Trace element composition of igneous zircon: a thermal and compositional record of the accumulation and evolution of a large silicic batholith, Spirit Mountain, Nevada

Geochemistry and origin of Carboniferous (Mississippian; Viséan) bentonites in the Namur-Dinant Basin, Belgium: evidence for a Variscan volcanic source

“…In felsic igneous rocks, whilst the major elements are hosted largely in the main rock-forming minerals, the trace element budget is commonly controlled by accessory minerals (Wark & Miller, 1993;Bea, 1996;Hoskin et al, 2000;Claiborne et al, 2010). These include apatite and zircon, which are both ubiquitous phenocrysts in the Viséan NDB bentonites.…”

“…It is feasible, therefore, that many of the trace elements that are routinely used to classify altered volcanic rocks (Hf, Nb, Ta, Ti, Y, Zr and REE) reside mostly in the unaltered apatite and zircon phenocrysts within the NDB bentonites. Negative Eu/Eu* anomalies are common in both igneous apatite and zircon; moreover, the magnitude of negative Eu/Eu* anomaly has been observed to correlate positively with magmatic fractionation (Hoskin et al, 2000;Belousova et al, 2002aBelousova et al, , 2002bClaiborne et al, 2010). Negative Eu/Eu* anomalies in igneous apatite and zircon have largely been attributed to the partitioning of Eu into feldspar and the subsequent removal of feldspar from the melt during fractional crystallisation (e.g.…”

Regional and temporal variability of melts during a Cordilleran magma pulse: Age and chemical evolution of the Jurassic arc, eastern Mojave Desert, California

“…Hafnium solid solution in zircon serves as a monitor of melt fractionation (Anderson et al, 2008;Barth and Wooden, 2010;Claiborne et al, 2010). Zircons from each of the three sequences exhibit comparable ranges in Hf concentrations, reflecting similar ranges of melt fractionation and internal trends typical of intrusive rocks (Figure 11 …”

Oxygen isotope and trace element geochemistry of zircons from porphyry copper system: Implications for Late Triassic metallogenesis within the Yidun Terrane, southeastern Tibetan Plateau

“…2 and in Appendix C. All of the PDL zircons have a relatively narrow range of δ 18 O zircon values (~5.8‰-6.9‰, n = 159) and enriched relative to zircons in equilibrium with mantle-derived melts (5.3 ± 0.6‰, 2σ; Valley et al, 1998;Cavosie et al, 2009 Cavosie et al, 2006), as these analyses have most likely been affected by secondary alteration (Hoskin, 2005;Wang et al, 2014a;Zeh et al, 2014), or sampled very small LREE-rich mineral or melt inclusions (Claiborne et al, 2010), or are hydrothermal zircons (Hoskin, 2005;Rayner et al, 2005). Analyses with low La concentrations (b0.1 ppm; Appendix E) and low La N /Yb N ratios (b0.003; Appendix D), all of which are indicative of significant heavy REE (HREE) enrichments (Fig.…”

“…The negligible Eu anomalies present within the PDL zircons are consistent with hydrous parental melts, as evidenced by the presence of hydrous phenocryst phases such as amphibole and biotite within bulk rock samples, a factor that probably suppressed the early crystallization of plagioclase (Blatter and Carmichael, 1998;Moore and Carmichael, 1998;Müntener et al, 2001) and resulted in weak or absent Eu anomalies. Hafnium can be used to monitor magmatic differentiation, as higher Hf concentrations are indicative of zircons generated from more evolved melts from which the early crystallized zircons have already been removed (e.g., Claiborne et al, 2006Claiborne et al, , 2010Castiñeiras et al, 2011;du Bray et al, 2011). Comparing hafnium concentrations with Eu anomalies in zircons from the same sample can therefore be used as an index of plagioclase fractionation (Castiñeiras et al, 2011;du Bray et al, 2011).…”