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Rocks In My Head

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Mood:  don't ask
Topic: geology et al
I've been reading an old book on the geology of Minnesota. Strange, I saw that book in Grandpa's bookcase for years but I don't recall opening it. I read most of the books in his private library, didn't I?

Today I pondered this moldy book and its fascinating concepts. Geologists use indirect clues to guess at the earth's age: the known rate of erosion and depositing said erosion into sedimentary rocks. The rate of radioactive decay. The fossils.

Although my knowledge of geology is sporadic and sparse, it is very real to me and not at all academic. Since my earliest childhood I have held in my hands rocks, fossils, crystals, dinosaur bone, ely greenstone, geodes that my elders used to make decorative objects and they took a great interest in the origins of these materials. I guess I never realized or valued this knowledge nor could I foresee the day that it would become so important to me.

But I have other interests. Writing. The farm. My part time secretarial job.

I'm thinking about writing a play. I can't afford to take the time; I should be writing the stories I can sell for the money to pay bills. But it's all related.

I have taken up painting as a hobby and I have created four complete failures. I don't mind that my paintings look like cartoons but it would be nice if the people looked like they are supposed to look, albeit cartoon-like.

Posted by oh5/ojhoff at 9:43 AM CDT
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up early
Mood:  not sure
Topic: geology et al
Rocks, stones, gems, minerals, fossils, crystals....there are so many terms and they each mean something slightly different. For example, people will ask me, "Are these agates?" Sometime it just depends on who you ask.

Rocks are what the earth's crust is made up of. Formations. Aggregate. This includes soil. Rocks are composed of minerals, specific chemical compounds or sometimes elements in crystalline form (usually).

So, what can be found in Minnesota? Quartz is common, Agates are a form of quartz and so is jasper. Then there are the oxides of iron, magnetite and hematite. Iron has been a very important mineral in the state. Limonite is abundant and used to make paint pigment (red and yellow ocher). Carbonates are formed from metal, carbon and oxygen, and in Minnesota include calcite, which makes up limestone (a rock), dolomite and siderite. Pyrite and gypsum are also common. Complex silicates (made from silica and oxygen, include feldspars, mica and garnet.

Granite, an igneous rock, is very common. So is gabbro. Sedimentary rocks found in Minnesota include conglomerates, some of which are very attractive. Also sandstone and shale.

The igneous and sedimentary rocks have metamorphized into slate, gneiss, schist, marble, quartzite and other common rocks. I just found a sample of garnet crystals in schist matrix in my collection. It's quite pretty.

I remember my grandfather pointing out to me some outcroppings in a field up by Blackduck. He said they were greenstone, and the remnants of the Killarney Mountains. Indeed, greenstone is the oldest rock in Minnesota and is classified as chlorite schist.

Posted by oh5/ojhoff at 5:31 AM CDT
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it's a good day
Mood:  energetic
Topic: geology et al
There is one aspect of the rock business that just occurred to me....a very distant memory. A few of the ladies branched out into shells and coral and they made shell jewelry. It was very popular. I don't imagine it would be now. They made pink roses out of little cup shells with gar fish scales dyed green for the leaves. The centers were yellow or black mustard seeds. They also made earrings out of seahorses and starfish.

I have often said, I am one of the few (although there are several thousand of us) who lives both east and west of the mighty Mississippi River. After it leaves the headwaters at Lake Itasca, it loops around. Springs on this farm feed into the Bungashing which feeds into the Mississippi. So I guess I am living in the Mississippi Watershed area. It is by far the largest drainage basin in Minnesota. There are a couple of othes, Rainy River and the rugged St. Louis River with its waterfalls and rock bluffs. The lakes in Minnesota were formed when the glaciers retreated and are left over from ancient glacial lakes such as Agassiz. Some of the lakes have filled in with peat.

I enjoy reviewing Minnesota's geological history now and then.

Posted by oh5/ojhoff at 11:04 AM CDT
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glaciation I guess
Mood:  quizzical
Topic: geology et al
Today I helped clean the lower level of the barn where rocks have been stored, and although I'll have to buy, hunt, or manufacture some things for variety, today I found a large enough cache to keep me busy all summer.

When I traveled with my grandparents as a kid, my grandfather used to decribe the lay of the land. He would say things like, "This all used to be ocean bottom". I discussed these subjects with him a lot but not enough. However, I can go back in time and revisit some of these subjects. I still have my grandfather's books, and his thoughts.

Minnesota topography might not seem very exciting but the lay of this land has been formed by the same geological forces as elsewhere: volcanism, diastrophism, and gradation. That is, the molten rocks that erupt on the surface because of great heat at the core of the earth, the warping and uplifting of the earth's crust due to stress, and the wearing down of the high places and filling in of the low places due to erosion. Minnesota is known for an even more dramatic geological process and that is glaciation. Glaciers gouged ridges in the bedrock and created rocky basins. They picked up everything from dust to boulders and deposited them in various formations. The last glacier retreated eleven thousand years ago.

I am trying to gather up all the science books and keep them in one place and hopefully to acquire more as new discoveries are made.

Here is a book review I wrote for a church newsletter:

by Timothy Ferris

This book was the text for an online cosmology course I took through Barnes and Noble University. It does require some concentration on the part of the reader, but the energy spent visualizing models of the universe, past and present, is well worth the effort.

Ferris premises this book on the Big Bang theory, which he feels is broad and pliant enough to endure. From that starting point, he explores not only a theoretical history of the universe, but also the human element, how people have viewed the cosmos from the days of the Greeks, on up through Copernicus, Newton, Kepler, Einstein, Hubble and beyond. The author provides a lucid description, and discussion, of mind-boggling concepts, from the view of a 10 dimensional, constantly expanding universe, to the idea that there are multiple universes, each with its own laws of physics.

There is something for everyone in this book, from historical and amusing personal anecdotes about scientists, to literary allusions, to the epilogue which asks the important question, “What about God?” The author feels that there is nothing in the universe that proves or disproves the existence of God. But in the end, he admits that the genesis is likely to remain a mystery.

The book was published in 1997. Discoveries have been made since then, and work done on refining the described theories. Still, this book is a good starting point for someone who wants to understand more about our universe.

Cleaning out the barn, I discovered that I am the owner of another book by this same author entitled "Coming of Age in the Milky Way". A good read for next winter.

I enjoy the metaphysical thoughts especially as they nowadays pertain to crystals and gems, but what would we do without science?

Posted by oh5/ojhoff at 7:28 PM CDT
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