BATH GEOLOGICAL SOCIETY
LECTURE MEETINGS 2007


Lecture Meetings at Bath Royal Literary and Scientific Institution,
16 Queen Square, Bath at 7.15 p.m.


January February March April May June July September October November December AGM 2008

January 4th

Glaciers and Their Legacy

Dr Geraint Owen, University of Wales, Swansea

Glaciers exist where snow remains unmelted through the summer, forming ice. The ice in the glacier moves towards the margins forming distinctive landscape features, including broad deep valleys and striated rock surfaces. Changes in the ice margin reflect changes in climate. Past glacial positions help to reconstruct climate changes since the end of the last ice age. Understanding the pattern of past climate changes helps us to appreciate the context of changes likely to occur in the future.


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February 1st

Annual General Meeting, 2007 followed by Geological Fun and Games


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March 1st

Dorset Geology through the Eyes of a Small Palaeontologist

Dr Adrian Rundle, Natural History Museum, London

The Dorset coast is world-famous for its fossils. Its reputation started with Mary Anning who collected ichthyosaurs and other large marine reptiles from Lyme Regis. Other fossils such as ammonites and brittle starfishes are collected but microfossils are almost totally ignored. The talk concentrates on a summary of the late Triassic to Early Cretaceous coastal rocks, what microfossils occur and how they can be extracted.


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April 5th

COLIN HORSTMANN MEMORIAL LECTURE
Marbles and other Decorative Stones

Dr Monica Price, Mineralogy, Oxford University Museum of Natural History


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May 3rd

A New Look at the Palaeogeography of the Chalk

Prof John Cope, National Museum of Wales

High sea-levels in the Late Cretaceous resulted in most of Britain being under the sea, but subsequent erosion has removed much of the evidence of its original extent. New techniques allow reconstruction of depositional histories over areas now stripped of Mesozoic cover and provide fresh evidence of the former extent of the Chalk and the dramatic way that it was removed from western Britain.


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June 7th

The Geology of the South Island of New Zealand

Ruth Weinberg

South Island, New Zealand forms the S.E. corner of the Pacific Rim of Fire and lies on the collision zone of the Pacific and Indo-Australian tectonic plates. The rocks that form the island were originally eroded from the Gondwana supercontinent; over the course of the past 250 million years, they have been re-eroded and re-formed to shape the land visible today. The three main areas; Southern Alps, Alpine Fault and Canterbury Plain, illustrate tectonic, glacial and erosion processes which are ongoing and visible in the landscape. Uplift of the Southern Alps has had considerable climatic effect and the commercial resources available today result directly from the tectonic adventure that is the South Island‘s history, producing a place of stunning natural beauty and high drama.


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July 5th

Australia's Mines and Mineral Wealth

Tim Colman, Economic Geology Programme, British Geological Survey

Australia is currently one of the main sources of the world‘s mineral wealth. First in the production of diamonds, bauxite and zirconium; second in lead, zinc, titanium, uranium: third in gold, nickel, iron ore and coal and fourth in copper, silver and manganese - all this is from a country slightly smaller than the USA with a population of only 21 million. The talk will give a brief history of the development of the Australian mining industry and describe some of the more recent discoveries.


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September 7th

Club Evening

This is an opportunity for members to display their collections and to give a short talk about interesting trips or geological activities.


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October 4th

Giant's Causeway: Antrim World Heritage Site - Lava Plateaux and End-Cretaceous Plate Tectonics

Dr Michael Le Bas, Southampton University

The Giant‘s Causeway can be appreciated in several ways: as a volcanic feature, as a curio in geological history, as a bit of folklore and as an impressive World Heritage Site. Its hexagonal basaltic columns received early note from gentlemen naturalists of the 17th Century with some prescient and some curious observations which, mixed in with local folklore, gives insight to the geological thought processes of the day. That the basaltic columns of the Causeway are part of a Tertiary lava plateau that covers much of Antrim, begs the question, "What is the relationship to the many Tertiary volcanic centres of Scotland, Ireland and the North Atlantic?" That will be addressed with excursions into Iceland and Greenland together with plumes and plates.


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November 1st

Catch a Falling Star — Meteors, Clouds and Waves at the Edge of Space

Professor N. J. Mitchell, Centre for Space, Atmospheric & Ocean Science, University of Bath

Every day about 40 tonnes of extra-terrestrial material collides with the Earth. This material is mostly in the form of tiny particles originating from comets. At heights of about 100km, friction heats the particles so that they vaporise, giving rise to the streak of light seen from the ground as a meteor or shooting Star‘. This meteor region of the atmosphere is the edge of space. The meteor region is notoriously difficult to investigate but hosts a wide range of poorly understood phenomena. Atmospheric tides and waves launched from below are thought to drive its circulation, coupling together different layers of the atmosphere. Smoke from meteors acts as condensation nuclei for ghostly, polar noctilucent clouds and the meteor region is also home of the giant lightning discharges known as sprites. Its great sensitivity has led to its being called the "miner‘s canary" of climate change.
Professor Mitchell‘s research involves using sophisticated radars to detect meteors in the atmosphere. The meteors are used as tracers of atmospheric motion and reveal the intricate dynamics of the meteor region. An array of radars at sites ranging from the Arctic to the Antarctic is being used to monitor and investigate this enigmatic port of the atmosphere. The lecture will outline the challenges posed and the techniques used in remote-sensing meteors and the meteor region. It will present some key recent results, and will look towards future problems.


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December 6th

Gas Bubbles in Solids

Rod White, Consultant Physicist specialising in problems associated with nuclear fuel elements
CEGB, British Energy, BNFL, OECD Halden Reactor (Norway), Nuclear Energy Agency (Paris).

Gas bubbles tend to precipitate out of solution when the gas is insoluble in the solid matrix. In many solids the bubbles may contain gases like helium, nitrogen or oxygen and thermodynamic stability will occur when the pressure in the bubble is balanced by the capillarity of the bubble plus any external restraining stresses. The bubble size distributions may change as a result of departures from thermodynamic equilibrium by means of atomic diffusion processes. Coarsening or Ostwald Rippening of the bubble populations may occur and the nature of the bubbles may change as a result. The processes are illustrated by studies of the bubble populations occurring in irradiated uranium dioxide UO2 (nuclear fuel) where a continuous supply of gas (xenon, krypton) occurs through the fission process and three principal types of bubble occur, namely, intragranular bubbles, lenticular bubbles on the grain faces and triangulated bubbles on the junctions of three grains. These grain edge bubbles eventually link up to form continuous pathways to the surfaces of the solid and are analogous to the structures in oil-bearing rocks.


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February 7th

Annual General Meeting, 2008


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