herm
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I love the Sierra Nevada, the California coast, and the Mojave Desert
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Post by herm on Apr 3, 2017 6:17:07 GMT -8
CoolkatThe rock on the trail just behind the hiker provides a clue. To my eye, that rock appears to be same (or similar) material as your previous photo of puddingstone. And it is apparent the rock on the trail is talus, as it is "floating" atop younger alluvium. Though I last worked as a geologist 20 years ago, it's always fun to apply my geologic knowledge while hiking. With this thread in mind, I had a discussion with my wife about a particular rock unit that we encountered on our local hike yesterday.
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herm
Trail Wise!
I love the Sierra Nevada, the California coast, and the Mojave Desert
Posts: 1,456
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Post by herm on Apr 3, 2017 6:32:02 GMT -8
BigLoad As an amateur, you sound like you know your stuff. Also, from my mangled attempt at quoting, it is apparent that I am a rank amateur in use of the features on the forum
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rebeccad
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Writing like a maniac
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Post by rebeccad on Apr 3, 2017 9:06:37 GMT -8
@harm --I can see that the problem with your quote is that you have a "close quote" tag at the front as well as the back. Remove the slash in the first brackets and it should work. The easy way to quote is to highlight the text you want, click in the little "quote" box that shows up, and hit "reply". It'll be there, all nicely formatted. Of course, this is not possible when using mobile devices (at least, I can't do it on my iPad. I can't tell if I can do it on my phone, because I can't see that tiny screen anyway )
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herm
Trail Wise!
I love the Sierra Nevada, the California coast, and the Mojave Desert
Posts: 1,456
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Post by herm on Apr 3, 2017 9:12:50 GMT -8
Thanks rebeccad, as you can see I fixed the post with your instructions. I'm using an older iPad, and highlighting text seems especially difficult. If nothing else, I'm perserverent.
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desert dweller
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Power to the Peaceful...Hate does not create.
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Post by desert dweller on Apr 3, 2017 11:18:11 GMT -8
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rebeccad
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Writing like a maniac
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Post by rebeccad on Apr 3, 2017 13:30:10 GMT -8
I'm using an older iPad, and highlighting text seems especially difficult. I too have an older iPad (gen 2?), and I find it impossible. It just won't let me highlight text in the forums, though I can in, say, a Pages document or an email.
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whistlepunk
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I was an award winning honor student once. I have no idea what happened...
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Post by whistlepunk on Apr 7, 2017 11:08:32 GMT -8
Not a geologist, but had a few geology/geomorphology classes in college. In the Whipple Mountains of southern California I saw sandstone dikes inside basalt. Very odd, I am still trying to understand how that happened. Maybe one of the geologist types here can explain how that formed.
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BigLoad
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Pancakes!
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Post by BigLoad on Apr 7, 2017 16:07:46 GMT -8
Not a geologist, but had a few geology/geomorphology classes in college. In the Whipple Mountains of southern California I saw sandstone dikes inside basalt. Very odd, I am still trying to understand how that happened. Maybe one of the geologist types here can explain how that formed. I had to cheat. vredenburgh.org/mining_history/pdf/WhippleMountains2016.pdfThe reference mentions fanglomerate and basalt, so my wild guess is that they aren't really dikes, but sedimentary deposition into stream-eroded declivities in the basalt or merely into joints in the basalt that formed before the sedimentary deposition.
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whistlepunk
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I was an award winning honor student once. I have no idea what happened...
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Post by whistlepunk on Apr 7, 2017 17:30:04 GMT -8
Possible. The sedimentary veins were only a few inches thick in places.
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desert dweller
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Power to the Peaceful...Hate does not create.
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Post by desert dweller on Apr 10, 2017 15:13:18 GMT -8
I'm calling this formation an example of Columnar Disjunction, though very eroded. It's a scanned negative from a picture taken with a small camera back in the early 80's. The location is in the Huachuca Mountains of southern Arizona. When I first saw it, I thought it was an ancient wall because the rocks were so uniformly placed. Then I took a couple of geology classes and saw examples of this type of formation.
This would have been formed when in a vertical position. Upheaval, during the orogeny, shifted it to the horizontal.
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Post by Coolkat on Apr 11, 2017 4:04:24 GMT -8
I'm calling this formation an example of Columnar Disjunction You can call it whatever you want. I just think it's cool. Will be interesting to hear what our resident geologists have to say.
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Post by red dog on Apr 11, 2017 7:36:19 GMT -8
Petrified Tree Stump from northwest New Mexico
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whistlepunk
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I was an award winning honor student once. I have no idea what happened...
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Post by whistlepunk on Apr 27, 2017 15:57:19 GMT -8
Some of the trees in Petrified Forest NP were so well preserved I could identify the species from the bark. Several were Douglas-Fir. I identified at least one Ponderosa Pine, and others I am reasonably confident were Incense-Cedar.
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foxalo
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Post by foxalo on May 30, 2017 8:01:25 GMT -8
Fun finds this morning while fossil hunting.
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Post by Coolkat on May 30, 2017 9:45:23 GMT -8
Finding fossils are always fun. It's been a very long time since I've run into any. When I was kid and would dig holes (to my parents' frustration) I remember finding plenty. I wish I had kept them now.
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