OERA Webinar Series – Georgia Pe-Piper, Saint Mary’s University

January 10, 2019 – 1:00 – 2:00 pm AST
Georgia Pe-Piper, Department of Geology, Saint Mary’s University, Halifax, Nova Scotia
“The Search for Sand: Mountains, Rivers and Deltas 150 Million Years Ago”

Most oil and gas in the offshore Scotian Basin is trapped in deeply buried sandstones that accumulated 160–100 million years ago. These sandstones formed from sand transported by ancient rivers to large deltas on the Scotian Shelf. Understanding where these rivers were located in the ancient landscape and what sort of sand they carried to the sea helps to locate the sandstone reservoirs in which petroleum can accumulate. The types of minerals in the sands influence the porosity of the sandstone reservoirs.

We use sophisticated techniques to characterize minerals in sandstones of the Scotian Basin, using their chemical composition, measuring their age isotopically, and determining their cathodoluminescence properties. We compare these results with known rock sources on land, and thereby reconstruct the ancient courses of the rivers that drained into the Scotian Basin. In our recent project we reconstructed the river supply of sand to the southwestern part of the Scotian Basin, documenting the types and general abundance of sand in three of four segments of this part of the basin. The rivers that provided sand to the Scotian Basin reservoirs drained an area extending from the then mountains of central Labrador to the uplands of northern Maine.