Amateur Geology

Geology, Geophysics, Oceanography, Meteorology etc.

Moderators: Calilasseia, ADParker

Amateur Geology

#1  Postby The_Metatron » Oct 23, 2016 4:00 am

To teach my boys Geology, I've decided on a very hands-on approach. We live in Cheyenne, Wyoming, and we're within easy reach of many geological formations. Not many better places to do this.

For a couple hundred bucks, I got some hardware for each of us for field work:

Image

I didn't omit eye protection, but they didn't arrive yet when I shot that photo.

Each of us has a good pair of leather work gloves, a rock pick, a loupe, eye protection, and a simple canvas musette bag to carry it. I got a chisel set to split layered rocks, as well as a field notebook (waterproof paper, pretty cool stuff).

I made those white PVC safety guards to cover the points on the rock picks. I think a better way might be to make a pouch for the hammer heads, and sew them to the back of the bags. We don't need to carry the hammers inside those bags.


Sent from my iPad using Tapatalk
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Ads by Google


Re: Amateur Geology

#2  Postby The_Metatron » Oct 23, 2016 4:07 am

Here's Tertius at the site:

Image

Image

Image


Sent from my iPad using Tapatalk
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#3  Postby The_Metatron » Oct 23, 2016 4:17 am

We were in the Sherman Mountains area of Medicine Bow state park, Wyoming. So, the samples we could get there are pretty much confined to Sherman granite.

I got a piece of of what I think is a feldspar occlusion in a Sherman granite boulder:

Image

Image


Sent from my iPad using Tapatalk
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#4  Postby The_Metatron » Oct 23, 2016 4:22 am

Sherman granite is really easy to break apart. I think the term is friable. I found a nice edge of a boulder I could knock off to get a fresh surface to inspect:

Image

Here's the sample I got from that edge. It's resting on 5mm grid graph paper:

Image

Image




Sent from my iPad using Tapatalk
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#5  Postby The_Metatron » Oct 23, 2016 4:27 am

And, we found some future archeological artifacts (5mm grid):

Image

As near as I can figure, someone blasting away with an AR-15, an AK-47, and a .40 caliber pistol.

Tertius picked up a handful of brass. I gave him a bucket, where he can keep all he can find. Yellow brass has decent metal value.

Image

Image

Image


Sent from my iPad using Tapatalk
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#6  Postby Weaver » Oct 23, 2016 5:42 am

AK brass has a rebated rim. That's more likely for use in a Mosin-Nagant.

I can recall my twin and I going along with my father on a couple of field trips with his college classes - being able to carry a rock hammer and to bash away at my heart's content was really great for both of us.
Image
Retired AiF

Cogito, Ergo Armatus Sum.
User avatar
Weaver
RS Donator
 
Posts: 19828
Age: 49
Male

Country: USA
United States (us)
Print view this post

Re: Amateur Geology

#7  Postby The_Metatron » Oct 24, 2016 6:18 pm

The boys really enjoyed their day out. Primus' homework is to tell me what he can find out about the Sherman granite. Tertius' homework is to tell me what he can about that Mosin-Nagant shell casing. I want them to know that the field work isn't the end of it, by a long shot.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Ads by Google


Re: Amateur Geology

#8  Postby igorfrankensteen » Oct 25, 2016 11:13 pm

I envy you. I wasn't able to do anything like you can with your guys. But I sure wanted to.
User avatar
igorfrankensteen
 
Name: michael e munson
Posts: 2114
Age: 63
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#9  Postby The_Metatron » Oct 26, 2016 7:45 pm

igorfrankensteen wrote:I envy you. I wasn't able to do anything like you can with your guys. But I sure wanted to.

I have to report that Primus was very pleased with how triangulation works.

We even did it with and without using magnetic declination.

If you're marking your bearings on the map with a protractor, you care about declination. You have to subtract it from the magnetic bearing and use that figure to draw the lines on the map. But, if your compass has a straight edge, and you can put your map on something flat (and non-magnetic), you can just align the map with magnetic north, and use the compass straight edge to draw the bearings as is. I learned that second part from an Army staff sergeant in Korea some 30 years ago. Doesn't work worth a damn on the hood of a car, though.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#10  Postby The_Metatron » Nov 07, 2016 5:18 pm

A couple weeks ago, we took our first field trip to the Medicine Bow National Forest to begin a study of geology. That trip was mainly to test our kit, pack out, and do some navigation training, which was successful. On the way out of the forest, we saw a formation at UTM grid coordinates 13T DF 7305 5830, that looked different. There was a peculiar pattern on one of the exposed faces of a rock:

IMG_1430.jpg
IMG_1430.jpg (220.06 KiB) Viewed 415 times


It turns out that is some sort of igneous rock, which I'll get to later. Here's a closer look at that pattern on the shear face:

IMG_1432.jpg
IMG_1432.jpg (287.42 KiB) Viewed 415 times


The angle of the sun was quite good, to show the relief of that pattern. My best guess is that is a flow pattern created when that rock was formed.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#11  Postby The_Metatron » Nov 07, 2016 5:26 pm

I took a small sample from that formation with the curious flow pattern, UTM coordinates 13T DF 7305 5830, elevation 7800 ft:


IMG_1433.jpg
sample orientation
IMG_1433.jpg (166.42 KiB) Viewed 414 times


These two pictures show the exposed surface of my sample, with a little bit of lichen on it, and the fresh surface where it cleaved:

IMG_1443.jpg
exposed surface
IMG_1443.jpg (101.61 KiB) Viewed 414 times

IMG_1445.jpg
fresh surface
IMG_1445.jpg (91.92 KiB) Viewed 414 times
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#12  Postby The_Metatron » Nov 07, 2016 5:29 pm

What strikes me is the very fine grain size of less than half a millimeter, in comparison to some of the crystal sizes of over ten millimeters for the samples we took last week from the same area.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#13  Postby The_Metatron » Nov 07, 2016 5:41 pm

The_Metatrix took a walk to the top of the formation at UTM 13T DF 7290 5815 while the boys and I were investigating that formation with the flow pattern. After we got down from that fairly steep hillside, we went to meet her.

Near the top, at UTM 13T DF 7295 5820, was a typical outcrop of the coarse grained Sherman granite, identical to what we sampled a couple weeks ago, and what is visible in pretty much any direction in that area:

IMG_1434.jpg
Sherman granite
IMG_1434.jpg (346.29 KiB) Viewed 411 times


Right next to that prominence though, was another formation of the same fine grained red granite I and the boys just investigated on the hillside to the north, on the other side of Middle Crow Creek. It shows the same fracturing as the coarse grained Sherman granite. But, being so fine grained, it weathers much better, and is much stronger.

Here, I've pried away a slab of that fine grained granite along a fracture line:

IMG_1437.jpg
fine grain
IMG_1437.jpg (213.83 KiB) Viewed 411 times


You can see the fresh, lighter colored areas where that slab broke away from its parent. The dark areas were where there was root wedging occuring. Tertius identified that process. Apparently, The_Metatrix has been going over some of these processes during their lessons, and Tertius was paying attention.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#14  Postby The_Metatron » Nov 07, 2016 5:47 pm

Here's a series of photos of part of that slab I pried away. One shows the fresh edge, and the two faces show the root wedging that had been happening where the rock was fractured long after it was formed.

IMG_1440.jpg
freshly broken edge
IMG_1440.jpg (80.61 KiB) Viewed 411 times

IMG_1441.jpg
root wedging
IMG_1441.jpg (111.41 KiB) Viewed 411 times

IMG_1442.jpg
more root wedging
IMG_1442.jpg (144.98 KiB) Viewed 411 times
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#15  Postby The_Metatron » Nov 07, 2016 5:49 pm

Here are a couple of close-up photos showing the fine grain of that red granite in a little better detail. I took these by simply holding my loupe (at 7x magnification) in front of my iPhone camera lens.

IMG_1461.jpg
IMG_1461.jpg (128.48 KiB) Viewed 411 times

IMG_1462.jpg
IMG_1462.jpg (136.73 KiB) Viewed 411 times
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Ads by Google


Re: Amateur Geology

#16  Postby The_Metatron » Nov 07, 2016 6:10 pm

So, what the hell is going on with these dramatically differently grained rocks right next to each other? Unsurprisingly, we aren't the first people to note this and ask that question.

In the map area, rocks mapped as Sherman Granite include a fine-grained facies, a medium-grained facies, a porphyritic facies, and a coarse-grained facies. These rocks are mapped as Sherman because they intrude all other rock units except younger dikes and are generally nonfoliated. The fine to medium-grained to porphyritic facies occur along the margin of the coarse-grained facies, which is the major rock type of this area. We believe that the finer grained to porphyritic facies is a border phase of the Sherman and is approximately the same age as the coarse-grained (typical) Sherman (Houston & Marlatt, 1997, p. 16).


I think their assessment is reasonable. A border phase would have been at the edge of the Sherman when it was formed. The edge would cool first, and fastest, resulting in less time for the crystals to grow and a finer grain structure. I think.

Houston, R. S., & Marlatt, G. (1997). Proterozoic geology of the Granite Village area, Albany and Laramie Counties, Wyoming, compared with that of the Sierra Madre and Medicine Bow Mountains of southeastern Wyoming (Vol. 2159). US Government Printing Office.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#17  Postby The_Metatron » Nov 07, 2016 6:23 pm

Our expedition didn't yield only geological interests. We also found some more modern day archaeological items and a curious biological specimen.

Primus found a spent rifle shell casing while walking along:

IMG_1457.jpg
case
IMG_1457.jpg (67.01 KiB) Viewed 404 times

IMG_1460.jpg
headstamp
IMG_1460.jpg (75.8 KiB) Viewed 404 times


The_Metatrix looked it up on the googles while Primus and I were measuring it with a caliper and cataloging our find. It's a 30-06 shell made by Twin Cities ammunition in 1953. Goddamned 43 year old rifle shell. She didn't tell Primus, so he can figure it out by himself.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#18  Postby The_Metatron » Nov 07, 2016 6:26 pm

Tertius found a steel Pepsi cola can, with the old type of pull tab that I haven't seen since the 1970s:

IMG_1451.jpg
can
IMG_1451.jpg (213.88 KiB) Viewed 402 times

IMG_1453.jpg
top
IMG_1453.jpg (145.61 KiB) Viewed 402 times


The list of ingredients is mostly obliterated by corrosion. But, you can make out that the second ingredient is sugar. They haven't used sugar for quite a while.

The_Metatrix found a can collector's web site that will help Tertius date the can he found.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#19  Postby The_Metatron » Nov 07, 2016 6:29 pm

Tertius also found a pine cone, unlike all the other pine cones in the area:

IMG_1446.jpg
cone
IMG_1446.jpg (116.02 KiB) Viewed 402 times


He found it under this tree, which we haven't identified, either:

IMG_1439.jpg
tree
IMG_1439.jpg (279.53 KiB) Viewed 402 times


And, I suppose in hindsight, it would have been good to take a photo of the rest of the cones underneath that tree, but I didn't think of it. Gives us a reason to go back and do some more work.

I think it's a pinus contorta, commonly known as lodgepole pine. It's very exposed on top of a hill, which I read can cause them to grow like this.
"In the face of overwhelming odds, I'm left with only one option: I'm gonna have to science the shit out of this."

Astronaut Mark Watney, logging about his status of being stranded on Mars, in Andy Weir's book, The Martian
User avatar
The_Metatron
Moderator
THREAD STARTER
 
Name: Jesse
Posts: 18414
Age: 54
Male

Country: United States
United States (us)
Print view this post

Re: Amateur Geology

#20  Postby theropod » Apr 13, 2017 12:08 pm

The_Metatron wrote:Our expedition didn't yield only geological interests. We also found some more modern day archaeological items and a curious biological specimen.

Primus found a spent rifle shell casing while walking along:

IMG_1457.jpg

IMG_1460.jpg


The_Metatrix looked it up on the googles while Primus and I were measuring it with a caliper and cataloging our find. It's a 30-06 shell made by Twin Cities ammunition in 1953. Goddamned 43 year old rifle shell. She didn't tell Primus, so he can figure it out by himself.


More than 20 years ago my wife and I took a little trip to the Medicine Bow area to look for dinosaur fossils. Yes we located some of those but we found a spent 45-70 case that was very old. It was situated inside a group of Teepee rings, which overlooked a wide valley. One cannot help but wonder how that round was expended.

RS
16 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.
User avatar
theropod
RS Donator
 
Name: Roger
Posts: 6636
Age: 63
Male

Country: USA
United States (us)
Print view this post

Next

Return to Earth Sciences

Who is online

Users viewing this topic: No registered users and 1 guest