Tuesday, March 10, 2009
OK, back by huge public demand . . . err of one. Palaeoporn 11 is back with mark-ups.
The photo is of a portion of an Anomalocaris appendage, and shows the typical preservation style of fossils in the Emu Bay Shale.
In the photo (click to enlarge) there are three segments (S) and two segment boundaries (SB) the segment boundary is doubled because the original appendage was roughly circular, and when you flatten a tube, you don't get the appendage boundary matching up when squashed.
The specimen has been re-crystallised during an episode of overthrusting. The surface of the fossil is normal calcite, but in the centre the calicite is in the a fibrous form (FC). The matrix where the fossil was, is smooth (M2), the normal matrix is M1.
There is no phosphatisation of muscle tissue, and so this is probably a moult. But that's another story . . .