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96058
From: La Man, [DNS_Address]
Subject: My 2nd just came back from a Mammoth camping trip.
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Just with the neighbors, like real camping not that sleeping in a cabin crap lol. Anyways I made sure to scare the hell out of her before she went insofar as volcanos, and chupacabras. Oh and bears. Question. They brought back this pretty big "rock", about the size of a basketball, light as a feather so obviously volcanic, but the thing was really smooth on the outside, no scratchy pumice feel to it at all. Would this or could this be ejects of lava as opposed to a pyroclastic flow? Thing is a trip. Just curious... It's dark gray in color |
Responses:
[96076] [96083] [96087] [96088] [96061] [96062] [96063] [96059]
96076
From: La Man, [DNS_Address]
Subject: Here are pictures of the rock FYI.
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Rock weighs 2 lbs 1 ounce, ruler shows the rough measurement, and more importantly it floats on water so definitely pumice. Some crystal like structures can be seen. Daughter also brought home some nice collection of small rocks. Look at the tiny obsidian. So yeah I think it is a tephra. |
96083
From: Jeff/Lake Almanor,CA, [DNS_Address]
Subject: Re: Here are pictures of the rock FYI.
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Rhyolitic pumice (Bishop Tuff, Pleistocene, 760 ka; Sherwin Summit, Owens Valley, California, USA) 3 Rhyolitic pumice in the Pleistocene of California, USA. Pumice is a felsic, frothy-textured, extrusive igneous rock. It is light colored and quite lightweight - most specimens float in water. Seen here is rhyolitic pumice that has eroded from a volcanic unit in California called the Bishop Tuff (it's not really a volcanic tuff, however). The Bishop Tuff is a ~760,000 year old deposit emplaced during a caldera-forming eruption of the nearby Long Valley Volcano. The unit consists of ash, air-fall pumice, and pyroclastic flow pumice. Locality: Sherwin Summit (= Big Pumice Roadcut) - roadcut along the northern side of Route 395, immediately east of intersection with Lower Rock Creek Road (= Sherwin Grade; = Old Route 395), just east of the “town” of Tom’s Place, Owens Valley, Mono County, eastern California, USA (37° 33' 28.80" North latitude, 118° 39' 26.23" West longitude) |
96087
From: Jeff/Lake Almanor,CA, [DNS_Address]
Subject: Since we will be in the center of this, one week from today
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I've been doing a greater search of the happenings in the volcanic history of the Long Valley Caldera region. Here's a boat load of info. |
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[96088]
96088
From: La Man, [DNS_Address]
Subject: Great Intel, thanks!
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My neighbors are tripping when I share the deets with them, to them its just a rock lol. LVC has always tripped me out. Nice to have a piece of it right here. Calderas are awesome. |
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None
96061
From: ao, [DNS_Address]
Subject: Re: My 2nd just came back from a Mammoth camping trip.
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Not to say I 'know' but.. It sounds like tephra, ie airborne volcanic product, which usually has an outer.. glassy.. smooth.. rind that is only visible on certain surfaces as more often than otherwise the original piece will break into smaller pieces. In other words rapidly cooled rocks often shatter. If this type of surface is rapidly quenched, cooled, it will appear glossy.. like glass. If it is slow in cooling it will appear less glossy.. matte, grayish. Though under close scrutiny.. under magnification.. it will still be a gorgeous collection of crystals. It sounds like an airborne piece that was initially buried, surrounded by other like pieces and as such had a chance to cool slower than if it was not insulated. Just a guess.. a wide one at that. |
96062
From: La Man, [DNS_Address]
Subject: Re: My 2nd just came back from a Mammoth camping trip.
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I only saw it once, am going to ask them to borrow it for awhile, the girls thought little of it, "just a rock", ah hellll nah I was salivating like it was a diamond lol. Your description is spot on though, matte grey finish, very lightweight. I'll look at it with a loupe. |
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[96063]
96063
From: Jeff/Lake Almanor,CA, [DNS_Address]
Subject: A possibility, Bishop Tuff
URL: https://www.atlasobscura.com/places/crowley-lake-columns
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We have reservations in June Lake for five night, at the end of this month. Just to explore more of the area between Lone pine and Mono lake, without just a few things at a time, while passing though. Including showing Val the Bristlecone pines, and Tioga pass. We may put this on our list, while hot spring hopping. More here @ Wikipedia https://en.wikipedia.org/wiki/Bishop_Tuff |
Responses:
None
96059
From: La Man, [DNS_Address]
Subject: *ejecta* autocorrected to ejects. (NT)
| (NT) |
Responses:
None
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