Autobiography: A 50-Year Quest for Understanding in Geoscience

Abstract

Readers will be led down a random path from continental dynamics to paleoclimate. A key to understanding continental dynamics is recognizing that differences in gravitational potential energy per unit area between high and low terrain govern much of large-scale continental deformation. Removal of mantle lithosphere, not just crustal thickening, plays a crucial, but difficult-to-test, role in changes in surface elevation. Although measuring past surface heights remains a challenge, indications of such processes suggest that surface uplift associated with such removal can affect relative plate motion. Climate change, from a warmer to cooler climate, and associated changes in erosion and sedimentation introduce further complications to determining past elevations. The phenomena that led to such cooling include a number of possibilities, but I favor the emergence of islands in the Maritime continent, which transformed the Pacific Ocean from one with a warm eastern tropical Pacific, as during El Niño events, to the present-day La Niña–like background state. Teleconnections from the eastern tropical Pacific to Canada affect the duration of summers and the potential of high-latitude ice to accumulate. ▪Lateral gradients in gravitational potential energy per unit area (GPE), a force per unit length, govern large-scale continental dynamics.▪Removal of mantle lithosphere and thickening of crust raise GPE; knowledge of mean surface elevations provides a test of these processes.▪Climate change from a warmer to cooler climate and from one with less to more erosion can give the false impression of elevation change.▪Emergence of Indonesian islands, more rain over them, a stronger Walker Circulation, and cooler eastern Pacific may have led to ice ages.