Provenance and Thermal-Burial Histories of Upper Jurassic Reservoir Sandstones, Terra Nova Field, Offshore Newfoundland: The Source-to-Sink Evolution of a North Atlantic Rift Basin

Abstract

The Jeanne d’Arc basin is located 300 km east of St. John’s, Newfoundland, and contains several of eastern Canada’s largest producing and prospective oil fields, including Terra Nova, Hebron, and the giant Hibernia field. The Jeanne d’Arc basin formed in response to protracted and episodic Mesozoic rifting that eventually resulted in the opening of the North Atlantic Ocean. Although the Grand Banks region of offshore Newfoundland has been the subject of exploration for over four decades, there are many unresolved questions about the provenance and thermal-burial histories of economically significant, rift-related Jurassic reservoir sandstones in the Jeanne d’Arc basin. The process-response relationships between rift flank exhumation and syn-rift basin subsidence in Grand Banks are also uncertain, but critical to understand the tectonic development of the Newfoundland-Iberia conjugate margins, which have been increasingly considered the products of magma-poor rifting.

We initiated new detrital zircon (U-Pb and Hf isotope) and apatite fission-track studies to test and develop new hypotheses for the source-to-sink evolution of the Jeanne d’Arc basin. Onshore studies focused on Ediacaran red-bed strata of the St. John’s area, eastern Avalon Peninsula, that were exhumed during Middle to Late Jurassic stretching and thinning episodes in the Grand Banks. Offshore studies focused on nine syn-rift sandstone samples of the Upper Jurassic Jeanne d’Arc Formation that were collected between 3262-3470 m deep from three wells in the Terra Nova field. Jeanne d’Arc Formation strata comprise a northward-thickening wedge of stacked channel sandstone, conglomerate, and shale, and represent part of an alluvial to braided fluvio-deltaic system that was established in response to the uplift of adjacent rift flanks in Atlantic Canada. Future studies will use detrital apatite and zircon thermochronometers in the Jeanne d’Arc Formation samples to constrain the thermal-burial history of the Terra Nova field. This multi-technique source-to-sink study will not only allow better prediction of characteristics of source, reservoir, and trap rocks at the basin scale, but also shed light on the history of the North Atlantic rift margin.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018