Igneous Fossils, like in Pompeii??

Darwinsbulldog · #1 by **Darwinsbulldog** » May 01, 2011 3:31 pm

I was thinking about Pompeii the other day, and wondered if there are similar ash-fossil beds elsewhere, perhaps of greater age. The Pompeii fossils are very young in geological terms, and casts. S we would expect older beds to be crushed beyond recognition. Anyway, Theorpod and I have been chatting about it, and he gave me a couple of references:-

Rose, W. I., C. M. Riley, et al. (2003). "Sizes and Shapes of 10‐Ma Distal Fall Pyroclasts in the Ogallala Group, Nebraska." The Journal of Geology 111(1): 115-124.
Abstract

Size distributions of distal ashfall particles from correlated 10‐Ma layers in Nebraska, measured using laser diffraction methods, are lognormal with mode diameters of ∼90 μm. This ashfall is ∼100% bubble‐wall shards of rhyolite glass and apparently represents a distal ashfall from an eruption 1400 km away. Measured terminal velocities of these ash particles are 0.2–18 cm/s, consistent with Stokes Law settling of spherical particles with diameters of 9–50 μm. Surface area of the ash particles, measured with gas adsorption, is 20–30 times the surface area of equivalent Stokes spheres. These results highlight the effects of shape and atmospheric drag in distal ashfalls. They also highlight atmospheric transport and fallout of distal ashfall particles, because these deposits resemble many other ashfalls preserved in the Great Plains of North America throughout the Tertiary and Quaternary. Because the ashfalls preserve major mammalian death assemblages, they demonstrate that deposits with modes of optical diameters >100 μm are still hazardous by aerodynamic definitions of lung disease risk and include particles substantially within hazardous PM10 ranges. The aerodynamically fine particle size may lead to substantial aeolian redistribution, causing local thicknesses of >2 m. Overall, the ashfall thicknesses observed are at least several times larger than would be expected based on exponential thinning from the volcano. Shape measurements of distal ash particles may be necessary to assess risk. The possible health risks in the central United States from a future rhyolitic eruption in the western United States may be significant.

[Paper is behind a paywall!]

http://www.jstor.org/stable/10.1086/344668

and:-

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

Anyway, has anyone heard of any other examples? Please post them here. :thumbup:

theropod · #2 by **theropod** » May 06, 2011 12:37 am

Interesting Paper HERE.

RS

Darwinsbulldog · #3 by **Darwinsbulldog** » May 06, 2011 2:17 am

I am amazed in the lack of interest in this topic in all but us, therepod. :think:

Not even creationists are interested! :scratch:

We may have to troll our own thread..you just can't get good help anymore! :dopey:

theropod · #4 by **theropod** » May 06, 2011 11:13 am

DB,

I'm off work today because of a funeral for a friend (golfing partner) and coworker. Ruptured aorta at 37! I will put some more time into this either sat or sun.

I'd just as soon have a fundite free thread with just a few posts than one wherein Byers, or his ilk, muddy the waters.

RS

Tyrannical · #5 by **Tyrannical** » May 06, 2011 1:01 pm

Since Volcanic areas tend to have rich soil, they can become popular human habitats. So in theory human settlements covered by ash and lava should be common. But digging through multiple layers of lava rock is not the same as dirt.

theropod · #6 by **theropod** » May 06, 2011 1:17 pm

Ground penetrating radar or some form of gavi-magnetic sensing? Artificial aperture radar from space?

RS

Darwinsbulldog · #7 by **Darwinsbulldog** » May 06, 2011 11:06 pm

theropod wrote:DB,

I'm off work today because of a funeral for a friend (golfing partner) and coworker. Ruptured aorta at 37! I will put some more time into this either sat or sun.

I'd just as soon have a fundite free thread with just a few posts than one wherein Byers, or his ilk, muddy the waters.

RS

Shit that is awful mate! Thirty-fucking seven!

Give my regards to the family. Fuck, waking up every single morning is a victory to be savored while it lasts.

Darwinsbulldog · #8 by **Darwinsbulldog** » May 06, 2011 11:08 pm

theropod wrote:Ground penetrating radar or some form of gavi-magnetic sensing? Artificial aperture radar from space?

RS

Can't one use sound also? Like set of a shotgun-shell? I remember in the Jussasic park movie, one of Grant's assistant had one and he looked at the output on a laptop.

The_Piper · #9 by **The_Piper** » May 07, 2011 12:08 am

Maine's state fossil was preserved by volcanic ashfall. Devonian plants, Pertica quadrifaria. I think the rocks are sedimentary.
http://osiris.virtualempire.com/me/me.html
Picture

theropod · **#10** by **theropod** » May 07, 2011 1:22 am

Piper,

Ash is sediment. Air is a very thin liquid and one of those papers cited above deals with the distal detection methods using settling sorting by clastic shape and density. The sediment will behave differently than ash in water, but the same basic principles will apply, so does wind blown sand, or dirt or in this thread, ash. Proximity to the eruption is critical for preservation as we see in Pompeii. A pyroclastic flow must also be "just so" and not so violent that a blast wave rips things to shreds but yet enough ash accumulates to protect the casts of once living creatures from the environment on a long term. Continued accumulation of eruptive material might well destroy such fossils is a compressive failure of the molds/cast to support the overburden.

I don't think there will ever be many macro fossils recovered from basalt deposits, but there are a few already. The "Blue Lake Rhino" is one such case and if I'm not mistaken there are some plant/tree remains in such flows. Search Google Scholar for the Deccan or Siberian traps, but I'm betting there is bloody little encased in that hot shit which forms a fossil. Somebody feel like shootin' me down? :cheers:

----------------

Yes, the death of my bud was very unexpected, of course an aorta rupture doesn't/didn't give him, or any of us, much warning. He "lived" for 2 days, but never regained consciousness, which is probably a good thing.

He was a pretty good streak golfer but had my problem of a snap hook on every 4th or 5th shot, and he always made me laugh at both myself and him went things really went south. Some of the guys at work had known him for years, but it had only been about 18 months for me. Considering the age difference we had a great deal in common, except he was a died in the wool faith head. We didn't argue about that difference one time, but we often exchanged positions and opinions. Not all faith heads are freaks, and he wasn't. I'll miss him.

It's this kind of shit that I have seen so many times in my life that when I read a thread like the one by somebody I get a little sick feeling I really don't like. All a part of being lucky enough to get old, I guess. :think:

RS

sennekuyl · **#11** by **sennekuyl** » May 07, 2011 4:00 am

Thanks for the papers. :oops:

still reading to try work out something I can actually understand.

edit: Of course that is just the abstracts. Sheesh. The articles sound like they could be nice.

Darwinsbulldog · **#12** by **Darwinsbulldog** » May 07, 2011 8:20 am

sennekuyl wrote:Thanks for the papers. still reading to try work out something I can actually understand.

edit: Of course that is just the abstracts. Sheesh. The articles sound like they could be nice.

PM me

The_Piper · **#13** by **The_Piper** » May 07, 2011 12:47 pm

theropod wrote:Piper,

Ash is sediment. Air is a very thin liquid and one of those papers cited above deals with the distal detection methods using settling sorting by clastic shape and density. The sediment will behave differently than ash in water, but the same basic principles will apply, so does wind blown sand, or dirt or in this thread, ash. Proximity to the eruption is critical for preservation as we see in Pompeii. A pyroclastic flow must also be "just so" and not so violent that a blast wave rips things to shreds but yet enough ash accumulates to protect the casts of once living creatures from the environment on a long term. Continued accumulation of eruptive material might well destroy such fossils is a compressive failure of the molds/cast to support the overburden.

I don't think there will ever be many macro fossils recovered from basalt deposits, but there are a few already. The "Blue Lake Rhino" is one such case and if I'm not mistaken there are some plant/tree remains in such flows. Search Google Scholar for the Deccan or Siberian traps, but I'm betting there is bloody little encased in that hot shit which forms a fossil. Somebody feel like shootin' me down?

----------------

Yes, the death of my bud was very unexpected, of course an aorta rupture doesn't/didn't give him, or any of us, much warning. He "lived" for 2 days, but never regained consciousness, which is probably a good thing.

He was a pretty good streak golfer but had my problem of a snap hook on every 4th or 5th shot, and he always made me laugh at both myself and him went things really went south. Some of the guys at work had known him for years, but it had only been about 18 months for me. Considering the age difference we had a great deal in common, except he was a died in the wool faith head. We didn't argue about that difference one time, but we often exchanged positions and opinions. Not all faith heads are freaks, and he wasn't. I'll miss him.

It's this kind of shit that I have seen so many times in my life that when I read a thread like the one by somebody I get a little sick feeling I really don't like. All a part of being lucky enough to get old, I guess.

RS

Thanks Theropod. I didn't expect pyroclastic flow would preserve too much.
I wasn't sure what DB was looking for, because I thought Pompeii was ash(sediment) too. In that case, Maine's fossil is relevant. But the thread title says igneous. :shifty:

I read the abstracts posted, but it was like reading Italian. I might have understood a few things per paragraph. I thought they were saying those sediments were dangerous or unhealthy. :scratch:

Sorry about your friend Theropod, that's way too young. :nono:

theropod · **#14** by **theropod** » May 07, 2011 1:09 pm

Piper,

Just because the sediment is composed of igneous material does restrict said material from sedimentation. Think of this possibility. A volcano spews a huge amount of pumice in sizes from a mm to over 100 cm. These don't get blown very far from the source, and the eruption ends. A span of time passes and a heavy rainfall event comes along. A great deal of the ejecta is transported into the stream system surrounding the volcano. The pumice is now sediment, but still igneous in nature.

Questions? Ask away. If I'm too ignorant to provide a reasonable answer I'll research the subject until I can!

RS

ETA:
Thanks for the kind words about my bud. Yes, he was far too young and in fairly good condition. Wonderful design that aorta, NOT!

Ash is dangerous and unhealthy. Dangerous in the sense that ash is heavy and can collapse roofs and bury whole cities and unhealthy in that breathing the stuff leads to silicosis. The composition of ash varies from eruption to eruption, but usually has a high percentage of tiny glass shards. These, once inhaled, tend to penetrate the soft membranes of the lungs and cannot be expelled via natural process, like coughing.

The_Piper · **#15** by **The_Piper** » May 07, 2011 2:24 pm

theropod wrote:Piper,

Just because the sediment is composed of igneous material does restrict said material from sedimentation. Think of this possibility. A volcano spews a huge amount of pumice in sizes from a mm to over 100 cm. These don't get blown very far from the source, and the eruption ends. A span of time passes and a heavy rainfall event comes along. A great deal of the ejecta is transported into the stream system surrounding the volcano. The pumice is now sediment, but still igneous in nature.

Questions? Ask away. If I'm too ignorant to provide a reasonable answer I'll research the subject until I can!

RS

ETA:
Thanks for the kind words about my bud. Yes, he was far too young and in fairly good condition. Wonderful design that aorta, NOT!

Ash is dangerous and unhealthy. Dangerous in the sense that ash is heavy and can collapse roofs and bury whole cities and unhealthy in that breathing the stuff leads to silicosis. The composition of ash varies from eruption to eruption, but usually has a high percentage of tiny glass shards. These, once inhaled, tend to penetrate the soft membranes of the lungs and cannot be expelled via natural process, like coughing.

Now I'm confused.

When the pumice sediment you mentioned that's flowed away and mixed with other sediments finally hardens into rock over time, it will be a sedimentary rock.
Volcanic ashfall into a marsh is how the Maine plants were preserved. When it happened, right when the ash cooled, would it have been like quicksand to walk through? (that's what I imagine) If so, the mud that finally preserved into rock from that event would be sedimentary rock too, right?

I can relate to losing a friend young and healthy. One of my best friends died when we were 32 of a brain anneurism. I feel pretty lucky to have made it this far too.

theropod · **#16** by **theropod** » May 07, 2011 3:38 pm

The_Piper wrote:
Now I'm confused.
When the pumice sediment you mentioned that's flowed away and mixed with other sediments finally hardens into rock over time, it will be a sedimentary rock.

The lithification is the last step in the much longer process, but the ejecta from a volcano that doesn't quickly solidify is sedimentary in nature before it turns into what most of us call rock. The lithification is not the determining factor. Much of the ash containing deposits in the Hell Creek isn't what a lot of folks would call "rock", but it is and it's a sedimentary deposit, even if it isn't as hard as granite. Think of dust that isn't volcanic in nature. Over time, and with compressive forces and chemical reactions, the ash, or dust, will become what most folks would call rock.

The_Piper wrote:Volcanic ashfall into a marsh is how the Maine plants were preserved. When it happened, right when the ash cooled, would it have been like quicksand to walk through? (that's what I imagine) If so, the mud that finally preserved into rock from that event would be sedimentary rock too, right?

Pretty much. There are places where ash, bentonite, is still very much like quicksand when enough water is involved.

The_Piper wrote:I can relate to losing a friend young and healthy. One of my best friends died when we were 32 of a brain anneurism. I feel pretty lucky to have made it this far too.

Seems awful that the "fall" caused all these perfect designs to exhibit basic flaws such as these, innit? :crazy:

RS

theropod · **#17** by **theropod** » May 07, 2011 5:40 pm

Update;

Above is an image of a preserved cast of a large tree in eastern Oregon, USA thanks to this SOURCE. I do not know how I let this one escape my memory, as I've been to this exact tree. Fuck, what a dimwit I can be!

Then, just because nobody seemed up to to the task of "shooting me down", we have THIS site about Hawaii, that was far too easy to find.

Still, these aren't the same as what DB is asking for, are they?

All I can find relating to the Deccan/Siberian traps is the fossils found either between layers of basalt. I find no citation as to possible cast fossils in the main eruptive events, but I bet there are some. As I've said from the beginning of this thread I think finding these fossils in OLD rock is going to be the problem.

DB, is our task to find a specific repetition of the Pompeii casts in a very similar depositional setting?

RS

zoon · **#18** by **zoon** » May 07, 2011 8:49 pm

Just been googling “fossil volcanic ash”:

Ashfall: Life and Death at a Nebraska Waterhole Ten Million Years Ago I think this is one of the “major mammalian death assemblages” mentioned in the OP (Mike Voorhies is the author of one of the references), which is spectacular enough to have become a state museum.

Mike Voorhies (1992) wrote:
Hundreds of skeletons of prehistoric animals have been found in a volcanic ash bed buried beneath the rolling farmlands of northeastern Nebraska. Some of the best-preserved fossil rhinos, horses, camels, and birds known anywhere have been, and are being, excavated by museum crews working in the Ashfall Fossil Beds in northern Antelope County. Unlike most fossil deposits, which consist of scattered bones accumulated over extended periods of time, the ash bed contains mostly articulated remains with bones still joined together in the proper order.Quick burial in volcanic ash accounts for the three-dimensional preservation of the skeletons of species that became extinct millions of years before they could have been seen by humans. These remarkably lifelike skeletons, some of which contain unborn young and stomach contents, give paleontologists an opportunity to reconstruct the life appearance and habits of these ancient species with an accuracy never before attainable.

Largest fossil spider found buried in volcanic ash – found a month ago, lived in the age of the dinosaurs 165 million years ago, but not larger than modern spiders, 1-inch body and 2.5 inch legs.

Ancient Sea Spider Fossils Discovered In Volcanic Ash More spiders, 425 million years old, found in 2004.

Prof Derek Briggs wrote: Volcanic ash that trapped ancient sea life in this location rapidly encased the creatures making a concrete-like cast of the bodies. The cavity later filled in with carbonate solids so we have a fossil record to study now.

theropod · **#19** by **theropod** » May 07, 2011 10:45 pm

zoon,

Sweet. I knew of the Nebraska site, but the other stuff is way cool. Thanks!

RS

The_Piper · **#20** by **The_Piper** » May 08, 2011 2:19 am

theropod wrote:
The_Piper wrote:
Now I'm confused.
When the pumice sediment you mentioned that's flowed away and mixed with other sediments finally hardens into rock over time, it will be a sedimentary rock.

The lithification is the last step in the much longer process, but the ejecta from a volcano that doesn't quickly solidify is sedimentary in nature before it turns into what most of us call rock. The lithification is not the determining factor. Much of the ash containing deposits in the Hell Creek isn't what a lot of folks would call "rock", but it is and it's a sedimentary deposit, even if it isn't as hard as granite. Think of dust that isn't volcanic in nature. Over time, and with compressive forces and chemical reactions, the ash, or dust, will become what most folks would call rock.

The_Piper wrote:Volcanic ashfall into a marsh is how the Maine plants were preserved. When it happened, right when the ash cooled, would it have been like quicksand to walk through? (that's what I imagine) If so, the mud that finally preserved into rock from that event would be sedimentary rock too, right?

Pretty much. There are places where ash, bentonite, is still very much like quicksand when enough water is involved.

The_Piper wrote:I can relate to losing a friend young and healthy. One of my best friends died when we were 32 of a brain anneurism. I feel pretty lucky to have made it this far too.

Seems awful that the "fall" caused all these perfect designs to exhibit basic flaws such as these, innit?

RS

Thanks again. I'm not too confused anymore, I was fine. :cheers:

What's the fall? Something to do with religion I'm guessing.

The trees you posted are as igneous as can be.
The ones in the Hawaii forest are particularly awesome looking.

Finding them in old igneous rock could happen by chance like with mining or construction, or where that layer happened to be at the surface eroding.

Check out the source of the first hit in this
Google search. :lol:

zoon wrote:Ancient Sea Spider Fossils Discovered In Volcanic Ash More spiders, 425 million years old, found in 2004.

I didn't even know there were such things. That one lived roughly around the time the rocks in my backyard were being deposited, in the same ocean. :dopey: