Elucidating the processes affecting highly primitive lavas of the Borgarhraun flow (northern Iceland) using trace elements in olivine ...

• Main Authors: Tollan, Peter, Gurenko, Andrey, Hermann, Jörg
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2020
• Subjects: Olivine; Trace element; Primitive; Basalt; Differentiation; Iceland
• Online Access: https://dx.doi.org/10.3929/ethz-b-000431955; http://hdl.handle.net/20.500.11850/431955

Olivine is typically the first phase to crystallise from basaltic melts and its chemistry can therefore inform on the earliest stages of magmatic evolution, not recorded by later crystallising phases. Despite the potential of olivine for understanding primitive differentiation, limited analytical capabilities have previously restricted the range of elements that can be routinely measured. Consequently, important processes controlling early magma evolution may have been overlooked or misidentified. This study reports a wide range of minor and trace elements in forsteritic (up to Fo92.2) olivine macrocrysts from the primitive Borgarhraun lava flow in northern Iceland. We define two distinct populations of olivine based on their forsterite (Fo) content and then apply minor and trace element data to discern mixing and crystallisation of subtly different high-MgO parental melts. High-Fo (90.9–92.2 mol%) olivines show approximately linear trends between Cr and other incompatible trace elements (Li, Na, Ca, Ti, Al ... : Geochimica et Cosmochimica Acta, 286 ...