THE MINERALOGY OF HIGH-PRESSURE HYDROGEN GENERATOR WASTE FROM PENRHYN(TONGAREVA), NORTHERN COOK-ISLANDS

Waste from a high pressure, ferrosilicon-caustic soda, hydrogen genera tor, operated for meteorological purpose on the atoll of Penrhyn (Tong areva) in the northern Cook Islands, consists of free silicon and a ra nge of silicates and carbonates that include quartz, tridymite, silici c acid (opal), trona, pirssonite, magaduite, Na5Fe(SiO3)4, and associa ted calcite and uricite. Possibly present are iron, natron, reinhardbr aunsite, silhydrite, Na2CO3.7H2O, SiO2.0.04H2O, Na5Fe(SiO3)4, Na2SiO3, nesquehonite, gypsum and portlandite. Both silicon and iron are being added in small but regular amounts to the conservative geochemical sy stem of the atoll in which they occur naturally at very low trace leve ls. While unlikely to be toxic, they may afford chemical markers for m onitoring the subsurface freshwater hydrology.