. Deformation of the Valensole molasses basin. An imbricate thrust stack below the Digne thrust. The base of the Tertiary (Les Poudignes d’Argent). The Nummulitic Flysch trinity and an emergent thrust tip preserved breaching the Tertiary seafloor.

THE GEOLOGY
This trip will concentrate in south east France on the so called “External” Zone of the Alps, basically defined by its relatively low metamorphic grade, general lack of rock cleavage and mountain heights of 3,000m and less. Most of the rocks are carbonates, sandstones, conglomerates and shales of  Jurassic, Cretaceous and Tertiary age. The overall aim of the trip will be, by using principally stratigraphy and structure, to track the overall evolution, on a large scale, of the mountain chain. We will thus see evidence of: 1 the early continental stretching that preceeded continental rifting; 2. the first formation of oceanic crust (ocean opening); 3. the later switch to plate convergence and the beginning of ocean closure; 4. the”first touch” of the continents during the collision; 5. final suturing of the two continents and the return to the “one continent” state.

In physical terms this will be carried out in a cross section from Pelvoux in the north to Digne and Barreme in the south (Figure 2). In the north the collision has deeply fractured the crust and thrust up very old (c.300 million years) granites and high grade metamorphic rocks (comprising gneisses and well exposed migmatites) which originally formed the base (“basement”) to the sediments that were laid down on the edge of the Tethys Ocean. These basement slices were thrust up late in the collision yet show the relics of the normal faulting that controlled sedimentation during the very earliest phase of the continental extension that preceded continental rifting and ocean opening.

Further to the south (around the Drac valley to the north of the town of Gap) we shall see a major unconformity lying above truncated major folds of an early episode of the Alpine collision (Figure 3 ) and huge and spectacularly exposed folds and thrusts in different types of deep water sediments that were deposited from the earliest collision/uplift of the first Alpine mountain chains (Figure 1).

Moving  southward between  Gap and Sisteron major folds and thrusts belonging to the main Alpine collision event and the earlier Pyrenean (Inberia-Eurasia collision)are well exposed  at large scales and often spectacularly outlined by Jurassic and Cretaceous limestones (Figure 4). Around Dignes we shall see the currently active Alpine thrust front as well as Triassic red beds and evaporites belonging to the continental conditions  that preceeded continental rifting and oceanic conditions. Lower Jurassic sediments here contain spectacular fossil localities (Figure 5).

Near Barreme we shall see more highly fossiliferous sediments, comparable to those in the Drac valley to the north, but showing here spectacular evidence of a collisional thrust breaching and deforming the ocean floor. And finally around Cruis itself (where we are staying) the last phase of this protracted and epic event produced the great sandstone and conglomerate-dominated Alpine erosional debris of the rapidly uplifting Alps ( the “Molasse”  deposits) of the Valensole plateau (Figure 6). These show the switch from marine sedimentation in the residual ocean waters  to continental sediments as the two continents become one again and the ocean was eliminated.

So a story of  the progressive opening and then collision of two huge continental masses recorded in the sediments that were laid down between them and around them and in their deformation.

We will be involved in most aspects of geology although stratigraphic interpretation and structural geology will predominate. Sedimentation processes, fossils, igneous and metamorphic geology will also be encountered. We will take advantage of spectacular mountain views of the geology and will examine the rocks in more detail in road and river cuttings and also with short walks into the hills themselves.

In the introductory lecture on the first evening and at other opportunities other current and exciting aspects of Alpine geology relating to the continental collisional process will be described, for example the ultra high pressure rocks as evidence for the subduction of the continents and their exceptionally rapid uplift and erosional stripping (“exhumation”).

 

 

 

 

 

 

Geology