Beautiful Permian wood from Döhlen Basin
deutsche Version

Wood from Permian conifers, summarily named Dadoxylon for simplicity, is usually less interesting to fossil collectors since most often it does not show distinct features like the central pith or wide pith rays. Despite of the usually dull aspect, the interest may be aroused by secondary phenomena related to degradation and silicification, which may result in beautiful pictures.
Permian wood cell fills
Permian wood with pith
  Fig.2: Wood cut lengthwise with central pith above. [ 1 ]

 Fig.1: Cross-section, cells with chalzedony fills: bluish white, black,
or clear with shadows in the depth (left).  Figs.1,2: same scale, widths 2mm.

The aspect of the chalzedony seems to be very sensitve to tiny differences in the chemical composition of the compartment. Hence, the fill of neighbouring cells may be clear, white, or black as in Fig.1 or variously coloured as in Fig.2.
Permian wood hollow cells Permian wood with white spots

  Fig.4: Cells with yellow stained chalzedony, recrystallized as white spots 
     with rare "daisy aspect". Picture width 5mm.

 Fig.3: Wood well silicified except for the hole in every cell: unexplained rare phenomenon. Picture width 4mm.

Permian wood deformed and bleached 
Permian wood debris, no charcoal
   Fig.6: Wood disintegrated while soft, then silicified: no charcoal. Width 5mm.

 Fig.5: Wood with small cells, deformed, partially bleached. Width 5.5mm.

Arguably, Fig.5 may be considered the most beautiful of these pictures. The flame-like aspect is due to bleaching along the radial wood rays and to slight radial compression which caused the rays to kink irregularly. The bleaching by carbon oxidation was possibly caused by oxygen diffusion along the rays. This wood differs from the others by narrower cells, hard to see here as tiny dots in some places, better seen with the same sample in [ 2 ].

Finally, Fig.6 may be considered the most controversial of these pictures. This sample from the Wilmsdorf golf course has provided essential arguments so that prominent palaeobotanists (M. Barthel, Berlin, and R. Roessler, Chemnitz) had to admit that they were wrong with their favourite interpretation of black Permian wood as fossil charcoal [3-5]. Looking carefully reveals that the wood was soft while disintegrating: See [ 6 , 7 ].
Additional evidence contradicting the charcoal interpretation is offered by the smallest parts in Fig.6. Crushed charcoal would never yield tube-like fragments representing individual cells. These details indicate that the tissue had lost its coherence, apparently by prolonged submersion, so that the wood could easily disintgrate, producing fragments of any size and shape, among them separate cells.
Unrelated to the above problem but worth mentioning are several cavities in the polished face of Fig.6. They are due to dissolved calcite crystals which had grown in the wood or in plain chalzedony. One not yet dissolved white calcite crystal is seen below.

Samples: from Döhlen Basin near Dresden, Saxony; kept in the own collection.
Fig.1: Kc/14.1, found by Andrea Weiss at Kleincarsdorf in 1997;
Figs.2-6: W/42.1, W/48.1, W/95.1, W/35.1, W/55.3, found during the preparation of the golf area at Wilmsdorf in the early 90s;

H.-J. Weiss     2019

[1], Fossil Wood News 31
[2], Fossil Wood News 33
[3]  R. Noll, D. Uhl, S. Lausberg : Brandstrukturen an Kieselhölzern der Donnersberg Formation.
      Veröff. Mus. Naturkunde Chemnitz 26 (2003), 63-72.
[4]  R. Rössler : Der versteinerte Wald von Chemnitz. Museum f. Naturkunde Chemnitz, 2001, 179.
[5]  R. Noll, V. Wilde :  Conifers from the „Uplands“ – Petrified wood from Central Germany, 
       in: U. Dernbach, W.D. Tidwell : Secrets of Petrified Plants, D'ORO Publ., 2002, 88-103

[6], Fossil Wood News 9
[7], Fossil Wood News 35
quartz crystal with wood inside
Fossil Wood News  34

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