(of an igneous rock) containing a higher proportion (taken together) of sodium and potassium than of aluminium.
〔地质〕（火成岩）过碱性的
Example sentencesExamples
This suggests that the peralkaline volcanic magma was derived from a lithospheric mantle source that had not been previously depleted in incompatible elements.
Finally, the eastern side of the mountain (122 million years old) is mostly peralkaline nepheline syenites and porphyrites.
To calibrate major elements, two peralkaline rhyolitic glasses were used.
Continental rifting started in the Early Cambrian with intrusion of crust-derived metaluminous to slightly peraluminous A-type granites, and culminated in the Mid-Cambrian with eruption of peralkaline rhyolites.
During the mid-1980s to early 1990s more research took place that involved detailed petrographical and geochemical studies on the syenites, alkaline, and peralkaline rocks.