Grain size distribution and depositional processes of the mineral component of abyssal sediments: Lessons from the North Pacific

Grain size analyses of the mineral component of abyssal Pacific surface sediments show two distinctly different size distributions that can be associated with sediments that are dominantly eolian and dominantly hemipelagic, respectively. In the range of 1 to 30 µm, eolian grains show a distinct size mode at about 2 µm (9Φ) and little material coarser than about 16 µm (6Φ). Hemipelagic grains are characterized by a much flatter size distribution that has a broad size mode near 2 µm (9Φ) and important amounts of material coarser than 16 µm (6Φ). This ability to distinguish between hemipelagic and eolian grains will obviate some long‐standing concerns in the interpretation of deep‐sea sediments. Examples of the utility of this technique are given for the North Pacific and South Atlantic.