Back to the Canyon (I know, I know, you're tired of it) for a little tour and tangent.
But first, on the last post, I accidentally deep sixed a picture of an adult mountain lion (cougar, painter, panther, puma). Here is it, just for the record:
They are not considered a big cat (although, since they're fourth in line after tigers, lions and jaguars, I don't understand the logic. But that would be me). However, they are far from small: the average length is 60-95 inches (including the tail). A tiger's average as the biggest big cat is 13 feet from snout to tail. Just to give a range of sizes. And at 5 feet to almost 8 feet, a mountain lion is a pretty intimidating animal to meet along a pathway (most of the time, since they're completely shy, you won't meet 'em. They don't like people at all. Can't imagine why!)
There have never been any cases around the Grand Canyon of a human being attacked by a mountain lion. They have a full time job keeping the Mule Deer and Elk under control (both are far more a cougar's cup of lap song).
Now, on we go to geology! And you've come to read this because you wanted to know all about the geology of the Grand Canyon, right?
Seriously, I think the thing that captivated me the most about Joseph Wood Krutch's book (Grand Canyon: Today and All Its Yesterdays) was the concept that, while either looking down from a looking down point or walking down (are you CRAZY?) or riding down into the canyon aboard a mule (more about those to follow), an individual is literally looking back at the geologic beginnings of our planet. Mr. Krutch's details have been corrected over the decades by more accurate dating methods, but the amazement only increases with those more accurate measurements.
Here's a pretty pic looking at the canyon (now, where did I stick that?) We're not looking all the way down to the bottom, but you get the general idea: there are a lot of horizontal layers (it's not a torte, but it reminds me of one...chocolate...ooops, I got distracted). Some of the layers are thick, some stick out as appearing more a solid rock layer than the layers around them, but there are a herd of layers or striae just waiting for us to look at.
I just noticed! There's snow in the picture! Cool!!!
Here is a less pretty picture, but it tells us a lot about the layers:
Much of the layering is sedimentary rock (sandstone, limestone (remember Kartchner Caverns?) are both sedimentary.
Some of the rock is metamorphic : they started out as one rock and were transformed by one or more methods, into another rock. So sandstone, for example, if subjected to heat and pressure, may metamorphose into quartzite. shale may transform into slate or schist, among other things (no giggling in the back - the word is shhhist). I'm saying "may" because it isn't a given that these changes will occur.
Igneous rocks are associated with volcanoes, but they can also be the product of a large "blob" of molten rock being forced to the surface, but not erupting
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