The Great Unconformity Geologic Wonder / Frenchman Mountain , Las Vegas , Nevada

[@earthandtime5817]

What kind of unconformity do you think the Great Unconformity is?

[@jaym8257]

Nonconformity

[@stevemiller1517]

It does not comply with uniforitarianism.

[@earthandtime5817]

@@stevemiller1517 interesting thought. Tell me more about why it does not comply? And thanks for the comment.

[@teddwayne]

Thank you ! My next trip to Vegas,Ill be checking this out . I did learn something :)

[@earthandtime5817]

You are welcome and I am glad you enjoyed. Please Let me know what you thought once back!

[@joeoutabout2947]

I've been hiking there before and didn't know what I was looking at. Now I know. It's great to listen to you explain it.

[@earthandtime5817]

@@joeoutabout2947 thanks for the kind words. It is a beautiful place. Hope to get back and do another video in the geology across the entire Frenchman Mountains.

[@TheLVheat]

great video and if a person keeps driving along north shore road its considered the most amazing 40 miles of exposed geology in the world. I live in Vegas and I like hiking to and spotting "time zones and occurences" such as the great dying and we also have cretaceous just east of town as well. Also in frenchman mountain I will be looking to document that there must be alamo impact breccia in the layers roughly half way up from the comet/bolide impact that occurred north of Las Vegas.

[@earthandtime5817]

That sounds like an awesome project. Please keep me posted and I would love to visit an impact site next time I am out in Las Vegas. I visited the shatter cones outside of Santa Fe and have a video in those if you are interested. Will link.

[@earthandtime5817]

kzbin.info/www/bejne/api5hWCtetear5Isi=q5BTvyciEpcHGktz

[@earthandtime5817]

Thank you for the kind words and the comment. Excited to hear more about your research as you continue working on it!!!

[@bluwtrgypsy]

So much fun to check off our bucket lists. This was very interesting, thank you. Happy and healthy New Year to you and your family.

[@earthandtime5817]

@@bluwtrgypsy happy new year. 🎆🎊. I hope you and your family have an amazing one! Thanks for being a regular commenter on the channel. I appreciate you!

[@johnbaenen5386]

Happy New Year friend.

[@earthandtime5817]

Happy new year. I hope 2025 will be a great one.

[@davec9244]

That area is always made me wonder. Looking on Google map the eroded sandstone jumps out at you. thank you.

[@earthandtime5817]

It is a fantastic and beautiful place. Thanks for the comment.

[@riverraisin1]

Hi Garrett. I love to watch those old 1930's B Westerns that were filmed up in Lone Pine, CA. I've never visited, but find the Alabama Hills to be very interesting geologically. If you ever get a chance and can get up that way I would like to learn a little bit about how and why they were formed and their relationship to the nearby Sierras. Thanks.

[@earthandtime5817]

Thank you for the info. I will add the Alabama Hills to my list. I appreciate the kind words. Happy new year.

[@jaym8257]

So an old geologist here. After a quick look online it appears that at that unconformity in the Cambrian there were no land animals and little in the way of land plants. So what was the rock surface doing over the course of a billion plus years? Was it slowly eroding (of course it was)? Is there evidence in the lower metamorphic layer of differential erosion and stripping away of sediment? Are there erosional features to see? There is enough time for mountains to have built and then eroded to a peneplain during that time.

[@llanitedave]

There used to be a set of nicely thought out informational panels set up at the Great Unconformity site and along the trail leading up the ridge. Frenchman Mountain as a whole is a remarkable geologic phenomenon, known sometimes as "The Mountain that Moved." The block that makes up Frenchman Mountain migrated some 40 miles from its eastern origin site over about a 2 million year period during the Miocene, leaving a trail of volcanoes and shear zones behind it. Unfortunately, those explanatory panels have been destroyed by vandalism, illustrating one of the hazards of trying to preserve and appreciate an urban unconformity.

[@earthandtime5817]

Thank you for sharing. I read about the info panels and was bummed they were not there. I hope to get back to Frenchman and do a video about the stratigraphic package there and its structural history. Appreciate the extra info.

[@captdoug]

While it's not as easy to get to as just driving down Lake Mead, the great unconformity in the Grand Canyon is much more pronounced. Thank you for a great video.

[@earthandtime5817]

@@captdoug thanks for sharing and the kind words. Hope to get to the contact in the Grand Canyon someday!

[@captdoug]

@earthandtime5817 Just below Havasupai Garden, before you get to the Devil's corkscrew you'll cut through the tapeats and can stand with your feet on the vishnu schist and your hand on the tapeats.

[@earthandtime5817]

@ thank you.

[@davydawgdawg]

Today I drove past the Granite Mountains in the Mojave National Preserve. The rocks looked like those of Joshua Tree.

[@earthandtime5817]

Good observation. I am not as familiar with the geology there, however there are a lot of granites in Southern California and it could be similar rocks! Thanks for the comment.

[@Robin-ng4lh]

I’d like to know what the black spots are in the Tapeats. I have lots of samples I took from this location.

[@earthandtime5817]

Great question. I didn’t take any samples. A thin section would be helpful. I was wondering if it is related to iron staining. I saw evidence for iron staining there.

[@TheLVheat]

as far as the uncomformity I am a believer that it represents snow ball earth time in which glaciers helped grind away alot of material which washed away

[@earthandtime5817]

I actually don’t know much about snowball earth other then what I read about it as an undergraduate. I will need to read up on it. Thanks! Appreciate the comment and knowledge!

[@peteklover2923]

I also put my hand on the Great Unconformity in the bottom of the Grand Canyon, the time involved in the gap is beyond our comprehension

[@earthandtime5817]

@@peteklover2923 thanks for sharing. That spot is on my bucket list. I have been in the Grand Canton but I never visited the contact. Someday! Happy new year.

[@scvcebc]

Snowball earth caused sea levels to drop and the ice ground down most of the land. Eventually new volcanoes emitted enough CO2 to warm the earth, melt the ice, cause sea levels to rise, then erosion of the remaining land deposited sand into the new shallow seas.

[@earthandtime5817]

Thank you. I need to read up on snowball earth. Been since my undergraduate that I have thought about it! Thank you for sharing.

[@carygrant8796]

The dike has to be younger than the gneiss. Did it intrude into the Toroweaps Sandstone?

[@earthandtime5817]

It is definitely younger. I did not see or read about it crossing into the sandstones. I believe the dikes are also in the billion year + range.