Spatial distribution of surficial sediments in part of the Kingston basin of northeastern Lake Ontario, Canada

Abstract

The distribution of surficial sediments in the interisland area of northeastern Lake Ontario is characterized by a generally homogeneous composition of fine grained muds with some local exceptions at the gaps leading into Kingston basin and in parts of North Channel. This pattern reflects principally differing levels of wave energy from the exposed areas of outer Kingston basin and Upper and Lower gaps to the more protected interisland area. Additional processes responsible for the distribution are currents at the Upper and Lower gaps and local slumping. The observed deposition of surficial sediments in the northern Kingston basin shows generally good agreement with the wave base calculations employing wind speeds of 60 km·h-1. The study region consists of three sedimentary environments. Above the wave base related to winds of less than 60 km·h-1 continual erosion and transport of all grain sizes leads to a constant source of sediment to the deeper parts of the Kingston basin. Above the wave base related to infrequent strong winds of more than 60 km·h-1, episodic removal of the fine grain sizes leads to winnowing of the fines and their being transported into North Channel and Kingston Harbour while the sands are left in place. Below the wave base the sediments are undistributed. Thus, there is no proximal-distal differentiation outward from the coasts nor along the channels. The sediment is transported with currents moving through North Channel and Kingston Harbour with similarly low velocities across the entire section.