paleonet odd ?microbial fossils

["James Farlow" <farlow@xxxxxxxx>]

For several years I have been coordinating study of fossils from the
Pipe Creek Sinkhole site, an earliest Pliocene (latest Hemphillian)
buried sinkhole deposit in Grant County, Indiana.  We have found
thousands of plant and animal fossils from this unconsolidated deposti
(cf. Farlow et al., 2001, American Midland Naturalist 145: 367-278;
Martin et al., 2002, Journal of Vertebrate Palentology 22: 137-151).

Recently we've been looking at the preservation of vertebrate bone from
this site.  There is little or no filling of pore spaces in the bone,
and the inorganic portion of the bone is only slightly modified
chemically from Recent bone.

In some of our thin sections of the bone, however, we see abundant
hemispherical (often paired) whatzits (to use a technical term) about 80
microns in diameter attached to the bone.  These objects are
mineralized.

I've wondered if these might be mineralized remnants of microbial
colonies.  Is there anybody on this list who knows about such things,
and would be willing to look at SEM images thereof, and offer an opinion
as to their identity?

James O. Farlow
Professor of Geology
Indiana-Purdue University Fort Wayne