mesostasis

mesostasis

[¦me·zō′stā·səs]
(geology)
The last-formed interstitial material, either glassy or aphanitic, of an igneous rock.
References in periodicals archive ?
The matrix consists of granulated phenocryst material and a mesostasis of partly recrystallized quartz and feldspar.
The UFU, of minimum 100 m thickness, is again dominated by massive, columnar-jointed, medium-grained basalt containing <20-30% mesostasis, and with minor amygdaloidal zones containing zeolite minerals.
The basalts are fine- to medium-grained and contain abundant, variably textured mesostasis (30-40%).
This mesostasis is interpreted to be a quenched basaltic melt.