Pioneering geophysical prospecting to enhance sustainable approaches to the detection of the buried past
Submitting Institution
University of BradfordUnit of Assessment
Geography, Environmental Studies and ArchaeologySummary Impact Type
CulturalResearch Subject Area(s)
Earth Sciences: Geophysics
Information and Computing Sciences: Data Format
History and Archaeology: Archaeology
Summary of the impact
Bradford's pioneering research into geophysical prospecting has
significantly changed the
approach to heritage management in the UK and internationally. Our
research has influenced the
development of commercial survey instruments in this field as well as
changing industry
guidance/practice. The changes include increased use of more sustainable,
non-invasive methods
for archaeological investigation and the gathering of richer data about
the buried past. Our
guidelines for legacy archaeological data have created standards in the
archiving of this valuable
information resource for public re-use. The group's involvement with Time
Team has enhanced
public awareness of geophysical prospecting which is demonstrated in the
increased use of these
techniques by community groups.
Underpinning research
For over 40 years Archaeological Sciences at the University of Bradford
has developed novel
equipment and methodologies that enhance sustainable approaches to
detection of the buried
past. Research into archaeological geophysics was initially led by
Professor Arnold Aspinall
(Lecturer 1966-1990, Honorary Lecturer 1990-2013). The research team is
now directed by Dr
Chris Gaffney (Honorary Lecturer 1993-2007, Lecturer 2007-2013), with
significant contributions
from Dr Armin Schmidt (Lecturer 1993-2010, Honorary Research Fellow
2010-present), as well as
Honorary Research Fellows Dr John Gater (1993-present) and Dr Roger Walker
(1990-present).
Gaffney, Gater and Walker jointly lead the Bradford Centre for
Archaeological Prospection (B-CAP)
consortium of industrial and university partners which is a conduit for
enabling research impact.
Much of the group's work is focussed on the understanding of, and value
placed upon, geophysical
techniques at both public and professional levels.
We pioneered Twin-Probe (TP) earth resistance measurements for
archaeological investigation
and this became the worldwide standard array. Theoretical studies carried
out at Bradford showed
that the TP presented particular interpretational difficulties when
features are shallow and smaller
than the array separation; clearly a disadvantage when looking for
archaeological features (1,2).
Aspinall, using an electrolytic tank, investigated non-linear arrays to
reduce potential orientation
dependence associated with the TP (2). The Square Array's (SA) 2D symmetry
reduces this error
by interchangeability of current and potential electrodes. Field tests
confirmed the enhanced
suitability of the SA for shallow prospection and pointed towards
integration of TP into the same
frame as well as collecting SA via the wheels of a cart. The cart concept
was further developed via
the B-CAP consortium (3).
Two books authored by Bradford staff, Revealing the Buried Past:
geophysics for archaeologists
(4) and Magnetometry for Archaeologists (5) bring together
research and practice across a wide
spectrum of intensive field and laboratory application. These volumes
bridge the gap between the
rigorous testing of novel techniques and interpretation in diverse
archaeological settings.
Reference 5 makes use of the archive of survey data collected during the
production of Time Team
and serves, not only as a research resource, but also as a conduit to
stimulating wider involvement
in geophysical survey through illustrations of strategies specifically
devised for a non-academic
audience. Research also includes a heritage management dimension (6).
Connected with our work on shallow geophysical data, we have also
researched and published
significant contributions with respect to documentation and archiving of
legacy data (7). This
includes the first national standards for metadata and archiving of
shallow geophysical data
allowing greater re-use and an expanded user-base beyond academia. This is
significant as
commercial activity forms the largest body of ground-based geophysical
data and signifies the
embedded relationship that these techniques have within modern
archaeology.
References to the research
1. Aspinall A, Gaffney CF. (2001) The Schlumberger array — potential and
pitfalls in archaeological
prospection. Archaeological Prospection 8(3): 199-209.
2. Aspinall A, Saunders MK. (2005) Experiments with the square array. Archaeological
Prospection 12(2): 115-129.
3. Walker R, Gaffney C, Gater JA, Wood E. (2005) Fluxgate gradiometry and
square array
resistance survey at Drumlanrig Dumfries and Galloway, Scotland. Archaeological
Prospection
12(2): 131-136.
4. Gaffney CF, Gater JA. (2003) Revealing the Buried Past: geophysics
for archaeologists.
Stroud: Tempus.
5. Aspinall A, Gaffney CF, Schmidt A. (2008) Magnetometry for
Archaeologists. Lanham: AltaMira
Press.
6. Gaffney C, Gaffney V. (2011) Through an imperfect filter: geophysical
techniques and the
management of archaeological heritage. Cowley D. (ed.) Remote sensing
for archaeological
heritage management in the 21st century. Europae Archaeologiae
Consilium. 117-128.
7. Schmidt A. (2002) Geophysical Data in Archaeology: A Guide to Good
Practice. ADS Series of
Guides to Good Practice. Oxford: Oxbow Books.
Evidence of Quality: Articles (1,2,3) are in the discipline's leading
research journal for near surface
heritage investigation. References (1,2,3,6) were peer reviewed. The books
(4,5,7) have Google
Scholar citations of 54, 173 and 24 respectively.
Details of the impact
A significant contribution of our research can be charted through the
change in professional use of
earth resistance surveying away from the dominance of the Twin-Probe to
the Square Array.
Bradford research highlighted the value of the Square Array configuration
to reduce orientation
problems and issues related to reversal of signal. The significance of
this can be seen by the
commercialisation of the Square Array (SA) by Geoscan Research. Geoscan
used the published
research to collect SA data via a cart system, as suggested by Aspinall.
In addition, via small
grants and a Case PhD with Geoscan Research, the Bradford group has
developed this into a low
footprint multi-sensor device with improved service delivery incorporating
GPS positioning. When
investigating archaeology buried beneath vulnerable surface deposits
measurements of many
parameters in one sweep is key to sustainable actions. This is a major
concern within heritage
management. The SA incorporating the cart system is now used widely for
heritage management
for archaeological purposes as well as speculative prospection for
planning purposes. Geoscan
Research has sold this system throughout the EU and exported to both New
Zealand and the USA
(a). In some areas, such as Eire, it is the dominant collecting tool for
earth resistance: data from
the National Roads Authority Archaeological Geophysical Survey Database
suggest that prior to
2008, 4% of resistance surveys used the SA with 33% thereafter. One Irish
group report 41 SA
surveys since 2008 (76% of all resistance surveys) as opposed to only six
SA surveys prior to that
period. The reasons for the popularity of the Bradford-inspired SA include
quality of data, increased
speed of survey and richer datasets (b).
Policy and Guidance
Bradford research into archive digital data format and associated metadata
for archaeological
geophysics led to the first guidance for data longevity (7). The reach of
the impact is demonstrated
in that the metadata schema proposed by Schmidt was incorporated into the
OASIS system
(Online Access to the Index of Archaeological Investigations) in 2007.
Subsequently contractors
and researchers undertaking geophysical survey have included metadata and
survey
documentation in OASIS submissions; many have also included grey
literature reports (c).
Schmidt's work demonstrates international reach with an updated version of
reference 7 including
good guidance for geophysical survey in the USA (d). The Bradford work
significantly influenced
the Institute for Archaeologists' Geophysical Special Interest Group
(GeoSIG) and, within their
inaugural meeting, archiving of geophysical data was identified as one of
the major issues for
commercial groups. The Bradford contribution forms part of the IfA's Draft
Standard and Guidance,
which has become a professional standard (e).
The value and impact of Bradford's research is clearly demonstrated in
the English Heritage (EH)
guidance on geophysical survey (f). Worldwide these guidelines are
recognised as the benchmark
for commercially-focussed evaluation and the authors draw heavily on
Bradford's contribution.
There are 15 references in the document to the Bradford geophysical group.
Ten are post-1993
and include references 2, 4 and 7. According to EH figures the document
has been downloaded c.
9000 times since 2008 while 2500 hard copies have been distributed (g).
These figures far
outnumber professional geophysicists working in archaeology, demonstrating
a wider reach to
consumers of geophysical surveys including planners, developers and
community archaeologists.
Unique downloads indicate that 15% are international and the reach can be
demonstrated as the
guidelines have been incorporated into many other guidance documents
including the Dutch
Quality Standard (KNA), Bavarian State, National Roads Authority
(Ireland), the EuroGPR
Guidelines for Archaeology, the Californian Transportation Cultural
Handbook, and the European
Association of Archaeologists guidelines (g). In addition, the
international value of reference 4 for
guiding new geophysical users is demonstrated by the 22 citations within
the archaeological
geophysics for Department of Defence guidance document funded by the
American government's
Environmental Security Technology Certification Program (h and i).
Interpretation and Public Engagement/Awareness
Public engagement with geophysical prospection has increased significantly
throughout the last
decade. The understanding and use of prospection techniques by the public
is strongly linked to
the work of the geophysical group at Bradford. The work of Gaffney and
Gater has impacted on
public perception by introducing new techniques and methods on successful
TV programmes.
Their long-term contribution to C4's Time Team is an obvious example of
this and is underpinned
by reference 4. However, the impact of this research is much deeper than
the 2-3 million regular
viewers and 15-20 million who watch occasionally. Community groups have,
as a result of the
visible demonstration of the techniques pioneered by the Bradford group,
undertaken surveys of
their own. Much of this activity is Heritage Lottery-funded. Since 2008
HLF has funded over £1
million on 34 projects that incorporated geophysics into their bids, and
this is a shift away from
watching to doing archaeology by a greater number of the public (j).
Sources to corroborate the impact
a. Geoscan Research. Square Array Testimonial document
b. Letter: Earthsound Geophysics. Describes increased commercial use of
Square Array.
"... we purchased a Square Array and we now use it for the majority of
our earth resistance
work. This has changed the way we carry out geophysical surveys...We
chose to purchase the
instrument following reviews of the square array and initial results of
the instrument (Aspinall
and Saunders 2005, Walker et al. 2005). We have found that the research
carried out by the
University of Bradford has been enormously helpful for the development
and practice of
archaeological geophysics and we closely follow their research outputs
to determine what
future impacts we can use in our commercial work."
c. Email: Deputy Director, Archaeology Data Service
"Most notably the metadata schema he proposed was incorporated into the
OASIS
system...this has enabled the more routine recording of surveys and
their results by local
Historic Environment Records and at a national level by English Heritage
and the RCAHMS."
d. Schmidt A, Ernenwein E, 2011, Guide to Good Practice: Geophysical Data
in Archaeology
http://guides.archaeologydataservice.ac.uk/g2gp/Geophysics_Toc
e. http://www.archaeologists.net/groups/geophysics
IFA, 2010, Draft Standard and guidance for
archaeological geophysical survey http://www.archaeologists.net/sites/default/files/node-files/geophysicsSG.pdf
f. English Heritage Guidelines (David A, Linford N, Linford P. 2008:
Geophysical survey in
archaeological field evaluation. English Heritage, Swindon.) http://www.english-heritage.org.uk/publications/geophysical-survey-in-archaeological-field-evaluation/
g. Email from Geophysics Manager, English Heritage
"... the guidelines attempt to synthesise the results of relevant
research and tests published by
leading researchers in the discipline and draw from these
recommendations for best practice.
As such I note that we have cited 15 works that draw upon the research
of present and past
staff and honorary lecturers at Bradford University and, in particular,
I'd draw attention to three
of these publications:
Schmidt A. 2002. We did not consider it necessary to attempt to define
standards for the digital
archiving of archaeological geophysical data within the guidelines
because we thought the
work that Armin Schmidt did for the Archaeological Data Service
comprehensively covers the
considerations and so we referred the reader to his publication.
Aspinall A and Saunders MK. 2005. In our discussion of earth resistance
methodologies we
drew upon Aspinall and Sanders's work as one of the few recent
publications re-evaluating the
square array, their examination of the directional sensitivity of the
alpha, beta and gamma
configurations was especially useful.
Gaffney CF and Gater JA. 2003. We drew upon this book extensively and
I see that we cited it
on no less than 10 separate occasions. It provides clear and concise
explanations of many of
the practicalities involved in geophysical data collection and
processing ... we referred the
reader to these explanations in many of our discussions of best
practice. We also leant heavily
on this work for discussion of the different levels of geophysical
survey employed for evaluation
archaeology. It provides a good overview of the considerations and
workflows that apply in
applications of archaeological geophysics beyond the academic sector."
h. Ernenwein E and Hargraves M.L. 2009 Archaeological Geophysics for DoD
Field Use: a Guide
for New and Novice Users http://serdp-estcp.org/Tools-and-Training/Resource-Conservation-and-Climate-Change/Cultural-Resources-Management/Archaeological-Geophysics-for-DoD-Field-Use-A-Guide-for-New-and-Novice-Users
i. Letter: Project manager, US Army Corps of Engineers Army Engineer
Research and
Development Center
"In the US, we frequently look to the UK as a model for the successful
integration of geophysics
into compliance, community, and academic archaeology, and we attribute
much of that
success to the University of Bradford research community...When writing
our guidance
document, we naturally took a very close look at the existing volumes of
similar character...we
found Gaffney and Gater's 2003 volume to be extremely useful. They
appeared to have found
just the right mix of fundamental concepts, technical details,
discussion of field issues that
confront the novice, and detailed examples that illustrate geophysics'
potential...Many
American geophysical practitioners recognize the University of Bradford
program and the
greater Bradford geophysical community as a historic and current leader
in geophysical
applications."
j. Head of the Historic Environment (Heritage Lottery Fund)
"...we are now seeing increasing numbers of applications for projects
that involve geophysical
survey... I am convinced that the popularity of the Time Team
programme...has raised the
profile of geophysical survey and encouraged greater public interest and
involvement ... and
the numbers of applications for community archaeology projects
(including a geophysical
component) have increased as a result."