| Abstract |
Carbon, hydrogen and oxygen stable isotope analyses have been made on dioxide,methane and water warm hot springs in the Coromandel Peninsula and Hauraki Plains. Most of the waters meteoric waters. Methane values vary widely, from -30 to -72 Warm springs swamps at Maketu and have microbial methane probably addedto the wafer near surface. and Miranda springs produce thermally derived methane. The Kaitoke springs at Great Barrier and Te springs also contain derivedmethane, and theHot Water Beach gas is similar to the Kaitoke gas in chemistry isotopic composition but by microbial oxidation. The Te gas, though,is not with a geothermal originand the springs and oxygen-isotopealtered water are further evidence for high Other spring gases have of thermogenic and microbial methane and are closely similar to major geothermal compositions. which is usually present in lesser amounts than N,, has isotopic values which suggest a geothermal origin at Te and but indicates a origin. The dominanceof the fluid flowsare tectonic flow rather than geothermal. data gives further of no major contribution from magmatic material except at Maketu, on boundary of |