SHAKE, RATTLE AND ROLL – Our Restless World

Charles Darwin was an enthusiastic geologist and entomologist. He is best known for his circum-world voyage on HMS Beagle that ultimately resulted in his joint publication with Alfred Wallace on the theory of evolution through natural selection. Less well known were his ideas on the creation of coral atolls, that are intimately involved with plate tectonics. This final lecture covers Darwin’s life including the Beagle voyage and concludes with aspects of climate change in the southern Hemisphere.

The Canadian Shield is the core of the North American continent and contains the oldest rocks known on Earth. Today it is one area of the world where climate is changing most rapidly. The talk covers the geological and exploration history of the Shield and other northern areas, concluding with concerns about our rapidly changing environment.

Life appeared on Earth less than one billion years after the planet was formed. Starting from bacteria of various types and evolving through cyanobacterial mats (stromatolites) that produced the oxygen we need to survive through photosynthesis. Advanced multicellular fossils appeared in latest Precambrian time (less than 1,000 million years ago). About 600 million years ago a diverse group of organisms preceded the explosion of life on Earth at the start of Cambrian time some 540 million years ago. A plethora of life on land followed with the first terrestrial plants, amphibians, reptiles, dinosaurs and mammals. This talk outlines some of the developments and setbacks of life on Earth.

In a continuation of the last lecture we shall explore subduction activity, concentrating on earthquakes and the catastrophic tsunamis that ravaged Indonesia and Japan in the past decade. The talk will also cover the Supervolcanoes, at Yellowstone, the Taupo area of New Zealand and in Indonesia (Tamboro and Krakatoa).

Seismic activity in the Mediterranean is a reflection of the collision of the African and Eurasian plates, with the former diving under the latter. This subduction activity creates violent volcanic activity, sometimes associated with very large earthquakes. Similar activity is seen in Western North America, central America and in western South America. This talk will investigate the Mediterranean areas of Santorini (Thera), the Aeolian Islands, Vesuvius, Pompeii, Herculaneum, Puzzuoli and the CampiFlegri fields, and Mt. St Helens and other Cascade volcanoes, north to Mt. Meager, just north of Vancouver.

Perhaps of more concern to humans are earthquakes. These take place in areas of tectonic stress. We are fortunate in Canada in only having a few regions that are of potential higher risk, although smaller, local earthquakes can occur by stress buildup even in stable areas. This lecture will explore more seismically active regions (and larger earthquakes) such as the transform San Andreas Fault, the Queen Charlotte Fault off western Canada, and the New Zealand (Alpine) fault.

Humanity is frequently awed by the spectacular grandeur of volcanic eruptions, especially those of oceanic islands where vast streams of lava cascade down the flanks of massive volcanoes, as seen in the recent 2018 Hawaiian flows. Most of these oceanic eruptions are “ridge systems” and are often unobserved since they take place beneath the world’s oceans. It is only when they appear above water that humans are able to observe them in places like Hawaii, the Galapagos islands, the Azores, Iceland, Kolbeinsey and Jan Mayen. This lecture explores some of these locations.