The veins usually have regular borders, and some brecciation
The leaching occurred along a series of solution vugs; the larger vugs accounted for some of the brecciation
and loss of bedding structure in the colemanite zone.
Hydrothermal activity appears to have occurred at moderate to shallow depths, and was both extensive and episodic, as indicated by the intense wallrock alteration halo within and surrounding the deposit and by evidence of multiple events of brecciation
and mineral deposition.
The regional geology has been reviewed by Francois (1987) in a comprehensive synthesis, surveyed by Gauthier and Francois (1989) In a following paper, Francois (in de Magnee and Francois, 1988) has laid particular stress on the role played by Roan evaporites and their diapiric ascent in various kinds of tectonic ruptures of the Kundelungu covering, followed by collapse brecciation
, to explain peculiarities like the dislocation of the three lower Roan groups in a megabreccia and the cropping out of this megabreccia as fragments, often of large size, which can be mingled with blocks of the Kundelungu Supergroups, as in cases of partial scraping of an anticline flank.
The alteration and veining at the CCS zone is similar to the Cliff Creek resource area and comprises multiple stages of quartz veining and brecciation
with associated potassic alteration and sulphides.
The intensity of alteration increases in the eastern part of the zone where very strong bleaching, brecciation
, intense clay alteration and veining indicated the presence of a large plumbing system which was fertile for Angularli-style mineralisation.
Alt CEO James Anderson commented "We are very encouraged by the wide zones of mineralisation intersected at Shepherds Bush with the level of hematite alteration, brecciation
and silicification along strike suggesting more significant gold mineralisation may be present in the area.
On the basis of field observation, silicification, brecciation
, and intense shearing, this limestone has characteristically peculiar geological features.
The migration of this fluid predates the principal fluid flow event that led to the brecciation
and extensive calcite mineralization (Figure 7).
The newly discovered mineral showing consists of mini-quartz stockworks, brecciation
and quartz/chalcedony alteration.
The front part of this limestone shows megaslab internal deformation, brecciation
and folding, as well as soft sediment deformation in the shale matrix.