geologictimepics

Geology and Geologic Time through Photographs

Archive for the month “September, 2014”

29 Sep 2014

Today’s hazards, yesterday’s hazards: Earthquake damage, ongoing rock fall, and basalt flow

The M 6.3 February, 2011 Earthquake in Christchurch, New Zealand caused more than considerable damage; 185 people lost their lives and estimates of damage now exceed $40 billion.  When I visited in January, 2014, there was still clear evidence of the destruction, such as this broken house teetering on the edge of a cliff face.  The cliff had apparently given way during the earthquake and taken the entire back yard with it.  Now, rock fall provides an ongoing hazard –hence the stacked shipping containers to keep it off the road.

And then there’s the lava flow –Miocene in age, filling an ancient river channel, as plain as day.  Some 10 or 11 million years ago, this lava flow probably burned everything in its path.

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photo downloaded from marlimillerphoto.com (type “New Zealand” into the search)

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27 Sep 2014

Glacially carved granite in Rocky Mountain National Park, Colorado

This landscape is so smooth and rounded that you can easily imagine the ice that must have covered it some 20,000 years ago.  And the ice must have been deep!  Look halfway up the mountain in the foreground on the left; it shows a distinct change of rock weathering akin to a bathtub ring–and the ring persists around much of the photo.  It likely marks the upper surface of the ice at maximum glaciation.

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Upper Glacier Gorge, a glacial cirque in Rocky Mountain National Park, Colorado.  View of the Spearhead (left) and McHenry’s Peak (just behind)

Like most landscapes, this one’s pretty young–and those glacial effects are even younger.  When compared to the age of the rock, it seems almost insignificant.  The granite bedrock, which is granite, is 1.4 billion years old!  Elsewhere in Rocky Mountain National Park, the granite intrudes even older metamorphic rock –1.7 billion years old.  Just .3 billion years older.  I think we forget that “just .3 billion years” is 300 million years –about the same length of time as the entire Paleozoic!  And the Pleistocene Epoch, during which the glaciers grew?  It started some 2 million and ended about 10,000 years ago

Granite sill intruding gneiss, Colorado.
1.4 billion year old granite intruding 1.7 billion year old gneiss in Rocky Mtn National Park.

images can be downloaded for free at marlimillerphoto.com

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24 Sep 2014

young and old, close and far

Here’s a photo of the Three Sisters Volcanoes in Oregon –looking northward.  The oldest volcano, North Sister, erupted more than 100,000 years ago and so is considered extinct.  Because no lava has erupted there in so long, erosion has cut deeply into the volcano.  By contrast, South Sister, the closest volcano on the left, most recently erupted only 2000 years ago and is much less eroded.

And then there are the stars –you can see the Big Dipper on the right side of the photo.  The closest star in the Big Dipper is some 68 light years away.

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You can see more photos of Oregon by typing the name “Oregon” into the search function on my website at http://www.marlimillerphoto.com/searchstart.html

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