- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Drift pumice collected in December, 1964, from the Herald Cays in the western Coral Sea is chemically and petrographically a dacite, unusually low in K 2 O and with very calcic plagioclase. It is apparently identical to pumice washed ashore in Fiji in March, 1965; both collections are divisible into light and dark varieties on megascopic, optical and chemical criteria. This pumice is distinguishable from the widely distributed pumice of the 1962 South Sandwich eruption; it is considered to have originated along the Tonga-Kermadec ridge on the basis of available seismic and compositional data.