KPT's Earth thread

WARNING: SCIENCE CONTENT

Most sand is quartz from rocks that started as giant boulders in the mountains, which is pretty much what Keith said. Quartz is the most stable mineral at the Earth's surface, its molecules are hard to break apart under surface conditions. So everything else included in the mountains (like feldspars or other minerals) tends to be broken down much faster as it is first eroded from the parent rock then eventually bounced down a river.

Geologists use three major ways to classify sands and sandstones: grain size, rounding, and sorting. Grain size is influenced by how much a grain of sand has been tumbled around and broken apart, so the smaller a grain is generally the farther it is from its parent rock. Rounding is also influenced by the distance from the parent rock: the less angular or more rounded a grain is, the more it has been bounced along and the corners polished off or rounded, so the farther it has traveled from its parent rock, generally. And sorting is also influenced by distance traveled from the parent rock. Sorting refers to the deviation from mean grain size. So basically, more consistently sized grains (better sorted) have traveled farther. This is influenced by how fast a river flows. As a river flows out of the mountains it runs quickly, of course. When it reaches a flat area (i.e. plains at the foot of the mountains) it slows down. That means the water isn't flowing fast enough to carry larger grains so the larger grains fall out of suspension and are deposited on the river bed. This creates an alluvial fan. As it reaches a delta the water tends to spread out, meaning the same water is flowing under the same pressure over a larger area, so again the flow rate slows and larger grains are dropped. Perpetuate this process through dozens or more changes in river flow rate from the top of the mountains to the ocean and you can see how it works. The finest grains, clay and silt, remain in suspension far out to sea, and are deposited as shale in ocean basins.

So if you are standing on a river bank in the mountains, you should see relatively large, angular rocks or sand grains that are of various sizes. They are all broken down from the rocks farther up in the mountains. The closer you get to the coast, the smaller, less angular, and better sorted they become. And of course the variety of grains is influenced by the original variety of minerals in the parent rocks. That's why there are beaches with black sand in Hawaii, where the parent rock is dark volcanic rocks, and white beaches in the Caribbean, where the parent rock is ancient carbonates like limestone.

There are standards set for each of these parameters, and to make our lives a lot easier, we have grain size cards to help guide us in classifying sands and sandstones:

OK. Hope that wasn't too much science for you. Sorry, I'm a nerd.

 

But I didn't even discuss eolian deposits!!

 

http://news.yahoo.com/nd-becomes-nations-second-leading-oil-producer-201729370--finance.html

BISMARCK, N.D. (AP) — North Dakota has passed Alaska to become the second-leading oil-producing state in the nation, trailing only Texas, state officials said Tuesday.
North Dakota oil drillers pumped 17.8 million barrels in March, with a daily average of 575,490 barrels, Assistant State Mineral Resources Director Bruce Hicks said. That compares with 17.5 million barrels in Alaska, though still far behind Texas.

 

Saw this yesterday. And WOOT! NoDak moving up in the world.

 

And ND still has a state sales tax and a state income tax. Makes you wonder where all the money is going.

 

the oilsands produce aboot 1.6 million barrels per day... just saying.

 

no, that's just the oilsands. that also doesn't include the the crude oil produced in Alberta.

 

if you want to talk oil reserves, we have 9 times more than you.

 

don't be

 

Dunno, they sure aren't using it to fix the roads.

 

On this day in 1980, Mt St. Helens went "BOOM."

 

Canada taxes gas to the max. Some of our states tax it pretty high as well.

We will be passing through Canada from MI to NY State this summer. I think I can make it without a gas up in Canada,

 

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