Rocks In My Head

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10/21/14
fall day, pleasant customer, resuming my reading of Minnesota geology

The day was windy, but sunny.  I had a customer to my shop.  He was considerate and called ahead.  A pleasant visit.  In the fall and winter, rock shop customers tend to be of the online variety.  I picked up my book Minnesota's Geology by W. Ojakangas and Charles L. Matsch once again.  I left off reading about Wisconsin glaciation, which was the last of the glacial periods and began around 75,000 years ago.  Skimming the material, I felt I didn't understand its intricacies well enough (yet) to blog about it.  

 Last week I was called dumb as a rock in one of my Facebook groups.  Or maybe it was more than a week ago.  It was a disagreement over nomenclature.  When someone is that blunt, I question myself.  Am I really dumb as rock?  I revisited my birthstone videos.  Yes, I could have googled that material and put them together.  But that's not what happened.  I carry around in my head a lot of facts and ideas.  I didn't regurgitate them from a questionable website. Even someone who uses Wikipedia as a primary source has to have some knowledge or interest, to even know where to begin.  The quality of those videos is better than I remember them. 


Posted by oh5/ojhoff at 6:00 PM CDT
Updated: 10/21/14 6:27 PM CDT
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10/06/14
rock customers from Hell

There is a cultural difference between northeastern and northwestern Minnesota.  Since it’s not consistent, some may deny it exists.  I am referring to regions known informally as the valley and the range.  My maternal grandmother was from the Red River valley and I understand that mentality better.

 

I have observed that people in charge of something…parking, what door to enter, etc….out by the river will tell you when you are breaking the rules,  with discomfort and reluctance, and sometimes they will just let it go.  People on the range are quite comfortable with enforcing rules.  They can be quite vociferous about it, even when it’s not a matter under their direct jurisdiction.

 

I remember going to a family reunion with my parents (both gone now) and we stopped into a cafe in Ada, Minnesota.  My dad was worried because it was Sunday and no gas stations were open.  We were almost out of gas.  Somebody said there was a station open in Twin Valley if we could get there before it closed.  A man in the cafe said, with a slight Norwegian accent, “You can always go out in the parking lot and siphon a little”.  It was a joke.  Both he and my dad understood that.  You might not want to say that in an eastern Minnesota town.  There might be someone at the next table who overhears the conversation and reports you for stealing gas.  They believe in law and order.

 

My brother was driving around an iron range town on a Sunday afternoon.  Nobody was on the streets.  The whole town was at the park for an arts festival.  He happened to go a couple of blocks in the wrong direction on a one way street.  An old lady outside her house screamed frantically, “You’re going the wrong way!”

 

It has been a couple of days since I had the rock customers from Hell at my place.  The man was drunk and he and his wife were crazy and unreasonable, and not very good examples of anything except drunk and crazy.  But I did detect a tinge of eastern Minnesota in their behavior.  I’ve run into it before.  Usually the people come to their senses and we part with a handshake and a semblance of friendship.

 

The man said I was guilty of false advertising because my website showed items I didn’t have in my shop.  Actually, I did have the items or reasonable facsimiles…tucked here and there in boxes and corners in various buildings on the property.  When people treat me right, I invite them in the house, offer a cup of coffee or hot chocolate, and search for an item that might please them.  Sometimes I come up with something even better than they anticipated.  I’ve shown people how to saw rocks, or grind them.  i send people out to my shop to serve themselves.  Sometimes I find money on the counter and I don’t know where it came from.

 

In case those people are reading this, I’d like them to know that even big box stores have different merchandise on their website.  The local community center bought  pro basketball equipment from Walmart.  It had to be ordered.  It wasn’t available in the store.  And it’s silly to accuse a small, struggling, micro mini hole-in-the-wall business of false advertising.  You save that for a car manufacturer or a pharmaceutical company, some big outfit with a CEO who makes a zillion dollars a year.  

 

Most people from eastern or western Minnesota are fine folks.  They just have, in some instances, different ways.  In my years doing craft fairs, I sold a total of two items to obviously intoxicated customers.  Both were items that said “velkommen” on them, Norwegian for welcome.  Both customers were friendly drunks.

 


Posted by oh5/ojhoff at 9:24 AM CDT
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06/27/14

I really would appreciate if anyone reading this would take a look at my ebay listings.  My ebay name is ojhoff218

www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 8:26 AM CDT
Updated: 06/27/14 8:27 AM CDT
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05/12/14
older glaciation

 

Older glaciations in Minnesota either eroded away or are buried under later deposits.  It is hard to figure out what happened but a few conclusions have been drawn.  One is that the ice must have been very thick (at least a thousand meters).  Another is that, based on the number of wind-polished and faceted stone surfaces, dust bowl conditions worse than those of the 1930's once took place.

 Limestone and shale deposits from the Cretaceous lie under the younger drifts.  Some contain plant fragments carbon-dated to 40,000 years ago.  In some cases the sands and soils were subjected to intense chemical weathering so that even the toughest rocks became soft clay.  How long this takes to happen is debatable. 


Posted by oh5/ojhoff at 11:38 AM CDT
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04/04/14
More on Glaciers
I continue to read about glaciers in the Minnesota geology book.  The Laurentide Ice Sheet covered all of Minnesota except, perhaps, a small area in the southeast.  Tongues of ice extended into other states.  The center of the sheet was Hudson Bay.  It is possible to reconstruct the flow of glaciers by measuring the direction of striations and grooves and by tracking erratics back to their bedrocks.  Two troughs directed the course of ice streams from the glacier:  the Superior-Minneapolis and the Red River and Minnesota River.  These were straddled by higher, more erosion resistant rock types.  The troughs, on the other hand, were made up of more erodable materials.  Ice bulges developed at the perimeter and it's possible to study the advances and retreats of glaciers by studying the kinds of till left behind.  (There were also earlier glacial periods).  I think the Laurentide Ice Sheet deserves an in-depth study of its own.

Posted by oh5/ojhoff at 11:05 AM CDT
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03/25/14

 Since I was blogging about Minnesota geology and glaciers, I thought it might be appropriate to link to the website of my uncle the glaciologist.  His site has some amazing, and alarming, information that we all ought to be aware of.  In particular, this statement:  " The statement “glaciers are sensitive to the climate” was made countless times in published articles and the presentations we made throughout the 1960s-1970s, but little did we know just how sensitive they were. The now impending demise of many of them suggests glaciers are much more sensitive to the earth’s climate than are humans. We should have heeded their warning signals long ago. "

 

www.hymet.com


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 8:17 PM CDT
Updated: 03/25/14 8:27 PM CDT
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03/17/14

www.oliviahoff.com   

I was blogging about Minnesota geology (the glacier ages), but I also want to remind any readers, if there are readers of my blog, that I do have an ebay store. My ebay name is ojhoff218

Posted by oh5/ojhoff at 5:09 PM CDT
Updated: 03/17/14 5:12 PM CDT
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02/19/14
glacial theory

The glacial theory was first proposed by Swiss naturalist and teacher Louis Agassiz in 1837.  His idea that the earth had experienced very cold climates and an expansion of glacial ice explained erratic boulders and striated bedrock across Europe.  He came to the U.S. to teach at Harvard and found further evidence for his theories.  Earlier conclusions about the distribution of boulders attributed the phenomenon to the great flood.  A detailed reading of glaciation in Minnesota was started by N.H. Winchell, head of the newly created Minnesota Geological Survey, in 1872.  He was assisted by New England glacial geologist  Warren Upham.  Within 10 years they had completed a great deal of fieldwork mapping moraines and presenting an accurate view of the ice border in North America.  


Posted by oh5/ojhoff at 9:23 PM CST
Updated: 02/19/14 9:25 PM CST
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02/15/14
More About Glaciers

 

 

Glaciers shape the landscape by means of erosion, which manifests itself as abrasion and deposition.  Ice loaded with rocks and minerals slides along like coarse sandpaper.  Evidence on bedrock outcrops appear as scratches, or striations.  On a large scale the process is called quarrying or plucking.  Often tapered,  blunt nosed hills called whalebacks are formed.  Another result is the excavation of basins which become lakes.  Terms associated with deposition are till (unsorted debris), moraines (distinctive landforms), drumlins (streamlined hills with long axes parallel to the ice flow), kames (conical hills), and kettles (collapse pits formed when buried ice melts).  Belts of lakes also mark the extent of former glaciers.  


 


Posted by oh5/ojhoff at 7:21 PM CST
Updated: 02/15/14 7:51 PM CST
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01/09/14
glaciation

 It's one of those long winter nights when Minnesotans ought to catch up on projects.  One of mine, long neglected, is blogging about MN geological history.  I couldn't remember where I left off so I looked it up.  I found the last topic I covered was the Cenozoic which brings us up to the Quaternary, 2 million years ago to the present.

 It's interesting.  The first few paragraphs describe erratics but do not mention them by name.  It talks about a 20 ton fine grained green-gray rock different than the pink granite bedrock upon which it rests on the floodplain of the Chippewa River.  Near the quartzite bedrock of Rock County are large granite fragments the Indians called the Three Maidens.  In Dakota County a granite boulder was honored by a continuous wash of red ochre, probably because it was obviously different than the bedrock.  This was long before European settlement.  These rocks were all carried by glaciers.  They are called erratics, which was the subject of my acrylic painting (of Finnish erratics) of which I am so proud to say was purchased by an employee of the Guggenheim and is displayed in her private gallery.

  

www.oliviahoff.com 

 

 


 

 


Posted by oh5/ojhoff at 1:09 PM CST
Updated: 01/09/14 6:38 PM CST
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10/20/13
neglect, ebay, etc.
Yes I neglect this blog.  I also neglect my website.  Today I took tentative steps to set up a site, not a mirror site but an adjunct, that is more smart device friendly.  I'll keep this one as well.  Also, I sell on ebay.  Take a look at ojhoff218

Posted by oh5/ojhoff at 1:08 PM CDT
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09/30/13
stromatolite
One of the more interesting rock formations I sell in my shop is stromatolite, aka algae jasper.  A very popular source is the Mary Ellen mine, now underwater.  This past summer a customer took photos of the mine pit and and sent them to me.  I told him what I knew, that my family signed waivers to collect specimens so many years ago.  He happens to have the same surname as our MN U.S. senator and there IS a family connection.  Smile

 


 

 


Posted by oh5/ojhoff at 11:01 AM CDT
Updated: 09/30/13 2:08 PM CDT
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07/17/13
Gathering my thoughts.....
It has been ages since I posted here.  So much has happened.  I don't think I've ever mentioned that I am now selling Thunder Bay amethyst.  I sold a few small jewelry making samples on Ebay and one of my customers said they had gold and copper flecks all through them.  I've never seen the flecks but I researched the subject and it's a possiblity.  Other metals that might be present are silver, platinum, nickel, chalcopyrite, and bismuth.


 


Posted by oh5/ojhoff at 1:20 PM CDT
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03/12/13
Erratics

My reading in the subject area of rocks, minerals, and gems has been, for nearly a year, in the area of birthstones.  It's a subject that says a lot about human history.  But to my way of thinking is somewhat less interesting than geology.  So I have gone back to studying the book Minnesota's Geology by Richard W. Ojakangas and Charles L. Matsch.  The subject is glaciation.  Many terms describe what was left behind when glaciers moved across Minnesota during the Quaternary (2 million years ago to the present).  One interesting term is erratics.  These stones can be any size from a boulder to a pebble.  They were transported from one area to another by the movement of glaciers.  They differ from the local bedrock in color and composition, sometimes so radically they have been mistaken for meteors.  I take an interest in these because the glaciers dragged in so much material to this local area.  Also, I who am not a seasoned artist sold a painting of Finnish erratics to an employee of the Guggenheim, which was a thrill and honor.  Since then I've read about erratics at length.  Technically, if a rock was moved due to human activity, it's an erratic.  By that definition, rockhounds have created a lot of these!

 


Posted by oh5/ojhoff at 11:51 AM CDT
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02/18/13

 


 

 

 

Topaz Prayer


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 3:31 PM CST
Updated: 02/18/13 3:33 PM CST
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Tourmaline in a Tailspin


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 3:26 PM CST
Updated: 02/18/13 3:27 PM CST
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01/27/13
opal


 

 

Grandpa’s Opal


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 2:44 PM CST
Updated: 02/17/13 5:43 PM CST
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01/22/13

 

 


 

 

Lapis Lazuli


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 7:32 PM CST
Updated: 02/17/13 5:42 PM CST
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Sapphire Blues


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 7:29 PM CST
Updated: 02/17/13 5:41 PM CST
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Sardonyx


www.oliviahoff.com 

 


 

 


Posted by oh5/ojhoff at 7:25 PM CST
Updated: 02/17/13 5:18 PM CST
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