Much of the abyssal North Pacific is blanketed by very slowly accumulating, fine-grained pelagic clay that is dominantly eolian in origin (Fig. 1). The clays are unfossiliferous, except for microscopic fish debris, and are enriched in hydrogenous sedimentary components such as manganese nodules and zeolites (Goldberg and Arrhenius, 1958; El Wakeel and Riley, 1961; Horn and others, 1970). The general character of the pelagic clay province has been known since the Challenger Expedition of 1872 to 1876 (Tizzard and others, 1885) when it was first sampled. Subsequent studies have shown that the region extends across the deep eastern and central North Pacific basin and that a second area of pelagic clay deposition in the western North Pacificlies west of the Hawaiian and Emperor Seamount chains. Because the two regions form a single sedimentary province controlled by similar sedimentary processes, the entire region will be considered in this review.
Figures & Tables
This new synthesis includes a section on plate kinematics, documenting the basis for a new interpretation of the magnetic anomaly patterns. It also includes: six chapters on various aspects of tectonics, petrologic characteristics, and hydrothermal processes of active ridges from the Galapagos Rift to the Juan de Fuca Ridge; a section on mid-plate volcanism, including the Hawaii-Emperor chain; five chapters on various aspects of northeastern Pacific sedimentary regimes; and nine chapters on the geology of the Pacific continental margin from the Aleutians to Guatemala, seen from the perspective of marine geology. Three separate oversize plates illustrate the bathymetry of the northeast Pacific; two more on the same base show distribution of sediment samples and types and magnetic anomaly data and tectonic interpretations; and others include a synthesis of the geology and bathymetry of the Hawaiian Islands, details of bathymetry along parts of the East Pacific Rise, and a major seismic profile across the Pacific margin of Guatemala.