North East Geological Society
Click here for the Official NEGS website
Lectures will be held at 7:30 pm
in the Arthur Holmes lecture theatre, which is downstairs from the Porter's
Lodge on the Science Laboratories site, South Rd., University of Durham.
They will be followed by coffee or tea, to which all speakers and audience
members are cordially invited.
2012 – 2013 programme
2011 – 2012 programme
2010 – 2011 programme
2009 – 2010 programme
2008 – 2009 programme
2007– 2008 programme
2006 – 2007 programme
2005 – 2006 programme
Michael Lim, Dept. Geography, University of Durham, Science Labs., South Rd., Durham DH1 3LE, UK firstname.lastname@example.org 17th November, 2009.
Geology plays a fundamental role in shaping our rocky coastlines, interacting with destabilising processes to control the rate and nature of cliff erosion. Recording, interpreting and predicting coastal cliff erosion is a critical component in coastal policy, assuming even greater significance in the context of global sea-level rise and forecast increases in the occurrence of extreme weather phenomena. Much of our understanding of cliff change is based on patterns in the mapped historic position of the cliffline. These surveys provide a valuable insight into landform behaviour but the levels of error that occur often exceed the absolute changes recorded, casting considerable doubt over the validity of results; results that hold far reaching implications for coastal communities. This lecture presents the results from an ongoing seven year research plan conducted by Durham University into rock cliff erosion on the North Yorkshire coast. The main aim of this work is provide a new quantitative understanding of the 3D nature of coastal cliff erosion and the processes driving it, re-evaluating current rates of retreat established along the coast and consequently providing better tools with which to assess future behaviour.
Andrew J. Dugmore, Geography, School of GeoSciences, University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, Scotland, UK email@example.com, 12th December, 2008
Tephrochronology, a dating technique based on the identification and correlation of layers of volcanic ash, can make key contributions to our understanding of human-environment interactions. This is because the isochrons defined by tephras permit accurate spatial and temporal correlations of environmental data and have such precision that effective integration with historical records and human timescales are possible. In this talk the principles, practice and application of tephrochronology are assessed as a part of a wiser discussion of human environment interaction and the Norse settlement of the North Atlantic. The end of Norse Greenland settlement is widely associated with the climate changes of the ‘Little Ice Age’, environmental destruction and an inability to adapt, but there is evidence in Greenland and across the Atlantic islands for both Norse sustainable practice and successful adaptation to climate change. As a result we propose that the choices made during the initial Norse colonization and settlement of Greenland, followed by a rising level of connection, intensification, and investment in fixed resource spaces, social and material infrastructure, increased the effectiveness of adaptation but at a cost of reduced resilience in the face of variation. When confronted by culture contact, rapid natural, social and economic changes the limitations of the pathway chosen by the Norse in Greenland seem to have been too great and social collapse could have been the result. The lessons drawn from a multidisciplinary assessment of the Viking settlement of the Atlantic islands in general and Norse Greenland in particular are disturbing in a modern context. It is possible to creatively adapt to new environments, build up centuries of community-based managerial expertise, wisely conserve fragile resources for communal benefit, codify the results, maintain century-scale sustainable patterns of life and society- and yet still face ultimate collapse and extinction.
Andy is a Professor of GeoSciences at the University of Edinburgh, and an Adjunct Research Professor on the Doctoral Program in Anthropology at the City University of New York, USA. His research is focused on understanding environmental change over timescales from decades to millennia, and their significance for human society. A key theme is the development and application of tephrochronology, a dating technique based on the identification and correlation of volcanic ash layers. Between 2002-7 Andrew co-directed a Leverhulme Trust Programme Award for the study of ‘Landscapes circum- Landám: Viking settlement in the North Atlantic and its human and environmental consequences’. He is currently embarking on two follow up programmes, ‘Footsteps on the edge of Thule’ which will assess the interactions of Norse and indigenous peoples in Greenland and Arctic Scandinavia (also funded by the Leverhulme Trust) and an NSF Office of Polar Programs IPY project on ‘Human ecodynamics in the Norse North Atlantic’.
Dr. Rob Chapman, 23rd February, 2006
The importance of Au to ancient societies has encouraged many archaeologists to search for the sources exploited in antiquity. These projects generally involve detailed studies of artefacts and comparison of their chemical characteristics with those reported for natural Au. However, descriptions of natural Au are frequently inadequate for provenancing studies, and the compositional variability of the material is not widely recognised. The present study describes a new approach to gold provenancing using the technique of microchemical characterization in which populations of gold grains are classified according to the alloy compositions and the assemblages of micro-inclusions of other minerals. This technique, originally developed to identify sources of alluvial gold during Au exploration, has proved applicable to provenancing studies in four main areas. Firstly, microchemical characterization of artefacts grouped according to archaeological criteria can indicate the number of sources exploited in relation to time and artefact taxonomy. Secondly, knowledge of the total variation in chemical characteristics of natural Au from a particular region provides an excellent database for provenancing and reduces the need for exhaustive sampling. Thirdly, it is possible to predict how Au alloys were modified during fabrication as a consequence of assimilation of mineral inclusions. Finally, identification of inclusion phases in artefact Au can provide information on metallurgical practices.
These principles have been applied to the search for the source of Au used for the unique traditions of prehistoric Irish metalworking. Studies of 180 Irish Au artefacts belonging to 4 major metalworking traditions dating from the Early Bronze Age (2400 BC) to the Iron Age, (150 BC) show that each group exhibits distinctive Ag and Cu contents. Parallel studies of 2267 natural Au grains from 58 alluvial localities and 4 bedrock localities throughout Ireland reveal a broad pattern of alloy compositions consistent with style of mineralization and host geology. The ranges of Ag contents of Early Bronze Age and Middle Bronze Age artefacts suggests that the Au source lies within Lower Palaeozoic sedimentary rocks of the Southern Uplands Terrane and significantly, that the same source (or sources) were used in both periods. A different source of relatively Ag-rich Au, (most probably at Croagh Patrick, Co. Mayo), was exploited in the Late Bronze Age. Iron Age artefacts have Ag contents higher than natural Irish Au. Evidence for evolution of metallurgical practice during the Bronze Age is provided by the increasing Cu content of the gold alloys (to levels far in excess of natural gold) and the nature of inclusions in artefacts of different ages. Elevated Sn in Cu-rich alloys suggests deliberate or accidental alloying with bronze.
This approach has provided the first clear indication that only a few individual indigenous Irish sources of Au were used during the Bronze Age and that their relative importance changed over time. Future archaeological investigations may adopt a geographical focus that was not previously possible.
Dr. Claire Fialips, 17th November, 2006
Clay minerals are abundant in soils and sediments and generally contain significant - if not high - concentrations of structural ferric iron (Fe(III)). Reducing conditions, even for a short period of time, can strongly affect the chemistry, structure and surface properties of iron-bearing clays. In particular, the chemical reduction of Fe(III) to Fe(II) in Fe-rich smectites results in structural rearrangements and dramatic changes in the swelling behaviour and cationic exchange capacity of the clay. Such changes can dramatically and adversely affect the fate of pollutants or the availability of nutrients in natural or artificial systems. However, in some cases, these changes could as well play in our favour in pollution remediation.
Dr. Anthony Cooper, 15th March, 2013
Gypsum (CaSO4.2H2O) is attractive as satin spar, beautiful as carved alabaster and practical as plasterboard; rock salt (NaCl) is an essential mineral, but both cause geological hazards capable of swallowing houses. Gypsum and salt can dissolve rapidly in flowing water and caves can form where this happens underground, sometimes resulting in catastrophic subsidence at the surface. In Northern England, around Ripon, Darlington and in parts of Cheshire, large holes have appeared, often without warning. Beneath Ripon there is a complex maze cave system formed in the gypsum with large breccia pipes leading upwards to collapse features at the surface. It has been suggested that Lewis Carroll’s vision of Alice falling down a deep vertical hole into an underground land was inspired by this subsidence at Ripon. There is a connection between the author, Croft near Darlington, the city of Ripon, and dramatic subsidence at the house where "Alice" is thought to have lived. Salt dissolves very rapidly causing subsidence problems and salt springs; in Cheshire these springs have the local name of “wich” hence the local place names such as Nantwich, Northwich and Middlewich. Gypsum and salt karst subsidence are geohazards that need to be considered in planning and development. They are difficult to investigate, but techniques including airborne multispectral remote sensing, stereo air photography, microgravity, ground probing radar, resistivity tomography and the use of drilling have all helped. The hazards require careful consideration, but can be addressed through the use of Geographical Information Systems (GIS), planning and novel construction techniques. The English soluble rock subsidence problems are not unique and similar problems also occur in Spain, Germany, France, Italy, Switzerland, Turkey, Lithuania, Ukraine, Russia, China, Canada, the USA and many other countries.