Page 242 - Caldera Volcanism Analysis, Modelling and Response
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Characterisation of Archean Subaqueous Calderas in Canada 217
Figure 13 Characteristics of early hydrothermal silici¢cation and late carbonate alteration.
Scale in all photographs 13 cm (pen). (A) Ma¢c breccia matrix pervasively replaced by silica-
rich £uids. Note carbonate altered basalt clasts. (B) Network style silici¢ed matrix in basalt
breccia. (C) Turbiditic tu¡: white chert is laminated portion of tu¡ bed (LmT) and brown
carbonate is GB portion of tu¡ bed (moderate carbonate alteration). D) Intensely carbonate
altered GB tu¡ and white laminated tu¡ (LmT).
