High-purity quartz mineralisation in kyanite quartzites,Norway

This study presents an evaluation of Norwegian kyanite quartzites from Gullsteinberget, Knøsberget, Kjeksberget, Sormbrua, Tverrådalen, Juovva?orrú and Nasafjellet as potential deposits of high-purity quartz (HPQ) for use as raw material for special applications in high-technology industries. Fine-grained quartz, which forms 70 to 85 vol.% of these rocks, generally contains less than 50 μg g^?1 (total sum) of the structurally incorporated trace elements B, Li, Al, Ge, Ti, Fe, Mn, K and P. The concentrations are in the same range as those found in HPQ products, which are being mined and produced in Norway and elsewhere. Quartz analyses were performed using laser ablation–inductively coupled plasma mass spectrometry. Complimentary whole-rock analyses and cathodoluminescence studies of quartz were carried out to reveal processes, which have led to the low trace-element concentrations in quartz. This discovery, together with a better knowledge of the processes leading to the formation of HPQ in kyanite quartzites, could lead to the recognition of a new global type of HPQ resource applicable for industrial use. However, the processing technology necessary to separate HPQ from kyanite quartzite economically has not been developed so far.     

Determination of REE, Y, Nb, Zr, Hf, Ta, Th and U in Geological Reference Materials LSHC-1 and Amf-1 by Solution and Laser Ablation ICP-MS

This paper presents data on REE and Y, Nb, Zr, Hf, Ta, Th and U abundances for two candidate reference materials (RMs), spinel lherzolite LSHC-1 and amphibole Amf-1, being currently developed at the Institute of Geochemistry SB RAS, Irkutsk. To determine the contents of these elements inductively coupled plasma-mass spectrometry was applied with: (i) solution nebulisation (solution ICP-MS) and (ii) laser ablation (LA-ICP-MS) of fused glass disks. The precision of results obtained by both techniques was better than 6% RSD for most elements. Accuracy was assessed by using the geochemical RMs JB-2, JGb-1 (GSJ) and MAG-1 (USGS). The trace element results by solution ICP-MS for JGb-1 and JB-2 agree with reference values presented by Imai et al. (1995, this Journal) within 1–10%. Significant differences were found for Nb and Ta determinations. The accuracy of LA-ICP-MS results evaluated by RM MAG-1 was within 4%, except for Eu (about 10%). The analytical results obtained for LSHC-1 and Amf-1 by solution ICP-MS and LA-ICP-MS were in good agreement with each other and with INAA and XRF data presented for the certification of these RMs. They can be considered as the indicative values for assigning certified values to the above-mentioned RMs.