Variolites are mafic, igneous, and typically volcanic rocks, e.g. tholeiite, basalt or komatiite, that contain centimeter-scale spherical or globular structures, called varioles, in a fine-grained matrix.

Komatiites and variolitic basalts are widespread in Archean volcanic sequences. Spinifex is a spectacular bladed olivine or pyroxene texture that characterizes komatiite, a rock almost exclusively restricted to the Archean; varioles are cm-scale leucocratic globular structures abundant in many Archean basalts.

The variolitic texture denotes rapid cooling and the quench growth of the crystals, such as is often found in submarine basalts, and should not be confused with spherulitic texture which indicates devitrification.

May 15, 2002 · In places the varioles dominate the rocks so that they are largely composed of spherical aggregates having planar contacts between individual varioles. Sections through little deformed variolitic pillow basalts show scant varioles in the altered former glass at the very edge of the pillow margin.

VARIOLITES (Lat. variola, smallpox), in petrology, a group of dark green basic igneous rocks which, especially on weathered surfaces, exhibit pale coloured spots that give them a pockmarked appearance.

ona-tized basalt close to the contacts of what appear to be thin flows. Primary textures are all but totally obliterated, with the exception of what appear to be several spherical fibror

Variolites are mafic to intermediate volcanic rocks containing centimetre-sized, spherical domains, termed varioles. Varioles are dominantly composed of plagioclase spherulites. Variolitic volcanic rocks host ore in many epigenetic Au deposits within Archean greenstone belts.

Studies of minor intrusions and lavas from Norway have shown that in certain rocks this structure exists almost invariably. Certain types of lamprophyres and spilitic pillow lavas are particularly prone to a variolitic development.

Sep 5, 2023 · The assimilation of organic carbon in the Yalguba section was recognized in the basalt pillow lavas underlying the studied variolitic lavas. These rocks contain carbonaceous matter in the amygdales, inclusions in feldspar, and devitrified volcanic glass and are characterized by high vesicularity.

Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance. Basalt forms when lava …