Hydrocarbons in Deep Oceans: From a New Global Tectonic Perspective

Dong R.Choi
Raax Australia Pty Ltd, Higgins, Australia

A vast amount of hard evidence has accumulated for the continental nature of the “oceanic crust”; presenting the world deep oceans as one of the future frontiers for hydrocarbon exploration. Recent studies of world oceans based on dredgings, drillings, paleogeography, and seismic profiling and other geophysical data falsified all tenets of plate tectonics (spreading, subduction and linear magnetic anomaly). A newly emerging global tectonics invokes vertical block movement interacting with the upward-moving deep mantle materials as a primary cause of tectonic movement at the Earth's surface. The new geodynamic picture indicates that the “oceanic crust” underneath the basaltic layer consists of the Precambrian and Lower Paleozoic rocks which were locally altered, metamorphosed or oceanized. The present oceans were formed since the Jurassic to the Paleogene time; before that time, the wide area of the present oceans formed lands that had gone through a normal continental history. Published seismic profiles in the continental margins reveal the presence of a well-layered, basin-filling, relatively undisturbed unit in the upper part of the “oceanic crust”. This unit is considered to be equivalent to the Proterozoic to Lower Paleozoic sequences on continents which are in many places represented by shallow water carbonates. Several seismic profiles taken across the northern Mid-Atlantic Ridge show graben/rift structures as commonly seen on lands. The graben has thick sedimentary layers under the younger volcanic fills. A comprehensive analysis of regional geological and geophysical data suggests that this sedimentary unit is an older basin-filling sediment with its possible age of Mesozoic (Jurassic to Cretaceous?). The above facts, though fragmental, warrant further systematic, in-depth study of the deep oceans for hydrocarbon exploration and exploitation.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece