| Title | Alteration Mineralogy of Sediments in the Huka Falls Formation of Thete Mihi Area, Wairakei |
|---|---|
| Authors | Ma Chi and P.R.L. Browne |
| Year | 1991 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | |
| Abstract | The Huka Falls Formation in the Te Mihi area of the geothermal system comprises hydrothermal eruption brecciasand sediments up to thick. Sixty core samples recovered from drillholes and 222 contain hydrothermal minerals grouped into3 zones;smectite, adularia-calcite-chlorite and that reflect the prevailing thermal regime. Smectites occur in the sediments where measured well temperatures are below and adularia-calcite-chlorite between 220?C.End member illite occurs where temperaturesexceed with interlayered illite-smectitehaving increasing proportions of illite at higher temperatures. |