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View Full Version : To AW rock hounds: Question about stones in the mountains of Northern Virginia



Tazlima
11-26-2014, 10:26 PM
If you're climbing a mountain in or near northern Virginia and you look at the typical rocks that are scattered around, what kind of rock are they? Granite? Shale? Sandstone? (I don't know my rocks).

:e2bummed: <- this little guy is looking at rocks and sad that he can't identify them.

It would be adjacent to an area with good soil for growing Christmas trees if that makes a difference.

Thanks!

vagough
11-27-2014, 05:53 PM
If you're climbing a mountain in or near northern Virginia and you look at the typical rocks that are scattered around, what kind of rock are they? Granite? Shale? Sandstone? (I don't know my rocks).

:e2bummed: <- this little guy is looking at rocks and sad that he can't identify them.

It would be adjacent to an area with good soil for growing Christmas trees if that makes a difference.

Thanks!

Hmmm….. mountains in northern Virginia.

I live in northern Virginia, so what you're probably talking about are the counties further west of Fairfax, where it starts to get hillier. Just as a point of reference, the fall line is at Great Falls, Virginia, so everything to the east of that line is considered the Tidewater (or coastal plain). To the west would be the Piedmont, and west of that is the northern part of the Blue Ridge and further west still the northern tip of the Shenandoah Valley.

This area is kind of complex, geologically speaking (and I defer to experts here, which I am not), because of how it was formed. But if you're looking around areas near, say, Loudoun, Fauquier, Rappahannock, or Culpeper Counties, you'd probably see granite, greenstone, and sandstone rocks predominately, with other kinds scattered about. Kind of depends on the specific site/location.

A good reference book is Roadside Geology of Virginia. If you give me the name of a town or a county, I can look it up for you on one of the maps in the book.

Tazlima
11-27-2014, 06:51 PM
Hmmm….. mountains in northern Virginia.

I live in northern Virginia, so what you're probably talking about are the counties further west of Fairfax, where it starts to get hillier. Just as a point of reference, the fall line is at Great Falls, Virginia, so everything to the east of that line is considered the Tidewater (or coastal plain). To the west would be the Piedmont, and west of that is the northern part of the Blue Ridge and further west still the northern tip of the Shenandoah Valley.

I was thinking of

This area is kind of complex, geologically speaking (and I defer to experts here, which I am not), because of how it was formed. But if you're looking around areas near, say, Loudoun, Fauquier, Rappahannock, or Culpeper Counties, you'd probably see granite, greenstone, and sandstone rocks predominately, with other kinds scattered about. Kind of depends on the specific site/location.

A good reference book is Roadside Geology of Virginia. If you give me the name of a town or a county, I can look it up for you on one of the maps in the book.

Thanks! I'll hit the library!

blacbird
11-28-2014, 06:17 AM
Get that book. The Appalachians are the remnants of a massive period of mountain-building in an ancient continental mass that connected what is now North America with what is now Europe. This mountain-range, uplifted through collision of ancient tectonic plates, would have rivaled the Himalayas at maximum elevation. The remnants today extend from Alabama northeastward through the Appalachians, New England, eastern Canada, Scotland and Norway. The cores of these mountains, now exposed by later erosion, would have a lot of hard metamorphic rocks like granite, schist, etc. But the flanks of the mountains contain younger sedimentary material, sandstones, shales and coals. It's a pretty complicated region. That recommended book should help a lot.

caw

King Neptune
11-28-2014, 07:33 PM
The mountains are part of the Appalachian range.
http://en.wikipedia.org/wiki/Alleghanian_orogeny
There are several sections (East to West) with different rock in different sections, so you can choose what you need.

vagough
11-28-2014, 07:59 PM
Get that book. The Appalachians are the remnants of a massive period of mountain-building in an ancient continental mass that connected what is now North America with what is now Europe. This mountain-range, uplifted through collision of ancient tectonic plates, would have rivaled the Himalayas at maximum elevation. The remnants today extend from Alabama northeastward through the Appalachians, New England, eastern Canada, Scotland and Norway. The cores of these mountains, now exposed by later erosion, would have a lot of hard metamorphic rocks like granite, schist, etc. But the flanks of the mountains contain younger sedimentary material, sandstones, shales and coals. It's a pretty complicated region. That recommended book should help a lot.

caw

I love the Roadside Geology books (there are several in the series). We've used the driving itineraries from the Virginia book to understand a bit more what we're seeing along various roadways.