OPEN UNIVERSITY
GEOLOGICAL SOCIETY
Ireland Branch Newsletter
2005 No.5
Calendar
Branch events
Mar
Sat 4 BRANCH AGM. Wellington Park Hotel, Belfast,
11am. (Further details below)
April
w/e tba Field trip to Metamorphic and Igneous rocks in
Connemara, leader Martin Feely, (NUIG)
Other events
Jan
Thu 19 IGA Lecture. Will it get hot or cold and how
fast? Rapid climate change: a geological perspective by Pete Coxon
(TCD). Davis Lecture Theatre (near Nassau St. entrance) TCD, 7.30pm.
All welcome.
Wed 25 CGA Lecture. Rocky experiences of a wildlife
sculptor, and the creation of fossilised crystalline granites! Patrick
O’Hara. Dept of Geology, NUI Cork. 8pm
Wed 25 BGS Lecture. Prospecting in Zambia, John Arthurs,
Ulster Museum, 7.30pm
Feb
Wed 22 CGA Lecture. Storms, waves and the impact
of the rising sea level on Ireland’s coastline Prof. Robert Devoy.
Department of Geology, NUI Cork. 8pm
Wed 22 BGS Lecture. The Mount Newman Story and the
Brockman Iron Ore Formation of north-east Australia by Leslie Wortley, Ulster
Museum, 7.30pm
w/e 24-26 IGRM (see item below) NUI Cork
Fri 24 Lecture by Dr. Mike Searle (Oxford) on Himalayan
tectonics. NUI Cork
Sat 25 Lecture by Prof Bill McGuire (Benfield Hazard Centre
on some aspects of geohazards. NUI Cork.
Mar
Wed 22 BGS Lecture. Iceland’s glacial landscapes
by Dr. Mark Cooper (GSNI), Ulster Museum, 7.30
Sat 26 CGA Field trip. Coastal dynamics in the Youghal
and Goat Island area, Co. Cork, led by Jim Curtin.
Wed 29 CGA Lecture. Darwin – Paramount geologist.
Padhraig Kennan, NUI Cork. Dept. Geology, 8pm
April Wed 26 CGA Lecture. Irish
National Seabed Survey – the shallow inshore dimension. Seán
Cullen (GSI). Department of Geology, NUI Cork, 8pm.
BGS Belfast Geologists' Society; CGA Cork Geological Association; IGA Irish
Geological Association; NUIG National University of Ireland Galway, TCD Trinity
College Dublin; NUIC National University of Ireland Cork, UCD University
College Dublin.
Happy New Year
EDITORIAL
It’s 2006 already and time to make those resolutions to get into the field
more often. Even if you only make it one more time than last year,
that’s progress. Some say that the best geologists are those that have
seen the most rocks. While that may be debatable there is a core of
truth in it. Although our Branch is relatively small and scattered,
when we do get together it can be great fun and it is always interesting.
Now it is up to you.
I see some new names on our mailing list and I would like to give them a
particular welcome to our Branch. I hope everyone did well in their
exams and that you will be continuing with your geological studies.
We hope to see you all at some of our Branch events during the year,
especially our new members.
It has been a long time since the last Branch Newsletter. During that
time I was fortunate to visit some spectacular geology in Western Australia
and Northern Territory. This included Shark Bay World Heritage Site
for the stromatolites and an overland trip from Perth to Alice Springs taking
in Kata Tjuta (the Olgas) and Uluru (Ayer’s Rock) which I may tell you all
about …… some other time!
Penny Widdison, Membership Secretary, has asked us to mention that subscriptions
are due on the 1st January and that you are expected to send them in promptly!
The basic subscription is £18.00 or €27.00. For further details
and EURO RENEWAL FORM see back page of this Newsletter, (a pound sterling
renewal form came with your National Newsletter.) Cheques in either
euro or pounds are acceptable.
Best wishes for a peaceful and prosperous New Year.
Susan
Congratulations to John Leahy, of this parish, who won the Moyra Eldridge
Photographic Competition outright with a photograph taken on our recent Branch
field trip to Iceland. Photographs were judged at the OUGS AGM in Shap
Wells last November. The winning photograph will be published in the
forthcoming OUGS Journal. Very well done, John.
Luxury hotel loses bid for beauty spot
A developer has been refused planning permission for a four-star hotel in
an area which has been described as having one of the most remarkable karst
landscapes in Ireland. The luxury 71-bedroom complex was proposed by
businessman Tim Regan for Nymphsfield, Cong, Co Mayo, an area situated on
the narrow isthmus of land separating Lough Corrib and Lough Mask.
The underground limestone strata between the lakes is riddled with fissures,
caves and chambers hollowed out by underground water swirling from Mask to
Carra.
Overturning a decision by Mayo County Council to grant planning permission
for the two-storey hotel, which would include six presidential suites, An
Bord Pleanala has noted the proximity of a national monument, Kelly's Cave,
and several geological features, including a deep cavern known locally as
Captain Webb's Hole.
The board ruled that the location of the site, which would include a leisure
centre and 25 staff accommodation units "would have an irreversible impact
on the geology, hydrogeology and ecology of the area". The board also
expressed concern that the site could not be drained and would therefore
be prejudicial to public health.
Tom Shiel © Irish Independent 7/11/05
ANCIENT OZONE HOLES
Researchers are investigating ancient ozone holes and their relationship
to mass extinctions, by measuring ultraviolet-B (UV-B) absorbing pigments
in plant spores and pollen. Barry Lomax and colleagues at the University
of Sheffield and other UK institutions are analysing spores in the British
Antarctic Survey's collection from South Georgia. They discovered
that since the 1960s spores from land plants have tripled their concentrations
of certain pigments to protect themselves against more UV-B light.
The increase in UV-B at South Georgia is a direct result of the hole in the
ozone layer, caused by human-made chlorofluorocarbons (CFCs.) The situation
may have been the same 251 million years ago, but with the ozone-destroying
chemicals coming from the Earth itself. At that time, the largest mass
extinction in the Earth’s history happened, as did the largest known eruption
of lava and potentially ozone-destroying gases from the Siberian traps.
“Volcanic eruptions can emit gases such as chlorine and bromine that can
destroy ozone,” said Barry. “Heated rocks near the volcanic Siberian
Traps flows may also release a wide range of organohalogens thought to harm
ozone,” he added.
The next step is to search for the plant pigments’ chemical remains in fossilised
spores and pollen. “The pigments break down to form compounds that
are stable over geological time,” said Barry. “So providing samples
have not been subjected to large amounts of heat, the signature should be
preserved.
Planet Earth, Autumn 2005. p.3
BRANCH MATTERS
Ireland Branch Report 2005
Organiser: Phyllis Turkington
This year we started with a two-day trip to Connemara on 30 April.
The trip was led by Dr Sadhbh Baxter from National University of Ireland
(NUI) Galway.
On the first day we visited Ordovician rocks of the Lough Nafooey Group,
Silurian transgressive sequences and Kylemore Formation metamorphic mineral
area. At the first location we saw pillow lavas, evidence the Knock-Kilbride
Formation basalt erupted under water. Various factors indicated that
the rocks seen in this group record the presence at the time of a chain of
volcanic islands off the coast of Laurentia. The formation seen here
can be interpreted as representing mass flow deposits infilling the topographic
lows between the Pillow Lavas.
Other sites visited on Day 1 included rocks of the transgressive Silurian
sequence. The base of the sequence is represented by pink spheroidal
weathered meta-andesite flows. Succeeding the meta-andesite is red,
cross bedded sandstone with pebble beds. The two units were formed
in a sub-aerial to fluvatile environment.
Overlying the sandstone are quartzites with worm tubes, originally beach
sand. Overlying the quartzites is a sandstone with trace fossils interbedded
with shelly faunas of Upper Llandovery age. Here can be found, brachiopods,
crinoids corals and bryozoans which indicate a tropical, marine, shallow-water
environment laid down in a progressively deeper water environment.
We saw lakeshore purple and green shales. The whole sequence here is
a good example of deposition in a transgressive environment.
At the next site we saw rocks of the Kilbride Formation which include shelly
assemblages of brachiopods, corals and crinoids. At this locality we
saw ‘in situ’ coral communities covered with a thin layer of volcanic ash,
growth of the coral colonies here ceased after a volcanic episode.
This is one of the examples of mass mortalities on an Irish Silurian (440-410Ma)
seafloor. Finally we stopped at Claggan Quarry of the Kylemore Formation.
The quarry is a ‘Staurolite’ zone. Here we found pink pegmatite with
well-formed crystals of andalusite , muscovite, quartz and tourmaline.
We also saw cordierite porphyoblasts.
On day two we visited Cleggan Boulder Beds, the Lakes Marble Formation,
the northern contact of the Galway Granite and a Magma mingling and mixing
zone.
Cleggan Boulder Beds are at the base of the Argyle Group (Middle Dalradian).
It is overlain by a thick sequence of quartzite. Both the Boulder Beds and
the quartzite are extensively invaded by fine-grained Oughterard Granite
which is considerably younger (463 ma) than the rocks they invaded (750-600
ma).
At the Lakes formation we saw tight D3 folds.
At our next stop we saw the northern contact between the Galway Granite (400ma)
and the Metagabbro-Gneiss suite (490ma). Here also is the Connemara Metamorphic
Complex.
Finally we stopped at the Magma mingling and mixing zone which forms a significant
unit within the central block of the batholith. Here we saw sheets
of granodiorite of various textures and colours distributed over a single
outcrop.
The branch also held a two day field trip to Kerry in July led by Dr Pat
Meere, NUI, Cork. The theme of the weekend was the Munster and South
Munster Basins.
For this field trip we were based in the Town of Kenmare which is in a central
position for the whole area. Besides being a scenic area for Tourists
the geology of the area shows Devonian and Carboniferous sedimentary rocks
extensively preserved in this area.
Background to the Munster Basins
Initial basin development may have taken place in the Dingle Peninsula area
as the Dingle Basin. To the south the northeast-southwest trending
Munster Basin developed as a half-graben. The earliest known sediments
in the Munster Basin are of Middle Devonian age.
The Munster Basin accumulated in excess of 7km of marine Devonian sediment.
A listric fault developed near the end of the Devonian known as the Cork-Kenmare
Fault System. This fault played a major role in controlling sedimentation.
In the Carboniferous 2.5km of marine sediments were deposited. To the
north of the Fault System a relatively stable platform developed while to
the south was an area of deeper water sedimentation known as the South Munster
Basin.
At the end of Carboniferous came compressional tectonics and the Variscan
deformation, deforming the whole area from south to north, producing large-scale
fold structures.
Over the two days we made a number of stops where we saw fine grained alluvial
sheet-flood sediment, coarse-grained fluvial influx sediments, Old Red Sandstone
and fine-grained green sandstone. We saw parallel lamination and cross lamination,
cross stratified ribbon and sheet sandstone. Finally we visited Black
Ball Head where we saw a deformed lamprophyric pipe. At this area around
the seashore can be seen numerous dykes and sills at Black Ball Head
and Whiteball head.
August saw the branch’s first trip overseas with a group of 25 travelling
to Iceland.
The trip was led by Professor Wolfgang Jackoby of the University of Mainz,
he was assisted by Dr Bettie Higgs from the National University of Ireland,
Cork.
Wolf has spent his summers in Iceland for the past thirty years and so was
able to give us a very good insight into the geology of Iceland. We
stayed in hostels which kept the cost down and had a cook, Adda, who travelled
round with us to ensure we were well fed.
Iceland is a geologists’ playground, and we saw a good variety of pillow
lavas on the Reykjanes peninsula, to the tranquility of the glacial lagoon
at Jokulsarlon and the mighty force of Selfoss in the south and Dettifoss
in the north. We were blessed with excellent weather throughout the
12-day trip with the exception on one day when it snowed heavily all day.
This gave us a truly memorable experience that evening of swimming in an
outdoor swimming pool in the snow.
About the branch.
This year has seen some old members leaving but we have also gained some
new members. The numbers have remained static. However we still
get a good turnout at the field trips, good numbers in proportion to the
total membership. The members who turn out for field trips all enjoy
the experience and we always learn something new.
BRANCH AGM
The Branch AGM will be held in the Wellington Park Hotel, 21 Malone Road,
Belfast on Saturday the 4th March, 2006, at 11am. The hotel is close
to the OU Offices and Queen’s University.
Tea and coffee will be provided.
The AGM will be followed by a talk given by Tony Lee.
After the meeting lunch will be available in the Bistro Restaurant (for a
modest sum.)
Please let Phyllis know if you wish to attend and whether you require transport.
If you would like overnight accommodation Phyllis will book you into a local
B&B.