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Droneybird explorations around the Southern Uplands Fault.

Years ago I used to drive the A77 through Ayrshire and just knew there was _something_ interesting about the landscape. Only recently have I learned that the collision and subduction associated with the Iapetus Ocean's closure during the Caledonian Orogeny (~420Mya) caused the emplacement of the Ballantrae Ophiolite Complex.

#geology #scotland #ophiolite #ballantrae #southernuplandfault #iapetus #drone #photography #ophiolite #ayrshire

Straight-down bird's-eye drone view of a gabbro outcrop, part of the ophiolite complex at Ballantrae

Ballantrae - the town by the beach - showing the gabbro outcrop just out to sea from the harbour wall; to the left, the bedrock becomes serpentinite

Drone photo from beside the memorial monument to the Varyag cruiser that ran aground offshore near Lendalfoot in the early C20. Looking inland, a flat plain makes a stark contrast with the subsequent elevated former coast / line of a raised beach.

#Serpentine minerals: low temperature #lizardite, high temperature #antigorite transport water into the mantle and lubricate the subduction channel; they're why we have subduction and also facilitate the return of some eclogites back up to the surface.

The Gros Morne #ophiolite of western #Newfoundland. Alligator skin motif coincidental. #MinCup23 #EarthSystemScience field trip to Newfoundland, 2022. #McGillUniversity #geology

Serpentinized peridotite ("lizard skin") from Gros Morne park, Newfoundland.

Wilson Cycle Phase 3: Ocean Closing

“I enjoy, and have always enjoyed, disturbing scientists.”

~ John Tuzo Wilson

“From great oceans, giant mountains will form. This is the prediction of the third phase of the Wilson Cycle where we see the closure of the vast oceans like the Iapetus Ocean, and the formation of continent to continent collision mountains.”

~ Professor Dougal Jerrom, intro to Wilson Cycle Phase 3: Ocean Closing video linked below

In the 24 minute video below (a great watch), we continue our travels with Professor Dougal Jerrom of Oslo University, to look at evidence of the closing of the former Iapetus Sea in the Caledonian of Norway. The video starts with a nice recap of the other videos.

Whenever there is an ocean closure, geoscientists always look for ophiolite. Ophiolites in the geologic record provide evidence of subduction zone tectonics. We have already seen the pillow basalts, sheeted dikes (gabbros) and peridotites that form ocean crust in earlier videos in this series. An ophiolite is then a bit of oceanic crust that got swept up in the continental collisions and provides the first proof of an ocean closure.

Next we learn about melange - the sediments that were scraped up during subduction, also known as an accretionary wedge. There are also remnants of the island arc formed during subdution all accreted between the bits of continental crustal blocks that eventually collided.

Enjoy the video below where you see glimpses of the geology of the beautiful Norwegian Caledonian.

Wilson Cycle Phase 3: Ocean Closing: https://youtu.be/jYlQCbDmEVw

More on the closing of the Iapetus Sea here: https://en.m.wikipedia.org/wiki/Iapetus_Ocean

Includes Step 5 of the Wilson Cycle: https://c.im/@vickyveritas/10962360456...

Refer to this great labeled diagram of the Wilson Cycle for the components of the ocean closure and continent to continent collision and mountain building: https://c.im/@vickyveritas/109628513962823739 
Note: We will see the last steps of the Wilson Cycle, the continent to continent collision and the formation of giant mountain belts, and the great grand finale of this series. Stay tuned.
 #JohnTuzoWilson #TheWilsonCycle #Caledonides #IapetusOcean #Norway #PlateTectonics #Ophiolite #AccretionaryWedge #granites #SutureZones #Laurentia #Baltica #geology #ScienceMastodon #NorwegianGeologyRocks @geology

Turbidites above the Resurrection Peninsula Ophiolite, Alaska.

We now know that the turbidites on Fox Island, near Seward AK are part of the Paleocene Orca Group.

Spectacular in scale, and thickness.

#Alaska #Ophiolite #Turbidite #Paleocene #Chugach

Cliff of layers of turbidites along a marine coastline with a small red zodiac in the foreground.

Pillow basalts of the 57 Ma Resurrection Peninsula Ophiolite, Alaska.

These are some of the most spectacular pillows I've seen.
These represent eruption of basaltic magma to the ocean floor, and they are directly related to the sheeted dike complex recently posted.

The Stellar sea lions have hauled out on a detached block with exposed flow tops.

#Alaska #Ophiolite #PillowBasalt #Paleocene #Chugach

Picture of pillow basalts in cross section and a loose block on a rocky coastline with Stellar Sea lions.

Sheeted dike complex of the 57 Ma Resurrection Peninsula Ophiolite, Alaska.

We recently determined the age of this complex by dating zircons in sediment interbedded in the overlying pillows. One of the most spectacular sheeted dike complexes I've seen (...and difficult to access).
These are feeders for basaltic magma to reach and erupt to the ocean floor.

#Alaska #Ophiolite #SheetedDikes #Paleocene #Chugach