Gerard de Geer - Global Expeditions, Teleconections, and Controversy

Global Expeditions, Teleconections, and Controversy

De Geer firmly believed the main control on varve sedimentation was solar radiation acting on glacier meltwater production, and that consequently, varved sediments represented a "..gigantic, natural self-registering thermograph" (De Geer 1926) and varve curves (varve thickness plotted against varve number or year), which he often referred to as 'solar curves', a reliable proxy for past changes in solar radiation. Ultimately, De Geer hoped his studies of varves would explain the fundamental cause of Ice Ages - "If the last glaciation everywhere should show to be synchronous and the origin of the last Ice Age thus to be of a general nature, the assumption of a cosmic cause would scarcely be avoidable."

In 1915 De Geer matched, or 'teleconnected', varve curves from Sweden to varve curves from Finland and Norway. This first attempt at long distance correlation marked the start of two decades travelling around the world by De Geer and his colleagues, searching out varve sequences for potential teleconnections. In 1920, De Geer travelled to North America with his wife and two assistants, Ernst Antevs, and Ragnar Liden. Antevs remained in North America at the end of the trip, where he worked on the North American varve chronology. Further trips included Erik Norin's visit to the Himalayas (1924–1925), Erik Nilsson's visit to East Africa (1927–28), and Carl Caldenius' visit to South America (1925–1929), and later New Zealand (1932–34).

However, by the mid 1930s De Geer's teleconnections had become the subject of increasing criticism from his former student Ernst Antevs. Antevs correctly argued that the teleconnections were bad science, and that De Geer's Trans-Atlantic correlations were inaccurate. De Geer felt his position was being caricatured and intentionally misunderstood by Antevs, but did little scientifically to rebuff the criticisms levelled at him.

In 1924 De Geer retired from teaching and became the founder-director of the Geochronological Institute at Stockholm University.