Wednesday, March 13, 2013

Richmond Beach

Saltwater Park in Richmond Beach is perched in a large divot (one of my favorite geomorphic terms) that apparently corresponds quite closely to a post-glacial delta on the shores of Lake Russell (or Lake Bretz?).

Steep glacial deltas are little more than well-organized piles of gravel which means that they often disappeared by the barge load in the 20th century to provide aggregate for a growing city.  The gravel mine explains the amphitheater- shaped divot and the barge-loading explains the beach.  Which might be easy to mistake for a spit of some sort if you didn't know the history - and didn't notice that it looks much more like a pile of gravel than a spit (for one thing, the backshore is much too high).


Richmond Beach is a great place to watch sunsets.  And I was here for a good one.

It's also a good place to watch trains.  While I was on the beach between here and Boeing Creek (previous post), a series of northbound trains passed, including two Sounders, the Empire Builder, and this coal train - which was probably on its way from southeastern Montana to a terminal near Vancouver, where the coal will be transferred to a ship going to Asia.  It will all be kilowatts and carbon dioxide in a couple of weeks. (For anyone interested in coal, a popular topic around here these days, there are more photos on my hshipman blog (selected for the word "coal", but they reflect my fascination with geology, trains, and the Wyoming landscape more than any particular position on the current environmental politics!)

And for geologists not interested in Pleistocene deltas, in Holocene beaches, or in the Anthropocene coal industry, I've included a picture of some real rocks - in this case bright red ones used to repair riprap along the railroad.  Those are Precambrian Belt Series rocks from western Montana and those are very, very old ripple marks from a billion year old shoreline (I included a similar photo from six miles north of here in a post five years ago:  Ripple Marks - June 2007).

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