Influence of the Montagnais mass transport event in the Nova Scotia continental margin

Abstract

The Montagnais mass transport deposit was triggered by a meteorite impact that affected the paleo- shelf edge of the Nova Scotian margin ∼51Ma ago. The location of the impact crater and the extension of the associated mass transport deposit (MTD) (93,000 km2) has been documented by previous authors using two-dimensional seismic data and well information. In this work, we explore the nature of the interaction between the MTD architecture and younger strata that are thought to be linked to turbidite deposition. The upper boundary of the Montagnais MTD is represented by an irregular surface that defines mounded geometries in the slope region. Two-dimensional seismic lines clearly show onlapping of younger deposits against these “MTD mounds” and therefore we hypothesize that MTD distribution exerted important controls in the distribution of these younger facies. In addition, we evaluate the effects that this catastrophic mass transport event had in shaping the architecture of the southern Nova Scotia margin and how the geology of the outer-shelf region varies from south to north as the area of influence of the meteorite impact decreases. Preliminary observations suggests that the meteorite impact played an important role shaping the geometry of the southern Nova Scotia margin by generating extremely steep slopes and a cuspate geometry of the shelf-break in map view. Toward the north this cuspate geometry transitions into a more linear architecture and the shelf-break is dominated by listric and counter-regional faults. A comprehensive understanding of the geology of the entire eastern offshore Canadian margin is needed in order to contextualize recent discoveries in this region.

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015