EGU Blogs

Geology Photo of the Week #7 – Oct 7-13

Sorry this post is a bit late…the Thanksgiving holiday was Monday, class this morning and then hockey! Anyway,  for the 7th edition of Photo of the Week we travel to the Pancake Rocks, in Punakaiki on the west coast of New Zealand’s South Island. I was there in 2011 for a conference in Wellington and went travelling around afterwards.  One of my stops was here. The Pancake Rocks are made of 30 million year old limestone that is very finely laminated. The daily pounding of the surf has led to the amazing convoluted structures in the picture. As to the formation of the Pancake Rocks themselves I cannot find a definitive answer…some sources claim that they are interbedded lime mud and coarser material. Others state that they contain stylolites. Unfortunately, I don’t remember from my own visit which is the case…although I feel like I would remember if it were stylolites so I am inclined to believe the bedding view. Plus the beds seem too regularly spaced for stylolites.  Does anyone else have a definitive answer?

Thanks for reading and let me know which hypothesis you support for the formation of the bedding.



Matt Herod is a Ph.D Candidate in the Department of Earth Sciences at the University of Ottawa in Ontario, Canada. His research focuses on the geochemistry of iodine and the radioactive isotope iodine-129. His work involves characterizing the cycle and sources of 129I in the Canadian Arctic and applying this to long term radioactive waste disposal and the effect of Fukushima fallout. His project includes field work and lab work at the André E. Lalonde 3MV AMS Laboratory. Matt blogs about any topic in geology that interests him, and attempts to make these topics understandable to everyone. Tweets as @GeoHerod.