Geological question...Quartzite?

[Jason Berard]

After spending the last 10 years living in the Upper Valley of the Connecticut River, near Hanover, NH I have become fairly familiar with the ridge that starts in Hanover and heads northeast towards the White Mountains. This would include Moose Mountain, Holt's Ledges, Smarts, and Cube.

The WMG describes the summit of Cube as being Quartzite, and I have see this rock exposed at various other points along this ridge. It is the slipperiest damn rock I have ever been on, even when it is dry as a bone!
I have lost my footing numerous times on Cube especially, even when the rock is completely dry.
So my question is...how/when was this rock formed, and what the hell makes it so friggin' slippery!?

Also, does it occur elsewhere in the Whites?

Dr. D, Jazzbo....anyone??

thanks!

 

[nartreb]

"Unlike sandstone, quartzite breaks through, not around, the quartz grains, producing a smooth surface instead of a rough and granular one."

That would help explain why it's slippery. In some cases glacial polishing may also play a role.

If the above quote is correct, a lot of the rough-textured mostly-quartz rocks I'm familiar with (the Gunks; the white chunks in the Northern Presis) probably aren't quartzite...?

Edit: on second thought a lot of the Presis near-pure quartz is pretty smooth. It tends to crumble into hailstone-sized (or somewhat larger) crystals, not polished slabs, but each broken face is pretty slippery to the touch. The rock in the Gunks is different - near-microscopic quartz grains are mixed fairly smoothly with equally small dark grains, and the overall texture is like sandpaper.

Re-edit: yep, the Gunks (the good climbing faces, anyway) are actually a Conglomerate, and I think they qualify as sandstone.

 

[Jason Berard]

The rock does look highly polished. I was looking for glacial striae(sp?)
on Eastman Ledges on Cube and couldn't find any, but that doesn't mean they're not there.....

Thanks for the replies, nartreb and Barkingcat.

 

[Amicus]

I was looking for glacial striae(sp?)

You got that right. I defer to those who know more on your other Qs and look forward (as a geol. novice) to their weighing in.

 

[bcskier]

Quartzite is metamorphic

The rock is a metamorphosed (changed through heat & pressure to a partially melted state and recrystallized) form of sandstone. Probably ancient beach/undersea deposits that became cemented into stone and after further burial metamorphosed into their present from.

It is very resistant to weathering, hence quartzite outcrops exist like Monument Mountain in Great Barrington, MA and Seneca Rocks in W. Virginia.

Quartz is the hardest common mineral. As stated before it fractures conchoidally or across any grain structure, like glass, which is logical since quartzite and glass are largely the same material: silica.

Quartz rock breaks down to become sand because it is so hard to destroy chemically. The grains will end up on a beach somewhere and over time they will be cemented to form sandstone which could eventually metamorphose to quartzite and the stage will be set for the whole process to start over again.

Because of its hardness my guess is you'll rarely, if ever, see glacial striae in quartzite outcrops.

Of course Dr. D. may want to revise some of this.

P.S. Quartzite is one of the slipperier rocks when wet but lichen-covered quartzite is off the scale.

 

[IndianChris]

bcskier has got that right...it is definately hard. Quartz is also the most common rock found on Earth's surface so it will be rare to find something stuck in a glacier that's harder which would cause the striations during an ice age. Actually Topaz and Corrundum are a lttle harder than quartz according to Moh's Hardness scale.

The rocks may have been formed during the Taconian or Acadian Orogenies about 400 mya when the Iapetus Ocean closed up (a kind of ancient Atlantic Ocean) and North America collided with an existing land mass (not Africa)

About that time, some of the earliest sharks, insects and plants had started to evolve on Earth. I can't imagine what the "east coast" of North America was like back then. In fact, the location of the white mountains to-be was much closer to the equator back then.

There is a series of books called the "Roadside Geology" series for every state. They wont describe the rocks in much detail up in the mountains but it is really cool to read up on the rocks that the highways cut through as you make your way to the trail head, if that interested.

 

[Amicus]

There is a series of books called the "Roadside Geology" series for every state. They wont describe the rocks in much detail up in the mountains but it is really cool to read up on the rocks that the highways cut through as you make t=your way to the trail head, if that interested.

A strong second on that. Based on a plug for these last Fall by Jazzbo, I got for Xmas the volumes for (1) NH and VT - a single volume by B. Van Diver and (2) Mass., by J. Skehan. They bring those highway cuttings to life! I find the Mass. volume esp. good, perhaps because it is 14 years newer and knowledge seems to be evolving rapidly.

 

[Dr. Dasypodidae]

Because of its hardness my guess is you'll rarely, if ever, see glacial striae in quartzite outcrops.
Of course Dr. D. may want to revise some of this.

Exactly; quartz-rich bedrock rarely reveals glacial striae because the bedrock is generally harder than the stone tools carried in the glacier ice. But, quartz-rich bedrock (ex. look for quartz blebs and veins that stand up in relief) commonly preserves glacial polish, which given that it has been at least 12,000 years since glacier ice left the Whites is testament to the durability of quartz. But, some times one can find striae preserved on softer bedrock if the protective mat of vegetation and soil is peeled away from the surface. And of course, one can find striae preserved on softer erratic stones in till (glacial sediments). Unfortunately, glacial polish on bedrock and striae on till stones tell us nothing about the direction of ice flow, although the composition of the erratics might do so if source areas can be identified (ex. red syenite erratics in till southeast of Red Hill in the eastern Squam Range).

 

[Jazzbo]

After spending the last 10 years living in the Upper Valley of the Connecticut River, near Hanover, NH I have become fairly familiar with the ridge that starts in Hanover and heads northeast towards the White Mountains. This would include Moose Mountain, Holt's Ledges, Smarts, and Cube.

The WMG describes the summit of Cube as being Quartzite, and I have see this rock exposed at various other points along this ridge.

"Geology of New hamphire" by Marland P. Billings devotes 6-7 pages to Clough Quartzite. Clough Quartzite is member of Bronson Hill collapsed island arc family of rock formations. Clough Quartzite is metamorphized sandstone and conglomerates deposited in ancient sea beds in relatively thin beds and then tilted and folded into anticlines typical of this area. It reveals itself surficially as long narrow belt along western NH border between Lisbon NH all way down south to Mass border. Thickness varies from 100 to 1200'. Fitch is a neighboring calcareous (limestone) formation that is fossiliferous featuring anciant Devonian fossils like brachiopods. It's not a continuous band but is broken up by faults and stuff.

My NH geologic map shows a very thick exposure is at Mt Cube. I think Mt Clough has good exposure. Billings says it is what Clough Quartzite is named after although he refers to it as Clough Hill???.

[/QUOTE]
It is the slipperiest damn rock I have ever been on, even when it is dry as a bone!
I have lost my footing numerous times on Cube especially, even when the rock is completely dry.
So my question is...how/when was this rock formed, and what the hell makes it so friggin' slippery!? [/QUOTE]

Purest quartzite is hard like glass and when exposed in ledges I imagine weathering causes it to get smooth and slippery. So I'm not surprised when you say it's slippery. Billings says Clough Quartzite freqeusntly stnads out in bold outcrops due to it's resistance to weathering and holds up many of the higher peaks of western NH. Moose Mt, Holts Ledge, Mt Cube, mt Clough, Sugarloaf, Hogback, Croydon. (Now there's an interesting looking mt. What a handsome treeless ridge viewed from Rt 89 on way to Hanover. What's up with Croydon? Is it private land or what?)

[/QUOTE]

Also, does it occur elsewhere in the Whites?

[/QUOTE]

Like i said earlier it's pretty much confined to western side of the state not in granite and plutonic unless it's been intruded by plutonic. Billings says it occurs as well in Maine near Rangely area.

 

[Dr. Dasypodidae]

"My NH geologic map shows a very thick exposure is at Mt Cube. I think Mt Clough has good exposure. Billings says it is what Clough Quartzite is named after although he refers to it as Clough Hill???.
......Billings says Clough Quartzite freqeusntly stnads out in bold outcrops due to it's resistance to weathering and holds up many of the higher peaks of western NH. Moose Mt, Holts Ledge, Mt Cube, mt Clough, Sugarloaf, Hogback, Croydon. (Now there's an interesting looking mt. What a handsome treeless ridge viewed from Rt 89 on way to Hanover. What's up with Croydon? Is it private land or what?)
Also, does it occur elsewhere in the Whites?
Like i said earlier it's pretty much confined to western side of the state not in granite and plutonic unless it's been intruded by plutonic. Billings says it occurs as well in Maine near Rangely area.

The Silurian Clough Quartzite is very much a part of the structure and stratigraphy of the granite/gneissic domes in western New England, where the geology is about as complicated as anywhere in the world, in my opinion (i.e., perhaps an understanding of nappes in geology is like learning brain surgery in medicine). Here are links to a 1997 NEIGC guidebook chapter for a field trip led by Tim Allen, a geology professor at Keene State, and a paper on nappes in American Mineralogist by Peter Robinson (geology professor emeritus at UMass.-Amherst) and others. The Geology of New Hampshire Part II (bedrock geology) by Billings is also available as a 9 mb pdf.

http://tim.thorpeallen.net/Research/Papers/WestCentralNHweb/

http://www.minsocam.org/ammin/AM76/AM76_689.pdf

http://www.bostonmineralclub.org/docs/GeologyofNH2.pdf

Croydon Peak is the high point of Sullivan County, and with fire tower lies inside a 35-square-mile private game preserve (also known as Corbin Park) managed and owned by the Blue Mountain Forest Association, which is required to allow access at least once per year for peak baggers (however, they are allowed to charge $50 per person for one-time access). But, where else in N.H. can you see Russian wild boar (the babies are cute) and Irish elk? Word is that Teddy Roosevelt once hunted at Corbin Park, which is also the place where buffalo were bred to re-establish the decimated herds in the western U.S.

http://www.peakbagger.com/list.aspx?lid=5171

http://www.manta.com/company/mmgtylr

http://www.meyette.us/CorbinPark.htm

 

[Jason Berard]

Thanks for all the great info, folks! Now I have some good resources to go check out besides the Roadside Geology book.

 

[Jazzbo]

Thanks for posting Dr D

Thanks for informative comments on Clough Quartzite and for info on Croyden Peak. I've always wondered about that place. Double thanks for link to the field trip paper. I love those types of articles. Some day when I have more time I'll have to follow routes of these.

For those interested in NH geology Billing's book bedrock geology is available for download or printing from NH DES at following site:

http://des.nh.gov/organization/commissioner/pip/publications/geologic/documents/geologyofnh2.pdf

Link to all of NH DES geologic publications available by mail is here.

http://des.nh.gov/organization/commissioner/pip/publications/geologic/

 

[Jason Berard]

Thanks for the links and the informative posts, all! I'm just beginning to think of the places I hike in more complex ways, and I always come away from a hike with more questions.

I keep thinking about how these places in New Hampshire and Vermont are now, and how they got that way....

Wind, Water, Fire, Ice sheets, Human and non-human disturbances, soil composition, and how all that and more effects what I see, hear, etc. on any given hike as far as plants, trees, birds, etc.

I also get to wondering how they will be in the future as these forces continue to shape the landscape.....

 

[IndianChris]

If you could go back in time, how far back would you go? What time would be most interesting to you from a natural science point of view?...not politically.

 

[Jason Berard]

No specific time, really. I would really like to be able to imagine a specific area, like Vermont and New Hampshire, and see this place as if in a time-lapse photography shoot and see it change. For example, if I have this right, the rock that forms the Middle Connecticut River Mountains near my house, were once sand on a beach somewhere, and were moved through tectonic shifts, and compressed into quartzite, and then exposed due to erosional forces, including the last Ice Age advancing and retreating.

Its like, what I think of as "this spot" used to be somewhere else.....

So where did what was here before that go? See? So many questions, so little time.