Geography Reference
In-Depth Information
variability, may each affect the data collection, data processing, data analysis and
data representation tasks. For the site, a range of possible metrics related to disorder
will be examined, eventually to establish a relationship between anthropogenic
mining impacts and landscape characteristics, and also to further analyse the
representation possibilities.
Data Preparation
The site chosen is an area of relict mining activity, active from the fourteenth
century, but primarily during the second half of the nineteenth century (mining has
now ceased in this area). The geology of the location is relatively straightforward,
consisting of sedimentary layers of the Carboniferous era, including some with
significant mineral resources, both in the rock and in mineralised veins. The main
mineral output was of barium and lead ores, along with some commercially viable
iron ore deposits. The workings were in the form of medium-sized quarries in the
exposed sandstone layer to the north, with small open pits from earlier centuries for
the more southerly measures containing barytocalcite and lead ore: these were
subsequently mined using vertical shafts and drift mining (adits) in the later
nineteenth century. A large amount of waste resulted from these operations and
spoil heaps typify the landscape. This site is near the settlement of Blagill, close to
Alston, Cumbria, in northern England.
The assessment and quantification of the disorder in this landscape relies on a
suitable-resolution digital surface model: airborne LiDAR survey data was
processed to provide a one-metre planimetric resolution gridded dataset. This
data did not have vegetation or buildings removed from the surface, but the actual
area examined has no trees or buildings covering the site, and the current land use is
uniform upland sheep grazing pasture. The initial investigation in this paper uses
this digital surface model (DSM) to assess, quantify, and characterise the nature of
the terrain.
Figure
1a
shows the shaded relief image of the surface model, with added
geological mapping (zones and fault lines) and a generalised 10 m contour map.
The grid coordinates of these maps are in metres, projected to the British National
Grid. It can be seen that the zones chosen for analysis have variability in their
geology, their height and their surface characteristics. Detailed analysis of the rock
types, their formation and their exploitation is given in Clarke (
2008
), which
indicates that the alternating layers of the Stainmore formation comprise mudstone,
sandstone and limestone, yielding rich ore deposits, whilst the Firestone zone
consists of relatively mineral-poor uniform sandstone. It is suggested here that
variation in mining activity results from the variable geology, and the remaining
evidence of that activity has affected the configuration of the current landscape,
a configuration that exhibits distinct differences in complexity and hence