contact breccia

contact breccia

[′kän‚takt ′brech·ə]
(petrology)
Angular rock fragments resulting from shattering of wall rocks around laccolithic and other igneous masses.
References in periodicals archive ?
Exploratory drilling has also been carried out in the Pardo Area (11 holes) The drilling intersected anomalous PGM values (300-500 ppb 3E) across significant widths along an 800 strike length in an area of newly defined contact breccia.
Particular emphasis is being placed on expanding targets identified by reconnaissance drilling, geophysics and geology especially along the northern contact of the intrusive, where platinum-palladium mineralization has been established to exist within the contact breccia zone over a strike length in excess of 15 kilometres.
The extent and nature of alteration and mineralisation styles observed to date at Oomargi all suggest the presence of a large mineralised porphyry system, with potential for higher grade copper-gold mineralisation in contact breccia zones based on megascopic observations of various mineral species.
Drill holes OM 001 and OM 002 intersected alternating zones of altered diorite porphyry, mineralised contact breccia zones, and phyllitic metasediments.
Some diorite porphyry clasts within the contact breccia zone in drill hole OM 001 contain abundant disseminated chalcopyrite.
Within the contact breccia zones strong magnetite and actinolite also occur within the propylitic assemblage.