The Briançonnais zone is a zone in the Penninic nappes in the Western Alps which preserves

continental crust Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as '' continental shelves''. This layer is sometimes called '' si ...

rocks derived from the Briançonnais terrane. The Briançonnais terrane or continental ribbon was a narrow strip of continental crust. It was part of the European continental margin before the Early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

opening of the Valais Ocean, which separated it form it. It was the eastern tip of the Iberian block (which also encompassed, besides the

Iberian Peninsula The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprisin ...

, the

Corsica Corsica ( , , ; ; ) is an island in the Mediterranean Sea and one of the Regions of France, 18 regions of France. It is the List of islands in the Mediterranean#By area, fourth-largest island in the Mediterranean and lies southeast of the Metro ...

Sardinia Sardinia ( ; ; ) is the Mediterranean islands#By area, second-largest island in the Mediterranean Sea, after Sicily, and one of the Regions of Italy, twenty regions of Italy. It is located west of the Italian Peninsula, north of Tunisia an ...

block and the

Balearic Islands The Balearic Islands are an archipelago in the western Mediterranean Sea, near the eastern coast of the Iberian Peninsula. The archipelago forms a Provinces of Spain, province and Autonomous communities of Spain, autonomous community of Spain, ...

, which later rifted from Iberia). Because paleogeographic reconstructions of highly deformed pieces of crust are always difficult, in the past there was a dispute among geologists about weather the Briançonnais terrane had originally been part of the Eurasian plate or the Iberian block (which was a unit of the Eurasian plate). The Briançonnais terrane and Briançonnais zone are named after the French town of

Briançon Briançon (, ) is the sole Subprefectures in France, subprefecture of the Hautes-Alpes Departments of France, department in the Provence-Alpes-Côte d'Azur Regions of France, region in Southeastern France. It is the highest city in France at an a ...

in the Hautes-Alpes department.

References

{{DEFAULTSORT:Brianconnais zone Geology of the Alps Terranes Geology of France Geology of Italy

See also

References