Mineralogical report on ceramics

Appendix A in Report on the Mineralogy of Sample Sherds from Taunton CastleCopyright © 2015 Somerset Archaeological & Natural History SocietyMineralogical analysis was carried out by QEMS-CAN using the methodology described by Andersen et al. (in press). Four major mineralogical types were recognised and the key mineralogical characteristics of these types are listed in Table A.1 on the next page. A list of potential minerals included in the QEMSCAN mineral groups is given in Table A.2 on page 29

Geochemical and mineralogical record of the impact of mining on the Teign Estuary, Devon, UK

Previous mineralogical and geochemical studies on the sediments in the Teign Estuary, Devon, UK, have shown that there are elevated levels of barium present within the surface sediments and the river catchment due to historical mining. For this investigation, 8 shallow cores (<1 m) were recovered from various locations in the estuary. These cores were subsequently logged, photographed and divided into approximately 5 cm depth intervals. The geochemistry and mineralogy of 68 samples from the cores were analysed. Bulk sediment geochemistry was determined by XRF and data for Ba, Cu, Pb and Zn are presented here. The mineralogy of the samples was determined by XRD. In addition, the samples from two cores were selected for mineralogical analysis using automated SEM-EDS (QEMSCAN®). The data show a sediment depth related geochemical trend with typically the lowest concentrations of Ba, Cu, Zn and Pb at the bases of the cores. Several of the sampling sites reveal a marked peak in the concentration of Pb and Zn mid-core; however, Cu values are low and invariant throughout. Postdating the Pb-Zn peak, there is a subsequent elevation in Ba in many of the cores studied, at a sediment depth of between 10 and 20 cm. Maximum concentrations of Ba reach 3360 ppm; Pb, 2220 ppm; Zn, 887 ppm and Cu, 258 ppm. Detrital minerals present include: barite, rutile, ilmenite, zircon, monazite, pyrite, cassiterite, sphalerite, galena and chalcopyrite. Framboidal pyrite is the only diagenetic mineral observed. The geochemical results are consistent with the historical mining records in the catchment, with barite mining postdating Pb-Zn mining. Both episodes of mining have released particulate mine waste, which has accumulated within the estuarine sediments

Does Carbon Limitation Reduce Nitrogen Retention in Soil?

Artificial soils made from waste materials offer an alternative to imported natural topsoils, notably in large-scale groundwork and reclamation projects. Benefits include diversion of waste from landfill and recycling. Nonetheless, there is limited information on the characteristics needed to support plant growth in the long term, particularly the existence of a sustainable nitrogen reservoir. Therefore, we assessed the efficacy of nitrogen cycling and retention within an artificial soil composed of 25 sand, 10 clay, 32.5 composted bark and 32.5 composted green waste over 52 weeks. Leachate was analysed for nitrogen species and nitrogen concentrations, and two of the soil columns had fertiliser added after 26 and 48 weeks. Results show that nitrate concentrations decreased from 6.73 to 0.36 mg N L−1 after 2 weeks, due to poor retention of this anion in soil, and remained low for 6 months, before increasing up to 5.87 mg N L−1 after week 26. This sharp increase in dissolved nitrate was preceded by a decrease in the ratio of dissolved organic carbon to dissolved organic nitrogen in the soil leachate. This finding indicates that the soil had become carbon-limited, leading to mineralisation of organic nitrogen by soil organisms and excretion of nitrogen. We also found that fertilisation of the soil did not alleviate carbon limitation and nitrogen loss was greater in fertilised soils, indicating nitrogen saturation. After the onset of carbon limitation, the dissolved nitrate concentrations in both the fertilised and unfertilised soils were close to exceeding the European Union threshold of concern for nitrate groundwater and river pollution. Thus, while the deployment of artificial soils is a viable option for landscaping projects, loss of nitrogen may be environmentally significant and soil management protocols must take account of both the carbon and nitrogen status of the substrate. © 2017 Springer International Publishing AG, part of Springer Natur

Geochemical and mineralogical record of historical mining, Hayle estuary, Cornwall, UK

The release pf particulate waste as a result of major historical mining activity within the polymetallic Cornubian orefield, Cornwall UK, has locally caused significant contamination of estuarine sediments. In this study the impact of historical mining on the southwest Hayle Estuary, Cornwall, UK, was evaluated by examining the sediment geochemistry and mineralogy of nine shallow (&lt;1 m) cores along with surface sediment sampling throughout the intertidal areas of the estuary. The sediment geochemistry of ll of the cores shows very elevated levels of tin and copper (maximum Sn value of 7041 ppm and Cu 29,869 ppm). Surface (uppermost 5 cm) sediment samples are also contaminated, with up to 4520 ppm Cu, 5455 ppm Sn, 2292 ppm As, 522 ppm Pb and 1777 ppm Zn. Core dating indicates that the sediments currently exposed at the surface were deposited prior to 1880. The detrital heavy mineral assemblage is dominated by cassiterite, chalcopyrite, arsenopyrite, sphalerite and pyrite along with minor galena, monazite, zircon, stannite, wolframite, plumbogummite, covellite, bornite and ilmenite. In addition, man made slag and smelt products are common. Diagenetic pyrite, chalcopyrite and atacamite are also present. The sediment geochemistry and mineralogy are interpreted to represent (a) the input of historic mine waste tailings and smelt waste into the estuary probably prior to 1880, and (b) the subsequent exposure of these contaminated sediments as a result of recent erosion

Characterisation of Nonsulphide Zinc Deposits using QEMSCAN.

This study develops QEMSCAN technology to rapidly acquire spatially resolved mineralogical data from non-sulphide zinc ores from Accha (Peru) and Skorpion (Namibia). The resulting modal and textural data provides significant additional information on the distribution of the ore minerals including detail on the trace minerals, grain size distributions, and mineral associations. The data were verified by XRD to assess clays and compositionally similar mineral polymorphs and EPMA to accurately establish mineral compositions

Impact of mining on the sediment geochemistry and Mineralogy of the Helford river, Cornwall

The geochemistry and mineralogy of the intertidal sediments of the Helford River, Cornwall have been examined to assess the potential impact of mining activity on sediment supply. Cores from Polpenwith and Polwheveral creeks show a pulse in Sn (1000-1100 ppm), Cu (800-900 ppm) and Zn (500-600 ppm) at a depth of 30 cm below the present day sediment surface; As and Pb values are typically low and show little down-core variation (&lt;130 ppm As and &lt;78 ppm Pb). Two cores recovered near Gweek have generally low and invariant down-core geochemical signatures, except for a single sample from the base of Core 2 which shows a sudden increase in Sn to &gt;1800 ppm. In addition, two cores were collected from the mouth of Mawgan Creek. Core 4 shows a low but invariant geochemical signature but Core 3 shows a significant down-core increase in Sn (&gt;1900 ppm Sn), Cu (588 ppm) and Zn (1297 ppm). The heavy mineral assemblage is dominated by cassiterite, chalcopyrite and sphalerite, along with less abundant zircon, monazite, ilmenite, rutile/anatase, sphene, wolframite, barite and rare slag products. Diagenetic pyrite, bornite and Fe oxides also occur. The geochemistry and mineralogy are consistent with the historical release of mine waste tailings into the Helford River. 210Pb dating of two cores suggests that the sediments are younger than 1880. Based on these data the most likely sources of the mine waste are from Wheal Caroline and Wheal Vyvyan to the north of the Helford River which are documented as being active between 1827 and 1864

Mineralogical analysis and provenancing of ancient ceramics using automated SEM-EDS analysis (QEMSCAN®): a pilot study on LB I pottery from Akrotiri, Thera

A wide range of existing mineralogical and geochemical methodologies such as optical microscopy, X-ray diffraction, manual scanning electron microscopy, ICP-MS and INAA have been utilised in the analysis of ancient ceramics, in attempts to elucidate patterns of regional trade and interaction. However, advances in automated scanning electron microscopy with linked energy dispersive spectrometers (SEM-EDS) have created the potential to offer a seamless combination of textural and mineralogical data based on the acquisition of energy dispersive spectra that has so far been unattainable with existing techniques. In this pilot study on pottery from the Cycladic Bronze Age site of Akrotiri (Thera), we have quantified the mineralogy of the ceramics based on automated SEM-EDS using QEMSCAN® technology and imaged the textures of the ceramics through compositional mapping. Thirteen samples were analysed and, based upon the automated analysis, four groups of ceramic compositions are defined. These data are consistent with, but also refine, previous traditional petrographic examination of the ceramic samples, and enable the likely provenance of the raw materials used in the ceramic manufacture to be identified. This technique allows the acquisition of fully quantitative data, not only for the larger inclusions within the ceramics but also for the typically finer-grained groundmass/matrix, whilst also providing the overall texture of the ceramic