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Low enthalpy geothermal resources - Miranda-Kaiaua area

TR 2012/19

Report: TR 2012/19

Author: AT Peter (University of Auckland)

Abstract

This report encompasses the western portion of the Hauraki Depression namely from the Miranda Hot Springs to the Kaiaua area.

The purpose of the survey was to assess the geothermal resources of the Miranda-Kaiaua area and see if there is a link between the two areas, whether they are one resource or two separate resources altogether. The field survey was conducted on 11 October 2010, measuring water temperatures of the hot spring and water bores along the Miranda-Kaiaua stretch. Water samples of thermal waters were also taken.

The preliminary geochemical analyses are looked at, identifying the chemical components of the sampled waters in the area. It should be stressed that not much information on previous work was gathered on the Kaiaua area and only field observations are discussed. Much of the report covers the Miranda hot springs.

The sustainability of the resource is also discussed.

Low enthalpy geothermal resources - Miranda-Kaiaua area [PDF, 794 KB]

Contents
  Acknowledgement i
  Abstract vi
1 Introduction 1
2 Previous work - Miranda-Kaiaua area 1
3 Miranda Hot Springs 2
3.1 Location 2
3.2 History of Miranda Springs 3
3.3 Present development 3
3.4 Land use 4
4 Miranda-Kaiaua geoscience 4
4.1 Geology 4
4.2 Hydrogeology 4
4.3 Geophysics 7
4.4 Geochemistry 11
4.5 Spring chemistry 12
4.6 Boron and chloride content 13
4.7 Water temperature 14
4.8 Bicarbonate (HCO3), salinity (NaCl) and magnesium (Mg) content 15
4.9 Soil chemistry 17
4.10 Geothermometers 17
4.11 Stored heat 18
5 Discussion 19
6 Recommendations 20
7 Conclusion 20
  References 21
  Appendix 1 - Analysis report of water samples from Kaiaua, 2010 23