rhyolitic tuff

rhyolitic tuff

[¦rī·ə¦lid·ik ′təf]
(geology)
A tuff composed of fragments of rhyolitic lava.
References in periodicals archive ?
This package in the northeastern part of the New River Belt is essentially coeval, and to some extent lithologically similar to units of rhyolite, rhyolitic tuff, basaltic tuff and flows, and red beds in the upper part of the Coldbrook Group in the Caledonia Belt, which also formed in an extensional tectonic setting as described by Barr et al.
Gravelly loam is interspersed with clay loam subsoil, and some of the land has rhyolite rock and soft rhyolitic tuff 20 to 40 inches down.
The El Tigre gold and silver deposit is related to a series of high-grade epithermal veins controlled by a north-south trending structure cutting across the andesitic and rhyolitic tuffs of the Sierra Madre Volcanic Complex within a broad gold and silver mineralised prophylitic alternation zone.
The Talang Kecap prospect is characterised by abundant epithermal quartz vein float in streams returning assay values up to 18.6 g/t Gold, intense clay alteration of host rhyolitic tuffs and in situ narrow banded quartz veins (1- 10 cm) carrying gold grades up to 12.1 g/t Gold.