UKGEOS Cheshire TH0424 Additional Core Scanning Dataset

The core was stored inside sealed PVC core liner prior optical imaging and XRF point measurements. The core was slabbed 1/3 to 2/3 down its length using a specially designed core clamp to allow for asymmetric core slabbing (Monaghan et al., 2021). High-resolution optical images of the slabbed and wet core sections within the core clamps were collected shortly after slabbing the core using a Geoscan V colour line-scan camera set to 10 ms exposure and a visible resolution of 50 µm. To visually enhance core features and structures the images were scaled using GQuickView (Geotek Ltd) and compressed into jpgs. The processed outputs are available in two folders LS_Processed_Images the scaled images and LS_Processed_Images_Ruler the scaled images with a ruler showing drilling depths. The jpg images are named using the core box number. The top of the image is the top of the core box, the base of the image is the base of the core box. Each corebox ID relates to a depth range listed within TH0424_Corebox_Depths.csv. In addition, a colour chart image was taken under the same illumination condition every 5th core section, which can be used for colour calibration and colour reference. The colour chart images are named using drillers depth of the 5 core sections imaged. XRF point measurements on the slabbed and wet core sections within the core clamps shortly after slabbing the core were collected at 5 cm intervals and 10 s exposure using a Geotek XYZ Core Workstation. The XRF data was acquired with no filter at 10kV for low Z range elements and with a 25-micron silver filter at 40kV for high Z range elements. XRF elemental data is presented as raw counts (peak area). The raw count data provides an indication of variation in elemental abundances along the core, but is not a quantitative analysis. Ka-Area is the peak area for the K-alpha emission line for that particular element. Ka AreaSd is the relative error, which is a function of uncertainty in the Ka emission line intensity and uncertainty in the background intensity at the line position. This uncertainty/error is expressed as 2 standard deviation (sd). The peak areas were fitted using bAxil, a software for XRF spectrum analysis and one fitting template. In this software, the overall chi-square value (Chi-squared) indicates the goodness-of-fit of the mathematical model compared to the experimental data, with lower values indicating a better fit. Ka-Areas of <500 counts should be considered with caution as signals for very low counts are primarily dominated by noise. The dataset was then processed to remove data points over cracks, missing core intervals and heavily fractured sections of core where no reliable data could be collected. The final dataset has been aggregated into XYZ_Processed_Data.csv and is presented in drillers depth. The XRF spectral data can be requested from ukgeosenquiries@bgs.ac.uk. In addition, replicate scans as well as reference sample points have been performed to ensure consistent acquisition conditions and to identify any instrumental drift. Replicate scans can be used to identify poor core condition, and corresponding poor XRF data quality. This data is compiled in XYZ_Replicates.csv and indicated within XYZ_Processed_Data.csv ("Replicate Scan?" column). The impact of water on X-ray fluorescence (XRF) point measurements was investigated using the last 7 m of core recovered from UKGEOS TH0424 borehole (94 to 101 m bgl). This core was slabbed, scanned wet in the clamps and then allowed to dry fully in the clamps for 54 days prior to re-scanning. The dataset: XRF_wet_vs_dry.csv provides a comparison of the wet (i.e. freshly slabbed) vs dry core XRF analysis.

INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology

Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services