Stress accumulation in the lithosphere

Abstract

It is shown that stress can accumulate in the lithosphere for 10 8–10 9 years. It is hypothesized that intraplate ruptures caused by tensional stresses are responsible for intraplate volcanism, seismicity, and tectonics. There are a number of mechanisms leading to the accumulation of stress in the lithosphere. Because the earth is an oblate spheroid, changes in latitude of the surface plates cause membrane stresses. Changes in temperature cause thermal stresses. Addition or removal of overburden generates stress. The driving mechanism for plate tectonics results in stress. And stresses are generated by changes in crustal thickness. Oceanic island chains such as the Hawaiian—Emperor are attributed to thermal stresses in the cooling, contracting oceanic lithosphere. Localized centers of continentalmargin volcanism in the central and south Atlantic are attributed to a combination of thermal stresses and stresses due to changes in crustal thickness. Continental volcanism such as in the East African Rift system is attributed to membrane stresses. It is concluded that tensional fracturing of the lithosphere is a more likely explanation for intraplate volcanism than deep mantle plumes.