A New Hypothesis for Earth Lithosphere Evolution

James G. A.Croll
University College London, London, United Kingdom

The past 50 years has seen a profound shift in the modelling of the processes thought to have shaped the continental and oceanic crust of our planet. There are however, increasingly acknowledged problems with the Plate Tectonic PT model.
This paper will briefly summarise what appear to be some of PT's more substantial areas of weakness. It will argue that massive and periodic changes from a dominance of tension to a dominance of compression forces within the crust are required to explain many important physical characteristics of the lithosphere. The new hypothesis for the origins of these cyclic variations of in-plane compression and tension is based on the immense changes in thermal regime that accompany the long term variations in the Earth's orbit around the sun and the relationships between its axis of spin and the orbital plane. The consequential alternations in levels of solar radiation reaching, changes in surface water and ice and their effects on solar reflection and thermal insulation to geothermal energy flux, can combine to produce massive temporal and spatial changes in the thermal regimes within the lithosphere. Restraint of the expansions when the crust warms, will induce massive compressive forces. During the cooling cycles these same restraints act to induce a dominantly tension field. This cycle of thermal loading will be suggested to act like a form of pump driving the many processes imperfectly accounted for by PT. But importantly, this new hypothesis will be demonstrated to resolve the many paradoxes of PT.

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