8. Tour de Géologie avec Tour de France

Géologie Massif du Galibier - MCAL

8. Grand Tour de Géologie during the Tour de France. V.300518

Tour de France - Stage 12 - July 19, 2019 - Bourg to Alpe d'Huez
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Tour de France – Stage 12 – July 19, 2018 –  Bourg to Alpe d’Huez
Tour de France - July 19, 2017 - MCAL
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Tour de France – July 19, 2017 – MCAL

The Tour de France is one of the most spectacular cycling tours on the world.

As a geologist for me the cyclists also cycle cross-sections through the geological landscape. I always study the geological background of the different stages. Together with the nowadays superb and continuous tv shots from the helicopter the Tour represents indeed also a geological excursion.

This article refers specifically to the area of 2 stages in the mountains, the Alps. One of this year (stage 12), located close to 2 others of last year, 2017. They appeal very much to me. As I happen to know the area. It is located close to the area where I did 2 full summers fieldwork for my thesis (long ago). Just across the border. In Italy, Piemonte, Cotton Alps.

Please join me on a dynamic geological cycling tour in the French Alps. Enjoy !

Contents (13)

1.  July 19, 20th, 2017.
Tour de France (men) & Tour La Course (women, July 20, 21; Annemiek van Vleuten, NL).

2. Foto: Mont Genèvre, Briançon – Ophiolite sequence – June 1974 – MCAL : Standing on the Upper Mantle, Ophiolite Sequence.

3. Géologie du Massif du Grand Galibier

4. Tour etappe – La Mure > Serre Chevalier – July 19, 2017

5. Geology: a brief overview of the history of the Alps.

Panorama Geologique du Massif du Grand Galibier

6. Tectonic framework of the Alps – Carte tectonique des Alpes

7. Etude géologique des massifs du Grand Galibier et des Cerces (zone Brianconnaise, Hautes-Alpes et Savoie).

8. Tour de France 2017

9. Geological notes (3) related with the photo “Mont Genevre, Briancon, France, 1974. Standing on the Upper Mantle, Ophiolite’s”.

10) Plastic Deformation of Gabbros in a Slow-spreading Mesozoic Ridge: Example of the Montgenèvre Ophiolite, Western Alps: R. Caby.

11) The Montgenevre ophiolite (Hautes Alpes, France): Meta—morphism and trace-element geochemistry of the volcanic sequence; Adrian D. Lewis and John D. Smewing – 1980

12) W-Alpine neotectonics and brittle deformation – Christian Sue

13) Les Alpes – Aux origines de leur Formation. – Video

 

1). July 19, 20th, 2017.
Tour de France (men) & Tour La Course (women, July 20, 21; Annemiek van Vleuten, NL).

Le Massif du Grand Galibier.
Awesome, impressive scenery, nature and mountains.

From La Mure to Serre Chevalier and from Briançon to Col d’Izoard.
Firework from the cyclists. A brutal 9% climb the last 10, a heroic struggle after already 173 km of exhausting work.

Simultaneously, Grand Tour de Géologie du Massif du Grand Galibier:
Exiting very dynamic, tectonic, compression-related, overthrusts, transcurrent faults and prime geological firework in the beautiful Alps.

Cycling across seven (7) different major thrusts and nappes. Brutal Alpine tectonic fire- and muscle work. Wowwww.

The Grand Galibier located on the Nappe Brianconnaise. Overriding and superposed on the Nappe Sub-Brianconnaise. With giant thrust faults that define both the Colle du Galibier and the Col du Lautaret.

The 167 cyclists left will unfortunately not have time to admire the outcrops and realise the dimension of the unique tectonic framework that they are crossing.

Where they could evidence, with geological eyes, the internal deformation inside the colliding European margin.

Related with westward motion of Apulia and thus witness the insight of true collision.

True collision that already began 31-34 million years ago (Lower Oligocene). Marking a major tectonic rearrangement of the Alpine chain.

With a NW displacement of some 10-15 km and temperatures of circa 280 degrees Celcius.

As nicely related, in their own cryptic language, by contemporary voyagers Mr. Phengite and Mrs. Chlorite – Phengite.

Mr. Phengite, born and since his childhood, happily grown-up without stress, though syn-kinematically under high pressure in shear zones. As told in his own cryptic language called 40Ar/39Ar dating. Mr. Phengite of the greater mica family, resembling muscovite but with some magnesium. Similar to the phengites in the Ovardites of Forte Fenestrelle, Val Chisone, in my thesis research area.

Mrs. Chlorite – Phengite relating her thrilling 10-15 km voyage in her enigmatic Thermobarometry language.

All with special thanks to the hard and continual work of the Crustal Penninic Thrust Front since 34 million years ago. Still thrusting and moving over the decollement horizon. As the Apulia tectonic plate moves westwards, continuously reshaping and sculpturing Mother Earth. Faithfully accompanied by her new-born sculpted mountains and earthquakes while converging with the European plate.

You are invited to have a look at the interesting geologic maps and cross-sections. The 4-D dynamic world of the geoscientist and the unique geo-thrill related with the prime Tour thrillers of today and tomorrow.

Enjoy ! Venez partager s.v.p. !

”  All-in-1 Consultant,  Available-to-Serve-You.

For grounded, vintage stewardship to successfully find lots of oil, mineral resources, develop your business and get sustained value for money ?

See <Contact & Contract Me> at marcelchinalien@gmail.com “.

Doei, salu2, ciao, até logo, grüssen, cordialement, salut, добрый день, ajoo, tur kos bon mi dushi hendenan na Switi Sranan i mi famiri na switi Korsou, tan bun allamala !

2) Mont Genèvre, Briançon – Ophiolite sequence – June 1974 – MCAL : Standing on the Upper Mantle, Ophiolite Sequence.

Mont Genèvre, Briançon - Ophiolite sequence - June 1974 - MCAL
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Mont Genèvre, Briançon – Ophiolite sequence – June 1974 – MCAL : Standing on the Upper Mantle, Ophiolite Sequence.

3). Géologie du Massif du Grand Galibier

Géologie Massif du Galibier - MCAL
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Géologie du Massif du Grand Galibier – MCAL

4) Tour etappe – La Mure > Serre Chevalier – July 19, 2017

Tour etappe - La Mure > Serre Chevalier - July 19, 2017 - MCAL
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Tour etappe – La Mure > Serre Chevalier – July 19, 2017 – MCAL

5) Geology: a brief overview of the history of the Alps.

Panorama Geologique du Massif du Grand Galibier

Galibier - MCAL
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Panorama Geologique du Massif du Grand Galibier – MCAL

6) Tectonic framework of the Alps – Carte tectonique des Alpes

Alps - Tectonic map - MCAL
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Tectonic framework of the Alps – Carte tectonique des Alpes – MCAL

7) Etude géologique des massifs du Grand Galibier et des Cerces (zone Brianconnaise, Hautes-Alpes et Savoie).

Si vous êtes intéressez s.v.p. consulter la publication classic écrit par Bernard Tissot (PDF gratuite en Internet).

Géologie Galibier - MCAL
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Géologie Galibier – MCAL

8) Tour de France 2017

Tour de France of 1989 is surely the greatest ever. A race that saw Greg LeMond overturn a 50-second deficit to Laurent Fignon on the final stage on the Champs Élysées to snatch the title by a mere eight seconds. After three weeks and more than 3200 kilometres in the saddle, this remains the smallest margin of victory in the Tour’s 100+ year history.

As a geologist and explorationist for me the Tour de France simultaneously represents a fascinating Tour de Geologie and Tour de Vin.
While the brave cyclists, such as Froome, Uran, Bardet, Landa, de Gendt, Quintana, Mollema, Ten Dam and the whole peloton cross the French countryside and mountains, they also cycle cross-sections through the geologic history, my geological maps, the maps and vineyards of the famous wine districts of France, that I avidly consult during the different stages.

On your own, whether belly-shaped, flat, or curved panoramic Oled TV with cinema sound system at home, by watching the Tour de France, you also experience the intensity and thrill of the Tour de France for example during its most challenging climbs. From the dizzying heights of the 2,715-metre ascent of Col de la Bonette to the historic Great St Bernard Pass.
On Col du Galibier, not far away from my own 6 month fieldwork area in the Italian Cottian Alps, with its incredibly tortuous 15 percent gradient climb.

A tough gradient that also my brand new Citroën 2CV  Deux Chevaux, Fourgonnette model (only 16 hp, 425 cc) and its driver had to experience and conquer back in 1973. Obtaining a maximum speed uphill of only some 15 kilometres in gear one. With the big load of pieces of la Bella Italia. Rock samples for my thesis. Just to mention the garnet schists, augen gneisses, grafite- and cloritoid micashists, cargneules, marbles, schistes lustres, prasinites and ovardites of Forte Fenestrelle, serpentinites and ofi-calcites. All first subducted, later obductic and now exhumed Palaeozoic basement to Jurassic metamorphosed rocks.

And Alpe d’Huez’s famous hairpins, where legendary cyclists such as Fausto Coppi and Marco Pantani once showed off their physical strength and stamina, and blasted home with unbelievable acceleration and will-power.

An extra exciting dimension to the emotions of the Tour and cyclists:
Tour de France, Tour de Geologie, Tour de Vin; Bycicles, Geology, Viticulture, Three-in-One.

Dimanche, 23 juillet 2017. Dernière étape de 103 kilomètres entre Montgeron dans l”Essonne et les Champs-Élysées.
Une étape promise aux sprinteurs Greipel, Boasson Hagen, Bouhanni, et Matthews ? Dylan Groenewegen, le jeune Néerlandais de 24 ans, champion de son pays dans 2016, maintenant aussi pour la premiere fois dans la Grande boucle. Vainqueur.

Champs-Élysées, 19:20 p.m.:

Froome, Uran, Bardet.

(on Uran, FYI see: http://www.noticiasrcn.com/videos/sencillamente-rigo)

9. Geological notes (3) related with the photo ” Mont Genevre, Briancon, France, 1974 “:
” Standing on the Upper Mantle, Ophiolites “.

Leiden geologists, f.l.t.r. Arie Schaap, Andre van der Meulen, Marcel Chin-A-Lien, Ray Bergval (R.I.P.). Not visible, taking the pic, Wilbert Hocks.

(Personal note for my very dear ” Ophiolitic & High Pressure-Low Temperature Metamorphic ” friends, wherever you are, Australia, South America, Sranankondre, NL:

Caríssimi amici ciaoo a tutti, Manneee, see you soon, voor een paar pilsjes en bitterballen in Pardoeza of Barrera, cheers, de ballueee, doei, take care).

Our visit to the well-known Mont Genèvre Ophiolite sequence, Briancon, France was part of our fieldwork, mainly in the Italian Cottian Alps. Where we studied within others the ophiolite and upper mantle rocks there exposed, such as in Val Chisone and Parco naturale Orsiera-Rocciavre .

10) Plastic Deformation of Gabbros in a Slow-spreading Mesozoic Ridge: Example of the Montgenèvre Ophiolite, Western Alps: R. Caby.

Published in: Mantle and Lower Crust Exposed in Oceanic Ridges and Ophiolites, pp 123-145.

Gabbros of the Montgenèvre ophiolite (external Piémont zone, western Alps), with the mineralogical, geochemical and isotopic characteristics of an oceanic ridge, show evidence of pervasive high-temperature deformation before the intrusion of basalt dikes.

This deformation is incipient in the layered troctolites immediately above a locally preserved paleo-Moho, and increases in intensity upward in the overlying olivine-poor gabbros producing an anastomosing system of mylonitic shear zones and several steep ultramylonite belts.

The mylonites and ultramylonites developed by solid-state shearing of the gabbros at temperatures in excess of 800–850°C, allowing recrystallization of augite subgrains in the wings of ductilely deformed magmatic diopside-salite clasts followed by crystallization of brown amphiboles.

On the basis of textural relationships it is proposed that synkinematic partial melting within the sheared gabbros, at temperatures of 850° C or higher, generated augite- and pargasite-bearing leucodioritic magmas which evolved in narrow magmatic conduits and percolated through tectonites and actively deforming mylonite zones, to form cross-cutting veins in adjacent less deformed gabbros.

The complex geometry of the structures and their kinematics, when restored to a stage before the onset of pre-Alpine and Alpine brittle tectonics, suggest that this tectono-metamorphic evolution started after rapid solidification of the gabbros. It is proposed that the gabbroic mass was pushed away from a spreading center due to the activity of extensional and transform shear zones, in response to spreading through continuous domal uplift of the underlying mantle peridotites from which, at deeper levels, new basaltic melt was extracted to produce off-axis basaltic volcanism.

The “magmatic” Moho became thereby transformed into a “tectonic” moho, followed by uplift of peridotites to the ocean floor where they became overlain by ultramafic-derived sediments such as to form a “sedimentary” Moho.

The scarce geochronological data suggest a long time span, of about 50–60 Ma, between magmatic crystallization of gabbros and diorites (212± 8 Ma) and the deposition of the oceanic cover (165–160 Ma), suggesting a slow-spreading paleoridge in the relatively narrow (<1000 km) Piemonte-Ligurian branch of the Tethys ocean.

11) The Montgenevre ophiolite (Hautes Alpes, France): Meta—morphism and trace-element geochemistry of the volcanic sequence; Adrian D. Lewis and John D. Smewing – 1980 – www.researchgate.net/publication/229399557_The_Montgenevre_ophiolite_Hautes_Alpes_France
Abstract
The Montgenevre ophiolite near Briançon in the French Alps consists of pillow lavas, pegmatitic and flaser gabbros and serpentinite in tectonic contact.
These rocks have been metamorphosed under prehnite—pumpellyite to greenschist facies conditions during two stages, an early sub-sea-floor metamorphism prior to emplacement followed by the Alpine metamorphism.
The pillow lavas can be divided into two groups, the Chenaillet Sequence showing moderate differentiation, and the Grand Charvia Sequence with a more restricted composition.
Forty-seven samples of the volcanic rocks have been analysed for Ti, Zr and Y by X-ray fluorescence, and eleven for rare-earth elements (REE) and Th, Ta, Hf and Sc by instrumental neutron activation (INAA).
Although the original stratigraphic relationship of the lavas has been obscured by emplacement tectonics, geochemical modelling suggests that they can all be related by up to 60% fractionation of olivine, plagioclase and clinopyroxene.
Their chemical composition and phenocryst assemblages are similar to modern ocean-floor basalts.
12)  W-Alpine neotectonics and brittle deformation – Christian Sue – csue@univ-fcomte.fr. , Audrey Bertrand
Aims of the field trip

The briançonnais area, South-East of the Pelvoux massif, is carved by a dense fault network, which corresponds to the last tectonic event in the alpine history.

Indeed, this fault network postdates all the alpine compression-related structures such as nappe piles, folds, schistosities and cleavages related to the different compressional phases. The late fault system is made of normal faults, which locally bear witness of transcurrent reactivation. They can be observed at every scale (kilometric to centimetric) in the field.

In terms of paleostress this extension is radial to the belt close to the Crustal Penninic Front and multidirectional in the eastern part of the internal zones. The paleostress field of the strike-slip phase is coherent with the extensional one and compatible with dextral shear along longitudinal faults.

The current tectonics has also been analyzed using seismotectonics, which allowed the recognition of several active faults. The ongoing tectonics is coherent with the observed brittle deformation. Indeed, the fault network observed on the field controls the present-day seismicity.

During this 2-days field trip we will follow the longitudinal fault system along the Durance Valley, and southward up to the High-Ubaye area. The first day will concern the role of the Penninic Front in the late alpine brittle extension, and its relationship with the High-Durance fault. The second day will be dedicated to neotectonic observations along the Serennes Fault system.

13). Les Alpes – Aux origines de leur Formation.

 

 

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