Long-distance correlation of spillover turbidites on the western levee of the Northwest Atlantic Mid-Ocean Channel (NAMOC), Labrador Sea

Abstract

Long-distance layer-by-layer correlation of turbidite sequences is the ultimate means to reveal the full-scale geometry of individual turbidites, which in turn is a prerequisite to assess depositional gradients (grain size, flow regimes) and sediment volumes transported by individual flow events. From previous successful long-distance (> 100 km) correlations (Grossheim and Vassojevich 1960; Hesse 1974, Ch. 46; Ricci-Lucchi and Valmori 1980; Pilkey 1987, 1988) it seemed that turbidites which are continuous for very long distances are found only in environments with a relatively simple, sheet-like geometry of the deposits, such as basin plains. In this chapter, the natural levee of a modern mid-ocean channel is added to the environments with long-distance continuous layers. Evidence for the correlation of levee turbidites is presented here in the form of a photocollage of X-radiographs (Fig. 40.1) from 11 piston and trigger-weight cores (twc) spaced up to 300 km apart on the western levee of the Northwest Atlantic Mid-Ocean Channel (NAMOC) of the Labrador Sea. The layer-by-layer correlation of thin-bedded turbidites can be demonstrated by visual inspection of an interval elm thick in cores between 54°30′ and 57°30′N (Fig. 40.1).