OPEN UNIVERSITY
GEOLOGICAL SOCIETY
 
Ireland Branch Newsletter
2005 No.4
Calendar
Branch events  2005
July
w/e 23-24    Field trip to West Cork/Kerry leader Pat Meere (UCC)
August
tba    One-day field trip to Silvermines, Co. Tipperary, leader Ed. Jarvis, OU Tutor
23-4 Sept.    Field trip to Iceland. There are a couple of places left.  Contact: John Leahy
September
tba    One-day field trip to the Co. Down Coast, leader Tony Lee

2006  April
w/e tba    Field trip to Metamorphic and Igneous rocks in Connemara, leader Martin Feely, (NUIG)     

Other events  2005
May
Sat 28    CGA geo-walk to Coumshingaun, Co. Waterford.
June
Wed 8    IGA Members’ Night, Room G01, Department of Geology, UCD.  8pm.
w/e 10-12    IGA field trip to Kilroot salt mine and geology of the Belfast area.
August
w/e 27-28    IGA field trip to Loop Head, Co. Clare, led by Peter Haughton (UCD)

BGS Belfast Geologists' Society; CGA Cork Geological Association; IAEG Irish Association for Economic Geology; IGA Irish Geological Association; NUIG National University of Ireland Galway, TCD Trinity College Dublin; UCC University College Cork, UCD University College Dublin.


 
A WORD FROM OUR BRANCH ORGANIZER

Hello everyone,
Our recent trip to Connemara was enjoyed by all who went on it. The weather was a bit showery but not cold and our leader Sadhbh Baxter gave us an excellent two days of geology.

Our next trip is on 23/24 July to Kerry, accommodation is being booked in Kenmare, and I would urge all who want to go to contact me as soon as possible.  The first ten people who book will get it at 35 euros per person per night.  Further accommodation in that area and at a reasonable price is very hard to come by at that time of year and so may be more expensive, as we get nearer the time.  The leader is Pat Meere from UCC and the trip promises to be very good.   Day visitors very welcome.

I recently attended a National Committee meeting in Keyworth near Nottingham, it was held in the British Geological Survey centre.  It had a marvellous shop and we were allowed to buy goods at 25% discount.  At the meeting the main item on the agenda was the election of a new Chairman of the OUGS.  Joe Jennings was elected.  Many of you will remember him, he was the national secretary before Linda Fowler.  We wish him good luck in his new job.

I look forward to seeing as many of you as possible on our next trip.
Phyllis.


EDITORIAL
The fearless few who made the effort were greatly rewarded by a wonderful field trip to Connemara led by Sadhbh Baxter. We saw a selection of sedimentary, metamorphic and igneous rocks in spectacular surroundings and, by Sunday afternoon, in glorious weather.  Don’t miss out on the next trip to Kerry.  Be there!

It appears that there are a couple of places left on the trip to Iceland next August/September.  If you would like to join the group please contact John Leahy a.s.a.p. at jal297@student.open.ac.uk.
In the last Newsletter I asked for contributions.  One of our Branch members, John Lombard, has obliged and sent a most interesting article about Table Mountain (see pp. 4-7.)  Many thanks John.

Details of the Branch finances as given at the recent AGM by Sheila Doyle are included below (P. 11.)

Interspersed throughout the Newsletter I have included some news items that were included in the BBC R4 programme The News Quiz.   I cannot really justify them on geological grounds, environmental grounds maybe; I simply thought them funny.  Hope you enjoy them.
Susan


FIELD TRIP DETAILS
23-24 July, 2005
Upper Palaeozoic sedimentary rocks in Cork/Kerry led by Pat Meere

The field trip will focus on the Upper Palaeozoic sedimentary rocks from south-west Ireland.  We will start by looking at the development of the Munster and South Munster Basins and go on to look in some detail at the inversion of these basins at the end of the Carboniferous during the last phase of the Variscan Orogeny in northern Europe.  We will pay particular attention to the role lithology plays in the development of different deformation styles.

Accommodation for this trip will be in Kenmare, Co. Kerry, where Phyllis has booked ten places at €35 per night.  She says that accommodation was very difficult to arrange and some of the hotel prices were quite exorbitant, so don’t waste time, book now!   There is a Booking Form at the end of the Newsletter.

Bring stout footwear and warm, waterproof clothing, though we hope that you won’t need them.  You will need a packed lunch each day.  

There will be a small fee to cover the leader's expenses (the more people that come the less this will cost.)

A young girl who was blown out to sea on a set of inflatable teeth was rescued by a man on an inflatable lobster.  A coastguard spokesman commented, “this sort of thing is all too common.”                                     
The Times

A LOOK AT TABLE MOUNTAIN

John Lombard, Ireland Branch Member

I spent a two-month holiday in South Africa recently.  While in Cape Town, a city with a beautiful location, I went on a trip to Table Mountain.  With the possible exception of Mount Fuji in Japan, Table Mountain must be the best-known mountain in the world.  Millions of people who have no interest in geology and who have never been to South Africa, will recognize its photograph and tell you something about it.

A 20 minute bus ride from the city centre brings you to the cable car station, and a ten minute ascent in the cable car brings you right to the plateau on the top.  It was mid-December (early summer) that day.  This is the best time to make the trip.  The vegetation is still green and the wild flowers are in bloom.  The view and the scenery are mind boggling, from the city far below out across the Indian Ocean you can see for hundreds of miles on a clear day.  The local plant life is of particular interest of botanists.  Called “fynbos” it constitutes one of the six recognized Plant Kingdoms.  The fynbos is noted for its own particular adaptations and life style.  There are over 8,000 species, ericas, proteas and pincushions among them.  They have evolved to cope with the wet/dry, warm/cold swings of the Cape Peninsula climate.

The Cape can also boast some of the oldest known traces of Homo sapiens.  One of the discoveries is a trail of footprints made by a human female 117,000 years ago.1
 
The history of Table Mountain goes back over 750 million years.  At that time South Africa formed a part of the supercontinent Rodinia.2  Huge quantities of sediment were shed from the land and deposited out in deep water forming thick sequences of shale.  About 600 million years ago, a granitic magma was intruded into the shale.  The intrusion occurred in such a way as to strengthen the shale, making it largely impervious to rifting and folding.1  It is for this reason that Table Mountain retains its characteristic outline.  Over the ages it has been able to withstand the tectonic pressures brought to bear on it.

Some 450 million years ago the local environment seems to have changed by marine regression.  Layers of fluvial sandstone were deposited over the shale.  These sandstones have since become metamorphosed into quartzite.  This is the rock type that a visitor to the mountain sees and walks on.  About 330 million years ago there was a world-wide episode of glaciation.  Deposits left by the ice sheets can still be seen on the summit.


It is interesting to note that this ice age came about as a result of the spread of land plants and the growth of forests.  This process had a double effect on the composition of the atmosphere.  Vegetation breaks down rocks and soils, partly because humic acid is one of its decay products.  This speeds up weathering and atmospheric CO2 is used up in the process.  Moreover, during this time, the Carboniferous Period, a great deal of vegetational biomass was buried in swampy conditions, eventually giving rise to coal deposits.  The combined effect of these two factors was to reduce the level of CO2 in the atmosphere, thereby reducing the greenhouse effect which helps keep our planet warm.  The result was a fall in global temperatures which triggered a climatic catastrophe lasting for tens of millions of years.3

It seems that mankind is not the only life-form that can really wreck the joint!

Anyway, to get back to Table Mountain, about 165 million years ago there was world wide continental break up as Gondwana parted company from Pangaea.   During this time the Cape area underwent transpression but, because of the toughness of the rock, there was little or no crustal shortening.  Instead, the pressure was deflected downwards and it was this that caused the geological uplift that gave us Table Mountain.  The pressure and uplift continue today but the mountain is not getting any higher.  Weathering and erosion are planing it down just as fast as tectonic pressure is forcing it up.  Today, the mountain is about 1,080 metres above sea level, but in the past it has been as high as 3,000 metres.1

In order to see the shale and granite basement that underlies the mountain you need to go all the way down to the sea shore.  Seapoint is a pleasant resort area just outside Cape Town.  At low tide the contact zone is well exposed.  Streaks of light-coloured granite can be seen intruding the darker shale.  This formation has played an important part in the progress of geology.  In 1836 Charles Darwin, on his way home from the Galapagos Islands in the Beagle, stopped off here.  He realized that the heavily eroded granite was very old but, nevertheless, it had to be younger than the shale into which it had been intruded.  The shale, itself a sedimentary rock, had, of course, come from a rock source even more ancient.  All this provided an early insight into the vastness of geological time and helped to pave the way for the system of Aeons, Eras and Periods that we use today.

To finish on a homely note, one of the tourist attractions on the summit is one of those multiple signposts.  The sign that points a little west of north reads:

            DUBLIN  ……………………..  9,994 km.

References
1.    See: www.capetown.at/heritage
2.    Evolving Life and the Earth, Open University selected text for S269, p.36
3.    Evolving Life and the Earth, Open University selected text for S269, pp.108-120.
 
PRESS CUTTINGS

UNDERWATER MOUNDS MAY REVEAL ALL ABOUT OUR ECOSYSTEM

HUGE underwater mounds just off the Irish coast are to be investigated by a team of scientists on a "floating university."  The mounds, located 100 miles off the coast of Kerry, are to be the focus of attention for scientists over the coming weeks and there are hopes that research into them will reveal the history of the Irish underwater ecosystem.  Last week the US research ship, the Joides Resolution, docked in Dublin port before setting off on a trip to the edge of the Porcupine Seabight off the south-west coast.

A team of scientists from around the world are to drill down and take samples from one of the mounds - 170 metres in height - which they hope will reveal the history of millions of years of underwater life.

The enormous mounds are covered in part by coral, usually associated with much warmer climates.  "I was amazed to find out that corals had been discovered at the bottom of the dark, cold waters of the Atlantic, once thought to be barren of life," said Marine Minister Noel Dempsey on a visit to the ship.  "These corals are now known to inhabit carbonate mud mounds with a rich biodiversity. The waters in the area are also nutrient-rich."

Ireland will be contributing €500,000 over five years into the Integrated Ocean Drilling Programme - a series of research programmes about the planet.

After the mound is drilled, the samples will be analyzed aboard the ship before being passed onto universities around the world.  Among the 25 technicians and 25 scientists aboard the Joides Resolution will be representatives from UCC and the Geological Survey of Ireland.
Shane Hickey © Irish Independent, 4/05/2005


Commenting on a complaint from a Mr. Arthur Purdey about a large gas bill, a spokesman for North West Gas said “We agree it was rather high for the time of year.  It’s possible Mr. Purdey has been charged for the gas used up during the explosion that blew his house to pieces.”
Bangkok Post









Earthquakes and Groundwater Level Records in Ireland

As reported in GSI News, Issue No. 2 (Winter 2005, available on the Geological Survey of Ireland website at www.gsi.ie), three GSI groundwater level monitoring wells (operated by OPW) in Co. Kilkenny showed significant fluctuations of water levels due to the 26 December 2004 earthquake off Sumatra.
The three wells have been monitored since the early 1980s and penetrate different aquifers:
    KNY 18/92: 20m deep in Quaternary gravel
    KNY 27/58: 62 m deep in Dolomitic Limestone
    KNY 31/72: 40m deep in Kiltorcan Sandstone
The fluctuations in water level are recorded by a pen writing on a chart on a clockwork-driven rotating drum. The recording ratio (i.e. movement of pen:change in water level) is normally 1:10 or 1:20.
The three wells simultaneously registered abrupt water level changes in the early hours of 26 December. The maximum fluctuations ranged from about 50 mm in 18/92, to 240 mm in 25/78, to 280 mm in 31/72. The differences probably relate to the differing storage coefficients in the three aquifers. Similar effects were seen in wells monitored by GSNI/EHS in Northern Ireland.
Recent study of water level recorder charts from the Kilkenny wells, and from another borehole in Carboniferous limestone in Co. Roscommon (Ros 14/91), has found traces of at least 80 seismic events since 1980. Comparison of the event dates with earthquake records on the USGS website indicates that the event magnitudes range from 6.2 upwards, with most of them being above 7. The 26th December record stands out as generating the largest water level fluctuation so far.
Apart from the intrinsic interest in recording such events at such a distance, there should be practical benefits from analysing the data - helping us to understand the nature of our aquifers, and to derive realistic storage coefficients in the affected aquifers. Work is continuing!
Geoff Wright and Jane Coll, Groundwater Section, Geological Survey of Ireland




Cities may be abandoned as salt water invades

THE water supplies of dozens of major cities around the world are at risk from a previously ignored aspect of global warming.  Within the next few decades rising sea levels will pollute underground water reserves with salt.  Long before the rising tides flood coastal cities, salt water will invade the porous rocks that hold fresh water.  "Even if we can fix the coastline, this saline incursion will increase," says Vincent Post, a hydrogeologist at the Free University, Amsterdam.  The problem will be compounded by sinking water tables due to low rainfall, also caused by climate change, and rising water usage by the world's growing and increasingly urbanised population.

Underground water is the largest reserve of fresh water on the planet.  Most cities use groundwater where possible because it is less prone to pollution than river water.  Many people have no alternative: more than two billion depend on it, including most of the world's rural poor and many of the world's megacities, including Mumbai, Bangkok, Jakarta, and Karachi.  Salt water …….. has penetrated 5 kilometres beneath Manila, in the Philippines, while the water table is sinking.  As sea levels rise, the invasion will accelerate, leaving some cities "at risk of abandonment", according to the International Association of Hydrogeologists, which organised last week's meeting at the University of East Anglia in Norwich, UK.
 
The conference highlighted the fact that the fate of underground water was one of the least-studied effects of climate change. "I don't think the scale of saline inundation facing these communities has been realised by governments," says Andrew Skinner, former director of environmental protection at the UK government's Environment Agency.

Africa is the continent most dependent on underground water.  It also has the largest water supply problem, and its groundwater reserves are probably the most vulnerable to climate change.  Yet the last impact assessment in 2001 by the UN's Intergovernmental Panel on Climate Change (IPCC) had just one brief mention of groundwater in Africa.  Four years on, little has been done.  Delegates last week said scientists had let Africa down.

The threat to underground water reserves is a problem in the industrialised world too.  Large areas of south and east England, for example, rely on underground water that is already over-extracted.  Water use may be restricted this summer because poor winter rains meant there was minimal recharge to underground water reserves.

Studies presented at the conference predicted a further 20 to 40 per cent decline in recharge to the UK's aquifers over the next 20 years.  At the same time demand for water for gardens and crop irrigation in the UK is likely to rise by a third or more.

Amarenda Sinha, a geologist at the University of Rajasthan in Jaipur, India, says the expected loss of most Himalayan glaciers by the 2030s will drastically cut recharge from rivers to groundwater reserves on the plains of northern India, which provide food for half a billion people.  He thinks the Indian government's $200 billion Rivers Interlinking Project, intended to divert water from the great northern rivers to the parched south and west, will fail.  "The water will not be available," he says.
Fred Pearce
© New Scientist, 7/05/05


At the height of the gale, the harbourmaster radioed a coastguard on the spot and asked him to estimate the wind speed.  He replied that he was sorry, but he didn’t have a gauge.  However, if it was any help, the wind had just blown his Land Rover off the cliff.
Aberdeen Evening Express