DOCSLIB.ORG

Groundwater Resource Investigations of the Rangitaiki Plains Stage 1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Groundwater Resource Investigations of the Rangitaiki Plains Stage 1 DISCLAIMER This report has been pr epared by the Institute of Geological and Nuclear Sciences Limited (GNS Science) exclusively for and under contract to Bay of Plenty Regional Council. Unless otherwise agreed in writing by GNS Science, GNS Science accepts no responsibility for any use of, or reliance on an y contents of this Report by any person other than Bay of Plenty Regional Council and shall not be liable to any person other than Bay of Plenty Regional Council, on any ground, for any loss, damage or expense arising from such use or reliance. The data presented in this Report are available to GNS Science for other use from September 2010. BIBLIOGRAPHIC REFERENCE White, P.A.; Raiber, M.; Begg, J.; Freeman, J.; Thorstad, J.L. 2010. Groundwater resource investigations of the Rangitaiki Plains stage 1 – conceptual geological model, groundwater budget and preliminary groundwater allocation assessment, GNS Science Consultancy Report 2010/113. 193p. Project Number: 631W0603 Confidential 2010 CONTENTS EXECUTIVE SUMMARY ...................................................................................................... VI 1.0 INTRODUCTION ........................................................................................................ 1 2.0 RANGITAIKI PLAINS – A GEOLOGICAL REVIEW ................................................... 2 2.1 Geological setting .......................................................................................................... 2 2.2 Review of existing geological information ..................................................................... 3 2.3 Stratigraphy ................................................................................................................... 6 2.3.1 Basement rocks of Torlesse (composite) terrane ............................................ 6 2.3.1.1 Kaweka terrane ................................................................................ 9 2.3.1.2 Pahau terrane .................................................................................. 9 2.3.1.3 Whakatane Mélange ........................................................................ 9 2.3.2 Matawai Group ............................................................................................... 10 2.3.3 Quaternary deposits ....................................................................................... 10 2.3.3.1 Quaternary rocks and sediments ................................................... 11 2.4 Conclusions ................................................................................................................. 14 3.0 GEOLOGICAL STRUCTURE ................................................................................... 14 3.1 Introduction .................................................................................................................. 14 3.2 Structural elements...................................................................................................... 15 3.2.1 Taupo Rift ....................................................................................................... 15 3.2.1.1 Edgecumbe Fault ........................................................................... 16 3.2.1.2 Otakiri Fault .................................................................................... 17 3.2.1.3 Braemar - Awaiti Fault ................................................................... 17 3.2.1.4 Matata Fault ................................................................................... 17 3.2.1.5 Te Teko Fault ................................................................................. 18 3.2.1.6 Rotoitipaku Fault ............................................................................ 18 3.2.2 North Island Fault System .............................................................................. 18 3.2.2.1 Waiohau Fault ................................................................................ 18 3.2.2.2 Whakatane Fault ............................................................................ 19 3.2.2.3 Waimana Fault ............................................................................... 19 3.3 Constraints on structure .............................................................................................. 20 3.3.1 Greywacke basement surface ........................................................................ 20 3.3.2 Matahina Ignimbrite ........................................................................................ 20 3.3.3 Large Okataina Volcanic Centre eruptions .................................................... 21 3.3.4 High sea level stand marine incursions .......................................................... 21 3.4 Overall basin structure ................................................................................................ 22 3.4.1 Rates of vertical tectonic deformation ............................................................ 23 4.0 GEOLOGICAL MODEL DEVELOPMENT: METHODOLOGY .................................. 24 4.1 Geological model ......................................................................................................... 24 4.1.1 Data sources .................................................................................................. 24 4.1.1.1 Topographic data ........................................................................... 24 4.1.1.2 Geological maps ............................................................................ 24 4.1.1.3 Well log data .................................................................................. 24 4.1.1.4 Other data sources ........................................................................ 25 4.1.2 Digital terrain model ....................................................................................... 25 4.1.3 Data checking ................................................................................................. 25 4.1.4 Assignment of lithological property codes and creation of pseudo-logs ........ 26 4.1.5 Generation of 3D lithological property models ............................................... 27 4.1.6 Definition of boundary surfaces for major geological units ............................ 27 4.1.7 Assembly of the 3D geological model without inclusion of faults ................... 28 4.1.8 Assembly of geological model incorporating faults ........................................ 29 4.1.8.1 Identification of faults and development of fault tree ..................... 29 4.1.8.2 Integration of faults and horizons ................................................... 30 GNS Science Consultancy Report 2010/113 i Confidential 2010 5.0 GEOLOGICAL MODEL ............................................................................................ 30 5.1 Digital elevation model and identification of geographic features ............................... 30 5.2 Key lithologies ............................................................................................................. 31 5.2.1 Occurrence of key lithological descriptions in well logs ................................. 31 5.2.2 Distributions of key lithologies within the study area ...................................... 32 5.3 Geology of the Rangitaiki Plains area in 3D ................................................................ 33 5.3.1 Major geological units included in the geological model ................................ 33 5.3.2 Boundary surfaces of major geological units ................................................. 35 5.3.2.1 Top of “Basement undifferentiated” model unit.............................. 35 5.3.2.2 Top of “Matahina Ignimbrite” model unit ........................................ 35 5.3.2.3 Top of “Volcanics undifferentiated” model unit .............................. 35 5.3.2.4 Top of “Q6-Q8 non-marine” model unit .......................................... 36 5.3.2.5 Top of “Q5 marine” model unit ....................................................... 36 5.3.2.6 Top of “Q2-Q4” model unit ............................................................. 36 5.3.2.7 Top of “Q1 marine” model unit ....................................................... 36 5.3.2.8 Top of “Q1 non-marine” model unit ................................................ 36 5.3.3 Geology of the Rangitaiki Plains area in 3D ................................................... 37 5.3.3.1 Unfaulted model and location of faults ........................................... 37 5.3.3.2 Final geological model .................................................................. 37 5.4 Three-dimensional geological model and groundwater flow in the Rangitaiki Plains . 38 5.4.1 Depth to static water level .............................................................................. 39 5.4.2 Groundwater flow directions/potentiometric surface ...................................... 39 5.4.3 Insights into groundwater flow and recharge in the Rangitaiki Plains ............ 39 5.4.3.1 Q1 non-marine model unit ............................................................. 40 5.4.3.2 Q1 marine and Q5 marine model units .......................................... 40 5.4.3.3 Q2-Q4 and Q6-Q8 model units ...................................................... 40 5.4.3.4 Volcanics undifferentiated .............................................................. 41 5.4.3.5 Matahina Ignimbrite ....................................................................... 41 5.4.3.6 Basement undifferentiated ............................................................
Load more

Recommended publications
  • Regional Plan for the Tarawera River Catchment
    Environment Bay of Plenty P O Box 364 Whakatane NEW ZEALAND Environmental Publication 2003/24 ISSN: 1175-9372 REGIONAL PLAN FOR THE TARAWERA RIVER CATCHMENT 1 February 2004 Environment Bay of Plenty Bay of Plenty Regional Council 1 February 2004 Tarawera River Catchment Plan Reader’s Guide READER’S GUIDE There may be some parts of this regional plan that you are interested in reading. To find these parts quickly, the following guide gives a brief summary of what each chapter is about. Chapter 1 - Introduction: Names the regional plan, outlines its purpose and aims, discusses topics and issues to be managed, the geographical area of the plan, and sets its duration. Chapter 2 - Preparation of the Regional Plan for the Tarawera River Catchment: Provides a summary of how the regional plan was prepared, research undertaken and the people and organisations consulted. Chapter 3 - Statutory Framework: Outlines the primary parts or sections of the Resource Management Act 1991 relevant to the preparation of the regional plan. It also includes definitions of “Issues”, “Objectives”, “Policies”, and “Methods”. Chapter 4 - Policy Framework: Establishes how this regional plan relates to other planning documents at the national, regional and district level. Chapter 5 - Responsibilities: Identifies the principle local body and governmental organisations with resource management responsibilities, and gives a brief resume of their primary functions and duties. Chapter 6 - Physical Description of the Tarawera Catchment: Provides background information on the area covered by the regional plan. Discusses the Tarawera River catchment in four sub-areas, namely the Tarawera Lakes and their catchments, the catchment of the Upper Reach of the Tarawera River, the catchment of the Lower Reach of the Tarawera River, and the Tarawera River mouth.
    [Show full text]
  • The Ngati Awa Raupatu Report
    THE NGATI AWA RAUPATU REPORT THE NGAT I AWA RAUPATU REPORT WA I 46 WAITANGI TRIBUNAL REPORT 1999 The cover design by Cliä Whiting invokes the signing of the Treaty of Waitangi and the consequent interwoven development of Maori and Pakeha history in New Zealand as it continuously unfolds in a pattern not yet completely known A Waitangi Tribunal report isbn 1-86956-252-6 © Waitangi Tribunal 1999 Edited and produced by the Waitangi Tribunal Published by Legislation Direct, Wellington, New Zealand Printed by PrintLink, Wellington, New Zealand Text set in Adobe Minion Multiple Master Captions set in Adobe Cronos Multiple Master LIST OF CONTENTS Letter of transmittal. ix Chapter 1Chapter 1: ScopeScopeScope. 1 1.1 Introduction. 1 1.2 The raupatu claims . 2 1.3 Tribal overlaps . 3 1.4 Summary of main åndings . 4 1.5 Claims not covered in this report . 10 1.6 Hearings. 10 Chapter 2: Introduction to the Tribes. 13 2.1 Ngati Awa and Tuwharetoa . 13 2.2 Origins of Ngati Awa . 14 2.3 Ngati Awa today . 16 2.4 Origins of Tuwharetoa. 19 2.5 Tuwharetoa today . .20 2.6 Ngati Makino . 22 Chapter 3: Background . 23 3.1 Musket wars. 23 3.2 Traders . 24 3.3 Missionaries . 24 3.4 The signing of the Treaty of Waitangi . 25 3.5 Law . 26 3.6 Principles of the Treaty of Waitangi. 28 Chapter 4: The Central North Island Wars . 33 4.1 The relevance of the wars to Ngati Awa. 33 4.2 Conclusion . 39 Chapter 5: The Völkner And Fulloon Slayings .
    [Show full text]
  • The Sedimentation and Drainage History of Haroharo Caldera and the Tarawera River System, Taupo Volcanic Zone, New Zealand
    The Sedimentation and Drainage History of Haroharo Caldera and The Tarawera River System, Taupo Volcanic Zone, New Zealand Prepared by K A Hodgson and I A Nairn Environment Bay of Plenty Operations Publication 2004/03 August 2004 5 Quay Street P O Box 364 Whakatane NEW ZEALAND ISSN 1176 - 5550 Working with our communities for a better environment Environment Bay of Plenty i Acknowledgements The Department of Conservation (Rotorua Lakes Office) permitted our studies in lake and river reserves. Fletcher Challenge Forests (and its successors) provided detailed contour maps and aerial photographs. Bryan Davy and Hugh Bibby (GNS) provided a pre- publication copy of their paper on seismic imaging in Lake Tarawera. PGSF Contract IANX0201 funded this study. Sedimentation and Drainage History, Tarawera River System Operations Publication 2004/03 Environment Bay of Plenty iii Executive Summary Haroharo caldera has been formed by the coalescence of multiple collapse structures over the last 350 kyr, the latest major collapse accompanying voluminous rhyolite pyroclastic eruptions at ~50 ka. The caldera has formed a sink for precipitation on surrounding catchments, with overflow via the Tarawera River through the Whakatane graben to the sea at ~30 km to NE. Lakes have probably always occupied at least part of the caldera floor, but the early lacustrine history is largely obscured by younger eruptives. Since 26 ka, the Haroharo, Okareka, Rotoma and Tarawera volcanic complexes have grown within the caldera during eleven eruption episodes, confining ten lakes on the caldera margins. Growth of the volcanic complexes has greatly altered drainage paths and ponding areas within and marginal to the caldera, so that the present ~700 km2 caldera catchment area is about half the ~1400 km2 area that drained into the caldera between 26 ka and 9.5 ka.
    [Show full text]
  • An Introductory Review
    1 Citation: Lowe, D.J. 2010. Quaternary volcanism, tephras, and tephra-derived soils in New Zealand: an introductory review. In: Lowe, D.J.; Neall, V.E., Hedley, M; Clothier, B.; Mackay, A. 2010. Guidebook for Pre-conference North Island, New Zealand „Volcanoes to Oceans‟ field tour (27-30 July). 19th World Soils Congress, International Union of Soil Sciences, Brisbane. Soil and Earth Sciences Occasional Publication No. 3, Massey University, Palmerston North, pp. 7-29. Quaternary volcanism, tephras, and tephra-derived soils in New Zealand: an introductory review David J. Lowe Department of Earth and Ocean Sciences, University of Waikato, Hamilton Introduction This two-part article comprises brief introductions to (1) volcanism and its products in general and to the broad pattern of Quaternary volcanism and tephrostratigraphy in North Island, and (2) the ensuing tephra-derived soils of North Island. Part 1 derives mainly from Smith et al. (2006), Leonard et al. (2007), and Lowe (2008a). Other useful reviews include those of Neall (2001), Graham (2008: Chapter 7), Wilson et al. (2009), and Cole et al. (2010). Recent reviews on tephras include Shane (2000), Alloway et al. (2007), Lowe (2008b, 2011), and Lowe et al. (2008a, 2008b). A history of tephra studies in New Zealand was reported by Lowe (1990). Part 2 describes the distribution and character of the main tephra-derived soils, these being Entisols and Andisols (mostly Vitrands and Udands) and Ultisols (Lowe and Palmer, 2005). Books on these and other soils in New Zealand include NZ Soil Bureau (1968), Gibbs (1980), McLaren and Cameron (1996), Cornforth (1998), and Molloy and Christie (1998).
    [Show full text]
  • Rangitaiki Community Board 22 August 2018
    RANGITĀIKI COMMUNITY BOARD WEDNESDAY, 22 AUGUST 2018 AGENDA Meeting to be held in the Edgecumbe Community Library, College Road, Edgecumbe at 5:30 pm Marty Grenfell CHIEF EXECUTIVE 16 August 2018 WHAKATĀNE DISTRICT COUNCIL WEDNESDAY, 22 AUGUST 2018 Rangitāiki Community Board - AGENDA TABLE OF CONTENTS ITEM SUBJECT PAGE NO 1 Membership .............................................................................................. 4 2 Apologies .................................................................................................. 4 3 Conflict of Interest ..................................................................................... 4 4 Public Forum ............................................................................................. 4 5 Presentation .............................................................................................. 5 6 Recovery Update ....................................................................................... 5 7 Confirmation of Minutes ........................................................................... 6 7.1 Minutes - Rangitāiki Community Board 11 July 2018 .................................................................. 6 8 Reports ................................................................................................... 13 8.1 Rangitāiki Community Board Activity Report to 31 July 2018 ................................................... 13 8.2 Request for Funding – Waterwheel Historical Trust .................................................................
    [Show full text]
  • Wednesday, April 28, 2021 Home-Delivered $1.90, Retail $2.20 Tuhoe Protest: ‘It’S Confiscation All Over Again’ Page 3
    TE NUPEPA O TE TAIRAWHITI WEDNESDAY, APRIL 28, 2021 HOME-DELIVERED $1.90, RETAIL $2.20 TUHOE PROTEST: ‘IT’S CONFISCATION ALL OVER AGAIN’ PAGE 3 TEAM COVID-19 PAGES 6-7, 12-13, 16 SPIRIT • Western Australia travel bubble reopened • Kiwis in India face more hurdles to get home Team Gisborne had every reason to smile after being named winners of the Team Spirit Award at the Halberg Games in Auckland • World rallies to help devastated India at the weekend. Back row (from left) are Team Gisborne members Oren Tibble and Tama Wirepa, team manager and Parafed • United States eases mask guidelines Gisborne-Tairawhiti regional development coordinator Lou Ellery and Raymond Braybrook. Front are Lezae Te Reo and former New Zealand Paralympics swimmer Rebecca Dubber, who presented the award. The Halberg Games is a three-day sports competition • British PM denies making open to athletes aged eight to 21 with a physical or visual impairment. Ms Ellery said anyone with a disability, of any age, was ‘bodies-piled-high’ comment welcome to join Parafed Gisborne-Tairawhiti via Facebook or by ringing her on 020 4080 9069. STORY ON PAGE 4 Picture supplied A GISBORNE woman’s of perjury had simply not He criticised her for plight through the court occurred, she said. confiding in three close friends system has been highlighted “(The woman) should have (those she called as witnesses) in national media reports as been free to leave her marriage. about the alleged abuse. a rare insight into existing She should have been able to The judge accused the concerns about the treatment secure a fair and reasonable woman as lying in an of women and children within matrimonial settlement and it “unreasonable pursuit” of more Family the Family Court system.
    [Show full text]
  • Nan's Stories
    BYRON RANGIWAI Nan’s Stories Introduction This paper explores some of the many stories that my grandmother, Rēpora Marion Brown—Nan, told me when growing up and throughout my adult life. Nan was born at Waiōhau in 1940 and died at her home at Murupara in 2017. Nan was married to Papa— Edward Tapuirikawa Brown. Nan and Papa lived on Kōwhai Avenue in Murupara. Nan’s parents were Koro Ted (Hāpurona Edward (Ted) Maki Nātana) and Nanny Pare (Pare Koekoeā Rikiriki). Koro Ted and Nanny Pare lived around the corner from her on Miro Drive. My sister and I were raised on the same street as my great-grandparents, just six or seven houses away. I could see Koro Ted’s house— located on a slight hill—from my bedroom window. Byron Rangiwai is a Lecturer in the Master of Applied Indigenous Knowledge programme in Māngere. 2 Nan’s Stories Figure 1. Koro Ted and Nanny Pare (see Figure 2; B. Rangiwai, personal collection) Koura and Patuheuheu Nan often talked about her Patuheuheu hapū and her ancestor, Koura (see Figure 2). In a battle between Ngāti Rongo and Ngāti Awa, Koura’s mokopuna was killed. (Rangiwai, 2018). To memorialise this tragedy, a section of Ngāti Rongo was renamed, Patuheuheu (Rangiwai, 2018, 2021b). Te Kaharoa, vol. 14, 2021, ISSN 1178-6035 Nan’s Stories 3 Figure 2. Whakapapa Koura was a Ngāti Rongo and Patuheuheu chief who resided at Horomanga in the 1830s and was closely connected with Ngāti Manawa (Mead & Phillis, 1982; Waitangi Tribunal, 2002). Local history maintains that Koura was responsible for upholding and retaining the mana of Tūhoe in the Te Whaiti, Murupara, Horomanga, Te Houhi and Waiōhau areas (Rangiwai, 2018).
    [Show full text]
  • A HISTORY of the TUARARANGAIA BLOCKS Wai894 #A3 Wai36 #A22 Wai 726 #A4
    A HISTORY OF THE TUARARANGAIA BLOCKS Wai894 #A3 Wai36 #A22 Wai 726 #A4 PETER CLAYWORTH A REPORT COMMISSIONED BY THE WAITANGI TRIBUNAL MAY 2001 CONTENTS LIST OF MAPS ....................................................................................................................... 5 LIST OF TABLES ................................................................................................................... 6 INTRODUCTION ................................................................................................................... 8 i.i Claims relating to the Tuararangaia blocks ...................................................................... 12 CHAPTER 1: THE TUARARANGAIA BLOCK: TE WHENUA, TE TANGATA ....... 16 1.1 Te Whenua, Te Ngahere ................................................................................................. 16 1.2 Early occupation and resource uses ................................................................................ 19 1.3 Hapu and iwi associated with Tuararangaia ................................................................... 22 1.3.1 Ngati Awa ................................................................................................................. 22 1.3.2 Ngati Pukeko ............................................................................................................. 23 1.3.3 Warahoe .................................................................................................................... 24 1.3.4 Ngati Hamua ............................................................................................................
    [Show full text]
  • Assessment of Flooding and Drainage Issues at Kopuriki
    Bay of Plenty Regional Council Assessment of Flooding and Drainage Issues at Kopuriki Bay of Plenty Regional Council Assessment of Flooding and Drainage Issues at Kopuriki Prepared By Opus International Consultants Ltd Peter Askey Whakatane Office Principal Environmental Engineer Level 1, Opus House, 13 Louvain Street PO Box 800, Whakatane 3158 New Zealand Reviewed By Telephone: +64 7 308 0139 Jack McConchie Facsimile: +64 7 308 4757 Principal Hydrologist Date: 30rd November 2017 Reference: 2-34346.00 Status: Issue 2 © Opus International Consultants Ltd 2017 Assessment of Flooding and Drainage Issues at Kopuriki i Contents Executive Summary ................................................................................................... 1 1 Introduction ....................................................................................................... 2 1.1 Background ....................................................................................................................... 2 1.2 Key Issues .......................................................................................................................... 2 1.3 Land ownership ................................................................................................................. 3 1.4 Resource Consents ............................................................................................................ 3 2 Lake Aniwaniwa and the Rangitaiki River .......................................................... 5 2.1 Lake Accretion Rates ........................................................................................................
    [Show full text]
  • 6118 NEW ZEALAND GAZETTE No. 228
    6118 NEW ZEALAND GAZETTE No. 228 2. The Whakatane District Council's proposed classification of The Road Classification (New Plymouth City) the roads as set out in the Schedule is approved. Notice No. 1, 1987 3. The Road Classification (Whakatane District) Notice No. 1, Pursuant to Regulation 3 (8) of the Heavy Motor Vehicle 1987, signed the 9th day of November 1987*, issued pursuant Regulations 197 4 and a delegation from the Secretary for to Regulation 3 of the Heavy Motor Vehicle Regulations 1974, Transport, I, Carne Maurice Clissold, Chief Traffic Engineer, which relates to the roads described in the Schedule, is give the following notice: revoked. Notice Schedule 1. This notice may be cited as the Road Classification (New Whakatane District Plymouth City) Notice No. 1, 1987. Roads Classified in Class One. 2. The New Plymouth City Council's proposed classification of the roads as set out in the Schedule is approved. All roads within the urban areas of Whakatane, Edgecumbe, Matata, Ohope, Taneatua, Te Teko and Waimana. Schedule Arawa Road. Roads Classified in Class One Awaiti South Road: from Hallet Road to Matata Road. All roads or parts of roads under the control of New Plymouth City. Awakeri Road: from Awakeri to Edgecumbe. Signed at Wellington this 9th day of December 1987. East Bank Road: from No. 2 State Highway (Pokeno to Wellington via Gisborne) to Edgecumbe. C. M. CLISSOLD, Chief Traffic Engineer. Foster Road: from White Pine Bush Road to Grace Road. (MOT. 28/8/New Plymouth City) lnl940 Galatea Road: from No. 30 State Highway (Te Kuiti to Whakatane via Atiamuri) to Whirinaki Road.
    [Show full text]
  • Te Hau Ora O Nga Kaumatua O Tuhoe
    Te Hau Ora o Nga Kaumatua o Tuhoe A Study of Tuhoe Kaumatua Mental Wellness Hinematau McNeill (2005) A thesis submitted to the Auckland University of Technology in fulfilment of the degree of Doctor of Philosophy Karakia TURUKI WHAKATAHA E Io Matua Kore Heke iho koe Pou ki te whenua Ko Papatuanuku Te aitanga a Maui-tikitiki a Taranga Ka puta ko te uwha Ka puta nga kaupapa katoa O tona Ao He Mauri He Mana He Ihi He Tapu Ka puta ko te ira tangata Ka whakamaua kia tina! Ui e Taiki e! 2 Mihi Tena koutou hai nga mahuetanga iho Mai i nga tihi tapu o o koutou maunga koawaawa Waihoki e heke ana ki tena ngutu awa ki tena ngutu awa Koutou nga kanohi ora o o koutou matua Ka heke ki te taheke-roa e kore e hokia He kohikohinga mahara ki nga tikanga taonga a kui a koro ma Ratau ka whakangangaiore ki te whakaata ake i roto o te mahara Hai morimori ma nga whakatipu reanga Kai te haere ake e kore ai e ngaro E memeha ano i te tirohanga kanohi Waiho i konei te kai-ngakau Ki te tangata mate Kia purua ko te moko Kia whakamaua kia tina Haumi e Ui e Taiki e! 3 Table of Contents Karakia ...................................................................................................................................... 2 Mihi ........................................................................................................................................... 3 Attestation of Authorship .......................................................................................................... 6 Acknowledgments....................................................................................................................
    [Show full text]
  • Putauaki Mt Resistivity Survey
    Proceedings 24* New Zealand Geothermal Workshop 2002 PUTAUAKI MT RESISTIVITY SURVEY C.J.BROMLEY Institute of Geological Nuclear Sciences, Taupo, N.Z. SUMMARY - New magnetotelluric resistivity soundings, supplemented by Schlumberger traversing measurements, have been collected in the vicinity of Putauaki (Mt Edgecumbe) to investigate the southern and eastern extent of the Kawerau Geothermal Field. They show that this field is associated with a large area of low resistivity totalling about Approximately 50% of this area is administered by the Putauaki and Te Tahuna Putauaki Trusts, and only a small portion has been tested with exploration drill holes. The volcanic peak of Putauaki itself yrs old) is on the southern boundary of the field. An association is inferred between the magma body feeding this vent and the heat source for the geothermal system yrs old). An area of particularly low resistivities ohm-m at lkm depth) and cold geothermal gas vents geothermometry is located near the centre of the revised low resistivity anomaly, about 1.4 east of the hottest existing Kawerau geothermal wells From this data, a geothermal hydrological model is inferred: a deep upflow, with associated intense hydrothermal alteration, occurs on faults centered beneath the gas vents, and supplies lateral flows to the northwest into the area of present production at Kawerau, as well as to the northeast. 1. INTRODUCTION normal step faults cause this drop in basement depth towards the centre of the Whakatane Fluids from the Kawerau Geothermal Field have Graben (Nairn, 1986). However, Wood and been utilised for process steam (up to 300 Brathwaite (1999) show that the most likely and electricity production (up to by the orientation of local basement faults, based on Tasman Pulp and Paper Mill since 1957 contours of basement elevations in Kawerau (Bloomer, 1997).
    [Show full text]