The olivine macrocryst problem: New insights from minor and trace element compositions of olivine from Lac de Gras kimberlites, Canada

The evolution of calcite-bearing kimberlites by melt-rock reaction: evidence from polymineralic inclusions within clinopyroxene and garnet megacrysts from Lac de Gras kimberlites, Canada

“…5a), phenocrystic rims on olivines in kimberlite show a characteristic trend of decreasing Ni at buffered Mg# (arrow in Fig. 5a) which has previously been attributed to the effect of opx dissolution (e.g., Pilbeam et al 2013;Bussweiler et al 2015).…”

“…The LDG kimberlitic olivine data can be divided into two main trends: (1) cores with high NiO (and low CaO) at variable Mg/(Mg + Fe) (Mg#) and (2) rims with decreasing NiO (and increasing CaO) at relatively constant Mg# (arrow in Fig. 5a) (e.g., Fedortchouk and Canil 2004;Brett et al 2009;Bussweiler et al 2015).…”

“…Twelve olivine mineral inclusions were measured in Cr-pyropes from Diavik, one in Cr-pyrope from Point Lake, and one in Cr-diopside from Diavik. Reference data for LDG kimberlite olivines divided into cores and rims are from Brett et al (2009) andBussweiler et al (2015). The arrow in (a) highlights the differentiation trend of phenocrystic rims (see text).…”

Orthopyroxene survival in deep carbonatite melts: implications for kimberlites

“…This reaction also produces more CO 2 , further accelerating ascent. This crystallization of olivine may contribute to the polybaric olivine assemblage observed in kimberlites (Kamenetsky et al 2008;Mitchell 2008;Brett et al 2009;Arndt et al 2010;Bussweiler et al 2015;Sobolev et al 2015) and causes the residual melt to evolve to more CaO-rich compositions which results in calcite later crystallizing as primary groundmass mineral. The consumption of orthopyroxene in the first reaction explains its scarcity in kimberlite samples at the surface.…”

High-resolution LA-ICP-MS trace element mapping of igneous minerals: In search of magma histories

“…The rich compositional archive has particularly been exploited in igneous petrology, where chemical zoning of individual crystals can be directly related to changes in magmatic environment (Bussweiler et al, 2015;Streck, 2008). Trace element variations during crystal growth bear important information on magma compositions and conditions during crystallization, complementing petrography and major element studies (Ginibre et al, 2007).…”