Rock Type Identification Needed

[swiftseeker2005]

Greetings all. While exploring awhile back, I found a deep gorge that had a huge rock (5ft tall) in the creek bed. It was the only rock of its type that I found in that area. I was wondering if anyone could identify its type and maybe offer a theory on how it arrived there (glacier maybe?). Any info appreciated.

 

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[jeff of pa]

Looks like Quartz.

Is the whole rock Quartz,

Or is it Conglomerate ? (SP)

 

[swiftseeker2005]

I guess the whole rock would be a conglomerate of the quartz and sandstone material. I have always found quartz in SE KY in small pebbles. I haven't ever found this much quartz in a huge rock like this before. Although most of the quartz is no bigger than a pea, the whole rock is packed tight with it. Is quartz usually found in a specific strata? Do you think it would be possible to find the strata that the sandstone seperated from?

 

[jeff of pa]

I'll Let that to Someone Who Knows More about it then I do.

Unfortunately, I'd Probably be wrong on my "Guess"

 

[bakergeol]

Hi SwiftSeeker

Glacial erratics(boulders) have been found on northern Kentucky. They were recognized because they were very large and were found at High elevations. The way to look for glacial erratics is to look for rocks which are not native to Kentucky. Sedimentary rocks(conglomerates, sandstones, shales. coals.etc) are the norm in your state. If you see cobbles in your boulder or in the stream of igneous or metamorphic rocks such as granite, gneiss,quartzite, etc it is glacial derived.
From your photo I don't see anything yet to suggest that your conglomerate is from Canada. A boulder that large couldn't have traveled far if found in a small stream(only large rivers would have the flood stage force to move large boulders). Look high above or perhaps it's source is at stream level.

I assume Kentucky has a state geological survey. There would be a geologist there to help you in your quest.- Perhaps a geological section near where you found it would help ID the conglomerate.


George

 

[swiftseeker2005]

Thanks for the info bakergeol. The spot where I found the boulder was in an ancient creekbed. I couldn't find where it had dislodged from the hills above it. There is a lot of sandstone in the area, but none with quartz in it that I could see. At one time the creek was rather large I believe. It is a very deep gorge and has several waterfalls on it. I guess I'll go back and search the cliff area above the gorge and see if I can find anymore like it.