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Characterisation of Archean Subaqueous Calderas in Canada            207

























































             Figure 8  (A--B) Western and (C--D) central segments of the Normetal caldera.TheVMS
             deposit and mineralisation is restricted to phase 5 (modi¢ed from Lafrance et al., 2000,with
             permission from Elsevier).


             currents. The matrix-supported lapilli tuff breccia and the clast-supported lapilli tuff
             breccia are interpreted as cohesive debris flow deposits transported down-slope via
             laminar flow conditions (Lowe, 1982). These fragmental deposits may be either
             pyroclastic or autoclastic in origin, but considering the predominance of effusive
             flows in this part of the sequence, autoclastic debris triggered by tremors or dome
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