490 likes | 773 Views
A2.3EG2 Environmental Geology Mike Paul. WELCOME TO THE MODULE. Module Aims. To provide an overview of environmental geology To focus on issues of urban geology mitigation of geohazards. Module Aims. ‘Hidden’ aims Experience of limited-contact module
E N D
A2.3EG2Environmental GeologyMike Paul WELCOME TO THE MODULE
Module Aims • To provide an overview of environmental geology • To focus on issues of • urban geology • mitigation of geohazards
Module Aims • ‘Hidden’ aims • Experience of limited-contact module • Seminar presentations and discussion • Familiarity with literature sources • General preparation for final year
Weekly Module Topics 1.Lecture: Role and scope of urban geology 2. No Class - Seminar 1 preparation 3. Seminar 1 progress tutorial 4. No Class - Seminar 1 preparation SEMINAR 1: URBAN GEOLOGY 5. Lecture: Introduction to geohazards 6. No Class - Seminar 2 preparation 7. Seminar 2 progress tutorial 8. No Class - Seminar 2 preparation SEMINAR 2: GEOHAZARDS
Teaching Programme • Overview lecture for each seminar: • Private preparation of seminar topic • Additional reading as directed • Personal research of the literature
Assessment • Seminar 1 (25% ):Integrated urban geology: case studies • Date • Seminar 2 (25%): Assessment, avoidance and mitigation of geohazards • Date • 2hr Module Examination(50%) • Format to be announced
Module Materials • All paperwork and lecture notes can be downloaded from the module home page. • Some journal articles are available from Mike Paul. • Library/databases (Athens password) for the rest. • Sets of other reading materials will be made available in due course.
A2.3EG2 Environmental GeologyLECTURE 1 ROLE AND SCOPE OFURBAN GEOLOGY
SUMMARY • The role of urban geology • Planning for land use • Identification of: • subsurface conditions • water supply • waste disposal sites • Identification of geohazards (later) • Conclusions
‘Environmental geology’ is the application of geological concepts and data to improve our use and protection of the environment in general. • ‘Urban geology’ refers to such applications in the planning and operation of towns and cities. • ‘Engineering geology’ refers to the use of geological data etc in engineering design.
Land use planning provides one of the principal applications in environmental geology. • It encompasses concepts of ‘usage zonation’, extraction of construction materials, water supply and waste management. • It also includes the indentification and avoidance of geohazards such as landslides, subsidence and underground gases. • It also interfaces with the related issue of ground contamination and the identification of former land use problems.
Land use planning makes use of standard geological maps, augmented by specialist thematic maps that are produced for the purpose. • In Britian, the BGS supplies a limited number of such maps as special sheets or series. These include the ‘Upper Forth’ series.
Upper Forth Map Series • The BGS ‘Engineering Geology of the Upper Forth’ project was carried out 1978-81 under contract to DoE. • Purpose was to provide generalised planning information for industrial location in Scotland. • The project was not aimed at any one specific type of user or any particular type of site
Upper Forth Map Series • The principal output was a series of eight maps plus an explanatory report. • A number of specialist reports were also produced. • The main report and maps was released as a BGS public report in 1986.
Upper Forth Map Series • The eight maps were divided into two groups: The first showed the distribution of materials • Solid geology • Depth to glacial till • Thickness of Holocene deposits • Mine workings • Drift geology
Upper Forth Map Series Solid geology map • This map was based on the existing BGS solid geology map, with the addition of commercial data about engineering properties • The data was generalised and attempted to cover the rocks on a stratigraphical basis.
Upper Forth Map Series Depth to glacial deposits • This map shows the generalised contours on the surface of the glacial till • This layer is of interest since it is a likely choice for end-bearing piles • The data was derived from existing borehole records and is only approximate
Upper Forth Map Series Thickness of Holocene deposits • This map shows the generalised isopachytes for the Holocene strata • These are principally the soft carse clays and so the map reveals the depth available for friction piles • This data was also obtained from commercial records
Upper Forth Map Series Extent of mineworkings • This map showed the extent of known workings in the principal seams below the map area. • Some information given about type of working • Known shafts also shown
Upper Forth Map Series Drift geology • This map shows the information from the existing drift geology maps of the area • The stratigraphy was simplified to provide more lithological information and less chronology
Upper Forth Map Series • The second part of the series showed an interpretation of this data for generalised planning purposes • Surface sediment classification • Cross-sections and type profiles • Suitability for heavy structures
Upper Forth Map Series Classification of Surface Sediments • The surface sediments map took the drift map and applied a geotechnical soils classification to the materials • based on commercial records
Upper Forth Map Series Type profiles • The relatively regular architecture of the sediments (due to the sea-level history) allowed type profiles to be devised • These were based on the expected succession of deposits and followed a regular spatial pattern • Eight such profiles were defined
Upper Forth Map Series Foundation suitability map • This was an attempt to generalise the likely types of foundation required over the area • Based on the type profiles and generalised engineering properties • Intended for use at a planning scale
Upper Forth Map Series • It is generally conceded that these maps had their problems: • the data was of varying reliability • the data had to interpolated in some areas • some interpretations were made by non-specialists • some key properties were not included • the interpretative maps were too general for many uses
The problems with the BGS maps highlight a number of general issues with such planning maps: • Who are they for? • What should they show? • How will they be used? • How good is the data?
The next steps • The next two weeks are for self study of selected problems in urban geology. • Each person should choose a topic from the list and prepare for the seminar discussion in week 4. • The first coursework will be based on the seminar discussion. • There will be tutorial help available in the lecture period in weeks 2 and 3