Page 219 - Caldera Volcanism Analysis, Modelling and Response

194 W.U. Mueller et al.

lava Lapilli breccias water. a
locus of and counterparts; with in structure. lobes/domes. submarine

and association situ in deposits. represent hyaloclastite domes of
process domes breccia may and reworked interaction and flows volcanic into balloon part central

Interpretation, complex A (a) and flows autoclastic breccias tuff carapace their with abundant Effusive composite Dykes Locus: edifice

volcanic to and of brecciated exogenous dyke lobate disorganized breccias; an near array and lobe prominent spherulites

of rocks brecciated Aphanitic rhyodacites contents to coherent of (5–150 m-thick); and lobes intrude tuff lapilli display may joint chilled margins and cracks
Salient characteristics and volcaniclastic and Coherent (a) lithofacies: porphyritic (SiO 2 rhyolites 68–78%); segments or flows domes endogenous terminations massive and lobes m-scale columnar arcuate margins; the flow-banded perlitic and common

Lithofacies/lithology and Coherent felsic brecciated lithofacies

(a)

by
and not age U–Pb field on cut flows

(Continued ) caldera flows felsic debris for based as Sill

1 mine stratigraphy Aphanitic pyroclastic favourable determinations, W2,732 Ma relationships, Roquemaure
Table Hunter