............................... 3 NO. 59 QUARTERLY NEWS BULLETIN ~ SEPTEMBER 2 0 1 6 VOLUME ..................... 35TH INTERNATIONAL GEOLOGICAL CONGRESS 27 AUGUST - 4 SEPTEMBER 2016 I CAPE TOWN, SOUTH AFRICA UCT du Toit lecture Pre-IGC field trips Mineral Scene ................................................................................................................................................................................................... GeoBulletin_Expression Form (A4)_OUTLINES CREATED.indd 1 2013/09/13 03:14:51 PM 35TH INTERNATIONAL GEOLOGICAL CONGRESS 27 AUGUST - 4 SEPTEMBER 2016 | CAPE TOWN, SOUTH AFRICA 35TH INTERNATIONAL GEOLOGICAL CONGRESS 27 AUGUST - 4 SEPTEMBER 2016 | CAPE TOWN, SOUTH AFRICA The International Geological Congress (IGC) is the principal event of the International Union of Geological Sciences (IUGS), one of the largest and most active non-governmental scientific organizations in the world. The IUGS promotes and encourages the study of geological phenomena, especially those of worldwide significance, and supports and facilitates international and interdisciplinary cooperation in the earth sciences. The event will be a Pan African experience with the support of the major African geoscientific societies and related organisations. A large number of African delegates are expected to attend and field trips are planned to all parts of the African continent. The Congress will have a very extensive Thetechnical International programme, Geological Congress featuring (IGC) is the papers,principal event posters, of the International short courses Union of Geological and Sciences (IUGS), one of the largest and most active non-governmental scientific organizations in the world. workshops. Principal themes are: GeoscienceThe IUGS in promotes Society, and encourages Geoscience the study in of the geological Economy phenomena, and especially Fundamental those of worldwide significance, and supports and facilitates international and interdisciplinary cooperation in the earth Geoscience. Your contribution to this programsciences. is crucial. The event will be a Pan African experience with the support of the major African geoscientific societies and Please contact Prof Laurence Robb at [email protected] organisations. A large number of African for delegates more are information. expected to attend and field trips are planned to all parts of the African continent. The Congress will have a very extensive technical programme, featuring papers, posters, short courses and workshops. Principal themes are: Geoscience in Society, Geoscience in the Economy and Fundamental Geoscience. Your contribution to this program is crucial. www.35igc.org Please contact Prof Laurence Robb at [email protected] for more information. www.35igc.org Volume 59 ~ Number THREE ~ SEPTEMBER 2016 contents Society News GSSA GB (GEOBULLETIN) 2 From the Editor’s desk - Chris Hatton 5TH FLOOR CHAMBER OF MINES 3 Executive Manager’s Corner - Craig Smith HOLLARD STREET 5 President’s Column - Jeannette McGill MARSHALLTOWN 207 GAUTENG SOUTH AFRICA University News PO BOX 6809 6 University of Stellenbosch MARSHALLTOWN 207 9 University of Cape Town SOUTH AFRICA Tel: +27()492 3370 Articles Fax: +27()492 337 Pre-IGC field trips e-mail: [email protected] 10 Craton Traverse Web: www.gssa.org.za 13 Eastern Limb Bushveld Complex COMMITTEE 14 Cape Granites Convener & Editor: Chris Hatton .................... 082 562 57 16 Barberton Greenstone Belt Advertising: Jann Otto ........................ 082 568 0432 2 Vredefort impact structure Centre fold Design & Layout: Belinda Boyes-Varley ........ 079 29 7748 22 Bushmanland Printing: Seriti Printing (Pty) Ltd ....... 02 333 9757 All submissions to (in order of preference): Media Monitor email attachments (in Word .doc) to: [email protected] 25 Antony Cowey disc/hard copy to: Chris Hatton Postal Address: Council for Geoscience Private Bag X112 Obituary Pretoria 28 Andrew Osmund Thompson South Africa 000 Tel : + 27 (0) 2 84 1149 General Fax: 086 679 859 Mineral Scene Contributions for the next issue should be submitted by: 30 Bruce Cairncross & Maria Atanasova 10th November, 2016. Geobulletin is provided free to members of the GSSA. Non-member The Geotraveller subscriptions per four issue volume are R350.00 for South Africa. 32 Finger lakes of the Gregory Rift Valley Overseas and rest of Africa, R350 plus postage. Surface mail, R200.00. Airmail, R300.00. The views expressed in this magazine are not necessarily those of the GSSA, its editor or the publishers. Other Business ADVERTISING RATES (Excl. VAT & Agency Commission): Geobulletin 42 Classifieds is published by the Geological Society of South Africa (GSSA) and appears quarterly during March, June, September and December each year. 2016 RATES: Jann Otto 082 568 0432 For detailed prices, mechanical and digital submission requirements, please contact the GB advertising co-ordinator, editor (see Contents Page for contact information) to obtain an up-to-date Rates Card or other information. DEADLINES FOR COPY AND ADVERTISING MATERIAL are 5th February (March 206 issue), 4th May (June 206 issue), 2th August (September 206 issue) and 0th November (December 206 issue). Please note that the design and layout of adverts and inserts is entirely the responsibility of the advertiser. If you wish to contract the services of the GB graphics and layout supplier for this service, please contact Belinda directly, well in advance of the advert submission deadline to make arrangements. * Casual insertions • 4+ insertions geobulletin SEPTEMBER 2016 from the editor’s desk Chris Hatton The climate change debate doesn’t seem to end. The relationship between carbon dioxide in the atmosphere and temperature is based on the measurements of carbon dioxide and hydrogen isotopes from the drill-core into the Vostok ice sheet. In this miraculous age of the internet anyone can look at the data themselves. Here you see a pattern which is unusually clear and unambiguous. When the carbon dioxide concentration in the trapped air bubbles goes from about two hundred ppm to three hundred ppm, the SOCIETY NEWS temperature goes up by about eight degrees. The fact that carbon dioxide is a greenhouse gas suggests that an increase in carbon dioxide caused an increase in temperature, rather than the other way around. The other unambiguous fact is that for the last 400 000 years the carbon dioxide in the air bubbles trapped in the Vostok ice sheet never went much higher than three hundred ppm. The exception is the last 00 years, when the concentration approached, and has now exceeded, four hundred ppm. The reasonable explanation for this is that burning of coal, starting with the industrial revolution, caused the increase. Because we humans burnt the coal, it is hard to deny that this recent increase in carbon dioxide can Civilisations rise and fall over hundreds of years. On be attributed to human activity. Because increased this relatively short time scale, the natural variations carbon dioxide causes an increase in temperature, in solar intensity may be the responsible agent. Here anthropogenic global warming must surely be real. It at the 35th IGC, which is just getting underway at the seems that we failed to pay proper attention when this time of writing, Bob Scholes related the rise and fall of issue was raised this issue in Geobulletin a few years Mapungubwe to the coming and going of rain cycles. ago. A few years on, and it appears to be time that Round about the time of Mapungubwe, English towns we geologists should also accept what most other which are now kilometres from the sea had sturdy rational humans already have; burning fossil fuel is harbour walls. The iconoclastic sedimentologist, not a good way to generate energy. Roger Higgs, pointed out that the changes in sea level necessary to account for this must have proceeded But then there’s the question of scale. The increases at a rate which is five times faster than the IPCC from two to three hundred ppm in carbon dioxide took uses in its forecasts. We may now be on the cusp of place over ten thousand years. In geological terms another rapid change. From this perspective it is the this is virtually instantaneous, but on a human scale, sun that is going to drive up temperature and sea-level this is too long to be of concern to the average citizen. is going to rise drastically in the next hundred years, 2 geobulletin SEPTEMBER 2016 Volume 59 ~ Number THREE ~ SEPTEMBER 2016 independently of carbon dioxide in the atmosphere. opening of the Mantle Room was announced. Some Humans can certainly do nothing about changes in of the xenoliths stored there were on display during solar intensity so if this is the main driving agent a the IGC. The opening of the Mantle Exhibition and miraculous application of human ingenuity will be other events from the cutting edge of science, which needed to take us through the turmoil ahead. for this week is at the 35th IGC will be reported on in the next issue. Meetings like this 35th IGC are where ideas are exchanged and solutions are sought for an ever- The South African Journal of Geology is about to expanding range of questions. In this issue we report become a print on demand journal. For a while at least on the pre-IGC field trips where delegates were able Geobulletin will continue to appear on paper because to examine at first hand the South African contribution it is a magazine which relies on its high-quality printed to the rock record of geological processes and images. The spectacular images in Mineral Scene, SOCIETY NEWS cycles. Chris Hawkesworth examined the longest which appears for the first time in this issue and will of these cycles, that relating to the formation of the be a regular feature, are a welcome addition to continental crust, in the du Toit lecture at UCT and Geobulletin. again in a plenary lecture at the IGC. In the pre- IGC presentation of the du Toit lecture at UCT the re- Chris Hatton executive managers Our esteemed editor has just informed me that he is going to press with the next issue – and he wants my column – yesterday.