Sunday 6 September 2020

Found in Ordovician Oxford Formation Rocks of Eastern Ontario

 This week I made two stops to look at the Oxford Formation outcrops on Iveson Drive, Ottawa (including the stop mentioned in my last blog posting) and picked up a number of loose specimens.

Below are photographs of a specimen showing three linked stromatolites.  The stromatolites are much smaller than the ones pictured in my last blog posting.  The specimen was found among the pieces of rubble in a  ditch beside Iveson Drive about ten meters west of the outcrop on the south side of Iveson Drive.  The silver ruler is 6 inches (15.2 cm) long.


Below is a photograph of a specimen showing soft sediment deformation, likely a precursor to a ball-and-pillow structure.  (The numbers on the ruler are in centimeters.)


 

Below is a photograph of a specimen of oolitic packstone. (The  numbers on the ruler record centimeters.)


Below are two photographs of various specimens containing trace fossils, most of which appear to be bedding parallel burrows or resting traces.



Below is a photograph  of a slab bearing a linear trace with dimples adjacent the linear trace, which is arguably the trace fossil Protichnites Owen, 1852.


 

For the  photo the top numbers record inches, while the upside down number record centimeters.

Mud cracks were also noted on a few specimens, and syneresis  cracks (also known as subaqueous shrinkage cracks) on others.


Christopher Brett
Ottawa



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