Continental Margins from Viewpoint of Petroleum Geologist (Keynote Address): ABSTRACT

Abstract

Major features of earth's surface are its continents and its ocean basins--which in turn reflect fundamental differences between continental and oceanic crusts. The broad zone of separation, or junction, between continental and oceanic domains has been called continental margin. It particularly includes seaward part of continental shelf, continental slope, and landward part of continental rise. Many of most exciting events in history of our planet have been concerned with interplay between continental and oceanic crust and between continents and oceans; and continental margin represents stage where, throughout earth history, this drama has been played. Important elements of continental margin are outer shelf, borderlands, marginal plateaus, slope, base of slope, rise, and marginal trenches. The origin of these features and nature of their sediments and local structures are essence of geology. Of particular interest to petroleum geologist are also sediment-rich semi-enclosed basins or seas associated world-wide with continental margin, barrier ridges and reefs so commonly developed near rim of continental slope, and growing evidence for impressive vertical movements of basin floors. Great advances in our understanding of processes active at continental margins have come from subsea geological and geophysical studies of last decades, and rapid additional progress may be expected from stimulus of the new global tectonics; but current hypotheses are still largely in a developmental stage. Factual data are still woefully inadequate. Moreover, continuing studies are needed, not only of present continental margins but also of past continental margins. For petroleum geologist, it is significant that through ages continental margin has been great mixing bowl in which has been brewed bulk of world's petroleum and from which bulk of its petroleum production to date has been derived. The continental margin should be fruitful meeting ground of petroleum geologist, geologist of oceans, and student of earth history. End_of_Article - Last_Page 722------------