Palynology and Geochemistry of the Triassic-Middle Jurassic Interval in the Argo F-38 Well

Principal Investigator:

Dr. Andrew MacRae, Saint Mary’s University

Start Date:      November 2016

End Date:       

The Triassic-Early Jurassic rocks of offshore Nova Scotia represent the earliest phases of the opening of the Atlantic Ocean, and are some of the oldest rocks relevant to petroleum exploration in the offshore area. The 2011 Play Fairway Analysis hypothesized the existence of an Early Jurassic-age, oil-prone source rock in the deeper-water offshore. Formation of a source rock would relate to conditions in the narrow ocean that existed during these times, but the location and character of such a source rock are unknown due to lack of well penetrations in the deepest parts of the basin and a poor understanding of the ocean environment at the time these rocks were hypothetically being deposited. A more thorough study of the ancient environments around the edges of the basin, where there are well penetrations, will help understand what was happening in its center.

This study focuses on the best section through rocks of this age, located in the Argo F-38 well on the eastern Scotian Shelf. Due to the harsh environments at the time (desert landscape and salt basins), palynology (the study of fossil pollen, spores, and algae) is the only effective fossil technique for determining the age and past environment.  The main outcomes of this study are threefold:

A)      a detailed succession of fossil pollen, spores, and dinoflagellates from below, within, and above the salt-bearing interval, which can then be used to determine age and thus serve as calibration for other sites;

B)      measurements of the concentration of bromine within a succession of salt samples, which can reveal environmental variations during deposition of the salt basin; and

C)      integration with other information from the region to yield a model of the ocean and crustal motion history of the area (i.e. ancient oceanography and tectonics).

Study results will be employed by petroleum exploration companies and anyone interested in the early history of the Atlantic Ocean, including how the Scotian Margin relates to the adjacent Grand Banks of Newfoundland, the US East Coast, and West Africa.