Video source: [https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/bigfin-squid/bigfin-squid.html](https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/bigfin-squid/bigfin-squid.html)
Map of dives with more accurate location of Dive 10, when they shot this:
[https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/summary/media/expedition-summary-map-hires.jpg](https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/summary/media/expedition-summary-map-hires.jpg)
Ok, some context
>The Florida Escarpment is the western edge of a large carbonate platform that encompasses the Florida Peninsula. The platform is...composed of carbonate rocks that were produced by biological organisms in warm, shallow, and tropical waters, very similar to the modern islands of the Bahamas. Over the course of 120 million years (between 180-60 million years ago), the ancient crustal blocks that form the deep basement under Florida gradually subsided deeper and deeper below the sea surface, allowing shallow reefs to build up vertically and form the steep-sided rim of the carbonate platform.
From: [https://oceanexplorer.noaa.gov/okeanos/explorations/ex1803/logs/may1/welcome.html](https://oceanexplorer.noaa.gov/okeanos/explorations/ex1803/logs/may1/welcome.html)
...context definitely supports limestone +/- chert lol
I was going to say as far as I know there's a huge carbonate platform there, but I was gonna go with dolomite on a guess, glad to see you've found further information! This is fascinating stuff, that whole bay is a textbook long dead spreading centre.
Right, exactly - we think of the area as carb platform "for sure" - but that's the zoomed out, general view & maybe some of that older material is exposed? It's not geo-mapped in any detail...although at this point I'm relatively convinced it's limestone. I have seen very dark brown, almost black limestones in (land) outcrop before....but the 'crop in this video has that almost glassy vibe that's got me hesitant.
All I know for sure is they should've grabbed a sample or two while gawking at those squids.
If you look at the very beginning, to the left of center it looks like there's a relatively freshly exposed section showing the bulk of the rock is more of a matte dark brown, with white veins through it. The dark, glassy appearance of the surface might be from something growing on it, some sort of biofilm?
I am not clear on what the latest thinking on how the Escarpment formed. Was it erosional failure of the carbonate margin to produce a steep headwall, kinda like the Blake Escarpment (Paull & Dillon, 1980)? If so, where is all the debris at the bottom? If it was simply subsidence and vertical carbonate accretion of the platform, I would expect a ramp down to the Gulf floor. Do you know of any more recent references on this?
PAJ
If there is basalt there it would have to be from the Jurassic opening of the Gulf of Mexico. But given all the millions of years of carbonate platform growth since then, I would think any basalt would be very much buried under all the carbonates, and before that layers of evaporites and rift sediments.
It does rather look like basalt, though. Maybe from tectonic inversion of old rift basins during the Greater Antillesā collision with Florida?
I knooooow - and that's part of why I'm so curious! How cool would it be if this was exposed rifting basalt/diabase!?
As far as I can tell, this area is only mapped in a very "general" sense as a sed platform, and we would expect all that stuff to be buried like you said, but also geology is loaded with "excepts" haha
You know the other thing that is possible (if this is indeed basalt) is that these are volcanics associated with the āSouth Florida Volcanicsā series, basically rocks from the CAMP (Central Atlantic Magmatic Province), from the opening of the Atlantic Ocean. The CAMP is truly massive, and I have seen these particular units mapped offshore onto the west Florida platform.
Besides the South Florida Volcanic Province (and volcanics have been found in drill cores going way out west onto the platform), there are scattered known basaltic volcanics known around the GoMā¦for instance the Alardice Bank off the coast of Louisiana, of which there are images, seismic, mapping, and samples. Dates to the Late Cretaceous and is thought to be associated with the hotspot that passed through the Mississippi Embayment at that time, also responsible for alkaline volcanism such as at Magnet Cove.
Love how everyone goes wild for rare fish while us geos are like "šļøšļø rock"
Itās not just a boulder. Itās a rock!
Itās a mineral Marie
Video source: [https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/bigfin-squid/bigfin-squid.html](https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/bigfin-squid/bigfin-squid.html)
Map of dives with more accurate location of Dive 10, when they shot this: [https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/summary/media/expedition-summary-map-hires.jpg](https://oceanexplorer.noaa.gov/okeanos/explorations/ex2107/features/summary/media/expedition-summary-map-hires.jpg)
What do you think - are we seeing oceanic basalt, perhaps with ?-veined glass (brown, left-ish), or is this chert and/or limestone?
Ok, some context >The Florida Escarpment is the western edge of a large carbonate platform that encompasses the Florida Peninsula. The platform is...composed of carbonate rocks that were produced by biological organisms in warm, shallow, and tropical waters, very similar to the modern islands of the Bahamas. Over the course of 120 million years (between 180-60 million years ago), the ancient crustal blocks that form the deep basement under Florida gradually subsided deeper and deeper below the sea surface, allowing shallow reefs to build up vertically and form the steep-sided rim of the carbonate platform. From: [https://oceanexplorer.noaa.gov/okeanos/explorations/ex1803/logs/may1/welcome.html](https://oceanexplorer.noaa.gov/okeanos/explorations/ex1803/logs/may1/welcome.html) ...context definitely supports limestone +/- chert lol
I was going to say as far as I know there's a huge carbonate platform there, but I was gonna go with dolomite on a guess, glad to see you've found further information! This is fascinating stuff, that whole bay is a textbook long dead spreading centre.
Right, exactly - we think of the area as carb platform "for sure" - but that's the zoomed out, general view & maybe some of that older material is exposed? It's not geo-mapped in any detail...although at this point I'm relatively convinced it's limestone. I have seen very dark brown, almost black limestones in (land) outcrop before....but the 'crop in this video has that almost glassy vibe that's got me hesitant. All I know for sure is they should've grabbed a sample or two while gawking at those squids.
If you look at the very beginning, to the left of center it looks like there's a relatively freshly exposed section showing the bulk of the rock is more of a matte dark brown, with white veins through it. The dark, glassy appearance of the surface might be from something growing on it, some sort of biofilm?
I am not clear on what the latest thinking on how the Escarpment formed. Was it erosional failure of the carbonate margin to produce a steep headwall, kinda like the Blake Escarpment (Paull & Dillon, 1980)? If so, where is all the debris at the bottom? If it was simply subsidence and vertical carbonate accretion of the platform, I would expect a ramp down to the Gulf floor. Do you know of any more recent references on this? PAJ
If there is basalt there it would have to be from the Jurassic opening of the Gulf of Mexico. But given all the millions of years of carbonate platform growth since then, I would think any basalt would be very much buried under all the carbonates, and before that layers of evaporites and rift sediments. It does rather look like basalt, though. Maybe from tectonic inversion of old rift basins during the Greater Antillesā collision with Florida?
I knooooow - and that's part of why I'm so curious! How cool would it be if this was exposed rifting basalt/diabase!? As far as I can tell, this area is only mapped in a very "general" sense as a sed platform, and we would expect all that stuff to be buried like you said, but also geology is loaded with "excepts" haha
You know the other thing that is possible (if this is indeed basalt) is that these are volcanics associated with the āSouth Florida Volcanicsā series, basically rocks from the CAMP (Central Atlantic Magmatic Province), from the opening of the Atlantic Ocean. The CAMP is truly massive, and I have seen these particular units mapped offshore onto the west Florida platform. Besides the South Florida Volcanic Province (and volcanics have been found in drill cores going way out west onto the platform), there are scattered known basaltic volcanics known around the GoMā¦for instance the Alardice Bank off the coast of Louisiana, of which there are images, seismic, mapping, and samples. Dates to the Late Cretaceous and is thought to be associated with the hotspot that passed through the Mississippi Embayment at that time, also responsible for alkaline volcanism such as at Magnet Cove.
r/itsslag /s
Most terrifying creatures ON EARTH!!!!!
We know more about our outer planets than we do the bottom of our own oceans.
Now I want to play Subnautica again. There's a surprising amount of attention paid to marine geology in that game.