See the 6 part Valles Caldera geology video by NMSU geologists during the Covid shutdown. Here is Part one. They made them about 10 minutes long each. I know it's a volcano, but it gets into the layers using geology maps. ua-cam.com/video/2gCm7et-N0s/v-deo.html
An extra fun fact is that Mount Diablo also has the largest coal field in the state of California, and its coal largely fueled the factories of San Francisco and the steel used to build the city
Just south of Mt Diablo is an area called Vasco Caves. This complex represents an area where the up lift of Mt Diablo caused the sea floor to flip over, thus the upper layers are older than the lower ones. Winds caused sand boils to erode the weaker sandstone layer into a cave complex. This area is where the original people believed life to have begun. Just east is a hot spring that has red ochre in patches on the ground, this is where they believe death began.
Glad you mentioned that. There's a lot going on out there, geologically speaking. Coal deposits a few miles away near Antioch, natural gas deposits out near Altamont Pass, not to mention a large number of fault lines (not even counting the San Andreas). I didn't know about the mercury mine off Morgan Territory Rd.
Wow! You reviewed a geologic feature that I can see from my front yard! Thanks! And as others have said, please keep making your science-based, calmly presented videos about dramatic events. I always look to you for proper reporting.
I grew up close to Mount Diablo in Contra Costa County. I thought it was an extinct volcano, too, until I found out otherwise. Thank you for your excellent explanation of how Mt. Diablo was formed!
If you're in the vicinity, this place has some fantastic hiking, and it's doable with a whole day to hike to the top of Mt. Diablo and back. Lots of history with Mt. Diablo as well, both with local Tribes and explorers and settlers of CA.
My dad and I hiked the trails of Diablo when I was in high school. I am still awed by its magnificence. Thank you for sparking some wonderful memories. It would be really great if you could discuss the orogeny of Mt Tamalpais, across the water from Diablo.
I have some family near the Bay Area, and whenever I go to visit it is really hard to miss such a mountain. It really stands out. Thank you for putting this video together. Now I know a little more about this fascinating mountain.
Absolutely brilliant - I've been waiting for this as Mt Diablo is mentioned in 2 of my favourite geology books : Jihn McPhee's Assembling California and SImon Winchester's A Crack in the Edge of the World. Both written years ago but so enjoyable. Thank you so much!
I used to live very near Mt Diablo when I was a kid. I could see it from my front yard. Been a very long time since then, but brought back so fond memories, as well as learning how it was formed! Very cool, and I thank you!
I was just trying to understand ophiolite formation a couple months ago. This definitely helps understand it's formation and my local geology. Thanks as always!
This is my favorite post in a long time. Highlighting different "provinces"and things, and saying where they came from is fascinating no matter where you are, or what else is being presented.
If you want a better picture of what likely led to these complexes from a geophysical perspective Nick Zentner's A to Z Baja BC livestream series from last winter. In essence the always Farallon slab picture has been falsified by multidisciplinary evidence from igneous petrology sedimentology seismic tomography instead they paint a more complex picture where the passive margin of North America, i.e. the former passive margin of western Pangaea (Native NA subduction was only to the north or rather this crust was further to the south), was pulled via the attached oceanic slab of the old Panthelassan ocean towards an oceanic subduction complex archipelago. Around 90 million years ago North America finally reached this archipelago and ultimately overrode it with the accretionary wedge and resultant subduction volcanism showing an increasing continental affinity as the amount of continental sediments from North America increased over time resulting in a much more natural transition in the sediment record. Deep ophiolites were excavated from the mantle as the underlying North American slab's increasingly continental affinity led to it becoming too buoyant to sink leading to the slab catastrophically failing and snapping back upwards. The mechanism for obduction here is that this was once the overlying oceanic slab in an oceanic oceanic subduction convergent plate boundary which ended up being carried onto the new North American continental boundary as the archipelago was overridden. No need for handwaving just gravity and inertia. We can see this process occurring today between Australia and New Guinea and Indonesia as the Australian continent overrides this formerly oceanic archipelago. The old boundary for North America's old passive boundary can be found to the east of the Sierra Nevada mountains where the added archipelago is being torn off of the old North American plate due to the sheering action from the relative difference in plate direction between North America moving southwest and the Pacific plate moving due north. Notably as this process occurs the Sierra Nevada Great Valley block is getting raised and tilted upwards and towards the west so the only remaining sediment records are the deeper remnant cores of what was the western margin of this archipelago and the deeper batholith which once anchored this old island arc the younger layers have already been eroded away the Baja peninsula regions. There are a number of old exotic terrains embedded to the west which indicate a complex subduction history which likely included back arc basins and sheering zones during the Mesozoic. Bits of this more complex history do survive in parts of Northern California and southwestern Oregon at or below sea level but it is mostly gone eroded away by millions of years of uplift. This newer picture of the geology out west also resolves the geophysical problems with the old model for forming the Rocky mountains (though that is mostly from a different portion of the overridden archipelago complexes.
@@Flugmorph What is wrong with calling out and explaining the nuances? Its important to be aware of model choice and the simplifications and challenges that result. Otherwise misconceptions and confusion can persist in the public mind. I hope to expose people to these newer ideas which made things click for me in a way that the old model didn't. Whoops I apparently forgot to post this comment... Not sure I should post this but I already wrote it so yeah.
Always love to hear about the complex geologic history of my old home stompin' grounds. Wish I still had my old geology book "Streetcar to Subduction" by Clyde Warhaftig which I would still avidly recommend to anyone who lives in the Bay Area and who wants to know more about it and how to actually visit these remarkable geological sites which they can actually visit using public transportation. I still wonder if the rumors are true of the occasional gold mining going on up in Diamond Heights. Incidentally I've always heard that the term Franciscan as in Franciscan Complex was pronounced with a hard second "c", as in "fran-sis-kan"....Cheerio.
Could you do a video in regards to how the Rocky Mountains formed? And possibly present other hypothesis regarding the formation of the Rocky Mountains?
Mt diablo is rad, so many cool little micro climates supporting a really diverse amount of flora. Its also quite a climb if you start from the bottom and boy what a view. Really neat to hear about the geology of it.
Been up there a few times. Like catching the sunset in autumn, watching the shadow of Diablo's peak stretching accross the delta. The radio reception up on top is incredible.
Thank You for doing this video finally. It's one I've been waiting for a long time....For anyone driving out of TRACY, CA to do the grind of a Central Valley to Bay Area Commute or taking the I-580 from I-5 you will see the perfect shaped "Devil Horns" that Spanish Conquistadors like CABLILLO likely saw coming up what is now "Byron Highway". Byron Road/Highway is indeed part of Cabrillo's Path taken from what is now Downtown Los Angeles to Central & Northern California.
I remember growing up as a kid in Concord thinking the area was a caldera. ( Weird as a kid) The surrounding hills almost formed a circle. Thank you for educating me on how the area was formed!
Even better examples of Farallon/Franciscan minerals CAN be legally collected further south in San Benito County at the Clear Creek BLM management area. Included are Pillow Basalt pillows that travelled all the way across the Pacific Ocean before crashing into North America, as well as remelted, multi-colored former Serpentine. And the gemstone Benitoite, too. Permits are now required, unlike the old days.
Wow, I always wanted to figure out how mt Diablo was formed, I always thought it was an extinct volcano due to the view I see in the valley i found out it wasn't but ur information today made me learn how it rlly formed
California state rock? I guess it make sense that every state has a state rock but I don't think I have every heard of any of them before. I learn something every day on this channel! What is YOUR state rock?
Looking it up via google the state rock of Virginia is as of 2016 apparently a rock called Nelsonite which is a type of plutonic rock with economically viable amounts of Titanium in the form of the mineral ilmenite and as a source for phosphates for use in fertilizer as its 2nd most common mineral constituent being the Phosphorus bearing mineral apatite. The name comes from Nelson county Virginia. Interestingly both of these minerals seem to be common with Carbonatites and high alkalinity igneous and volcanic rocks. I had never heard about this rock before so thanks for the prompt. :)
Saw the name Melange, andinstantly thought of the Spice Melange from the Dune series. The Melange must flow! up a hill! to eventually become a moutain. Great video as Always!
Does anyone know if GH has, like, a super-doctorate or something? Crikey, he's a prolific and unceasing fountain of information regarding volcanism (among other geologic phenomena). Certainly he is the go-to for lots of YT viewers for info on this particular subject matter, myself included.
Would be interesting to have some videos about block and fold mountain formation. Would be curious to see some of your informative narrated animations on how the Appalachian mountains formed. 🙏🏻
I thought the North American plate in its collision with the Siletzia aggregation of farallon and the other two plates to the north which I cannot remember to my failure this morning without coffee. That the reversal of a subduction zone created the material that you're talking about
I should note that there is a more complex geological story for California addressed in Nick Zentner's Baja BC A to Z livestream series from a year ago. Notably there is a strong case that the Franciscan complex and the nearby Sierra Nevada batholith are remains of an oceanic archipelago which North America collided with around 100-90 Ma. Slab failure turns out to be critical in getting those ophiolites to the surface as they effectively rode the passive margin of the North American plate as the buoyancy difference between oceanic and continental crust became too great for the slab pull to overcome leading to the slab breaking and rebounding. The transition in the sediment record from oceanic to continental is also naturally explained and matches the trend observed in the island arcs along the Sunda trench as the Australian continent approaches the subduction zone with a clear increase in continental affinity of both the accretionary sediments and arc volcanoes as one goes towards the east where we can see the transition to New Guinea which has already become welded to the Australian continental self with new subduction zones forming to the north on what used to be the archipelagos' passive margin as Australia continues to move north. From igneous petrology we know the overriding transition here occurred around 100 to 90 million years ago as slab failure volcanism is preserved within the magma chemistry of the Sierra Nevada Batholith complexes. So yes subduction zone reversal was important but it occurred long before Siletzia being nearly twice as old. In a more modern context the suture between this accreted archipelago and old North America seems to be around the dividing point between the Sierra Nevada great Valley block/microplate and the old craton which is exposed on the eastern divide of the various Grabens forming as this accreted batholith arc complex is getting sheered off due to the relative plate motion of North America and the Pacific Plate. To the east are rocks dating back to the Paleozoic, & Neoproterozoic while to the west outside of a few exotic terrains the rocks are all Mesozoic in age or younger. As the block's uplift is associated with a rotational tilt component the Franciscan complex are some of the only sedimentary layers remaining of this accreted crustal block. This picture is likely still too simple because the Franciscan complex is apparently even more complicated but erosion limits what evidence can be reconstructed from this Mesozoic geologic story. The particularly cool thing about this arc collision story is that it is even preserved in the changes of Fauna (and flora) within the fossil record as around this time there is a sharp transition in dinosaurs species evolutionary affinities which shift to include species of anatomically Asian ancestry during the late Cretaceous. In essence you had something of a land bridge/continental interchange and or rafting situation which allowed dinosaurs from Asia to enter north America. Some likely didn't fare so well but others most famously T. rex thrived and ultimately drove their former North American counterparts extinct. While these accreted terrains don't reserve dinosaur fossils themselves the timing of this faunal turnover matches that of the rocks recording the eventual accretion of these new terrains which notably include much of British Columbia, basically almost all of Alaska(minus Yakutat which is a currently still accreting northern block of Siletzia since that oceanic plateau appears to have ben a Pacific analog of Iceland) and some parts of northern Washington state. In essence Siletzia fit in-between these other accreted terrains with the crustal blocks to the north showing clear evidence of rotation preserved in the form of metamorphic core complexes and inter-plate volcanism. Its fascinating stuff the videos are long but so worth it and the papers associated with it are great mind opening reads.
@@Dragrath1This is fascinating but very complex - I can't understand it without illustrations, and I would like to. Is there any chance you could cooperate with GH on making a video on it, and maybe a longer one rather than the normal five minutes?
Thanks for this great video on my nearby mountain. There IS volcanism nearby, that would be interesting to hear about, as well as fossils local to the area around Mt. Diablo.
If you are curious about California geology, I recommend "Assembling California" by John McPhee, which is somewhere between science reporting and literature - very detailed.
I grew up with this mountain as my horizon! It was the only place we could see snow occasionally- and we all grew up thinking it was an extinct volcano. There used to be a functional lighthouse at the top also, closed due to WW2 I think...
The entire west coast of North America is composed of exotic terranes, which were accumulated as North America plowed westward. While the Farallon plate subduction is generally still held up as a good model, the entire history of the west coast is far more complex than that, with some terranes that had travelled far (independent of North America) before they were accumulated.
So some interesting nuances from Nick Zentner's A to Z Baja BC series is that the picture given of the Farallon slab subduction portrayed is too simplistic and involves too many hand waved events or "some how this happened scenarios" where no geophysical process is in place to explain why the behavior changed. Instead there is a newer more complex geologic picture where it seems this part of California was likely once part of a larger oceanic archipelago where subduction was occurring from multiple angles and directions before getting overridden by North America around 90 million years ago as the then passive margin of North America was pulled into the subduction zone to the east much like what is occurring with the Australian plate dragging sediments from Australia's continental shelf down into the Sunda trench . Eventually as seen in New Guinea the more buoyant nature of the continental crust will lead to the slab breaking off and snapping back upwards bringing up a significant amount of mantle material. This slab failure process plays a critical role in explaining how mantle rocks became forced up towards the surface and is chemically recorded within the Sierra Nevada batholith Additionally obduction as we now know it generally requires an oceanic oceanic subduction zone to form as the surviving obducted crust represents remains of the overlying slab. All the parts of this process can be seen in action within modern New Guinea and Indonesia. For example the transition to more continental sediments can be seen gradually within Indonesia as the increasing amount of subducted sediment from Australia is getting fed into the trench and the overlying accretionary edge and represents the approach of the North American plate to the margin before the arc was ultimately overridden by North America. No handwaving is involved unlike the scenario provided here the transition is geophysically driven by slab pull and can be chemically identified within the batholithic rocks of the Sierra Nevada batholith and Franciscan complex sedimentary layers with the ability to trace continental sediments back to their source rocks and show that these rocks formed in a more complex archipelago scenario rather than a conventional Farallon plate scenario. In essence the "Farallon slab" was at one point the overlying slab which an older ocean slab attached to the then passive margin of southern North America. This slab continued to subduct pulling North America with it depositing the signature of increasing continental sediment contributions within both magma sand accretionary materials up until the increasingly continental affinity of the overlying slab led to it ultimately snapping back off from the rest of the oceanic slab due to its more buoyant character.
Mt. Diablo is not a high mountain when compared to the elevation of other mountains in the West. However, Mt. Diablo is actually an impressive looking mountain nonetheless since the mountain rises directly above sea level.
I was wondering, does deposition of material on the subducting plate from erosion off the landward plate, push the subducting plate down to any noticeable degree? Especially considering most of that deposition is right in front of the subducting zone?
The closest volcano to Mt. Diablo is Round Top in the Oakland/Berkeley hills just over 15 miles to the West. The Robert Sibley Volcanic Regional Preserve is just above and South of the Eastern portal to the Caldecott Tunnel.
I was always looking for information about this California peak...I thought it was an extinct volcano too until just now😮 Ugggg I am 50 yrs old and didn't know this..😂😂😂😂 guess I need to go back to geology school 😂😂😂😂😂
Not a volcano? You just disappointed so many of my friends who live in the Bay Area. I mean I live nearby but I'm just surprised. ;-) Growing up here we were taught that if there was Mercury to mine or gold that meant that it was a volcano in the past (not to mention all the hot springs).
Well it is in essence at least subduction related in origin. (The story given here is a bit out of date based on what I've learned on Nick Zentner's channel these rocks instead appear to be parts of a mature volcanic archipelago that North America eventually overrode between 100 to 90 Ma as Australia is doing today with regards to New Guinea and Indonesia)
how would it be determined the depth? i assume the serpentine/mantle rocks definitely a big marker in this case, but in other areas, would there be something like affects of water pressure that deep having evidence in the rocks? anything else i'm missing lol?
I believe that silica deposits come from the life form of diatoms which use Si as the structural basis of their exoskeleton. I believe that flint is a sedimentary rock which gains its hardness from the silica included by the sedimentary deposition of diatoms.
It's not really a mineral but a rock type - a poorly sorted sandstone in a clay matrix, dark grey or blue-grey because it is chemically reduced rather than oxidised, and produced by turbidity currents (avalanches of poorly consolidated sediment into a deep marine trench adjacent to a subduction zone). Or so says Wikipedia, tightening up on what I already more or less knew.
I saw a really good lecture from a geophysicist that showed how continental plates moving at METERS PER SECOND slammed together and raised the mountain ranges all around the world. Sure explains why you have marine fossils in sedimentary layers, miles above sea level
Most of western North America from the Rockies westward is simply the results of accretion tops of oceanic plates, piling up as their undersides slide under the continental plate. The Olympic mountains of Washington state is a classic example of such a melange mess of microplates (terranes) being stuck onto the leading edge of the NA plate moving west.
There is a volcano in El Salvador that is interesting to me. Lake Ilopango. I was wondering if you could look into it. As the volcano collapsed like Mt Mazama in Oregon. Also one of its eruption caused a year without summer and it is theorized an eruption of this volcano could have caused a tragedy coinciding with horrific deaths in the Byzantine capital of Constantinople of poison gas.
Any connection with deaths from poison gas in Constantinople seems most unlikely to me. The rest is entirely plausible though - there are plenty of 'years without a summer' not yet linked to a specific volcano/eruption.
Almost all of North America west of the Rockies is "accreted terrane"; that is, it originated as undersea formations or even islands clumped on to the continent.
And just think, in another 100 million years, LA will be up near Seattle, parts of Alaska will be colliding with Russia, humans will be extinct, at least 4 new Hawaiian islands will have been formed, and every super volcano on the planet will have erupted at least once and that’s just naming a few things.
I really like this one. I'd love to see more videos on different geologically interesting sites (other than volcanos)
See the 6 part Valles Caldera geology video by NMSU geologists during the Covid shutdown. Here is Part one. They made them about 10 minutes long each.
I know it's a volcano, but it gets into the layers using geology maps.
ua-cam.com/video/2gCm7et-N0s/v-deo.html
An extra fun fact is that Mount Diablo also has the largest coal field in the state of California, and its coal largely fueled the factories of San Francisco and the steel used to build the city
Just south of Mt Diablo is an area called Vasco Caves. This complex represents an area where the up lift of Mt Diablo caused the sea floor to flip over, thus the upper layers are older than the lower ones. Winds caused sand boils to erode the weaker sandstone layer into a cave complex. This area is where the original people believed life to have begun. Just east is a hot spring that has red ochre in patches on the ground, this is where they believe death began.
Glad you mentioned that. There's a lot going on out there, geologically speaking. Coal deposits a few miles away near Antioch, natural gas deposits out near Altamont Pass, not to mention a large number of fault lines (not even counting the San Andreas). I didn't know about the mercury mine off Morgan Territory Rd.
Wow! You reviewed a geologic feature that I can see from my front yard! Thanks! And as others have said, please keep making your science-based, calmly presented videos about dramatic events. I always look to you for proper reporting.
Me, too, though actually from the backyard! Who knew our modest mountain had such a unique geological past. ✌😎🌎
As an east coast transplant to california, any video that helps explain the complexities of the geology are most appreciated. This was wonderful.
I grew up close to Mount Diablo in Contra Costa County. I thought it was an extinct volcano, too, until I found out otherwise.
Thank you for your excellent explanation of how Mt. Diablo was formed!
If you're in the vicinity, this place has some fantastic hiking, and it's doable with a whole day to hike to the top of Mt. Diablo and back. Lots of history with Mt. Diablo as well, both with local Tribes and explorers and settlers of CA.
Just remember to not leave any valuables in your vehicle.
My dad and I hiked the trails of Diablo when I was in high school. I am still awed by its magnificence. Thank you for sparking some wonderful memories.
It would be really great if you could discuss the orogeny of Mt Tamalpais, across the water from Diablo.
I have some family near the Bay Area, and whenever I go to visit it is really hard to miss such a mountain. It really stands out. Thank you for putting this video together. Now I know a little more about this fascinating mountain.
Absolutely brilliant - I've been waiting for this as Mt Diablo is mentioned in 2 of my favourite geology books : Jihn McPhee's Assembling California and SImon Winchester's A Crack in the Edge of the World. Both written years ago but so enjoyable. Thank you so much!
I live just south of Mt. Diablo. I had no idea how it was formed. Thanks much!
I used to live very near Mt Diablo when I was a kid. I could see it from my front yard. Been a very long time since then, but brought back so fond memories, as well as learning how it was formed! Very cool, and I thank you!
I was just trying to understand ophiolite formation a couple months ago. This definitely helps understand it's formation and my local geology. Thanks as always!
This is my favorite post in a long time. Highlighting different "provinces"and things, and saying where they came from is fascinating no matter where you are, or what else is being presented.
Thanks for the daily videos! Keep up the great work!
very interesting plate upduction and folding processes here
If you want a better picture of what likely led to these complexes from a geophysical perspective Nick Zentner's A to Z Baja BC livestream series from last winter.
In essence the always Farallon slab picture has been falsified by multidisciplinary evidence from igneous petrology sedimentology seismic tomography instead they paint a more complex picture where the passive margin of North America, i.e. the former passive margin of western Pangaea (Native NA subduction was only to the north or rather this crust was further to the south), was pulled via the attached oceanic slab of the old Panthelassan ocean towards an oceanic subduction complex archipelago. Around 90 million years ago North America finally reached this archipelago and ultimately overrode it with the accretionary wedge and resultant subduction volcanism showing an increasing continental affinity as the amount of continental sediments from North America increased over time resulting in a much more natural transition in the sediment record.
Deep ophiolites were excavated from the mantle as the underlying North American slab's increasingly continental affinity led to it becoming too buoyant to sink leading to the slab catastrophically failing and snapping back upwards.
The mechanism for obduction here is that this was once the overlying oceanic slab in an oceanic oceanic subduction convergent plate boundary which ended up being carried onto the new North American continental boundary as the archipelago was overridden. No need for handwaving just gravity and inertia. We can see this process occurring today between Australia and New Guinea and Indonesia as the Australian continent overrides this formerly oceanic archipelago.
The old boundary for North America's old passive boundary can be found to the east of the Sierra Nevada mountains where the added archipelago is being torn off of the old North American plate due to the sheering action from the relative difference in plate direction between North America moving southwest and the Pacific plate moving due north. Notably as this process occurs the Sierra Nevada Great Valley block is getting raised and tilted upwards and towards the west so the only remaining sediment records are the deeper remnant cores of what was the western margin of this archipelago and the deeper batholith which once anchored this old island arc the younger layers have already been eroded away the Baja peninsula regions. There are a number of old exotic terrains embedded to the west which indicate a complex subduction history which likely included back arc basins and sheering zones during the Mesozoic. Bits of this more complex history do survive in parts of Northern California and southwestern Oregon at or below sea level but it is mostly gone eroded away by millions of years of uplift.
This newer picture of the geology out west also resolves the geophysical problems with the old model for forming the Rocky mountains (though that is mostly from a different portion of the overridden archipelago complexes.
@@Dragrath1 bruh chill
@@Flugmorph What is wrong with calling out and explaining the nuances? Its important to be aware of model choice and the simplifications and challenges that result. Otherwise misconceptions and confusion can persist in the public mind. I hope to expose people to these newer ideas which made things click for me in a way that the old model didn't. Whoops I apparently forgot to post this comment... Not sure I should post this but I already wrote it so yeah.
I love these kind of animated diagrams starting at 2:40. Certainly makes a Million Years feel like a short time!
Always love to hear about the complex geologic history of my old home stompin' grounds. Wish I still had my old geology book "Streetcar to Subduction" by Clyde Warhaftig which I would still avidly recommend to anyone who lives in the Bay Area and who wants to know more about it and how to actually visit these remarkable geological sites which they can actually visit using public transportation. I still wonder if the rumors are true of the occasional gold mining going on up in Diamond Heights. Incidentally I've always heard that the term Franciscan as in Franciscan Complex was pronounced with a hard second "c", as in "fran-sis-kan"....Cheerio.
Could you do a video in regards to how the Rocky Mountains formed? And possibly present other hypothesis regarding the formation of the Rocky Mountains?
Mt diablo is rad, so many cool little micro climates supporting a really diverse amount of flora. Its also quite a climb if you start from the bottom and boy what a view. Really neat to hear about the geology of it.
Been waiting for this one for a while, thank you
Beautifully described piece. Amazing reconstruction!
Thanks as always! This is such a fascinating mountain!
I love the graphics in this one. It’s so hard to envision, otherwise. Very interesting!
Been up there a few times. Like catching the sunset in autumn, watching the shadow of Diablo's peak stretching accross the delta. The radio reception up on top is incredible.
Mount Diablo got a lyft, not a uber.
😐😉
Thank You for doing this video finally. It's one I've been waiting for a long time....For anyone driving out of TRACY, CA to do the grind of a Central Valley to Bay Area Commute or taking the I-580 from I-5 you will see the perfect shaped "Devil Horns" that Spanish Conquistadors like CABLILLO likely saw coming up what is now "Byron Highway". Byron Road/Highway is indeed part of Cabrillo's Path taken from what is now Downtown Los Angeles to Central & Northern California.
Love your podcast
Great diagram and description! Thank you GH!!!
Wait, Mt. Diablo isn't an extinct volcano??? Fascinating! Thanks for this video!
I remember growing up as a kid in Concord thinking the area was a caldera. ( Weird as a kid) The surrounding hills almost formed a circle. Thank you for educating me on how the area was formed!
So interesting, I just love this channel, thank you
Nice! I could see my house in the video! Never knew the interesting geology of my local mountain
Loves the diagram at the end shownig how complex this all is!!!
Even better examples of Farallon/Franciscan minerals CAN be legally collected further south in San Benito County at the Clear Creek BLM management area. Included are Pillow Basalt pillows that travelled all the way across the Pacific Ocean before crashing into North America, as well as remelted, multi-colored former Serpentine. And the gemstone Benitoite, too.
Permits are now required, unlike the old days.
Beautifully done!! What a great explanation. Love it!
That was absolutely fascinating!
From my apartment I had a picture perfect view of Mt. Diablo. I lived in Lafayette, California at the time.
Nice. I'm a Mendocino local so I enjoyed this one.
Fascinating information. Thank you.
Thanks for all of your hard work man!
Very cool. Myself and many other mountain bike riders have that geology ground into their skin.
Wow, I always wanted to figure out how mt Diablo was formed, I always thought it was an extinct volcano due to the view I see in the valley i found out it wasn't but ur information today made me learn how it rlly formed
I live right at the base! so cool to see a small feature from where I live on this channel :) thank you for covering mt diablo!
it's so fascinating to see a map of land masses that had been added to the west coast of the usa.
California state rock? I guess it make sense that every state has a state rock but I don't think I have every heard of any of them before. I learn something every day on this channel!
What is YOUR state rock?
Marble.
I would hate to be the state whose state rock is Kid.
@@ThatOpalGuy 🤣
Prairie agate
Looking it up via google the state rock of Virginia is as of 2016 apparently a rock called Nelsonite which is a type of plutonic rock with economically viable amounts of Titanium in the form of the mineral ilmenite and as a source for phosphates for use in fertilizer as its 2nd most common mineral constituent being the Phosphorus bearing mineral apatite. The name comes from Nelson county Virginia.
Interestingly both of these minerals seem to be common with Carbonatites and high alkalinity igneous and volcanic rocks.
I had never heard about this rock before so thanks for the prompt. :)
Saw the name Melange, andinstantly thought of the Spice Melange from the Dune series. The Melange must flow! up a hill! to eventually become a moutain. Great video as Always!
Does anyone know if GH has, like, a super-doctorate or something? Crikey, he's a prolific and unceasing fountain of information regarding volcanism (among other geologic phenomena). Certainly he is the go-to for lots of YT viewers for info on this particular subject matter, myself included.
Wow. I've visited here and I had no idea. Folks in fact had us believing it was an extinct volcano at the time
Would be interesting to have some videos about block and fold mountain formation. Would be curious to see some of your informative narrated animations on how the Appalachian mountains formed. 🙏🏻
I thought the North American plate in its collision with the Siletzia aggregation of farallon and the other two plates to the north which I cannot remember to my failure this morning without coffee. That the reversal of a subduction zone created the material that you're talking about
What you describe happened a bit further north in Oregon, Washington, and Vancouver Island.
Juan de Fuca and Gorda plates are which came to my mind but haven't checked them out.
I should note that there is a more complex geological story for California addressed in Nick Zentner's Baja BC A to Z livestream series from a year ago. Notably there is a strong case that the Franciscan complex and the nearby Sierra Nevada batholith are remains of an oceanic archipelago which North America collided with around 100-90 Ma. Slab failure turns out to be critical in getting those ophiolites to the surface as they effectively rode the passive margin of the North American plate as the buoyancy difference between oceanic and continental crust became too great for the slab pull to overcome leading to the slab breaking and rebounding. The transition in the sediment record from oceanic to continental is also naturally explained and matches the trend observed in the island arcs along the Sunda trench as the Australian continent approaches the subduction zone with a clear increase in continental affinity of both the accretionary sediments and arc volcanoes as one goes towards the east where we can see the transition to New Guinea which has already become welded to the Australian continental self with new subduction zones forming to the north on what used to be the archipelagos' passive margin as Australia continues to move north.
From igneous petrology we know the overriding transition here occurred around 100 to 90 million years ago as slab failure volcanism is preserved within the magma chemistry of the Sierra Nevada Batholith complexes. So yes subduction zone reversal was important but it occurred long before Siletzia being nearly twice as old.
In a more modern context the suture between this accreted archipelago and old North America seems to be around the dividing point between the Sierra Nevada great Valley block/microplate and the old craton which is exposed on the eastern divide of the various Grabens forming as this accreted batholith arc complex is getting sheered off due to the relative plate motion of North America and the Pacific Plate. To the east are rocks dating back to the Paleozoic, & Neoproterozoic while to the west outside of a few exotic terrains the rocks are all Mesozoic in age or younger. As the block's uplift is associated with a rotational tilt component the Franciscan complex are some of the only sedimentary layers remaining of this accreted crustal block.
This picture is likely still too simple because the Franciscan complex is apparently even more complicated but erosion limits what evidence can be reconstructed from this Mesozoic geologic story.
The particularly cool thing about this arc collision story is that it is even preserved in the changes of Fauna (and flora) within the fossil record as around this time there is a sharp transition in dinosaurs species evolutionary affinities which shift to include species of anatomically Asian ancestry during the late Cretaceous. In essence you had something of a land bridge/continental interchange and or rafting situation which allowed dinosaurs from Asia to enter north America. Some likely didn't fare so well but others most famously T. rex thrived and ultimately drove their former North American counterparts extinct. While these accreted terrains don't reserve dinosaur fossils themselves the timing of this faunal turnover matches that of the rocks recording the eventual accretion of these new terrains which notably include much of British Columbia, basically almost all of Alaska(minus Yakutat which is a currently still accreting northern block of Siletzia since that oceanic plateau appears to have ben a Pacific analog of Iceland) and some parts of northern Washington state. In essence Siletzia fit in-between these other accreted terrains with the crustal blocks to the north showing clear evidence of rotation preserved in the form of metamorphic core complexes and inter-plate volcanism. Its fascinating stuff the videos are long but so worth it and the papers associated with it are great mind opening reads.
@@Dragrath1This is fascinating but very complex - I can't understand it without illustrations, and I would like to. Is there any chance you could cooperate with GH on making a video on it, and maybe a longer one rather than the normal five minutes?
Thanks for this great video on my nearby mountain. There IS volcanism nearby, that would be interesting to hear about, as well as fossils local to the area around Mt. Diablo.
How did the Hg form to mined in the area? Would you please make a video about this topic?
I'm interested in how ore bodies form too.
If you are curious about California geology, I recommend "Assembling California" by John McPhee, which is somewhere between science reporting and literature - very detailed.
I have hiked up this mountain a few years ago. My legs were sore afterward.
I grew up with this mountain as my horizon! It was the only place we could see snow occasionally- and we all grew up thinking it was an extinct volcano. There used to be a functional lighthouse at the top also, closed due to WW2 I think...
This is a cool video. Can you do one on the Mt. Peak aka turtle back mountain in Western WA.
Great video
The entire west coast of North America is composed of exotic terranes, which were accumulated as North America plowed westward. While the Farallon plate subduction is generally still held up as a good model, the entire history of the west coast is far more complex than that, with some terranes that had travelled far (independent of North America) before they were accumulated.
If you visit in around late september to mid october and go on the more northwestern side you can also see tarantulas.
This is actually interesting 🤔
So some interesting nuances from Nick Zentner's A to Z Baja BC series is that the picture given of the Farallon slab subduction portrayed is too simplistic and involves too many hand waved events or "some how this happened scenarios" where no geophysical process is in place to explain why the behavior changed.
Instead there is a newer more complex geologic picture where it seems this part of California was likely once part of a larger oceanic archipelago where subduction was occurring from multiple angles and directions before getting overridden by North America around 90 million years ago as the then passive margin of North America was pulled into the subduction zone to the east much like what is occurring with the Australian plate dragging sediments from Australia's continental shelf down into the Sunda trench . Eventually as seen in New Guinea the more buoyant nature of the continental crust will lead to the slab breaking off and snapping back upwards bringing up a significant amount of mantle material.
This slab failure process plays a critical role in explaining how mantle rocks became forced up towards the surface and is chemically recorded within the Sierra Nevada batholith
Additionally obduction as we now know it generally requires an oceanic oceanic subduction zone to form as the surviving obducted crust represents remains of the overlying slab. All the parts of this process can be seen in action within modern New Guinea and Indonesia. For example the transition to more continental sediments can be seen gradually within Indonesia as the increasing amount of subducted sediment from Australia is getting fed into the trench and the overlying accretionary edge and represents the approach of the North American plate to the margin before the arc was ultimately overridden by North America. No handwaving is involved unlike the scenario provided here the transition is geophysically driven by slab pull and can be chemically identified within the batholithic rocks of the Sierra Nevada batholith and Franciscan complex sedimentary layers with the ability to trace continental sediments back to their source rocks and show that these rocks formed in a more complex archipelago scenario rather than a conventional Farallon plate scenario.
In essence the "Farallon slab" was at one point the overlying slab which an older ocean slab attached to the then passive margin of southern North America. This slab continued to subduct pulling North America with it depositing the signature of increasing continental sediment contributions within both magma sand accretionary materials up until the increasingly continental affinity of the overlying slab led to it ultimately snapping back off from the rest of the oceanic slab due to its more buoyant character.
Thanks.
Speaking of unusual California metamorphism, you could do an episode on the state gem Benitoite.
Cool.
I can see Mt Diablo from my house. Strange to think that it has risen ~5 inches in my lifetime
Mt. Diablo is not a high mountain when compared to the elevation of other mountains in the West. However, Mt. Diablo is actually an impressive looking mountain nonetheless since the mountain rises directly above sea level.
In hiking Mt. Diablo, I found a petrified clam, the complete clam, around five inches around and inch plus thick.
I'd love to know how the Mercury ore developed.
Colorado has some whacky folds too.
I was wondering, does deposition of material on the subducting plate from erosion off the landward plate, push the subducting plate down to any noticeable degree? Especially considering most of that deposition is right in front of the subducting zone?
Ive been up there before but it was rainy and cold and i saw traces of snow
The closest volcano to Mt. Diablo is Round Top in the Oakland/Berkeley hills just over 15 miles to the West.
The Robert Sibley Volcanic Regional Preserve is just above and South of the Eastern portal to the Caldecott Tunnel.
YOOOOO I LIVE NEAR THIS MOUNTAIN LETSGOOOOOOO EAST BAY REPRESENT 🎉🎉🎉🎉🎉🎉🎉
I was always looking for information about this California peak...I thought it was an extinct volcano too until just now😮
Ugggg I am 50 yrs old and didn't know this..😂😂😂😂 guess I need to go back to geology school 😂😂😂😂😂
Not a volcano? You just disappointed so many of my friends who live in the Bay Area. I mean I live nearby but I'm just surprised. ;-)
Growing up here we were taught that if there was Mercury to mine or gold that meant that it was a volcano in the past (not to mention all the hot springs).
Well it is in essence at least subduction related in origin. (The story given here is a bit out of date based on what I've learned on Nick Zentner's channel these rocks instead appear to be parts of a mature volcanic archipelago that North America eventually overrode between 100 to 90 Ma as Australia is doing today with regards to New Guinea and Indonesia)
You should really look at the video "How the rockys were formed" differing view on the topic
No room for westward subduction? Or eastward and westward subduction of faralon plate?
how would it be determined the depth? i assume the serpentine/mantle rocks definitely a big marker in this case, but in other areas, would there be something like affects of water pressure that deep having evidence in the rocks? anything else i'm missing lol?
1:15 I can see my house!
You should have mentioned why it’s called Mount Diablo.
I believe that silica deposits come from the life form of diatoms which use Si as the structural basis of their exoskeleton. I believe that flint is a sedimentary rock which gains its hardness from the silica included by the sedimentary deposition of diatoms.
Greywacke is a gold mining claim about 30km north of where I live. It never occurred to me that is was actually a mineral.
It's not really a mineral but a rock type - a poorly sorted sandstone in a clay matrix, dark grey or blue-grey because it is chemically reduced rather than oxidised, and produced by turbidity currents (avalanches of poorly consolidated sediment into a deep marine trench adjacent to a subduction zone). Or so says Wikipedia, tightening up on what I already more or less knew.
@@davidcranstone9044 well I guess I’m just getting smarter every day👍🤓
I've been to Mount Diablo. Near the peak, there are masses of obsidian; so at some point it had at least some volcanic activity.
I saw a really good lecture from a geophysicist that showed how continental plates moving at METERS PER SECOND slammed together and raised the mountain ranges all around the world. Sure explains why you have marine fossils in sedimentary layers, miles above sea level
So before the erosion that carved out Mt. Diablo the whole coast to the west was higher in elevation?
Please give metric measurements for the rest of us in the world!
Some rough conversion factors: 3 miles is about 5 km, 1.6 km per mile, 3 feet is about 10% less than a meter.
Most of western North America from the Rockies westward is simply the results of accretion tops of oceanic plates, piling up as their undersides slide under the continental plate.
The Olympic mountains of Washington state is a classic example of such a melange mess of microplates (terranes) being stuck onto the leading edge of the NA plate moving west.
im only 20 miles from here! i go every october for the tarantula migration
"Please subscribe if you like this video" - of course, that's what I have done! :)
ANOTHER MS PAINT MASTERPIECE. GUD WORK CORPORAL
There is a volcano in El Salvador that is interesting to me. Lake Ilopango. I was wondering if you could look into it. As the volcano collapsed like Mt Mazama in Oregon. Also one of its eruption caused a year without summer and it is theorized an eruption of this volcano could have caused a tragedy coinciding with horrific deaths in the Byzantine capital of Constantinople of poison gas.
Any connection with deaths from poison gas in Constantinople seems most unlikely to me. The rest is entirely plausible though - there are plenty of 'years without a summer' not yet linked to a specific volcano/eruption.
Iknow for sure he had a video on at some point so im sure a new updated and better video is on the way
Almost all of North America west of the Rockies is "accreted terrane"; that is, it originated as undersea formations or even islands clumped on to the continent.
Why is the therapod at 2:32 doing the moonwalk?
And just think, in another 100 million years, LA will be up near Seattle, parts of Alaska will be colliding with Russia, humans will be extinct, at least 4 new Hawaiian islands will have been formed, and every super volcano on the planet will have erupted at least once and that’s just naming a few things.
Strange mountain. It's hotter at the top than it is at the bottom.
Why are the rocks not allowed to be collected?
National/State park. Taking anything from a National/State park is illegal without permits.
I can see Mount Diablo from my house.
I am confused why Oklahoma has so many earth Quakes.
Probably man made from the oil industry
Geologie's Carl Sagan
holy shit i literally see my house