[meteorite-list] Frequent Meteorwrong identified-pholad bivalve borings

From: E.J <jonee_at_meteoritecentral.com>
Date: Thu Apr 22 10:27:51 2004
Message-ID: <3FBB4518.9060302_at_epix.net>

Some of us have seen the recent "Gao-Gibeon(sic)" meteor-wrong auctions
and, from time-to-time we see these submitted for meteorite
identification. The holes are formed by "boring clams". Take a look at
the following link for a photo of their borrows in bedrock. It is easy
to see how a fragment of the rock, tumble-polished by wave action can
look so unworldly.

Elton


http://www.lakeneosho.org/TEMP9a.html

Here is a description submitted to Paleo List _at_ yahoogroups by Dr Norm King.

*I would like to share this with the membership.

Many of us know about boring clams from our Paleontology
studies. However, there may be some that had a few questions
like my dad asked.

Dad sent me the following questions after viewing the web page.

Never heard of a "rock boring clam"....
Dumb questions 1 2 3 ....
1 How large are they?
2 Do they produce HCL acid ?...
3 How do they bore ?
Maybe Dr. King should help me...
DAD

I referred the questions to Dr. Norm King and he sent him the following
response ... I found the reply interesting and informative. There
may be on the list who will find the following interesting also.

Barry

Dr. Kings reply to Dad's questions
__________

Well, the boring clams were only looking for a place to live
where no predators could get to them.

These particular types of Pholads (Family Pholadidae) bore
by mechanical abrasion. Members of other families use chemical
means. Some bore into wood, and are often called pile worms or
ship worms, causing a great deal of destruction to pilings in coastal
regions.

They begin as tiny swimming juveniles that settle onto a rock or
sediment or wood surface. As they grow they move farther into the
substrate, making a larger boring except for the aperture. The
aperture remains small--just large enough for them to stick their
siphon through. Since the body grows but the opening stays the
same size, they are trapped in their borings.

They pull in a current of water and filter out plankton. Most other
clams eat the same way, although a few have siphons (rubbery tubes)
that literally vacuum up food particles from the sea floor.

Cool, yes?
Norm
*
Received on Wed 19 Nov 2003 05:25:28 AM PST