Unlike samples from Antarctica, the volcanic rocks from the GR have not passed through continental crust prior to eruption and therefore provide the first uncontaminated view into the upper mantle in the polar regions. The nearby rift valley is about 4500 m deep. Ti and incompatible trace elements.
Most glasses are fresh, though some show signs of incipient low-temperature alteration.
From their shapes and sizes, the glass shards most likely formed by spalling of glassy rinds of a nearby volcanic outcrop. Geochemically, the glasses are relatively unfractionated tholeiites with E-MORB trace element compositions. Antigorite is the main mineral phase indicating elevated alteration temperatures. Relicts of brown spinell altered into magnetite and chlorite constitute a minor phase. At present, more investigations into the nature of these unique samples are undertaken.