Analyses of Silicate Rock and Mineral Standards

Abstract

Bulk chemical analyses including some minor constituents are reported for six standard silicate rocks available from the U.S. Geological Survey. In addition to the conventional rock analyses, determinations of a number of constituents have been made by various instrumental methods. Three new standard mineral samples are available from The Pennsylvania State University. These include albite from Amelia County, Virginia; adularia from Val Cristallina, Switzerland; and pyroxene from near Libby, Montana.

Choice of X‐ray mass attenuation coefficients for PIXE analysis of silicate minerals and rocks

“…This was a 'rank 4' sample, suggesting that the composition initially taken from the literature may not be entirely credible. Goldich et al [14] mention that their composition differs substantially from the numerous earlier reports summarized by Deer et al [15] The nine analyses summarized by the latter authors are consistent within 1% variation from the mean for mass fractions of Na, Mg and Al. We therefore adopted the composition of the most recent of the works summarized by Deer et al, viz.…”

“…The only outlier in the silicon collection is the pyroxene Px‐1. Its composition was determined by Goldich, likely using the same methodology as for Ab‐1. As mentioned earlier, the Goldich SiO 2 mass fractions differ from the complied values of Deer et al , and so it seems possible that the SiO 2 composition was underestimated, causing the overall inflated result seen here for Δ ε a ( hυ ).…”

“…This database was first modified by substituting FFAST values for all those elements found in major and minor quantities in the silicate reference materials. This required us to obtain FFAST MACs for every K X-ray emitted by the elements Z = 8, 11-17, 19-30 [10] Indian Indian Ocean: USNM 113716 2 [13] VG-A99 Makaopuhi Lava Lake, HI: USNM 113498-1 2 [13] VG-2 Juan de Fuca Ridge: USNM 111240-52 2 [13] Olivine Cape Ann Fayalite: Rockport, MA; USNM 85276 3 [13] San Carlos San Carlos, Gila Co., AZ: USNM 111312-444 2 [13] Pyrobole Px-1 Clinopyroxene: Libby, MT: Px-1 4 [14] Rhyolite Peru 215 Rhyolite: Muscani, Peru: RLS-215 1 [11] Mexico-132 Rhyolite: Tulancingo, Mexico: RLS-132 1 [11] Feldspar Or-1 Orthoclase: Adularia orthoclase: Val Cristallina, Switzerland: OR-1 4 [14] Lake Co. Plagioclase: Lake Co., OR: USNM 115900 3 [13] Albite Ab-1 Albite: Amelia Co. VA: Ab-1 4 [16] The rank describes the perceived degree of reliability of literature analyses available to the authors. in the absorbing elements Z = 8, 9, 11-17 and 19-30.…”

“…Several additional standards provided in the Jarosewich compilation were derived with slightly less rigor than those ranked second and were ascribed a rank of three. The fourth rank includes some materials studied with older methods with uncertain reliability from a modern perspective.…”

Pyrohydrolysis for the rapid determination of small and large amounts of fluorine in fluorides, silicate minerals and rocks using an ion-selective electrode.

“…Addition of free silica, particularly for FLANAGAN, 1973FLANAGAN, 1973FUGE, 1976SEN GUPTA, 1968GOLDICH, 1967HALL and WALSH, 1969FLANAGAN, 1973FUGE, 1976SEN GUPTA, 1968GOLDICH, 1967FLANAGAN, 1973NBS CLARK BAST 1972 theoret. …”