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Re: Geologic Mapping C
Posted: January 3rd, 2019, 1:26 pm
by syo_astro
Unome wrote:Qu€€nMon€y wrote:The rule says tracing paper and pin. What kind of pin?
The ideal pin would of the capped type sometimes used with nametags. Any type of pin with a flat head should work, provided you can avoid being poked by the tip pointing upwards.
I believe I mentioned an example on the first page:
viewtopic.php?f=285&t=12238#p359151 as well as noting that you should find example videos on youtube to see the process (which should help show you why / the type of pin you need):
viewtopic.php?f=285&t=12238#p359155. Note for both those cases those are just examples, not necessarily the best or cheapest (aka I was just putting that together quickly as examples, you should look into it yourself of course).
Not sure what Unome means by capped pin for nametags (maybe/probably same thing?), but hopefully that should work/helps. Specify if it doesn't, etc!
Re: Geologic Mapping C
Posted: January 4th, 2019, 7:17 pm
by poonicle
On one test, the formula for true thickness was given as T = Wsin(d) + Hcos(d) where T = true thickness, W = width, H = height, d = dip, whereas on another test, the formula for true thickness was given as T = Wsin(d) where T = true thickness, W = width, d = dip. Which one is the correct formula? I am very confused.
Re: Geologic Mapping C
Posted: January 4th, 2019, 7:28 pm
by UTF-8 U+6211 U+662F
poonicle wrote:On one test, the formula for true thickness was given as T = Wsin(d) + Hcos(d) where T = true thickness, W = width, H = height, d = dip, whereas on another test, the formula for true thickness was given as T = Wsin(d) where T = true thickness, W = width, d = dip. Which one is the correct formula? I am very confused.
What is height?
(Note that a formula for true thickness can be derived using basic trig in emergencies!)
Re: Geologic Mapping C
Posted: January 5th, 2019, 3:30 am
by Unome
UTF-8 U+6211 U+662F wrote:poonicle wrote:On one test, the formula for true thickness was given as T = Wsin(d) + Hcos(d) where T = true thickness, W = width, H = height, d = dip, whereas on another test, the formula for true thickness was given as T = Wsin(d) where T = true thickness, W = width, d = dip. Which one is the correct formula? I am very confused.
What is height?
(Note that a formula for true thickness can be derived using basic trig in emergencies!)
I would strongly recommend deriving the formula yourself, so you understand how it works. There are several standard formulas for true thickness that cover various situations.
Re: Geologic Mapping C
Posted: January 12th, 2019, 1:18 pm
by Snayhill
Hello Everyone!
I was just wondering if anyone here know what lines that are not faults in a relative dating/strata diagram are. Here's a link
https://d2vlcm61l7u1fs.cloudfront.net/m ... IiQrsg.png. I'm specifically talking about "G" in this picture.
Thanks!
Re: Geologic Mapping C
Posted: January 12th, 2019, 1:37 pm
by UTF-8 U+6211 U+662F
Snayhill wrote:Hello Everyone!
I was just wondering if anyone here know what lines that are not faults in a relative dating/strata diagram are. Here's a link
https://d2vlcm61l7u1fs.cloudfront.net/m ... IiQrsg.png. I'm specifically talking about "G" in this picture.
Thanks!
What does line G represent? It's not a fault because there isn't any relative motion across it as you can see in line K
Re: Geologic Mapping C
Posted: January 12th, 2019, 8:36 pm
by fabishkf
joint
Re: Geologic Mapping C
Posted: January 21st, 2019, 8:12 pm
by bluesm0ke
Unome wrote:UTF-8 U+6211 U+662F wrote:poonicle wrote:On one test, the formula for true thickness was given as T = Wsin(d) + Hcos(d) where T = true thickness, W = width, H = height, d = dip, whereas on another test, the formula for true thickness was given as T = Wsin(d) where T = true thickness, W = width, d = dip. Which one is the correct formula? I am very confused.
What is height?
(Note that a formula for true thickness can be derived using basic trig in emergencies!)
I would strongly recommend deriving the formula yourself, so you understand how it works. There are several standard formulas for true thickness that cover various situations.
Do you think you could post those formulas here? I'm having a hard time grappling more complex true thickness problems that don't just use the basic formula. thanks
Re: Geologic Mapping C
Posted: January 22nd, 2019, 12:46 pm
by Unome
bluesm0ke wrote:Unome wrote:UTF-8 U+6211 U+662F wrote:
What is height?
(Note that a formula for true thickness can be derived using basic trig in emergencies!)
I would strongly recommend deriving the formula yourself, so you understand how it works. There are several standard formulas for true thickness that cover various situations.
Do you think you could post those formulas here? I'm having a hard time grappling more complex true thickness problems that don't just use the basic formula. thanks
I don't have the third one memorized, and can't seem to find it, but I'm pretty sure it's on one of the test exchange tests.
Re: Geologic Mapping C
Posted: January 24th, 2019, 6:45 pm
by poonicle
bluesm0ke wrote:Unome wrote:UTF-8 U+6211 U+662F wrote:
What is height?
(Note that a formula for true thickness can be derived using basic trig in emergencies!)
I would strongly recommend deriving the formula yourself, so you understand how it works. There are several standard formulas for true thickness that cover various situations.
Do you think you could post those formulas here? I'm having a hard time grappling more complex true thickness problems that don't just use the basic formula. thanks
yeah, i'm not gonna lie, i asked that question before TSTs when i didn't know that much about the event. my accuracy improved a lot when i started drawing stuff out then applying trig as opposed to formulas--i'm not very good at identifying which formula applies to which situation yet, but drawing a picture really, really helps imo
that being said, i found
T = w*sin(D - S) where D = dip, S = slope, T = true thickness on one practice test. hope that's helpful