Brianconnais geology and Tethyan rifting

Part of The Shear Zone Channel. In the Cottian area of the Western Alps, the rocks of the Brianconnais provide a geological time machine back to when the region lay on the continental margin of Europe - on the edge of the Tethys ocean. Join Rob as he explores the stratigraphy of famous sites to build a geological history - one that informs ideas of how the continental crust rifted to form Tethys - and a curious history of earlier rifting too...

[@myroncook]

I enjoy your videos, Rob.

[@robbutler2095]

thanks!

[@hongyuanZhang-pr6wt]

I can also get a good image in my head although I did not have the travel chance in the past there. It is an excellent and systematic intruduction for the Alps's Tethyan marginal sequence. Field outcrops and inner figures, both pointed out to that rifting environment.

[@robbutler2095]

Thanks!

[@cybernescens]

Rob, these field videos are superb. Thank you for your detailed observations and interpretations.

[@robbutler2095]

Thanks - glad you like them.

[@cybernescens]

​@robbutler2095 could you point me to the relevant literature on "thermal subsidence" and reequilibrium?

[@robbutler2095]

@@cybernescens Sure -the basic ideas go back to Dan McKenzie (also see the video on "making oceanic lithosphere") - as covered in "Understanding subsidence in sedimentary basins" - but most basic text on basins cover it ....hope that helps for starters.

[@cybernescens]

@robbutler2095 you're the man. Thanks Rob.

[@ThomasEckhardt]

Great informative Video, this place must be a geologists dream come true! Is there any evidence of volcanism in the Permian rifting?

[@robbutler2095]

Thanks - lots of good stuff in the Alps. Volcanism during Permian - yes indeed... the seds are volcaniclastic... (immature)

[@SaeedAhmed-sb4qb]

Very nice work and good contribution in geology

[@robbutler2095]

Thank you - glad you enjoyed it. More Alpine videos to follow....

[@lundysden6781]

nice work!

[@robbutler2095]

Thanks!

[@manojkumar-cb3wf]

hello mr.Rob , can you please make some videos on geological mapping of granitic terrains?

[@robbutler2095]

A film on the Cairngorms is on my list...

[@manojkumar-cb3wf]

@@robbutler2095 thank you very much mr. rob.

[@FredWilbury]

I was intrigued by this video as recently got very interested in the geology around Polzeath , unfortunately I’m stuck the middle of evolution and creation how are the years you show worked out

[@robbutler2095]

Not sure I get your question. Is it about calibrating geological time? The relative age and global correlation is via classical palaeontology, especially ammonites (for the Jurassic). The biostratigraphic timescale is calibrated by radiometric dating, e.g. of interbedded volcanics and again globally correlated by the record of magnetic polarity switches which is also recorded in rocks. Tested and refined repeatedly over the past 50-80 years by earth scientists from all around the world. Google - Geological Timescale. Apologies if your question was more elaborate... or try me again!

[@FredWilbury]

@@robbutler2095 many thanks for your reply most helpful I probably worded my question a bit unclearly. I’ve a lot to learn

[@andrewjohnston9115]

Really enjoyed your explaination of a pretty complex Geological sequence, I'd love to see a full series focussing on the Alpine geology. Can you recommend a good general text explaing the alpine orogeny?

[@robbutler2095]

Ha - a single text on Alpine geology... it's a big ask. Nothing really out there in modern terms - which is part of my motivation for the videos. I'm building a series in the coming weeks that will grow into a geotraverse of the old continental margin, then I'll do an intro summary... so watch this space!