sustainability Article Dilemma of Geoconservation of Monogenetic Volcanic Sites under Fast Urbanization and Infrastructure Developments with Special Relevance to the Auckland Volcanic Field, New Zealand Károly Németh 1,2,3,* , Ilmars Gravis 3 and Boglárka Németh 1 1 School of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand; [email protected] 2 Institute of Earth Physics and Space Science, 9400 Sopron, Hungary 3 The Geoconservation Trust Aotearoa, 52 Hukutaia Road, Op¯ otiki¯ 3122, New Zealand; [email protected] * Correspondence: [email protected]; Tel.: +64-27-4791484 Abstract: Geoheritage is an important aspect in developing workable strategies for natural hazard resilience. This is reflected in the UNESCO IGCP Project (# 692. Geoheritage for Geohazard Resilience) that continues to successfully develop global awareness of the multifaced aspects of geoheritage research. Geohazards form a great variety of natural phenomena that should be properly identified, and their importance communicated to all levels of society. This is especially the case in urban areas such as Auckland. The largest socio-economic urban center in New Zealand, Auckland faces potential volcanic hazards as it sits on an active Quaternary monogenetic volcanic field. Individual volcanic geosites of young eruptive products are considered to form the foundation of community Citation: Németh, K.; Gravis, I.; outreach demonstrating causes and consequences of volcanism associated volcanism. However, in Németh, B. Dilemma of recent decades, rapid urban development has increased demand for raw materials and encroached Geoconservation of Monogenetic on natural sites which would be ideal for such outreach. The dramatic loss of volcanic geoheritage Volcanic Sites under Fast of Auckland is alarming. Here we demonstrate that abandoned quarry sites (e.g., Wiri Mountain) Urbanization and Infrastructure could be used as key locations to serve these goals. We contrast the reality that Auckland sites are Developments with Special Relevance underutilized and fast diminishing, with positive examples known from similar but older volcanic to the Auckland Volcanic Field, New regions, such as the Mio/Pliocene Bakony–Balaton UNESCO Global Geopark in Hungary. Zealand. Sustainability 2021, 13, 6549. https://doi.org/10.3390/su13126549 Keywords: geoheritage; geoconservation; geohazard; resilience; quarry; urban expansion; geodiver- Academic Editor: Francesco Faccini sity; scoria cone; tuff ring; base surge Received: 5 May 2021 Accepted: 7 June 2021 Published: 8 June 2021 1. Introduction Intracontinental monogenetic volcanic fields are the most common on-land manifesta- Publisher’s Note: MDPI stays neutral tion of volcanism on Earth [1]. For centuries societies have utilized volcanic landforms for with regard to jurisdictional claims in resources, resulting in modified landscapes. Recently, abandoned quarry sites have become published maps and institutional affil- significant geosites, often featuring exposed magmatic plumbing systems of monogenetic iations. volcanoes, easily accessible, and ready to be visited and utilized as geosites for volcano geology and hazard education [2–14]. The UNESCO IGCP Project (# 692. Geoheritage for Geohazard Resilience) promotes sites allowing complex volcanic processes to be engaged with and visualized by laypeople and scientists alike [15–18]. Though a promising new Copyright: © 2021 by the authors. avenue for protection and utilization of abandoned quarries, high rates of urbanization Licensee MDPI, Basel, Switzerland. and increasing economic value of geological commodities seen as necessary for local eco- This article is an open access article nomic and development needs may override geoconservation policies and in some cases distributed under the terms and result in overexploitation [2,19–31]. Here we provide demonstrative case studies from two conditions of the Creative Commons monogenetic volcanic fields and highlight the paradoxical situation whereby in an intact Attribution (CC BY) license (https:// condition their inner structure remains hidden, while the destructive practice of quarrying creativecommons.org/licenses/by/ can reveal the succession of eruptive phases and their geological components. Therefore, a 4.0/). Sustainability 2021, 13, 6549. https://doi.org/10.3390/su13126549 https://www.mdpi.com/journal/sustainability Sustainability 2021, 13, x FOR PEER REVIEW 2 of 26 in an intact condition their inner structure remains hidden, while the destructive practice Sustainability 2021, 13, 6549 2 of 25 of quarrying can reveal the succession of eruptive phases and their geological compo- nents. Therefore, a balance must be defined between excavation and preservation, and when quarrying ceases added value must be recognized by activating educational areas andbalance recreational must be paths. defined In between this work excavation we demonstrate and preservation, this paradox and when unfolding quarrying in real ceases time inadded a rapidly value growing must be urban recognized environment by activating almost educational perfectly areascoinciding and recreational with the areal paths. extent In this work we demonstrate this paradox unfolding in real time in a rapidly growing urban of the Quaternary Auckland Volcanic Field, considered to be an active volcanic field. environment almost perfectly coinciding with the areal extent of the Quaternary Auckland Auckland city, the largest in New Zealand, is built on a still active basaltic monoge- Volcanic Field, considered to be an active volcanic field. netic volcanic field: the Auckland Volcanic Field [32] (Figure 1). Fourteen significant scoria Auckland city, the largest in New Zealand, is built on a still active basaltic monogenetic conesvolcanic within field: the the Auckland Auckland VolcanicCity metropo Field [litan32] (Figure boundaries1). Fourteen are managed significant by scoria the conesTūpuna Maungawithin theo T Aucklandāmaki Makaurau City metropolitan Authority boundaries(https://www.m are managedaunga.nz/, by theaccessed Tupuna¯ 1 June Maunga 2021). Thiso T amaki¯is a co-management Makaurau Authority framework (https://www.maunga.nz/ between Auckland Council, accessed and 1 indigenous June 2021). groups This withis a cultural co-management ties to the framework scoria cones. between While Auckland we acknowledge Council and cultural indigenous and groups historical with im- portancecultural tiesof these to the sites scoria as cones. significant While wepopu acknowledgelation centers cultural prior and to historical European importance settlement [33,34],of these the sites potential as significant of these population sites for engagement centers prior in to a Europeangeological settlement context is [not33,34 made], the ex- plicit.potential In comparison of these sites to for other engagement sites in inwider a geological Auckland, context geological is not made outcrops explicit. are In limited, com- dueparison to centuries to other of sites human in wider modification Auckland, geological[35]. The level outcrops of protection are limited, for due cultural to centuries and ar- chaeologicalof human modification sites through [35 the]. TheMaunga level ofAuthority, protection in for addition cultural to and aspirations archaeological for these sites sites tothrough be designated the Maunga as a World Authority, Heritage in addition site, mean to aspirationss this is unlikely for these to sites change, to be and designated we do not argueas a Worldotherwise. Heritage site, means this is unlikely to change, and we do not argue otherwise. FigureFigure 1. Auckland 1. Auckland Volcanic Volcanic Field Field (AVF) (AVF) on a simplified geologicalgeological map map with with the the main main volcano volcano types types (A) ( andA) and the areathe area in a in a GoogleEarthGoogleEarth satellite satellite image image ( B) marking majormajor quarryquarry sites sites host host significant significant volcanic volcanic geoheritage geoheritage sites sites and/or and/or recreational recreational facilities.facilities. The The black black rectangle rectangle shows shows the the greater greater Wiri Wiri Mountain Mountain studystudy area.area. SignificantSignificant volcanic volcanic heritage heritage sites sites with with some some geoheritagegeoheritage and and recreational recreational purposes purposes areare markedmarked with with blue blue circles. circles. Other Other abandoned abandoned quarries quarries under under urbanization urbanization pressure pres- sure are marked with red circles (A—Ōtuataua & Pukeiti; B—Te Tātua-a-Riukiuta/Three Kings; C—Maungarei/Mt Wel- are marked with red circles (A—Otuataua¯ & Pukeiti; B—Te Tatua-a-Riukiuta/Three¯ Kings; C—Maungarei/Mt Wellington; lington; D—Pupuke). Yellow circles represent scientifically significant partially quarried tuff ring sites studied extensively D—Pupuke). Yellow circles represent scientifically significant partially quarried tuff ring sites studied extensively (1— (1—Maungataketake/Ellets Mountain; 2—Moerangi/Waitomokia/Mt Gabriel; 3—Crater Hill; 4—Pukewairiki/Highbrook Maungataketake/Ellets Mountain; 2—Moerangi/Waitomokia/Mt Gabriel; 3—Crater Hill; 4—Pukewairiki/Highbrook Park). Park). Sustainability 2021, 13, x FOR PEER REVIEW 3 of 26 Sustainability 2021, 13, 6549 3 of 25 South of the Auckland City boundaries, rapid urbanization and industrialization sinceSouth the mid-20th of the Auckland Century City has boundaries, seen no protecti rapidon urbanization afforded to and sites industrialization