Abstract
Deep-water channel morphologies, stratigraphy, and population densities in relation to stacking trajectories and climate states remain poorly constrained, and are highlighted by a sampling of 142 submarine channels. From the perspective of channel kinematics, turbidite channels exhibit tripartite lateral - random - vertical trajectories or unidirectional channel-complex trajectories, whereas contourite channels display oblique upslope trajectories. Turbidite channels tend to be deep and narrow and have two to three times more lateral migration than contourite channels, whereas contourite channels tend to be shallow and wide and have two to three times more vertical accretion. We relate such differences between channel morphology and stratigraphy to density contrast between flow and ambient fluid for contourite versus turbidite channels, which seems to have favored lateral channel migration in turbidite channels but channel thalweg deposition in contourite channels. Additionally, channels formed during a greenhouse climate state display low degrees of morphological and architectural variations, and are the minority in our global channel database (8% of total), although the Earth has been in a greenhouse state for 72% of the past 540 m.y. Icehouse channels, in contrast, exhibit high amplitudes of morphological and architectural variations and are the majority in the global channel family (92% of total), although the Earth has been in an icehouse state for 18% of the past 540 m.y. Such differences in channel-population densities between greenhouse and icehouse climates (8% versus 92%) suggest a weak global correlation of channel-population densities with warming greenhouse climates.
The effects of deep water cycling on planetary thermal evolution