Author Topic: cool geology  (Read 1610 times)

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Offline velkyn

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cool geology
« on: October 17, 2008, 08:58:30 AM »
Just more geology amusement from me.  Please feel free to add your cool geology stuff

Just north of me in Pennsylvania is the "whaleback", an old strip mine that shows the folds in the rocks very well. 

I found a great blog that shows some lovely pictures of it.  It's a very popular place for schools to take their students since fossils just litter the ground.  Most are from the Carboniferous.

http://nvcc.edu/home/cbentley/geoblog/2008/01/whaleback.html



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Offline Davedave

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Re: cool geology
« Reply #1 on: October 17, 2008, 10:46:09 AM »
On October 3, 2007, there was a landslide on Mount Soledad, in a very expensive neighborhood in San Diego.  The area had been evacuated literally the day before and the people had not yet been let back in.  I toured the affected area with a group of city geologists about four weeks after the slide and the residents had still not been allowed to return.  People's doors and garages were still open, you could see furniture strewn about inside, there were hungry dogs barking at us, still trapped in people's backyards.  Someone must have been feeding them, but I don't know who that might have been.  Anyway, here are the pictures.



This is approaching the top of the slide, from the south.  This used to be a very wide two-lane road.  This road was just reopened yesterday (10/16/08).



Buncha damn looky-loos, posing as geologists!  Okay, only one - me.



A close-up of the devastation.  Notice the dryness of the soil.  This was a matter of deep concern to the city geologists.  This area is well-known to be unstable, but to have a slide of this magnitude with no rain, no leaking water main, no nothing, well, it's pretty scary for the people whose job it is to protect people.  To their credit, though, the city geologists had it pegged.  They ordered an evacuation the day before the slide.  They had been up there doing some unrelated testing and made the call and got it right.  I half-suspect that the reason the city geologists let the community geologists do this tour was to show off having got one right.



From the other edge of the top of the slide, looking back.  Asphalt does not handle lateral stresses well.  The whole area looked like Godzilla had smashed a foot down to crumple the hillside.  It was a little surreal when I saw these pictures (taken by the geologist who tipped me off to the tour), because you see pictures of this and that disaster on the front page of the paper from time to time.  It's hard to describe the difference of having been there to see the scale firsthand.  It seems to me that these pictures probably look pretty run of the mill, as far as disaster photos go, but having been there, these pictures have the opposite effect on me.  When I saw them, it really sunk in just how massive the whole thing was.



You can see the southernmost house affected by the slide.  Obviously, it used to be side by side with the house next door.  We were under strict orders NOT to step foot on private property, not even to steal the motorcycle in the garage next door.  In fact, looting was entirely prohibited, if you can believe that.  What a bunch of squares!



This is the toe of the slide.  This is where the land from the landslide landed.  Again, under strict instructions not to step foot on private property, but as you can see here, that wasn't always easy to do.  Yes, that is a roof we are standing next to.  At the base of the hill, there had been a narrow access road, then a line of houses.  The land from the slide got under the road and pushed it onto the roofs of the houses.  We saw a fire hydrant that surveyors determined had moved twenty feet vertically.  If the public road is on top of the roof of a private residence, is walking on the road walking on public property or private property?  This is also where the dog was.  I think someone had been chucking meat over the house to the dog for the last four weeks.



A palm tree.  Thrown through a wall.

« Last Edit: October 17, 2008, 12:41:46 PM by Davedave »

Offline Davedave

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Re: cool geology
« Reply #2 on: October 17, 2008, 11:24:43 AM »


Why the city didn't want to let the residents back in.  Geologists are funny folks.  First of all, here we see a geology grad student, blissfully unaware of the patio dangling over his head.  Let me assure you, though, the geologist that took this picture was not thinking, "This is gonna be a great 'before' pic when that patio creams that grad student."  Nope.  He was thinking, "Nice shot of some extruded hillside."



Another shot only a geologist could love.  I invite velkyn to speculate on what the hell this contains, but the geologist I was with spent 15 minutes gleefully examining this little spot.



A stuck auger.  Whoso pulleth out this auger of this stone and asphalt is rightwise King born of all England.

You may also have noticed the large drill rig in the background of a number of these shots.  I'm certain that the City Geologist appreciates that I note that there is no evidence, repeat, no evidence that the drilling they were doing caused the landslide.



You may think this is another tedious picture of wreckage, but if you look carefully, you should be able to spot the top of the head of a geologist standing fully upright in a gouge.  I do not believe the geologist's name is Waldo, however.  (Spoiler Alert: It's a little back in the picture, but towards the middle.  She's posing.)



Location, location, location.  When hanging around drunk geologists, I like to play a little game I call "Start a Conversation About the Geologic Formations Underlying Everyone's Houses".  When they get together, they actually make fun of each other, based upon the relative geologic security of the formation they live on.  It sort of forms the basis of the geologist social pecking order.  "Oh, you live on the such-and-such formation?  Ha!  Hope your kids don't think they're gonna inherit that house."
« Last Edit: October 17, 2008, 11:49:26 AM by Davedave »

Offline Irish

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Re: cool geology
« Reply #3 on: October 17, 2008, 11:52:07 AM »
Damn!!!  :o
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Offline velkyn

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Re: cool geology
« Reply #4 on: October 17, 2008, 12:01:45 PM »
wow!  My guess that there is evidence of a fault line in this pic
  It reminds me a bit of a photo I took at a roadcut I was working near many years ago. 

DD,do you know what that big drill was there for?  Looks to me that they were putting in something big like piers considering the size of the auger attached to it. 
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Offline Davedave

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Re: cool geology
« Reply #5 on: October 17, 2008, 12:07:34 PM »
The little one that you see stuck was drilling in progress when the slide began.  The ground started moving and the people disconnected the auger and ran like hell.  Joking aside, I think the large rig was brought up after the slide.  My recollection is that they were drilling the big hole intending to actually put a geologist down into the boring, to survey the layers and test the moisture levels and shear characteristics of the soil.  Because Mount Soledad is known to be so active (and the residents so wealthy and litigious), the city wants to more thoroughly characterize the area.  There are several known faults running directly beneath the mountain.  They may also have intended to drop I-beams to help stabilize the area.  Mostly, this is undertaken privately by the homeowners (to the tune of $200,000+), but in this case, with a fairly major through-road at stake, they might have already been starting to prepare for rebuilding.  Also, of course, many of the neighbors were probably considering doing some support work themselves and doubtless the city would want to conduct some sort of examination of the area before approving and permitting those plans.
« Last Edit: October 17, 2008, 02:17:17 PM by Davedave »

Offline velkyn

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Re: cool geology
« Reply #6 on: October 17, 2008, 12:23:47 PM »
The little one that you see stuck was drilling in progress when the slide began.  The ground started moving and the people disconnected the auger and ran like hell.  Joking aside, I think the large rig was brought up after the slide.  My recollection is that they were drilling the big hole intending to actually put a geologist down into it, to survey the layers and test the moisture levels and shear characteristics of the soil.  Because Mount Soledad is known to be so active (and the residents so wealthy and litigious), the city wants to more thoroughly characterize the area.  There are several known faults running directly beneath the mountain.  They may also have intended to drop I-beams to help stabilize the area.  Mostly, this is undertaken privately by the homeowners (to the tune of $200,000+), but in this case, with a fairly major through-road at stake, they might have already been starting to prepare for rebuilding.  Also, of course, many of the neighbors were probably considering doing some support work themselves and doubtless the city would want to conduct some sort of examination of the area before approving and permitting those plans.

oh my.  I'm way too familiar with those little augers.  We used them to drill monitoring wells.  If they were insane enough to think to put someone where simple samples could have told them the exact same thing, yeesh. 
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Offline Davedave

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Re: cool geology
« Reply #7 on: October 17, 2008, 12:39:11 PM »
Everybody loves that in-situ information.  Yeah, I'm pretty sure they were going to drop a PG down the hole to directly examine the layers and fault lines.  I'm not confined-space certified, so it ain't gonna be me (not that I know enough geology to do anything anyway).

Yeah, we use the little ones too.  10-inch mostly, I think, to get 2-inch and 4-inch diameter wells.  I'm not involved much on the drilling side.
« Last Edit: October 17, 2008, 02:17:32 PM by Davedave »

Offline velkyn

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Re: cool geology
« Reply #8 on: October 17, 2008, 03:27:28 PM »
Everybody loves that in-situ information.  Yeah, I'm pretty sure they were going to drop a PG down the hole to directly examine the layers and fault lines.  I'm not confined-space certified, so it ain't gonna be me (not that I know enough geology to do anything anyway).

Yeah, we use the little ones too.  10-inch mostly, I think, to get 2-inch and 4-inch diameter wells.  I'm not involved much on the drilling side.

tsk!  Then you don't know the joy of decontaminating the damn things! ;D
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Offline Davedave

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Re: cool geology
« Reply #9 on: October 17, 2008, 04:03:05 PM »
Yeah, I bet.

I went on a trip at the beginning of the year to Sharktooth Hill in Kern County.  It's been a dream of mine to go since I was a little kid, but it's private property and has been closed to the public for a number of years now.  Didn't take a lot of pictures of the geology of the site, but I think my friend took some pictures of the haul.  In all, ~100 shark teeth up to about an inch and a half long, two whale and one dolphin vertebrae, a couple of gastroliths, plus an ambiguous fossil-like thing.  As sure as I bring a girl, though, she pulls the prize fossil of the whole trip - a beautiful seal canine tooth with a complete root maybe 3 1/2 inches long.  Just gorgeous.  Two people, five hours of digging each, not too bad.  It's all Miocene stuff.  It's an extensive bed with a ton of whale bones.  The mammalian bones were pretty beat up, only the ribs and the vertebrae were still easily identifiable, but the shark teeth are in perfect condition.  Very soft matrix made the fossils easy to remove, plus it eroded far faster than the fossils themselves, so everything was sticking out.  It was like picking fruit.  Now, I've just got to ID them...
« Last Edit: October 17, 2008, 04:05:57 PM by Davedave »

Offline velkyn

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Re: cool geology
« Reply #10 on: October 21, 2008, 11:32:44 AM »
Yeah, I bet.

I went on a trip at the beginning of the year to Sharktooth Hill in Kern County.  It's been a dream of mine to go since I was a little kid, but it's private property and has been closed to the public for a number of years now.  Didn't take a lot of pictures of the geology of the site, but I think my friend took some pictures of the haul.  In all, ~100 shark teeth up to about an inch and a half long, two whale and one dolphin vertebrae, a couple of gastroliths, plus an ambiguous fossil-like thing.  As sure as I bring a girl, though, she pulls the prize fossil of the whole trip - a beautiful seal canine tooth with a complete root maybe 3 1/2 inches long.  Just gorgeous.  Two people, five hours of digging each, not too bad.  It's all Miocene stuff.  It's an extensive bed with a ton of whale bones.  The mammalian bones were pretty beat up, only the ribs and the vertebrae were still easily identifiable, but the shark teeth are in perfect condition.  Very soft matrix made the fossils easy to remove, plus it eroded far faster than the fossils themselves, so everything was sticking out.  It was like picking fruit.  Now, I've just got to ID them...

cool.  There's a good site near here for trilobites but the exposure is under I-81 and they keep people away since digging could compromise the roadway. 
"There is no use in arguing with a man who can multiply anything by the square root of minus 1" - Pirates of Venus, ERB

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