This earthcache will take you to an area where Mother Nature
provided Twenty-one natural mineral springs.
The rocks you will be examining are named Monterey Formations.
This is a siliceous-rich shale that was deposited in California
during the Miocene (about 15 million years ago). The shale is
considered a biochemical sedimentary rock because of the high
organic content. Diatoms are single-celled plants that live in the
photic zone (upper 200 meters in the ocean). They are abundant in
this rock.
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The springs pick up their warmth, odors, flavors and mineral
characteristics from the rocks though which they percolate. One of
the springs is a constant 98 degrees. Another, which was capped off
early on, bore traces of arsenic. Some springs are salty, some
carbonated and most are sulfurous. The sulfur in the water is the
source of the rotten-egg odor which permeates the air, and the
water in the creek, in the area of the springs. The grottoes and
fonts of the springs are a source of confusion today. Each spring
seems to have a stone bathtub around it and the obvious conclusion
is that people in the 1800’s indulged in the waters, made their way
down the stone steps and bathed outdoors in these tubs. In reality,
each grotto is more like a fuzzy little architectural statement
marking an individual spring. Today the mineral springs have become
polluted by agricultural runoff from ranching operations above the
park.
This is a Beautiful, but Smelly area for you to enjoy. The above
coordinates will take you to a plaque in which you will need to
answer five questions and then walk to the grottoes and post a
picture of you at one of them.
1. What did the land that Alum Rock Park sits on use to be?
2. How many millions “of “years ago was that?
3. What caused the sedimentary rocks to form?
4. Alum Rock Park is on a fault. What kind of water features has
that created?
5. Name the minerals listed on the plaque.
Email the answers to me. Don’t post the answers in your log.
Post the picture with Your log.