...Figure 3 A) General view of calcite discharge aprons on left-hand bank of Otamakokore Stream. White arrow indicates downstream direction. B) Surface of discharge apron (see Figure 3A for position). Note channel in lower part of apron. C) Spring vent divided into two parts by ridge. Spring...

... ) and Atiamuri, from tephra-rich sinter remnants capping hillocks in the Otamakokore and Whirinaki stream valleys, and from the mid-Tertiary Waitaia Sinter of Coromandel ( Skinner, 1976 ). Conventional X-ray powder diffraction showed all these additional specimens to contain high proportions of opaline...

... - ' of slightly alkaline water into the Otamakokore Stream (Lloyd 1987). The Quaternary lavas and tephra of the underlying bedrock contain extensive areas of hydrothermal alteration (Wood 1994). CALCITE PRECIPITATION A T W A I K I T E SPRINGS, N Z 483 f Fig. 2. ( a ) <;cncr-,ll \ I C W of the c i ~ l c ~ t c...

... samples from New Zealand late Pleistocene, >30,000 BP, sinters of Umukuri ( Sannazzaro et al. , in press ) and Atiamuri, from tephra-rich sinter remnants capping hillocks in the Otamakokere Stream valley, and from the late Tertiary Waitaia sinter of the Coromandel Volcanic Zone (CVZ). Conventional XRD...