From 24th June to 10th July 2019, two
MSc students from the University
of Portsmouth’s Engineering Geology degree joined the British Geological
Survey’s Marine Geoscience
team in the Lyell Centre,
Edinburgh, to undertake their thesis projects.
Lauren Farnworth and Tristan Campbell-Reynolds arranged the
placements through Gareth Carter and Emrys Phillips, having expressed an
interest in offshore infrastructure planning and installation. The aim was
for Lauren and Tristan to undertake preliminary site assessments for different
types of offshore infrastructure in an area of the Outer Bristol Channel: one
focusing on wind turbine foundations and the other on sub-sea cable route
assessments.
In order to do this Lauren and Tristan carried out detailed
geomorphological mapping of the seafloor at a scale of 1:10,0000 using
multibeam bathymetry data. This approach allowed Lauren and Tristan to identify
and map out the potential geological constraints which would impact on the
siting of the offshore installations: for example potentially mobile sandwaves
and hard bedrock exposed on the seabed.
Initially, BGS 1:250,000 offshore bedrock and seabed
sediment maps were consulted before the students undertook their own analyses
and interpretation at a higher resolution. Seabed sediment mapping was
conducted using sediment grab and core sample data to understand where
sediments of different grain sizes were accumulated as this can affect the
foundation design for wind turbines or the approach used for laying
cables. The geology concealed beneath the seabed was interpreted based on
BGS open access core and borehole logs available from the Offshore GeoIndex,
allowing the students to create 3D fence diagrams which show the likely
subsurface structure and ground conditions across the proposed sites.
Lauren and Tristan are using their interpretations of the
data to construct conceptual “ground models” which the renewable industry need
to proceed into the development phase of any offshore infrastructure. As part
of this, Lauren and Tristen were able to tentatively identify areas of their
respective sites that would or would not be suitable for certain infrastructure
types based on the surface and subsurface geology, and make recommendations on
future Site Investigation and Survey works required to increase the resolution
of the ground models.
Aside from the experience of carrying out a site
investigation desk study, Lauren and Tristan also became part of the BGS marine
geoscience team and benefitted from talking to a range of scientists and
technical experts who work at the BGS.
Of their experiences, the students said:
The BGS open data was very useful as it allowed me to access shallow cores, boreholes, seabed grabs, seismic reflections and the 1:250 000 scale offshore geological maps, which aided me in producing my 1:10k scale map.
Lauren Farnworth
 |
| Lauren's map (in progress), showing the geomorphology, superficial and bedrock geology of part of the Bristol channel. |
So much of the data that BGS provide is taken for granted by us students and after seeing the enormous amount of work that goes into developing and maintaining the public resources like offshore geoindex and the BGS websites, I certainly have a new found respect for the hard work the whole team puts in to make our lives easier.
Tristan Campbell-Reynolds
The BGS is the MEDIN
Data Archive Centre (DAC) for marine geology, geophysics and backscatter. If
you are interested in using the open access marine data, see our marine data
webpages and please contact offshoredata@bgs.ac.uk
for more info. Marine data can be downloaded under an Open
Government Licence in various formats (e.g. GIS layers, seabed particle
size data, or pdf core logs) using the “Clip & Download” tool on the Offshore Geoindex.
A Web Map Service is also
available. You can also deposit
data with us.
Bathymetry data held by the UK Hydrographic Office (UKHO)
can be accessed from the Admiralty
Marine Data Portal. Data and reports from the offshore renewable and marine
aggregate industries can be accessed from The Crown Estate’s Marine Data Exchange.
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