Kinematics of Submarine Slope Failures in the Deepwater Taranaki Basin, New Zealand

Abstract

Mass transport deposits (MTDs) are formed by gravity driven processes whereby dominant transport direction is downslope. Here we use 2D seismic data from the deep water Taranaki Basin to describe two volumetrically extensive MTDs (MTD 1 and 2) that were emplaced within the Plio-Pleistocene succession. Key kinematic information, derived from the observed architectural relationships between the Aotea Seamount and MTD 2, suggest that this unit had a SW transport direction. This is in marked contrast to the NW transport direction derived for the underlying MTD 1. Given the geometry of these MTDs, we suggest that MTD 1 was triggered during the early stages of evolution of the Giant Foresets Formation when the system was prograding toward the north. On the other hand, the geometry of MTD 2 allowed us to infer that its headwall region was located toward the east (near the Northern Graben) in an area known to have been tectonically active at the time of deposition (c. 1.8 Ma to recent). These observations raise the likelihood of a tectonic trigger for MTD 2.