Can you identify these types of rock formation?
June 1, 2011 3:49 PM Subscribe
Can you help me figure out what geological forces shaped these two rock formations?
The first rock formation is here . What caused the rock to be shaped like this and what kind of rock do you think it is? The second rock is here . What type of fold is this and how do you think it could have been formed? I have searched google and wikipedia and have only become more confused with all the terminology. Don't worry, this isn't for school credit or anything very important. Educated guesses welcome. As you can tell, I know next to nothing about geology, so simple answers would be preferred. In case it matters, these pictures were taken in western North Carolina. Thank you.
The first rock formation is here . What caused the rock to be shaped like this and what kind of rock do you think it is? The second rock is here . What type of fold is this and how do you think it could have been formed? I have searched google and wikipedia and have only become more confused with all the terminology. Don't worry, this isn't for school credit or anything very important. Educated guesses welcome. As you can tell, I know next to nothing about geology, so simple answers would be preferred. In case it matters, these pictures were taken in western North Carolina. Thank you.
Best answer: #1 - Pillow Basalt created by molten lava extruding on the seafloor.
#2 - Metamorphosed via heat and pressure probably during the formation of what would become the Appalachian Mountains
posted by humboldt32 at 4:20 PM on June 1, 2011 [3 favorites]
#2 - Metamorphosed via heat and pressure probably during the formation of what would become the Appalachian Mountains
posted by humboldt32 at 4:20 PM on June 1, 2011 [3 favorites]
The problem here is that it's difficult, almost impossible, to tell from just a photograph. For example:
#1 - Pillow Basalt created by molten lava extruding on the seafloor.
It could be that. But it could just as easily be regular, plain-jane granite that happens to be showing a lot of weathering and erosion by flowing water. The rock itself is perhaps even placed in that spot by glaciation.
You could get several different answers here, and each will be just as likely as the next.
posted by Cool Papa Bell at 5:06 PM on June 1, 2011
#1 - Pillow Basalt created by molten lava extruding on the seafloor.
It could be that. But it could just as easily be regular, plain-jane granite that happens to be showing a lot of weathering and erosion by flowing water. The rock itself is perhaps even placed in that spot by glaciation.
You could get several different answers here, and each will be just as likely as the next.
posted by Cool Papa Bell at 5:06 PM on June 1, 2011
I completely agree. Those were my best guesses given the photos.
posted by humboldt32 at 5:35 PM on June 1, 2011
posted by humboldt32 at 5:35 PM on June 1, 2011
The second one looks like a foliated schist, formed under high pressure (relative to temperature) at a subduction zone from metamorphosed shale and mica. Still thinking about the first one.
posted by sunnychef88 at 5:40 PM on June 1, 2011
posted by sunnychef88 at 5:40 PM on June 1, 2011
As we don't even know what type of rock this is (though I'm guessing it is most likely granite as you mentioned wester NC), your best bet is to give a call to the forest service for whichever park you were in and see if someone there would know.
Where exactly in Western NC?
posted by TheBones at 5:48 PM on June 1, 2011
Where exactly in Western NC?
posted by TheBones at 5:48 PM on June 1, 2011
If you know their exact or approximate location, the local university library should have geological maps of the area.
posted by Monday, stony Monday at 6:45 PM on June 1, 2011
posted by Monday, stony Monday at 6:45 PM on June 1, 2011
Best answer: Everything has been mapped, so the location will be the key. #1 looks like granite or something similar coarse-grained, not likely basalt, especially in western NC. #2 could be as others surmised. There also looks to be a fault cutting up the fold on the right side.
posted by TDIpod at 10:39 PM on June 1, 2011
posted by TDIpod at 10:39 PM on June 1, 2011
This thread is closed to new comments.
The fold was likely formed when the seafloor where it was deposited was moved/uplifted/munged somehow.
I got nothin' on the first picture...
posted by dolface at 4:04 PM on June 1, 2011