ABSTRACT

Silt sized quartz can be chemically separated from deep-sea sediments, by dissolution of other minerals, without altering its particle size. The extracted quartz can then be used for particle size analysis. The resulting polymodal size frequency distributions can be resolved into their individual modal components by means of an analog curve resolver.

The method has been applied to three rather different sets of samples to assess its value in interpreting the origin and dispersion of quartz in the deep-sea: samples from Astoria Fan reveal the textural character of fine-grained quartz supplied by the Columbia River; two pairs of samples straddling the Mendocino Escarpment show that this major deep-sea topographic barrier has suprisingly little effect on the textural character of fine-grained detrital quartz; and, the technique reveals systematic temporal variations in the size distribution of quartz in a northeast Pacific core near the southern end of the Gorda Ridge spanning the last 30,000 years.