Oolitic sands form from accretion of crystals onto a grain of sand, or fecal pellet, or in saturated or super saturated liquids as the grain rolls around. Typically calcite or aragonite in tidal pools and flats. If my failing memory serves me they form in some places around the Great Salt Lake now and formed around the shores of Lake Bonneville. The hill behind (west) of the state park at Yuba has some marble sized examples. Bill B. On Mar 8, 2004, at 11:03 AM, Kim Hyatt wrote:
I've followed most of the comments regarding the spherules - they triggered a vague memory of something that I could only recently recall. I'm reminded of the spherules in oolitic limestone. They are the right size, just a millimeter or two, but my memory fails how they formed on earth. Can anyone with a geologic background respond?
-----Original Message----- From: Joe Bauman [mailto:bau@desnews.com] Sent: Monday, March 08, 2004 9:52 AM To: Utah Astronomy Subject: [Utah-astronomy] Annooyance, Part 2
Hi Friends, here's another closeup by Opportunity, one of the more recent views by the microscopic imager. You'll see this time and again in pictures of "blueberries": They are roughly symmetrical, with a sort of point at top and seams running down the sides. Sometimes they are elongated. You can see what I'm talking about a bit more clearly if you use your photo manipulation software to darken the image and increase contrast. Frequently these things are on stalks, possibly due to material weathering away under them but maybe the stalks are part of a growth cycle. Sometimes the stalks are quite dramatic. Anyway, I am not giving up on the idea that they could be strange lifeforms, that are difficult to recognize as life becuase they're so alien. The closest I can come to an Earth analogue is fungus, like mushrooms, or plants like succulents. Sometimes they remind me of primitive animal life like echinoderms (sand dollars are the remains of echinoderms). Here are views of living sand dollars.
http://www.seashells.org/identcatagories/naturalsand.htm
Anyway, take a glance at this interesting image from Opportunity:
http://marsrovers.jpl.nasa.gov/gallery/all/1/m/039/ 1M131648550EFF0544P2953M2 M1.JPG
Best wishes, Joe
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