Publications

The Giant Foresets Formation is located on Taranaki basin, New Zealand. The depositional environment is deep water setting, which turbidite system is preserved along the submarine channel. The focus of this paper is the canyons which represent the primary conduits for sediments to travel from shelf to basin floor. Numerous canyons are observed and can be grouped into two types: type A canyons (oriented perpendicular to strike) and type B canyons (oriented parallel to strike). The seismic method for identifying and mapping the sand and shale in the canyons is AI inversion. It can be seen on cross plot data that acoustic impedances (AI) differentiate the sands and shales. To support the AI inversion result, other seismic attributes were used directly for interpretation. Typically, canyons oriented perpendicular to strike are characterized by sand prone turbidites deposited at the canyon base as indicated by high amplitude and inversion values associated with arcuate ribbon form patterns inferred to be channel fills. The typical slope of the canyon floor is ~1.7 degrees with maximum canyon width of ~2km and aspect ratio of ~9:1. Canyons oriented parallel to the strike of shelf progradation are characterized by the absence of high amplitude and inversion features at the canyon floor. The sinuous nature of the thalweg and the presence of a single vs. multiple inferred channel threads, nonetheless argues in favour of the presence of turbidites, albeit muddy. The slope of these canyon floors is ~0.7 degree, maximum canyon widths are ~2.2 km and aspect ratio is ~18:1. On the basis of the mud prone fill of these canyons, it is inferred that these canyons are not connected to shelfal fluvial systems.