The geochemistry of rock and water samples from Curtis Island volcano, Kermadec group, southwest Pacific
Abstract
Curtis Island is the emergent summit of a dacitic volcano straddling the Kermadec Ridge with a well-developed crater which exhibits mild solfataric activity. Apart from several narrow dacitic dykes the island is composed entirely of pumiceous pyroclastic deposits containing clasts which are mainly dacitic to rhyolitic in composition, but include rare basalt. Their chemistry is comparable to that of rocks forming other islands of the Kermadec Group. Boiling and hot springs produce dilute acid-sulphate waters that are believed to form from steam (and H 2S gas) condensing and mixing with rain water. This probably descends into the vent area and is then expelled. Hydrothermal alteration has produced a mineral suite dominated by natroalunite, chlorite, quartz, diaspore and smectites reflecting both the high Al, Fe and Mg contents of the crater floor rocks and the low pH of the altering fluids.
- Publication:
-
Journal of Volcanology and Geothermal Research
- Pub Date:
- May 1988
- DOI:
- 10.1016/0377-0273(88)90035-2
- Bibcode:
- 1988JVGR...34..233S