Geology of the Ottawa Region with Dr. Wouter Bleeker, October 13,2018

October 21, 2018

It was a great way to spend a Saturday for the lucky group who joined Wouter on a tour around the Ottawa area.  We met at Starbucks in Kanata Centrum and nearby in the mall was our first stop.  Here we had an introduction to local sedimentary rock stratigraphy and looked at the Nepean Formation sandstone, of about 500 Ma, with a variety of features.  There are very interesting stromatolite fossils which are a little disorganized looking, perhaps they experienced some disturbance long ago, such as an earthquake or a hurricane. Also in this area are concretions in the sandstone, holes left behind as crystals dissolved away.

Second stop was the Clark Quarry in Stittsville where we donned hard hats and wandered around looking for fossils while being awed by the towering layers of limestone (about 450 Ma) and observing a cross section of a major fault system. Dr. Bleeker is studying this system and attempting to determine the time the faults occurred.  Also found there are two bentonite layers in the limestone.  These are ash layers from an ancient volcano which was located somewhere in the Carolinas. The eruptions were about 2 million years apart!

Next we crossed the Ottawa River and made our way to Parc Lac Beauchamp in Gatineau where one can clearly see the unconformity between the basement rock of about 1.2 billion years old (which has been tilted, uplifted and eroded) and the sandstone layer.  Between the two layers are 100s of millions of years missing!  Nearby we also found excellent examples of glacial striations and chatter marks.

Last stop was the Champlain Lookout where the Eardley Fault brought the ancient Grenville basement layers up to overlook the much younger sandstones and limestones of the Ottawa Valley below.

We are very much looking forward to continuing the story next year with Wouter.

Introducing the Nepean Sandstone

Concretions

Stromatolites

At the Clark Quarry

Fossil Coral

Examining a Bentonite Layer

Bentonite

Fault

Unconformity in Parc Lac Beauchamp

Chatter Marks. They line up N-S so could help you find your way.

View from the Champlain Lookout