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An altered basalt containing albitized feldspar accompanied by low-temperature, hydrous crystallization products such as chlorite, calcite, and epidote.



a paleotypal basaltic rock in which feldspar is represented by secondary albite. Spilites form as the result of underwater eruptions. Spilites have a microlithic or, less frquently, diabasic structure and consist of long, narrow microlites of albitized plagioclase with chlorite and ore minerals filling the spaces between the microlites. Together with keratophyres, spilites make up spilite-keratophyre formations of the geosynclinal stage of development of the mobile belts of the earth’s crust.

References in periodicals archive ?
All this period is developed almost at the margin of the recent continental drifting and plate tectonic model, but under the precept of the association of ophiolites (serpentine, gabbro, diabase, spilite, and related rocks), and interpreted the radiolarites as deep-sea conditions (Steinmann, 1905, 1927).
A minor feldspar component occurs in trace quantities, as do fragments of slate, lydite and spilite rocks.
South of the Puerto Nuevo block the San Hipolito Formation is represented in the eastern vicinities of the San Jose de Castro--Bahia Asuncion Road, by serpentinites and spilites; in the Sierras El Chorrito and Los Ajos (some 5 km east of Puerto Nuevo), and in the valley of Arroyo San Cristobal (FIGURES 16 and 17) by abundant ophicalcites, spilites, volcano-sedimentary strata, thin bedded gray siliceous deposits, radiolarites, with interbedded limestone and pink dolomite; on either side of the Puerto Nuevo Canyon, at about 2 km from Puerto Nuevo, by ophicalcites, light gray limestone, and some sandstone.