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(a) Photomicrograph of a glass-bearing gabbroic crystalline nodule from an Icelandic basaltic lava flow, showing the randomly oriented euhedral laths of plagioclase forming a framework in which the melt-filled pores (now partly filled by clinopyroxene) are essentially planar-sided.
(b) A glass-bearing amphibole-dominated crystalline nodule entrained in an alkali basaltic flow in Western Turkey. Note how the melt-filled pores commonly have smoothly curved walls and a generally cuspate shape.
(c) The frequency of plag-plag-melt dihedral angles in the Icelandic gabbro nodule, measured using the Universal Stage. Note the low median and high standard deviation.
(d) The frequency of amphibole-amphibole-melt dihedral angles in the Turkish nodule shown in (b), measured using the Universal Stage. Note the low median and low standard deviation. The spread of observed 3-D angles is most likely due to the anisotropy of interfacial energies in this system.
(e) The variation of angle population observed in a suite of amphibole-dominated glassy nodules from Western Turkey. The samples fall on an array connecting an initial growth-dominated pore structure with a fully texturally equilibrated pore structure. Where they lie on this array is controlled by the rate at which the melt-filled mush cooled before entrainment.
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