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GRAPTOLITE NET
is edited by
Piotr Mierzejewski, the Count of Calmont and Countess Maja A. Korwin-Kossakowska
since 2002
DISCOVERIES ON GRAPTOLITES BY X-RAY STUDIES
Merete Bjerreskov
Acta Palaeontologica Polonica 1978, 23, 4, 463-471
ABSTRACT (p. 461):

"The X-ray method has been used for analysing pyritized graptolites with the purpose of
finding traces of the unknown soft parts. The investigated material comprises mainly
Llandoverian graptolites from Bornholm, Denmark, which occur in dark grey shales and
frequently are pyritized. The graptolites are generally uniformly filled with pyrite
throughout the rhabdosomes. However, at a few horozons from the
cyphus Zone, pyrite
is observed specially concentrated in the distal part of the thecal tubes, both in
diplograptids and monograptids. In other specimens from the same horizon pyrite is
found in rounded concentrations just outside the thecal apertures.
  Continuous extraskeletal pyrite is rare, but is nevertheless found (preferably around
the distal parts of some
Retiolites rhabdosomes). The pyrite replacements within the
thecae and outside the thecal mouths have almost equal form and size throughout each
rhabdosome, and may have replaced decaying soft parts. However, with the present
material it has not been possible to clarify any exact structures". [
selected radiographs]
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Related pages:

Soft tissues in graptolites from Latvia
Review of claimed soft parts