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Massive, out-of-place mystery rock

Forums: More Stones Again, Rocks, Geology
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Luber905
 
Reply Sat 16 Jul, 2016 11:32 am
The images that follow are of an odd rock that I spotted while kayaking on Gurd Lake, Grundy Provincial Park in Ontario, Canada. The lake is a long shallow pan lake and any shoreline or nearby rock formations are gently sloped and very smooth. There is virtually no loose rock or gravel. This rock sticks out like a sore thumb - it's at the edge of the shoreline on a small point about halfway down the lake. It's approximately 2.5-3 meters high and 3-4 meters wide, somewhat egg-shaped. It seems clear the rock was halfway submerged at some point, as is apparent from the colorations and attached underwater debris on one end of it. In at least one of the photos, it's apparent there is a fairly fresh break along the bottom of the rock as well as a sheet that is broken off near the bottom of one end, as if the rock was dropped there. Any help with this mystery would be appreciated!

http://imgur.com/AgJKIaV
http://imgur.com/chEezS8
http://imgur.com/6YZAz2Z
http://imgur.com/SLk9O4X
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Type: Question • Score: 4 • Views: 1,119 • Replies: 15
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ehBeth
 
  2  
Reply Sat 16 Jul, 2016 11:37 am
@Luber905,
Looks like a glacial erratic. They're all over the bottom end of the shield.
0 Replies
 
ehBeth
 
  2  
Reply Sat 16 Jul, 2016 11:42 am
@Luber905,
http://mw2.google.com/mw-panoramio/photos/medium/97427363.jpg

https://en.wikipedia.org/wiki/Glacial_erratic

http://www.turnstone.ca/gabbro.htm

https://andrewmclachlan.wordpress.com/tag/red-tailed-green-rat-snake/
ehBeth
 
  2  
Reply Sat 16 Jul, 2016 11:46 am
@ehBeth,
http://www.panoramio.com/photo/98381637


and

http://geology.cwru.edu/~huwig/catalog/slides/167.A.1.jpg

___

one of the best parts of high school geography in Eastern Ontario was field trips to erratics (I never told them we had two on our property - I wanted to see more!)

farmerman
 
  2  
Reply Sat 16 Jul, 2016 06:09 pm
@ehBeth,
Its a neat erratic. Its not too hard to pinpoint its provenance. Ive attached a sat map of the Grundy Lake Park. Our OP can see the Scour marks left by a glacier. But since this is sorta SUdbury province, those "scour marks" could be cooling crcks of the country rock.

https://www.google.com/maps/@45.9531459,-80.5626572,6089m/data=!3m1!1e3
When you visited the site (OP, not beth) did you see any scratch nmarks on the rock ledge along the banks of the lake. Following those cratch marks to the est or NW would give us an idea from where the :LAST glacier was coming out of.

Ontario Geo Survey has all sorts of geo maps that locate and pinpoint the various erratic fields, end moraines, muck polygons, bank moraines , eskers etc etc. These maps are like a forensic tool to locate where these erratics came from.

rosborne979
 
  1  
Reply Sat 16 Jul, 2016 06:26 pm
@Luber905,
Yup, almost certainly a glacial erratic.
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izzythepush
 
  2  
Reply Sun 17 Jul, 2016 07:20 am
Dartmoor is full of "foreign" rocks deposited by glaciation.

https://farm6.staticflickr.com/5831/23002934169_6b4655f58b_z.jpg
ehBeth
 
  1  
Reply Sun 17 Jul, 2016 09:03 am
@farmerman,
farmerman wrote:
Ontario Geo Survey has all sorts of geo maps that locate and pinpoint the various erratic fields, end moraines, muck polygons, bank moraines , eskers etc etc. These maps are like a forensic tool to locate where these erratics came from.


I've got quite a few of these. They're fun to 'read'.
0 Replies
 
farmerman
 
  1  
Reply Sun 17 Jul, 2016 11:53 am
@izzythepush,
you guys call em orthostats ND i UNDERSTND ITS NATIONAL HOBBY AMONG HIKERS AND HISTORIANS TO DEVELOP A BELIEVABLE TALE AS TO HOW AND FROM HERE THEY WERE BORN
We dont hqve too many glacial balanced rocks except for one or two in the NE in Vt Pa NY. Our biggest ones are in desert lands and neqr ,loess deposits.

neat balancing act but Im not certain they are certain that its a sonehenge doggie with a soccer cap.
izzythepush
 
  1  
Reply Sun 17 Jul, 2016 11:59 am
@farmerman,
The Devil has been blamed for a lot of it. I once saw a documentary about a rock band who lived on the moors. They had a two mile walk to the nearest pub, on the way they passed a rock formation where legend has it demons engage in gladiatorial combat for the Devil's amusement. Despite being rational people, the conversation was more muted on the way back..
farmerman
 
  1  
Reply Sun 17 Jul, 2016 12:03 pm
@izzythepush,
was alcohol involved?

Heres a balanced rock near Penn Stte U an its a party spot for geology dept dweebs.

https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTBw5V4-XmV3YG4cqDvJpp3WPnIDf8HINTN5vODcx9ZwApnfgiL
izzythepush
 
  1  
Reply Sun 17 Jul, 2016 12:23 pm
@farmerman,
No, rock musicians are well known for going on a four mile round trip for a glass of Ribena.
farmerman
 
  1  
Reply Sun 17 Jul, 2016 01:32 pm
@izzythepush,
Ribena? some sort of Britswill Ill wager a truppence
izzythepush
 
  1  
Reply Mon 18 Jul, 2016 02:56 am
@farmerman,
They now do it in strawberry. And apricot!
farmerman
 
  1  
Reply Mon 18 Jul, 2016 04:03 am
@izzythepush,
I looked it up. Fruity carbonated beverages are a no-no in my diet. Sugary Phiosphate carbonic acid solutions will rot teeth, bones, spike your glycemic index and cause ague among those particulrly prone to ague
izzythepush
 
  1  
Reply Mon 18 Jul, 2016 06:01 am
@farmerman,
It's not carbonated, it's a squash. Everything will bloody kill you anyway.
0 Replies
 
 

 
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