Thornbury

Geology Next Meeting

Wednesday 25 March

This meeting will take place in the Coach House, not the Stuart Room.

Tony Turnbull will describe techniques for determining the age of rock deposits. The study of geology would be incomplete without a method of dating rocks and fossils, thus being able to know in absolute terms the timing of sedimentary deposits, geological events such as eruptions, the age of fossils etc. Many diverse methods have been devised to remedy this; some are purely relative, so that it is possible to say which rock or fossil happened before another. Others provide an absolute date before the present. The synergy of these two types of measurement helps provide a quantitative assessment of the geological events of our planet. (Figure 1)

After coffee Les Strong will present Continental Drift - a mechanism proposed in the early 1900s by Albert Wegener (Figure 2) and how evidence for the process led to the theory being accepted only 60 years ago. Understanding continental drift helps to explain why violent geological events like earthquakes, volcanoes, and tsunamis occur.