Selenium and tellurium concentrations of Carboniferous British coals

Abstract

Standard mode and collision/reaction cell mass spectroscopy methods have been utilized in order to overcome spectral interferences and provide ultra‐low quantification of selenium (Se) and tellurium (Te) in British Carboniferous coals for the first time. The accurate detection of Se and Te in coals is becoming increasingly important, as coals and pyrite have been identified as potentially significant trace element sources. The mean Se concentration of British coals bear comparison to that of world coals, with anomalous Se content (concentrations above 4 mg/kg) across westerly exposures, often coinciding with high sulphur (S) content and visible pyrite. New Te data for British coals gives a mean concentration of 0.02 mg/kg, with anomalous Te in Ayrshire. There is a positive correlation in the Te/Se ratio across the sample set. The close relationship between Se and Te, as well as Se–Te with both early syngenetic and later cleat‐filling pyrite, confirms an important role for sulphides in Se and Te sequestration in British coals. The high Se‐Bowland Shale and/or Ordovician volcanics may have provided the trace element source for British coals of similar or younger age. Regional intrusive activity (shallow tabular intrusions or more extensive plutons) and episodes of intense deformation can alter the thermal maturity of coals and may have driven the movement of trace element‐rich fluids through strata, locally enriching coals in Se and Te.

Gold in Irish Coal: Palaeo-Concentration from Metalliferous Groundwaters

“…Minerals 2020, 10, x FOR PEER REVIEW 2 of 15 (5) The context of trace element sulphur in the gold is variable, suggesting that it is a natural precipitate rather than a man-made artefact. Bulk ICP-MS analysis of the coal shows a mean selenium content of 9.7 ppm (n = 9; Table 1), higher than the mean selenium content of British coals (2.1 ppm; [44]). Samples generally free of visible pyrite and siderite (CC1-CC2) contain 0.7 to 0.8 ppm selenium, while pyritic coal samples contain 4.2 to 7.1 ppm selenium and heavily pyritic-sideritic coal samples contain up to 25.8 ppm selenium.…”

A thermal maturity map based on vitrinite reflectance of British coals

“…In addition to providing a frame of reference for thermal maturity in sedimentary sections of Carboniferous age, the database of vitrinite reflectance has applications for diverse purposes that involve national surveys. For example, the data can be used in assessments of coal bed methane (DECC 2013), shale gas potential (Smith et al 2011), geothermal energy (Gluyas et al 2018) and the interpretation of trace element data in coals (Bullock et al 2018 Lat., latitude; Long., longitude; R 0 , mean vitrinite reflectance; n, number of analyses; Inferred Fm, inferred host formation; CM, Coal Measures (Upper, Middle, Lower); WG, Warwickshire Group; CG, Clackmannan Group; LCG, Limestone Coal Group; LCF, Lower Limestone Formation; YG, Yoredale Group; n.g., number of analyses not given or not deciphered from source. Depths given estimated based on seam stratigraphy, shaft excavation depth or borehole data (where available).…”

Advocating the Use of Bayesian Network in Analyzing the Modes of Occurrence of Elements in Coal

“…Bullock et al 93 found Te enrichment at the pyrite rim of the coal using LA-ICP-MS techniques. In addition, Bullock et al 94 indicated that the average concentration of Te is associated with early syngenetic and later cleat-filling pyrite by investigating British Carboniferous coals. closely associated, which is to be expected for these siderophile elements.…”