ENVIRONMENTAL GEOLOGY
GL 2001.6
This course introduces the concepts of environmental geology within an Earth System.
The course reviews material previously studied in first and second year material courses
for resources, their development and location both globally and within the UK.
Geological Hazards are then evaluated; both natural and manmade. Finally some Global
issues are addressed.
Environmental Geology
What is it?
Reading list
Course Text Book

Woodcock, N (1994) " Geology and Environment in Britain and Ireland" UCL
Press
Other Text



Coats, D. R. (1981) "Environmental Geology" John Wiley
Keller, E. A. (1976) "Environmental Geology" Merill
Tank, R. (1973) "Focus on Environmental Geology" Oxford Uni. Press
Course Outline




Background
Resources
Natural Geologic Hazards
Manmade Hazards - Waste Disposal
Background


Environmental Geology - What is it?
Course Concepts
Earth System Sciences
"The Earth's Past as a Guide to the Earth's Future." Woodcock (1995)


Careers
Links with other Courses
Resources






What are they?
Renewable/Nonrenewable
Geologic Influence on Resources - UK resources
Review of Previous courses - Metallic, Non-metallic, water
Energy Resources - Nuclear
Energy Resources - Renewable
Geologic Hazards - Causes, Risks, Prediction, Mitigation





Earthquakes
Landslides
Subsidence
Radon
Volcanoes
Man-made Hazards - Waste Disposal




Managed vs. Un-managed Disposal
History of Waste Disposal
Types of Waste Disposal
Problems
Nomenclature
Earth Sciences - the study of the lithosphere and inner Earth
Earth System Sciences - the study of interactions of all environmental components;
lithosphere, hydrosphere, biosphere, atmosphere, magnetosphere, (political sphere?)(fig)
Lithosphere - crust and upper mantle
Hydrosphere - all the waters on face of Earth and in crust
Biosphere - all regions occupied or potentially occupied by living organisms
Atmosphere - the continuous gaseous envelope surrounding the Earth
Magnetosphere - the space pervaded by the Earth's magnetic field
Some Environmental Issues Today








Fossil Fuels vs. Nuclear Fuels?
Sensitive Economic Extraction of Resources
Recycle vs. Energy Consumption
Hazardous discharge and biodiversity
Old waste disposal sites and SSSI's
When is contamination safe?
Prediction of Geologic hazards
Global warming or just a lot of hot air ?
read Mellanby, K (1992) "Waste and Pollution, the Problem for Britain". Harper Collins.
Resources - What are they?
Reference during this course is made extensively to the material taught by Drs. Stevens
and MacNeill during the first year courses on metallic and non-metallic materials. Also
references will be made to the first year course on groundwater (G1001).
Non-renewable Resources - review previous courses Geology First Year
Courses





Base metals - Fig WES G1001
Precious metals - Fig WES G1001
Building material - Fig GMcN G1001
Hydrocarbons - Fig GMcN G1001, Oil and Gas Resources, USGS
Nuclear
Renewable Resources (Renewable energy, CREST)
Renewable





Water (CRB G1001)
Solar
Geothermal
Biomass(biomass, CREST)
Wind(Wind Power, CREST)
Resource Geology of Britain





Global and UK consumption
Global and UK reserves
Resources and their locations in the British Isles
Energy consumption in the UK
Energy resource distribution in the UK
To find out more about energy in the UK and elsewhere in the World visit the following
sites:
Energy and the environment at;
http://www.wam.umd.edu/~tfagan/enrgyenv.html
EPA - US Environmental Protection Agency;
http://www.epa.gov/
Renewable Energy;
http://www.eren.doe.gov/
Global change;
http://www.usgcrp.gov/
UK National Energy Foundation;
http://www.natenergy.org.uk/
UK Nuclear Industry
http://www.users.zetnet.co.uk/n-base/
http://www.ukaea.org.uk/
UK Solar Energy Society;
http://www.demon.co.uk/tfc/uk-ises.html
Energy Resources
Potential Renewable Energy resources for the UK






Hydroelectric 0.7%
Wave 6%
Solar 6%
Tidal 6%
Biomass 13%
Wind 22%
Nuclear Energy - non-renewable energy



Resources
World reserves concentrated in few countries. China and former Soviet Union
aside present levels of consumption will last only 50 years.
World resources estimated at 1860 thousand tonnes
Nuclear Energy - World Reserves
Nuclear Energy - Fuel Cycle
Geothermal Energy - Renewable/Partially Renewable
Types of Geothermal Energy:
Geothermal Aquifer 





low enthalpy system
average heat flow
high heat gradient
low thermal conductivity e.g. mudstones
few km deep,
heat exchange by pumping hot saline water
Hyperthermal Systems (Geothermal, US DOE)






high enthalpy
high heat flow (300mWm-2) e.g. intrusions
ground water directly heated and moved by hydrothermal convection
water trapped and taped via fracture system
water steams on release of pressure
renewable on human time scale due to great heat
Geothermal Hot-dry Rock (e.g. Cornwall)




higher heat production than average
pump water into induced fracture system
problems with keeping fracture system active
may be important for the future but technically difficult
Hazards


Natural Hazards
Man-made Hazards
Study Methods




Causes - identification of processes
Risk areas - mapping hazard areas
Prediction - monitoring hazard development
Mitigation - hazard engineering
Natural Geologic Hazards





Earthquakes
Landslides
Subsidence
Radon
Volcanic
Landslides
Types of Landslide (fig)






fall - rock, topples
creep
flow
slide - rotational, debris, mud, rock
slump - sagging
compound
Causes (fig)






loading of head - sedimentation, man-made load
strength reduction - weathering, bioremoval
wetting
undercutting
change in pore pressure
ground instabilities from external sources - earthquakes
Landslides - Landslide Classification
The National Landslide Review
Table insert
Groups of Landslide failure




First time Failure - previously unsheared ground. Large rapid displacements. e.g.
Holbeck Hall Slide. (case history)
Failures on Pre-existing Shear Surfaces - surfaces often non-landslide origin. e.g.
slopes activated by inappropriate earthworks, Aberfan, 1966. (video)
Reactivation of Previous Slips - new movements on pre-existing surfaces. (fig
Mam Tor)
Seismic Induced Slips - all of the above induced by high seismic activity.
(see: Auburn Dam - USGS)
Risk Areas





steep slopes
non vegetated areas
lose soil areas
most coastal areas
high seismic potential areas
For further information on hazard risk areas and prediction
see Hazards - lanslides home page, USGS
Prediction






surface/subsurface geological mapping (fig)
visual inspection - slope analysis (fig)
water levels
tilt meters
strain gauges
passive seismic monitoring
Mitigation



lower moisture content (fig)
reduce slope angles
construction of artificial barriers
Subsidence
subsidence - downward displacement of surface material caused by natural
or artificial removal of underlying support (collapse) or by compression of
ground (consolidation)
disaster when this is rapid
Subsidence
hydrocompaction - reduction in dry strength of material by addition of water tend to be
evident in sediments with high void ratios and a clay content of approximately 12%
Piping - subsurface flow of water under high hydraulic heads. Erodes channels in sands
Karsting - solution of cavities in (mainly) limestones
Mantled Karsts - layer of soil over limestone karst masks presence of karst beneath
Thermokarst - karsting in regions with permanently frozen ground. Differential melting
of subsurface.
Volcanokarst - piping in volcanic terrain
Consolidation
consolidation - natural compression of saturated sediment or rock under
influence of static load
primary consolidation - initial stress causes water expulsion, compression of
material, usually rapid event
secondary consolidation - adjustment of internal structure, further
compression, usually long term event
Effective stress - (Terzaghi, 1936)
Subsidence - High Risk Areas



plate boundaries
carbonate geology areas
mining areas
Prediction




surface and sub-surface geology mapping
large-scale strain guages
precise geodetic levelling - satelite surveying?
cavity detection using geophysical methods

mapping man-made hazards - underground mining, (Case Histories, Norwich,
Glenrothes practical class)
Mitigation



subsidence risk maps
building regulations
fluid injection - repressurization of the ground