Wonderful presentation! The movies really help to understand how everything came to be. I am a senior citizen studying geology and really appreciate you taking the time to put this together. You gained a subscriber..... and a fan.
Thank you so much! I'm glad you enjoyed this presentation. I have many more on my RU-vid channel so take a look to see if there are others you might be interested in... maybe some from my Volcanology course? Look here: ru-vid.com/group/PLI0JQTDth_kB1lqEOIPPC5f1VUy2PdIqt
I'm a senior and am thrilled to find this. I have been trying to teach myself geology starting with Geology for Dummies and Roadside Geology while my husband and I are driving all over California to learn about our California/Federal water system. From SF to Mono Lake all this fascinating geology has been before my eyes as I was privileged as a child to backpack in the Sierra and now I'm beginning to grasp how our beautiful state came to be. Thank you, thank you for the excellent presentation. I also lived right on the Hayward Fault as a child...all so wonderful to learn about.
Thank you so much for posting this. I came here to do a little bit of background research before reading John McPhee's "Basin and Range" and it has been extraordinarily helpful. One thing I've learned so far - if it's geologic, weird, and happening in North America.. it's that darn Farallon Plate again!
You are quite welcome! I'm glad that you found the video useful, and I hope that you enjoy McPhee's "Basin and Range"! If you subscribe to my channel, you will find many more videos that explain aspects of the geology you find in that book, particularly where the rocks are concerned. Check out more of the Mineralogy & Petrology and Volcanology videos (and maybe the Continental Extension and Rifting video in my Global Tectonics class)!
Great video! I was wondering about how the formation of the White and Inyo Mountains fit into this story. Should I think of them as fairly old sediments (like 400 mya) that have been recently uplifted with the Sierra Nevada? Whenever I'm hiking in those ranges, I notice how steep the rock layer seams are.
The White and Inyo Mountain ranges are part of the western Basin & Range province where the crust is undergoing extension in an east-west direction because there are distant tectonic stresses that are stretching the crust across western North America. Normal faults form perpendicular to those stresses (i.e., trending north-south) - think of the normal faults like tears in the upper crust of the tectonic plate. If you look at the topography of western North America (using Google Maps or Google Earth) you will see a pattern of north-south trending mountain ranges in the Basin & Range - composed of Paleozoic (and some Proterozoic) sedimentary rocks from the former passive margin along western North America - separated by long, north-south trending basins containing young (Cenozoic) sedimentary rocks, granitic rocks, and "bi-modal" (both mafic [basaltic] and felsic [rhyolitic]) volcanic rocks. The valley that forms between the Sierra Nevada and the White-Inyo Range (the valley that runs between Owens Lake and Mono Lake) formed as a result of both Basin & Range extensional forces, and the right-lateral strike-slip faulting and deformation (shear forces) that result from the tectonic stresses along the transform plate boundary (between the Pacific plate and the North American plate) to the west along the San Andreas fault. The White-Inyo Mountains are uplifted as part of one of the ranges in the Basin & Range province - in the footwall of north-south trending normal faults that uplift older Paleozoic/Proterozoic rocks in the ranges - and drop down younger, Cenozoic sedimentary rocks along with Quaternary sediments in the hanging wall of one of the basins that form both on the west and east sides of the White-Inyo ranges. I hope that helps! You can download a detailed geologic time scale at www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx - this time scale will give you the ages Iin millions of years [Ma]) that correspond to the different time periods/epochs. And you can find 1:62,500 geologic maps of the Sierra Nevada and western Basin & Range here: geomaps.geosci.unc.edu/quads/quads.htm#mountbarcroft.
Im curious how the monterey bay canyon at moss landing was formed. Its located ,im guessing 75 + miles south of SF. Just north of the short straight red line(which dissappears) on the narrow tan land between SF and the santa barbara locations. The canyon appears it could have been formed by a large amound of water drainage during its northerly travels? Possibly from The future SanJuaquin valley,south end of Sacramento valley? or ? ( I just noticed this has been somewhat answered by you regarding a question by david howard a year ago( just a short scroll down from here) . Can you add anything else? I used to live in the area,Santa Cruz, in 70-80s and did some lightweight scuba diving off monterey somewhere. It would give me the creeps if I thought about it while diving ... even now it gives me the creeps and Im way away from there living on a fault zone near palmSprings. I mean close..100 ft more or less. Our pool is hot springs fed as are many neighbors in the general area. That doesnt creep me out...Oh well.
Hi Mary, Thanks for the detail! In the first animation how does the motion of the North American plate play a role? How does Baja pushing on the Sierra Nevada at the Garlock fault affect spreding in the basin and range?
I think the overall east-west extension taking place in the Basin & Range combined with the right-lateral strike-slip motion on the San Andreas combine to "tear" California away from the rest of North America along the eastern Sierra Nevada Mountain range following the Eastern California Shear Zone [ECSZ] and the Walker Lane belt [WLB]. The Garlock fault is a left-lateral strike-slip fault effectively connecting the San Andreas to the Eastern California Shear Zone (and the Walker Lane belt to the north). The slip along the Garlock fault accommodates the difference in stresses between the extension in the Basin & Range province to the transform plate boundary along the San Andreas. I think it's possible that the plate boundary between the Pacific and North American plates migrates to the eastern Sierra Nevada/western Basin & Range over geologic time.
Can you do something like this with the San Jacinto Mtn range, Cochella Valley and Colorado River ancient delta at the south end of the salton sea? That would be interesting.
I might be able to put together something on those topics but it'll be a while - the academic year keeps me pretty busy so summer time is when I can record more videos. Subscribe to my channel and you will probably find more topics that you'd be interested. And keep an eye out for new videos!
Did small basins open up around the rotated SB block? It looked like it in first animation, not so in last. Do we have a record of them and how did the close?
A couple of questions I’ve had as I’ve watched the cartoons here and elsewhere regarding the transition from the subduction under California of the Farallon plate to the development of the San Andreas. How does the rotation of the Santa Barbara block interact with the development of the Channel Islands and the deep channel between them and the coast? There is some discussion of the Monterrey Canyon being the remnant of an early Sacramento River discharge out of what was then the southern end of the Central Valley at the southern end, near modern day Sabta Barbara. What has been of interest to me has been the conjecture in my part that the canyon formed along a transform fault that was part of the spreading ridge that subducted. As that weak zone was subducted, it would have been easier for the canyon to form along that weak zone, even if it were due to a river discharge. How could this idea be developed or discarded?
Hmm... interesting ideas. My first thought is that spreading ridges are high points in the ocean floor bathymetry that are composed of young, relatively hot and buoyant crust. If you were to subduct a spreading ridge, I don't think it would result in a canyon - I would expect old, cold, and dense oceanic crust in a topographically low point like a subduction trench (or canyon). In fact, Lomize & Luchitskaya (2012) said that in the case of the South American margin where the Chile ridge subducted beneath the South American continent "subduction of the spreading ridge leads to uplift of the continental margin, cut off the accretionary wedge by means of tectonic erosion, emplacement of a fold-thrust structure and longitudinal strike-slip faults, and creates settings favorable for obduction of the young oceanic lithosphere." In that study, they suggest that pieces of the oceanic lithosphere (oceanic crust + uppermost mantle) would obduct (as opposed to subduct) onto the continental margin to form ophiolites. There are a number of different ways you could test these ideas with a little field geology, geochemistry, and geochronology. For now, I'm going to stick with an erosional model for the formation of the submarine Monterey Canyon.
Does anyone know where I can find a video of similar quality that focuses on the area of Bakersfield ? I recently moved there and I am wondering how it all came together. I see crazy looking striations on the hills , there is abundant oil but it's so thick it requires steam to extract it and the curiosity is killing me . There is plenty of information on California as a whole but I am hoping for something a bit more regional.
Check out the San Joaquin Geological Society: sanjoaquingeologicalsociety.org/ They have a geology page that may have what you're looking for: www.sjvgeology.org/geology/index.html. Good luck!
Stupid Question..... How much did the tectonic domino effect emanating from the high speed kidney punch India gave Asia 50 million years ago end up effecting the western North America?
Thanks for your (not stupid) question! It's hard to say how much of an effect, if any, the India-Asia collision affected North America. Certainly, the Indian plate slowed down a lot after it collided with Asia. From ~55 to ~50 million years ago, the Indian plate slowed sharply from 18 ± 5 cm/yr to 10 ± 2 cm/yr (Guillot et al., 2003) and it kept slowing down to about a 4.5 ± 0.5 cm/yr convergence velocity from 20 million years ago to today. This change surely had a knock-on effect on the stresses impacting the other surrounding tectonic plates. The most important impact of the India-Asia collision was the vertical growth of the Himalayan Mountains. The rise of the Himalaya, and the Tibetan Plateau, caused major changes in atmospheric circulation and led to the onset of the seasonal Asian monsoons. The monsoon rain that falls across India/south Asia (south of the Himalaya) caused central Asia (to the north of the Himalaya) to dry out and may have helped develop the Gobi and Mongolian deserts (a "rain shadow" effect). These climatic changes may have also led to an intensification of glacial periods following the uplift of the HImalaya and Tibetan Plateau.
Great presentation . I'm guessing most folks don't really think God made the world any more ? I hope I'm wrong . How old is this planet ? How do we really know ?
@Lrhc Conrad We know what we do about our world because of physical Geological, Mineral, and Flora & Fauna EVIDENCE, which we can, have, and continue to observe. Many of these natural geological processes can be observed in action throughout our world right now....vulcanism, seafloor spreading, earthquakes, tsunamis, wildfires, tectonic plate movement, floods, glacial movement & deposition, etc. We can relate these current events and their observable results (time, geographical location, & physical properties) to past events, and project back in time to date past geologic events and the history of our earth. We also currently have MANY living organisms (of all sizes) both on land and in the sea/lakes/rivers which we observe and definitively know where they live/grow, what types of nourishment they require, temperature ranges/necessary climatic conditions, how long it takes for them to reproduce, and the period of their life cycle. Along with the geological evidence itself, nearly all of these modern organisms and their ancestors have been preserved within the geology (ice & mineral fossils, etc.) and reveal a timeline, their past geological positions, and the climate/conditions at that point in time. Which God or Gods do you propose created our world? The Hindu Gods, the Greek Gods, the Aztec, Mayan, or Tolmec Gods, the God of Israel, the Polynesian Gods, Nordic Gods ...? Depending on what continent and culture you come from, there are very long-established "creation myths" and their respective God or Gods that modern Christianity simply discount and "overrule" because we have "a history book" (written by men) which was pieced together over time and relevant to the time in which it was written. Faith, and the belief in a God or Gods, is a way for the human mind and existence to be "comforted" and to "not have to explain" the many (sometimes scary) things in our world that we have not been able to understand, and/or currently cannot understand or make sense of. We "leave these things to God". A "belief system" (via Faith in a God or Gods) is also a way to control, manipulate, and ultimately unify a society's behavior. For instance, to be united to work towards a common unified goal, and usually to "expand the empire, its wealth, and the society's power and longevity". If you don't unify a group of people with a common ideology, they will never become a "society", and will never work together towards basic common goals to develop that society...moral standards, codes of conduct, infrastructure, wealth, power, heirarchy, longevity, etc. Religion and faith are a way to accomplish this. But as we've seen throughout history, societies have risen and fallen. As the human race begins to understand more and more about our physical world and the processes & events that were previously incomprehensible to us, we naturally have less need for "faith" or Gods to "explain" these things. But there are obviously many things that we still don't understand, or realities we do not want to accept. So Religion and Faith in an "all-knowing" God continue to give us that "comfort", and allow us to relate to each other with a common ideology and societal goals.
The age of the Earth is estimated to be ~4.6 billion years old. Geologists use radiometric dating of minerals like zircon in the Earth's oldest rocks to calculate an age. Here's a run-down of the procedure: Radioactive isotopes of uranium decay to stable isotopes of lead, and radioactive isotopes of potassium decay to stable isotopes of argon, at a constant rate that we can measure. We use mass spectrometers to collect and count the number of each isotope remaining in a mineral. The ratio of those isotopes is used to calculate the age of the mineral and the rock it was found in. To learn more, check out this short video from Scientific American: www.scientificamerican.com/article/how-science-figured-out-the-age-of-the-earth/ -- Or this one from the Smithsonian Magazine: www.smithsonianmag.com/smart-news/how-do-we-know-earth-46-billion-years-old-180951483/. -- From National Geographic: education.nationalgeographic.org/resource/how-did-scientists-calculate-age-earth. -- From the U.S. Geological Survey: pubs.usgs.gov/gip/geotime/age.html. -- From the National Park Service: www.nps.gov/subjects/geology/age-of-the-earth.htm Enjoy!
Dr, you’re wrong about the northern location of the San Andreas fault at 5:58. At the northern end the San Andreas fault is the line west of the line you drew on…. 🫣 It goes off the coast around Point Arena.
And you are who? The certitude which you say she is wrong suggests to me you don't understand much about science. As far as the northern terminus of the San Andreas, most things I have seen shows it terminating under the ocean at the MEndecino triple Junction. As far as the SA fault itself goes, it is not always a single sharp boundary--increasingly lots of smaller parallel faults nearby may move, or a complex set of faults around what we think of as the main fault. Some places the SA is plainly obvious but in others it may be a series of closely parallel faults, some of which move one time, and others at other times.
