Cymdeithas Daeareg Gogledd Cymru
North Wales Geology Association
Programme :
2016-17
at a
Glance
Which way to meetings?

Thursday 10th November 2016
Assessing the hazard of low frequency, high magnitude landslide events
Speaker: Stephen Parry

Wednesday 23rd November 2016
Gold Rush: Prospecting and Small Scale Mining for gold and diamonds
Speaker: Jim Richards

Wednesday 7th December 2016
Annual Members' Evening - Short Presentations
Speakers: TBA

Saturday January 21st 2017
Annual General Meeting

Wednesday April 26th 2017
A Tale of Two Quakies
Speaker: Mark Easton

Saturday July 15th 2017
Field Meeting: Penrhyn Quarry, Bethesda
Leader: David Jameson

Sunday August 6th 2017
Field Meeting: FossilPlants Garden, Llanberis
Leader: Robbie Blackhall-Miles


Thursday
November 10th 2016
Assessing the hazard of low frequency,high magnitude landslide events; the role of the engineering geologist.
Speaker: Stephen Parry, Parry Engineering Geology Services
Room CBB115, Best Building, University of Chester.
Location details and map: Find

Tea & Coffee from 18:30h, Lecture commences at 19:00h

During a severe rainstorm on 7 June 2008, over 2,400 landslides were recorded on Lantau Island, the largest island in Hong Kong. Numerous road links were severed and many landslides impinged on existing residential developments. This was one of the most notable storms to have occurred in Hong Kong in several decades, with a 4-hour rolling rainfall equated to a return period of 500-1000 years. A number of the landslides developed into major debris flows, with significant secondary entrainment and long run out distances. Such hazards were underrepresented in the existing data sets at that time.

The presentation will outline the approach to landslide assessments in Hong Kong, discuss the hazard from debris flow with reference to the 2008 storm, illustrate the uncertainty associated with assessing debris flow hazard and examine how this uncertainty can be reduced.

Whilst there are limited historical records of debris flows in the UK, they have been documented in North Wales, the Lake District and Scotland, with the impact on the A83 at Rest and be Thankful being most notable. There is also evidence that the frequency of such events is increasing and the lessons learnt in Hong Kong are useful for the evaluation low frequency, high magnitude debris flows in the UK.

Wednesday
November 23rd 2016
Gold Rush: Prospecting and Small Scale Mining for gold and diamonds.
Speaker: Jim Richards
Meeting Room, Pensychnant, Conwy.
Location details and map: Contact/Find

Refreshments from 19:00h; Meeting to commence at 19:30h

Gold rushes have had a major impact on world history; from the settlement of California to the development of Australia, and modern rushes continue to shape parts of West Africa, Brazil, Indonesia and elsewhere. This talk follows the journey of British and Australian geologist Jim Richards who has been involved in various modern-day gold and diamond rushes around the world; prospecting, alluvial mining and exploring for minerals.

Y Fron
Image ©Keene Engineering.

This includes time spent in Guyana in South America, mining bonanza grade gold and diamond deposits from the rivers on top of the tepui plateaus of the Pakaraima mountains; hunting for giant gold deposits in the jungles of Laos in South-east Asia; and finding high grade gold mines in the deserts of Western Australia.

Currently, Jim is the Executive Chairman of a publicly listed mineral exploration company based in Perth, Australia. His lead project is an alluvial diamond prospect in the remote Kimberley region of Western Australia which contains some of the world’s finest yellow diamonds, BlinaDiamonds. Jim’s memoir Gold Rush is being published in the UK on 4 November 2016.

Wednesday
December 7th 2016
Annual Members' Evening
Speakers: See below (in no particular order):
Meeting Room, Pensychnant, Conwy.
Meeting to commence at 19:30h
Refreshments and Nibbles from 19:00h
Location details and map: Contact/Find

Gary Eisenhauer:
Fossil lagerstätten of Southern Germany.

A quick tour through three fossil lagerstätten in Southern Germany: Grube Messel, Posidonia Shale and the Plattenkalk. Whilst also taking in some of the museums and other places of geological interest on the way.

Keith Nicholls:
The Ordovician/Silurian Boundary (but in Oslofjord rather than the Welsh Basin).

A brief introduction to the Lower Palaeozoic (specifically - you guessed it - the O/S boundary section) of the Oslofjord Islands and Oslo City hinterland. Illustrated by some of the most joyfully coloured geological maps you will ever hope to see.
I will also have on display two posters I presented at IGCP 591 : Nicholls, Buckley & Wilkins on the Hirnant Limestone, and Nicholls, Appleton and Roberts on the Llyn Geirionydd Graptolites.

Jonathan Wilkins:
Snowdonia Periglacial Geomorphology - off the beaten track.

The upland areas of Snowdonia are rich with the legacy of glacial erosion during the last glacial maximum. Visitor pressure on Cwm Idwal is now so high that parking vehicles can be a limiting factor at popular times. However, there are a number of rewarding and fascinating glacial and post-glacial features close at hand within the rather less visited areas around Llanfairfechan and Abergwyngregyn. This talk will take in some of the gems of the district.

Peter Ellwood:
Kimmeridgian of Portugal

Details on the night.

Saturday
January 21st 2017
ANNUAL GENERAL MEETING
and
Charting the History of the Yellowstone Super-volcano, USA
Speaker: Dr. Thomas Knott, University of Leicester
Meeting Room, Pensychnant, Conwy.
Location details and map: Contact/Find

Annual General Meeting commences 10:00h
Refreshments at 11:00h
Lecture to commence at 11:30h

Super-eruptions are amongst the most catastrophic events at the Earth's surface, with devastating regional environmental consequences and likely effects on global climate.

Yellowstone eruption deposits It is well-known that Yellowstone, USA, has erupted catastrophically in recent times, but possibly less widely appreciated that these were just the latest in a protracted history of numerous catastrophic super-eruptions that left a trail of destruction along the Snake River from Oregon (16 million years ago) to Yellowstone (most recent). New, previously undiscovered, records of super-eruptions are now being revealed in the volcanic record of the central Snake River Plain of Idaho. Characterisation and wide-area correlation of these immense deposits, from one mountain range to another, is hindered by the monotonous nature of the volcanic units, which has limited the use of conventional field-based techniques. Trace-element geochemical analysis has enabled the fingerprinting of individual ash layers. Combined with other techniques (e.g. mineral chemistry and palaeomagnetism) this data can be used to trace individual layers for hundreds of kilometres and to deduce the size of individual eruptions. One such is the newly-defined Castleford Crossing eruption that effectively enamelled an area greater than 14,000 square kilometres with searing-hot volcanic glass around 8 million years ago. The volume of this vast deposit is estimated to have exceeded 1,900 cubic kilometres, with a maximum depth of 1.3 km in the concealed caldera of the super-volcano. The magnitude of this eruption is similar to or greater than better-known eruptions at Yellowstone, and is the first of an emerging record of additional super-eruptions from a period of intense magmatic activity between 12 and 8 million years ago.

Tom will be giving a fine account of this project which was conducted in association with the Universities of California and Idaho, USA, and describing field work in a very challenging and scenically fascinating area

Wednesday
April 26th 2017
A Tale of two Quakies
Speaker: Mark Easton, Opus International Consultants
Meeting Room, Pensychnant, Conwy.
Location details and map: Contact/Find

Meeting to commence at 19:30h

Within the last 7 years, the Canterbury and Marlborough regions of New Zealand' South Island have been significantly impacted by a series of damaging earthquakes. Following a period of relative quiet, the increased rate of seismic activity has created a groundswell in knowledge and corresponding techniques to better understand and mitigate the impacts on civil engineering projects.

This presentation, whilst primarily focused upon geological effects and natural hazards (such as liquefaction and coseismic landsliding), will also cover the wider implications of living and developing in actively seismic countries such as New Zealand, which is currently well deserving of its nickname as 'The Shaky Isles'.

Mark Easton is a Principal Geotechnical Engineer and has worked for Opus International Consultants (Opus) since 2005. Mark has spent the last 11 years with Opus, based in Christchurch, New Zealand and is currently seconded to Opus UK based in the Bristol office.

Mark has spent much of his recent career involved tin the Response and Recovery phases that follow natural hazard events / disasters. Notably, this has included the 2010 Darfield, 2011 Christchurch and most recently the 2016 Kaikoura earthquakes.

Saturday
July 15th 2017
Field Meeting:
Penrhyn Quarry, Bethesda
Leader: David Jameson, GWP Consultants
Based on the Llanberis Slates outcrop, Nant Ffrancon, Bethesda

Visits to this site are not easily organised due to its status as a working quarry and home to the iconic ZIPWORLD attraction for adrenalin junkies. We are therefore very pleased that we have been assisted in this task by David Jameson, who has worked in this site for many years as a consultant.

Llyn y gafr
Image ©Eric Jones. Geograph.org.uk #225970

We will start with a 30 minute introductory briefing in the canteen/workshop area giving a brief history, geological background and structural setting with respect to quarry stability and production. In the quarry we will look at the detailed stratigraphic sequence within the slates and cross cutting dykes and the major faults which delimit the productive slate strata.

High visibility jackets, hard hats and solid boots are mandatory for all participants because this is a working site. Please provide your own jacket and hat where possible as the quarry is not set up for large numbers of visitors, and only a limited supply is available. It is an exposed, upland area and participants must be prepared for the conditions. Please contact Gary Eisenhauer to register your interest. Numbers will be limited by transport arrangements, as this cannot be a walking trip due to the distances involved. There is a short technical paper which can be distributed to anybody with a wish to read a bit more about the site before the visit.

Joining details will be given to participants when they are finalised, but a 10:00h start in Bethesda should be assumed.

Sunday
August 6th 2017
Field Meeting:
FossilPlants Garden, Llanberis
Leader: Robbie Blackhall-Miles
Avisit to Robbies specialist garden in Llanberis

Llyn y gafr
Image ©RB-H. fossilplants.co.uk

FossilPlants is the North Wales garden of Robbie and his partner Ben. A backyard Botanic Garden working to promote the conservation, education and scientific understanding of those plants that were around before the extinction event that saw the demise of the non-avian dinosaurs; the K-Pg boundary.

This very small garden hosts an impressively large collection of plants from all over the world. Many of these plants are threatened with extinction and it is for this reason that the garden became a institutional member of of BGCI (Botanic Gardens Conservation International).

The garden houses many members of the Proteaceae and is working towards a Plant Heritage National Plant Collection of South East Australian Banksias. Other notable groups of plants in the garden are Illicium, Chloranthus and Southern hemisphere ferns.

Please contact Gary Eisenhauer to register your interest. Numbers are not particularly limited, but the size of a tour party is restricted by the small size of the garden so splitting into groups may be necessary. This will be a relaxing trip, and services in the town are nearby, as is the lakeside resort of Padarn Country Park.

Joining details will be given to participants on application to Gary.