urbpan: (cold)
[personal profile] urbpan






Is there a geological term for a rock that contains two or more distinct layers of stratification?




We followed the stream up to Jamaica Pond, which is mostly frozen.



The water birds are concentrated on the unfrozen part of the pond.



Pigeons are there to remind us that we're in a city park.

Date: 2006-01-10 08:20 pm (UTC)
From: [identity profile] lostnorange.livejournal.com
Buurrrrrrrrr!!! And Beautiful!

Date: 2006-01-10 11:20 pm (UTC)
From: [identity profile] bunrab.livejournal.com
Rock built up in layers is called "sedimentary." Is that the word you were looking for?

Date: 2006-01-11 11:38 am (UTC)
From: [identity profile] marmota-monax.livejournal.com
The rock in question looks like it might be some gneiss (soft gray color), some quartzite (blotchy gray with white crystals), with quartz veins between the two. You can see how the gneiss has worn away more than the quartz and quartzite sections, because it is a softer rock than the other two types.

While this rock may have started out as a fine sandstone (sedimentary) it changed over millions of years to gneiss and quartzite and quartz (all metamorphic) due to massive pressures and heat put upon it below the the earth's surface. The quartz veins happen when rock becomes liquid and then recrystallizes as it intrudes itself through the surrounding rock during metamorphism.

Profile

urbpan: (Default)
urbpan

May 2017

S M T W T F S
 123456
78910111213
1415 1617181920
21222324252627
28293031   

Most Popular Tags

Style Credit

Expand Cut Tags

No cut tags
Page generated May. 24th, 2025 11:32 am
Powered by Dreamwidth Studios