Making mountains – drivers and consequences Professor Peter Cawood University of St. Andrews

Date: Thursday, 12 April 2012
Time: 7:30PM - 9:00PM
Type: Lecture

Professor Peter Cawood (St Andrews University)

JOINT CELEBRITY LECTURE

Mountains are one of the key manifestations that we live on a dynamic planet. They are driven by the movement of surface plates that are in turn a response to the Earth’s heat engine. Classic models of mountain building involve the collision of buoyant surface plates (e.g. Himalayas, Caledonides). Such models fail however, to explain those mountains that form in an environment of ongoing subduction of oceanic plates beneath continental plates (e.g. American cordilleras). The history of these two types of mountain ranges is linked: phases of mountain building along the periphery of continents are synchronous with, and driven by, phases of global supercontinent assembly. Such a temporal link may reflect the termination of subduction zones within the interior of the supercontinent during phases of continental assembly, which are compensated for by increased mountain building along the exterior of the supercontinent.

Recent work has discovered a previously unrecognized mountain belt that extends around North Atlantic that is particularly well preserved in Scotland. It developed on the margin of the supercontinent of Rodinia some 1000 to 700 million years ago and is termed the Valhalla Mountains. The belt formed through major clockwise rotation of the whole of Europe with respect to North America (which included Scotland). This motion created an ocean basin and subsequent plate movements along the edge of the basin resulted in the formation and deformation of the preserved rock units. The early history of the belt overlapped, and probably interacted with, the Grenville collisional belt, which was responsible for assembly of the Rodinian supercontinent. The Valhalla belt predates, but formed the basement to, the well-known Caledonian belt.