Dilemma of Geoconservation of Monogenetic Volcanic Sites Under Fast Urbanization and Infrastructure Developments with Special Re

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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 components. 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 explicit.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 pressure 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 as culturally signifi- since thecant mid-20th and once Century as spectacular has seen as no those protection within afforded Auckland to City sites [36]. as culturally Demand signiﬁcant for extractable and oncescoria as has spectacular led to the as physical those within degradation Auckland of co Citynes, [36 and]. Demand in some forcases extractable destruction. scoria Lack has of ledmeaningful to the physical geoconservation degradation policies of cones, sees and this in some continue cases into destruction. the present. Lack Geological of meaningful out- geoconservationcrops exposed by policies quarrying, sees showing this continue the internal into the structure present. of Geological a scoria volcano, outcrops are exposed located byat quarrying,an industrial showing park (marked the internal with structure black rect ofangle a scoria on volcano, Figure 1) are in locatedWiri, South at an industrialAuckland. parkWe document (marked with threats black facing rectangle these on geosites Figure 1monitored) in Wiri, South through Auckland. several Wevisits document over two threatsyears. facing these geosites monitored through several visits over two years. InIn western western Hungary, Hungary, 100 100 years years of of quarrying quarrying has has left left a a legacy legacy of of exposed exposed outcrops outcrops at at monogeneticmonogenetic volcanoesvolcanoes (Figure2 2).). Though the Bakony–Balaton Bakony–Balaton UNESCO UNESCO Global Global Geopark Geop- arkmanages manages some some abandoned abandoned quarries, quarries, locations locations outside outside the theboundaries boundaries of the of the geopark geopark are arenot not afforded afforded the thesame same protection protection or level or level of conservation of conservation management management [32–34]. [32– We34]. high- We highlightlight this thisat a at100-year-old a 100-year-old abandoned abandoned basalt basalt quarry quarry that thatmay may be brought be brought back back into intopro- production,duction, placing placing pressure pressure on onlocal local communit communitiesies who who value value the the geoheritage geoheritage and and other other en- environmentalvironmental values. values. These These two two sites sites demonstrat demonstratee the need to developdevelop “ethical”“ethical” guidanceguidance onon geoconservationgeoconservation of of signiﬁcant significant sites sites in in an an industrial industrial and and urban urban context. context.

FigureFigure 2. 2.Plio-Pleistocene Plio-Pleistocene monogenetic monogenetic volcanic volcanic ﬁelds fields (Bakony–Balaton (Bakony–Balaton Highland Highland and and Little Little Hungar- Hun- iangarian Plain Plain Volcanic Volcanic Fields) Fields) in western in western Hungary Hungar showingy showing the most the important most important quarry sites quarry with sites volcanic with geoheritagevolcanic geoheritage values and values variable and protection variable protection status. status.

2.2. MaterialsMaterials andand MethodsMethods HereHere we we provide provide geological geological observations observations of of volcanic volcanic geoheritage geoheritage sites sites within within the urbanthe ur- regionban region of the of citythe city of Auckland, of Auckland, New New Zealand. Zealand. These These sites sites are are listed listed in in geopreservation geopreservation inventories and appeared in various form of reports and books arguing for their geoheritage inventories and appeared in various form of reports and books arguing for their geoher- values from a semiquantitative way [35–38]. We demonstrate the under-utilization of the itage values from a semiquantitative way [35–38]. We demonstrate the under-utilization abandoned or still operating raw material quarry sites, in contrast to another region with of the abandoned or still operating raw material quarry sites, in contrast to another region similar volcanic geoheritage values in Central Europe, where such quarry sites are widely with similar volcanic geoheritage values in Central Europe, where such quarry sites are used for geoeducation purposes and in many cases fall under strong Geoconservation widely used for geoeducation purposes and in many cases fall under strong Geoconser- policies, especially those located within a UNESCO Global Geopark. First, we demonstrate vation policies, especially those located within a UNESCO Global Geopark. First, we the geological aspects of monogenetic volcanic ﬁelds by deﬁning their meaning, geological values, and potential role in geohazard resilience programs. We provide some narrative comparative data to show the similarities between the Quaternary Auckland Volcanic Sustainability 2021, 13, 6549 4 of 25

Field and the Plio-Pleistocene volcanic fields in the western Pannonian Basin in Hungary. After establishing the case to explore the geoeducation potential of these volcanic fields, we locate the key sites and analyze the current utilization of the preserved geoheritage values in the context of volcanic geology. Subsequently, we use GoogleEarth Pro historic satellite imagery to identify the degree of geoheritage site losses through the last 25 years in contrast to their volcanic geoheritage values. In addition to using the semiquantitative method to define the degree of geoheritage loss, we provide direct records of field visits in the last five years demonstrating rapid degradation of sites subject to rapid urbanization, in particular the southern territory of the greater Auckland area (Figure1). In conclusion, we emphasize the potential for abandoned quarries to provide information that could greatly enhance the communities’ understanding of volcanic processes and their hazards within the framework of volcanic fields.

3. Results The two volcanic fields we explore are typical monogenetic volcanic fields within intracontinental settings. The key aspect of monogenetic volcanism is short and single- phase eruptions through simple volcanic conduits that source magma usually directly from the deep mantle region [1,39]. In recent years, numerous works have targeted the diversity of monogenetic volcanism and demonstrated the great variety of processes, time, and space scales over which they operate. While some monogenetic volcanoes may display some complexity, even the most complex monogenetic structures are simpler and smaller in volume than a typical polygenetic volcano such as a strato- or caldera volcano. The “monogenetic” nature of volcanism and the common formation of monogenetic volcanic fields that may include up to thousands of small volcanoes pose difficulties in assessing volcanic hazards, especially uncertainty in predicting future events within a volcanic field. While many volcanic fields, particularly Quaternary, display some recognizable patterns in eruption history, an equally large number display ambiguity in spatial and temporal evolution. To overcome this problem, volcanic hazards of such active volcanic fields are often dealt with by analyzing the full eruption spectrum of volcanic eruption types over the life of the volcanic field [40–45]. Geoheritage of monogenetic volcanic fields provides an invaluable asset in facilitating geoeducation in resilience to volcanic hazards. A common problem in geoeducation in young volcanic fields is geosites may be intact and potentially active volcanic geoforms [46–48]. Geological features may tell a “story” about the processes forming those volcanoes that may be subject to a lack of accessibility. This could be overcome by a network of geosites (e.g., various level of geoparks) interlinked within a volcanic field or across different volcanic fields, thereby representing a potentially vast spectrum of time. We demonstrate here that a young monogenetic volcanic field such as the Auckland Volcanic Field can have strong links to eroded Plio-Pleistocene volcanic fields of similar geotectonic settings such as those in Central Europe [49].

3.1. Volcanic Geoheritage Values of Monogenetic Volcanic Fields 3.1.1. Auckland Volcanic Field The Auckland Volcanic Field (AVF) is a Quaternary active monogenetic volcanic field that has at least 54 identified volcanic geoforms generated across a 250 ka time span [35,50,51]. The youngest eruptions took place from Rangitoto volcano, the largest volume eruptive center about 600 years ago (502+/−11; and 532+/−17 to 606+/−30), while the oldest known eruption measured date back to 260,000 +/−29,000 years from the Pupuke maar [51]. The eruption frequency shows that most of the eruptions took place in the 35 to 25 ky time-window [51]. Most of the volcanoes in this field commenced eruption with a brief explosive phreatomagmatic phase that formed a basalt tuff ring succession often capped by a magmatic unit of scoria and lava indicating the exhausted aquifers due to the progression of volcanic growth [52]. In the slightly elevated and central areas of the AVF which provided early settlement sites and the subsequent downtown area of Auckland, scoria cones are common (Figure3A). These scoria cones are average in Sustainability 2021, 13, 6549 5 of 25

size, eruptive volume (e.g., Dense Rock Equivalent or DRE-~0.7–0.002 km3), and edifice geometry compared to other sites around the world [53] and served as important settlement sites for the indigenous Maori¯ [54] (Figure3A). In the present day, they are mostly protected as parks and recreational spaces well utilized by inhabitants of the city. However, they offer very little geologically unique aspects mostly due to the fact that they are grass covered with no exposures preserved or readily accessible [55–57]. In the southern part of the city, volcanoes are typically phreatomagmatic volcanoes, and explosion craters (shallow maars) surrounded by tuff rings are common [58]. A significant landmark in the region is Mangere¯ Mountain (Te Pane o Mataoho), a complex elongated scoria and spatter cone complex with multiple craters (Figure3B) associated with an extensive lava fields hosting some lave tubes. Mangere¯ Mountain forms the basis of a recreational domain but also provides a unique example of geocultural aspects of scoria cones of the AVF and could be described as a “volcanic geology delight”. The volcano is the centerpiece of the Mangere¯ Mountain Education Center (http://www.mangeremountain.co.nz/, accessed 1 June 2021), providing a study path and basic volcanic geology overviews for independent and group visitors, thereby playing an important role in geoeducation in the region (Figure3C,D). Further south, in the low coastal plains of Auckland, monogenetic volcanoes display a dominant basal structure of a maar and tuff rings, with broad craters partially filled with lava lakes and scoria cone complexes, such as Maungataketake Mountain (Figure3E). These locations are in a highly urbanized area of Auckland featuring large logistic centers, factories, and transportation hubs developed over the last decades. In fact, it is the geomorphology of this region known as the “Manukau Lowlands” that has made it ideal for rapid industrial expansion covering broad regions extending to the coast of the Manukau Harbor [59–61]. Currently, Auckland is undergoing rapid traditional sprawling suburbanization, bringing many negative effects and allowing little to no room for integration of ecosystem and geosystem services within the urban growth [61]. In addition, local development drives high demand for raw materials, resulting in significant modification of geosites, and in some cases outright destruction [54,62]. Some quarries continue to operate, while others have been repurposed as industrial and waste storage facilities for the fast-growing urban surrounds (Figure3E). In the same region, volcanic geoheritage sites are also abundant, one of the most intact featuring an exposed cross section of tuff ring adjacent to a coastal exposure of ancient fossil forest with preserved tree trunks at Maungataketake [54,58] (Figure3F,G). While these sites provide superb examples of eruptive products of a phreatomagmatic explosive eruption, the only locations where one could see into a monogenetic volcano interior are the already quarried sites. However, lack of public access and engagement with these sites, coupled with rapid urbanization and continued modification of sites risks permanent loss of geoeducation potential. Rapid urbanization of rural areas contiguous with the Auckland metropolis may also be in conflict with farming communities in rural south Auckland, which may also take place on landscapes with an important geological and cultural story to tell [63,64]. Based on our investigations, we recognize a need to reimagine Auckland as a complex multi-faceted ecosystem, underlain by a geoheritage and geoconservation framework which would sit at the center of a holistic and integrated conservation and urban development strategy [63,64]. Sustainability 2021, 13, 6549 6 of 25 Sustainability 2021, 13, x FOR PEER REVIEW 6 of 26

FigureFigure 3.3.Significant Significant volcanicvolcanic geoheritagegeoheritage valuesvalues ofof thethe AucklandAuckland VolcanicVolcanic Field. Field. ( A(A)) Mount Mount Eden Eden scoria cone with lookout to Auckland City; (B) Mangere Mountain scoria cone complex with a tho- scoria cone with lookout to Auckland City; (B) Mangere Mountain scoria cone complex with a tholoid; loid; (C) explanatory board within the Mangere Mountain scoria cone crater; (D) explanation board (C) explanatory board within the Mangere Mountain scoria cone crater; (D) explanation board about about the stages of scoria cone formation; (E) quarried interior of the Mangataketake tuff ring/scoria thecone stages complex of scoria exposing cone formation; the shallow (E) quarriedsub-crater interior zone ofof thea monogenetic Mangataketake volcano, tuff ring/scoria unfortunately cone complexquickly quarried exposing away the shallow with nosub-crater public access; zone (F of) Pleistocene a monogenetic forest volcano, under a unfortunately tuff ring succession quickly of quarriedthe Maungataketake away with notuffpublic ring; (G access;) explanation (F) Pleistocene board to explain forest under the origin a tuff of ringthe fossil succession forest beneath of the Maungataketakethe phreatomagmatic tuff ring; tuff (successionG) explanation of Maungateketake. board to explain the origin of the fossil forest beneath the phreatomagmatic tuff succession of Maungateketake. Currently, Auckland is undergoing rapid traditional sprawling suburbanization, 3.1.2.bringing Western many Hungary negative effects and allowing little to no room for integration of ecosystem and Ingeosystem Western services Hungary, within two distinctthe urban monogenetic growth [61]. volcanic In addition, fields arelocal recognized development as Bakony–Balatondrives high demand Highland for raw and materials, Little Hungarian resulting Plainin significant Volcanic modification Fields [65,66] of (Figure geosites,2). Bothand fieldsin some display cases a outright typical landscape destruction formed [54,62]. by numerousSome quarries eroded continue monogenetic to operate, volcanoes. while Mostothers of have these been volcanoes repurposed formed as industrial large phreatomagmatic and waste storage edifices facilities that werefor the subsequently fast-growing filledurban with surrounds various (Figure late magmatic 3E). In the infills same like region, those volcanic in Auckland geoheritage [49]. Hungarian sites are also locations abundant, one of the most intact featuring an exposed cross section of tuff ring adjacent to a Sustainability 2021, 13, x FOR PEER REVIEW 7 of 26

coastal exposure of ancient fossil forest with preserved tree trunks at Maungataketake [54,58] (Figure 3F,G). While these sites provide superb examples of eruptive products of a phreatomagmatic explosive eruption, the only locations where one could see into a monogenetic volcano interior are the already quarried sites. However, lack of public access and engagement with these sites, coupled with rapid urbanization and continued modification of sites risks permanent loss of geoeducation potential. Rapid urbanization of rural areas contiguous with the Auckland metropolis may also be in conflict with farming communities in rural south Auckland, which may also take place on landscapes with an important geological and cultural story to tell [63,64]. Based on our investigations, we recognize a need to reimagine Auckland as a complex multi-faceted ecosystem, underlain by a geoheritage and geoconservation framework which would sit at the center of a holistic and integrated conservation and urban development strategy [63,64].

3.1.2. Western Hungary In Western Hungary, two distinct monogenetic volcanic fields are recognized as Ba- Sustainability 2021, 13, 6549 kony–Balaton Highland and Little Hungarian Plain Volcanic Fields [65,66] (Figure 2).7 ofBoth 25 fields display a typical landscape formed by numerous eroded monogenetic volcanoes. Most of these volcanoes formed large phreatomagmatic edifices that were subsequently filled with various late magmatic infills like those in Auckland [49]. Hungarian locations areare Plio-Pleistocene Plio-Pleistocene inin age age [ 67[67],], in in contrast contrast to to Auckland; Auckland; hence, hence, the the volcanoes volcanoes have have been been eroded back to their core of crater and upper conduit filling successions [68], with no eroded back to their core of crater and upper conduit filling successions [68], with no pre- preserved successions of former tuff ring or medial to distal parts of their original volcanic served successions of former tuff ring or medial to distal parts of their original volcanic edifices preserved [69]. edifices preserved [69]. In addition, the high quality alkaline basaltic late magmatic infills, mostly solidified In addition, the high quality alkaline basaltic late magmatic infills, mostly solidified lava lakes, provided raw materials over 150 years, creating large, abandoned quarries lava lakes, provided raw materials over 150 years, creating large, abandoned quarries with superbly exposed geological features of interiors of monogenetic volcanoes (Figure4 ). with superbly exposed geological features of interiors of monogenetic volcanoes Quarrying commonly exposed the subvolcanic magmatic bodies of columnar jointed (Figure 4). Quarrying commonly exposed the subvolcanic magmatic bodies of columnar basaltic intrusions (Figure4A), showing fantastic variations of peperites and mixtures of jointed basaltic intrusions (Figure 4A), showing fantastic variations of peperites and mix- coherent magma and host sediments (Figure4B–D). tures of coherent magma and host sediments (Figure 4B–D).

Figure 4. Older and partially eroded monogenetic volcanoes expose the sub-crater or shallow subvolcanic architecture of monogenetic volcanoes, demonstrating that quarry sites can have exceptional geoheritage values such as those in western Hungary. In the western part of the Bakony–Balaton Highland Volcanic Field, outside of the Bakony–Balaton UNESCO Global Geopark territory, active and semi-active quarries (A,B—Sümegprága, C,D—Bazsi) expose such intrusive bodies with peperite (C,D), indicating the role of intruding basalt melt and wet unconsolidated sediments.

Peperites are so abundant in the abandoned western Hungarian basaltic quarry sites that they form a very solid base of scientiﬁc information on the formation of magma- sediment mingling textures as world class examples [70–72] (Figure5). Various peperite textures such as blocky (Figure5A) and globular (Figure5B) as well as multiphase intrusive basaltic bodies are commonly exposed in large quarry walls that now fall under formal protection and function as key geosites to explain how magma and wet sediment can interact prior an explosive disruption. Sustainability 2021, 13, x FOR PEER REVIEW 8 of 26

Figure 4. Older and partially eroded monogenetic volcanoes expose the sub-crater or shallow subvolcanic architecture of monogenetic volcanoes, demonstrating that quarry sites can have exceptional geoheritage values such as those in western Hungary. In the western part of the Bakony– Balaton Highland Volcanic Field, outside of the Bakony–Balaton UNESCO Global Geopark territory, active and semi-active quarries (A,B—Sümegprága, C,D—Bazsi) expose such intrusive bodies with peperite (C,D), indicating the role of intruding basalt melt and wet unconsolidated sediments.

Peperites are so abundant in the abandoned western Hungarian basaltic quarry sites that they form a very solid base of scientific information on the formation of magma-sediment mingling textures as world class examples [70–72] (Figure 5). Various peperite textures such as blocky (Figure 5A) and globular (Figure 5B) as well as multiphase intrusive Sustainability 2021, 13, 6549 basaltic bodies are commonly exposed in large quarry walls that now fall under formal8 of 25 protection and function as key geosites to explain how magma and wet sediment can interact prior an explosive disruption.

Figure 5. Former quarries in western Hungary commonly became significantsignificant geosites showing the exposed interior of monogenetic volcanoes, including blocky peperite in Hajagos-hegy (A), globular peperitic sills in Ság-hegy (B), and com- monogenetic volcanoes, including blocky peperite in Hajagos-hegy (A), globular peperitic sills in Ság-hegy (B), and complex plex interaction of lava and cone building pyroclastic rocks at Badacsony (C). For textural details, the reader is referred to interaction of lava and cone building pyroclastic rocks at Badacsony (C). For textural details, the reader is referred to the the electronic version of the paper to “zoom” into the images. electronic version of the paper to “zoom” into the images. As a result, numerous abandoned quarry sites in western Hungary have become key As a result, numerous abandoned quarry sites in western Hungary have become key geosites, providing a unique view of monogenetic volcanism, as visitors can access the geosites, providing a unique view of monogenetic volcanism, as visitors can access the once violent volcanic conduit within the “frozen” interaction features that can be seen once violent volcanic conduit within the “frozen” interaction features that can be seen todaytoday (Figure (Figure 55).). Many of of these these sites sites facilitat facilitatee visualization visualization of of processes processes acting acting within within a cratera crater lake lake formed formed by bycaptured captured fresh fresh water water subsequently subsequently invaded invaded by lava, by lava, as seen as seenat Kis- at somlyóKissomly inó Westernin Western Hungary Hungary [73] [73 (Figure] (Figure 5A).5A). Wh Whileile this this site site enjoys enjoys regional regional protection protection as aas reserve, a reserve, other other locations locations such such as Uzsa as Uzsa still stillfunction function as an as active an active quarry, quarry, resulting resulting in con- in tinuedcontinued removal removal of the of the interior interior of ofa aformer former lava lava lake-filled lake-filled tuff tuff ring/scoria ring/scoria cone cone complex (Figure 55B).B). While manymany ofof the the abandoned abandoned quarries quarries may may not not be consideredbe considered visually visually attractive attractive sites, sites,their geologicaltheir geological values values are significant are significant and relevantand relevant to various to various aspects aspects of monogenetic of monogenetic vol- volcanismcanism (Figure (Figure6A–E). 6A–E). Locations Locations like thelike Pula the abandonedPula abandoned alginate alginate quarry quarry (still functioning (still func- tioningas local as source local of source fertilizer) of fertilizer) has limited has protection limited protection status (Figure status6F). (Figure Pula is 6F). a Pliocene Pula is fossila Pli- “lagerstätte”ocene fossil “lagerstätte” (literal translation (literal from translation German—“place from German—“plac of storage”,e a of lagerstätte storage”, isa lagerstätte a sedimentary is a sedimentarydeposit that deposit exhibits that extraordinary exhibits extraordinary fossils with fossils exceptional with exceptional preservation—sometimes preservation—sometimes including includingpreserved softpreserved tissues) softformed tissues) within formed a deep within maar a deep crater maar that crater accumulated that accumulated laminated craterlami- natedlake sediments crater lake rich sediments in micro rich and in macro micro fossils and macro over 100fossils m inover thickness 100 m in [74 thickness–76]. The [74– site 76].provides The site one provides of the most one of complete the most paleoenvironmental complete paleoenvironmental and paleontological and paleontological records of recordsterrestrial of floraterrestrial and faunaflora and of Central fauna Europeof Central through Europe the through Pliocene. the While Pliocene. the fossilsWhile arethe fossilscarefully are guarded carefully and guarded transferred and transferred to collections, to collections, the low volume the low exploitation volume exploitation of the site ofmean the site new mean discoveries new discoveries are inevitable are inevitable due to the due gradual to the extraction gradual extraction of raw material. of raw material. Overall, the western Hungarian monogenetic volcanoes provide older analogues for the core of young Auckland volcanoes; hence, the interconnection between such fields can be invaluable for volcanic hazard resilience and geoeducation. Although Auckland has many abandoned quarry sites, there is little to no utilization of sites for volcanic geology education, as well as significant lack of promotion of potential connection of the AVF to similar fields elsewhere as a potential tool for broader geoeducation. This is particularly obvious in the southern part of the field where recent pressure of urbanization requiring a large volume of raw materials, leaving behind “scars” on the landscape that were once geo-culturally significant sites. While urbanization is viewed as inevitable in the greater Auckland area, modified sites that have “opened up” interiors of volcanic structures could function as key geosites in understanding eruption mechanisms of monogenetic volcanoes occurring in the future of this still active volcanic field under- lying a city with a population of over 1.5 million inhabitants. Here we present a location where superb exposures associated with monogenetic volcanism have been documented as rapidly disappearing and are still threatened by seemingly unstoppable industrialization. Sustainability 2021, 13, 6549 9 of 25 Sustainability 2021, 13, x FOR PEER REVIEW 9 of 26

FigureFigure 6. 6.Abandoned Abandoned quarry quarry sites sites of of monogenetic monogenetic volcanoes volcanoes quickly quickly became became recreational recreational and and geoed- ge- oeducational sites such as Kissomlyó exposing a lava lake emplaced into a Pliocene tuff ring (A). ucational sites such as Kissomlyó exposing a lava lake emplaced into a Pliocene tuff ring (A). Large Large active quarries such as Uzsa (B) allow visitors to see the changing quarry walls gradually active quarries such as Uzsa (B) allow visitors to see the changing quarry walls gradually exposing exposing the interior of a large tuff ring–scoria cone complex. Abandoned quarry sites within the theBakony–Balaton interior of a large UNESCO tuff ring–scoria Global Geop coneark complex. act as important Abandoned geosites quarry (C) sites with within information the Bakony– boards Balatonabout the UNESCO geological Global features Geopark visibl acte in as the important sites such geosites as those (C) of with the information hydroclastic boards flow of about Szentbé- the geologicalkkálla (D). features Quarries visible such as in those the sites outside such the as thoseterritory ofthe of the hydroclastic protected ﬂowareas, of suchSzentb as émanykkálla aban- (D). Quarriesdoned quarries such as nearby those outside Sümegprága the territory (E), function of the protected as alternative areas, geos suchites; asmany however, abandoned their protection, quarries nearbydue to Sümegprdemand áforga raw (E), functionmaterials, as can alternative be problemati geosites;c at however,times. An their abandoned protection, alginate due toquarry demand of a forformer raw materials,maar lake canat Pula be problematic(F) functions at as times. an internationally An abandoned significant alginate geosite quarry with of a formerexceptionally maar lakewell-preserved at Pula (F) functions fossil assemblages as an internationally like those of signiﬁcant Messel in geosite Germany with or exceptionally Foulden Hill well-preserved in Otago, New Zealand [77]. For textural details, the reader is referred to the electronic version of the paper to fossil assemblages like those of Messel in Germany or Foulden Hill in Otago, New Zealand [77]. For “zoom” into the images. textural details, the reader is referred to the electronic version of the paper to “zoom” into the images. Sustainability 2021, 13, 6549 10 of 25

3.2. Volcanic Geoheritage Values of Auckland Volcanic Field 3.2.1. Wiri Mountain Region, South Auckland—A Complex Phreatomagmatic Volcano Wiri Mountain (Matukutururu¯ ) is part of a roughly NE-SW trending volcanic chain heavily altered by active quarrying and rapid urban expansion of South Auckland. Based on Ar-Ar and C14 geochronology and paleomagnetic data, Wiri Mountain very likely

Sustainability 2021, 13, x FOR PEER eruptedREVIEW in a time window between 32 and 34 ky, similarly to the nearby Ash11 Hill of 26 (32 ky)[51] (Figure7).

Figure 7. Wiri Mountain and its surrounding with the key sites mentioned in the paper, on Figure 7. Wiri Mountain and its surrounding with the key sites mentioned in the paper, on GoogleEarth Pro Satellite image from 2021 (A). Historical aerial photography from 14 April 1972 GoogleEarth(Source: https://retrolens.co.nz/ Pro Satellite imagemap/#/, from accessed 2021 1 (JuneA). Historical2021) fitted on aerial the current photography GoogleEarth from Pro 14 April 1972 (Source:2021 satellite https://retrolens.co.nz/map/#/ image to show the extent of urbanization, accessed in the 1 June region 2021) (B). Wiri ﬁtted Mountain, on the current Ash Hill GoogleEarth Proand 2021 a newly satellite recognized image “unknown to show tuff the ring” extent are marked of urbanization by yellow dashed in the ellipses region in (B (B).). Wiri Ash Hill Mountain, Ash and the newly recognized “unknown tuff ring” are marked by thick red ellipses in (A), showing the Hillcomplete and a coverage newly recognizedof their geoforms “unknown under urban tuff ring”layers. areThemarked outline of by the yellow remains dashed of Wiri ellipsesMoun- in (B). Ash Hilltain andis marked the newly by dashed recognized red ellipse “unknown in (A). The tuffyellow ring” starare marks marked the entrance by thick of the red Wiri ellipses lava tube in ( A), showing theon ( completeA). Scale is coverage1 km long in of both their (A, geoformsB). Arrows and under associated urban number layers.s refer The to outline the figure of numbers the remains of Wiri showing features from the sites the arrows point. Mountain is marked by dashed red ellipse in (A). The yellow star marks the entrance of the Wiri lava tubeWirion Mountain (A). Scale is unique is 1 km as long it exposes in both continuous (A,B). Arrows sections and of associated a former numbersbasal tuff referring, to the ﬁgure numbersincluding showing a 15 m thick features proximal from thelapilli sites tuff the succession. arrows point. These features are typical of the initial explosive phreatomagmatic phase of tuff ring formation in the region (Figure 8A,B). This section exposes a transition zone of pyroclastic rocks covered by subsequent basaltic Sustainability 2021, 13, 6549 11 of 25

Wiri Mountain is unique as it exposes continuous sections of a former basal tuff ring, including a 15 m thick proximal lapilli tuff succession. These features are typical of the initial explosive phreatomagmatic phase of tuff ring formation in the region (Figure8A,B ). This section exposes a transition zone of pyroclastic rocks covered by subsequent basaltic lava flows (Figure8A). The transition zone indicates eruption style changes from purely phreatomagmatic to more magmatic explosive eruption-generated phases of the eruption. The lava flow appears to be part of a ponded lava lake that was exploited over 100 years of active quarrying, leaving behind a large crater in the ground. The main phreatomagmatic edifice is inferred to be in the northern part of the volcanic complex, while the southern regions feature distal phreatomagmatic pyroclastic successions. These more distal sections provide a nearly 200 m long and 2–4 m thick pile of pyroclastic rocks that could be accessed and studied to observe slight changes over this explosive stage of volcano growth. Within this pile of pyroclastic rocks, at least five distinct units were identified (Figure8C,D), suggesting a very complex initial eruption history of the tuff ring growth phase of the volcano. This section has been gradually demolished prior to completion of scientific research on the rocks, preventing any future work on the site. In summary, the Wiri Mountain basal section is one of the best exposures in New Zealand of a near continuous succession of pyroclastic rocks typical of explosive phreatomagmatic eruptions of monogenetic volcanoes. Therefore, this provides valuable displays of products derived from the type of eruptions described. Detailed research and analysis of these rocks and volcanic features could be used to model a realistic eruption scenario that formed this volcano. This information could be utilized for geoeducation ventures related to volcanic hazard resilience of the population. As nearly all the volcanoes in the AVF have commenced eruption with explosive phreatomagmatic explosive processes forming a basal tuff ring, a near-continuous section both laterally and vertically has significant scientific value that should be preserved before modification causes further damage. While quarrying at these sites may have damaged the original geoform, exposing the near-vent tuff ring successions provides a great opportunity to preserve those remaining sections for scientific research and geoeducation. Wiri Mountain also has a unique and complex magmatic capping unit forming the upper part of the volcanic succession (Figure9). While the section itself is not significantly different from other complex and large volume monogenetic geoforms, the significance of the Wiri Mountain capping section lays in the fact that it is well exposed due to the quarrying, and displays a threefold pyroclastic unit indicating long lasting and gradually changing explosive phases in the final stage of the edifice growth (Figure9A,B). Sustainability 2021, 13, x FOR PEER REVIEW 12 of 26

lava flows (Figure 8A). The transition zone indicates eruption style changes from purely phreatomagmatic to more magmatic explosive eruption-generated phases of the eruption. The lava flow appears to be part of a ponded lava lake that was exploited over 100 years of active quarrying, leaving behind a large crater in the ground. The main phreatomagmatic edifice is inferred to be in the northern part of the volcanic complex, while the southern regions feature distal phreatomagmatic pyroclastic successions. These more distal sections provide a nearly 200 m long and 2–4 m thick pile of pyroclastic rocks that could be accessed and studied to observe slight changes over this explosive stage of volcano growth. Within this pile of pyroclastic rocks, at least five distinct units were identified (Figure 8C,D), suggesting a very complex initial eruption history of the tuff ring growth phase of the volcano. This section has been gradually demolished prior to completion of scientific research on the rocks, preventing any future work on the site. In summary, the Wiri Mountain basal section is one of the best exposures in New Zealand of a near continuous succession of pyroclastic rocks typical of explosive phreatomagmatic eruptions of monogenetic volcanoes. Therefore, this provides valuable displays of products derived from the type of eruptions described. Detailed research and analysis of these rocks and volcanic features could be used to model a realistic eruption scenario that formed this volcano. This information could be utilized for geoeducation ventures related to volcanic hazard resilience of the population. As nearly all the volcanoes in the AVF have commenced eruption with explosive phreatomagmatic explosive processes forming a basal tuff ring, a near-continuous section both laterally and vertically has significant scientific value that should be preserved before modification causes further damage. While quar- Sustainability 2021, 13, 6549 rying at these sites may have damaged the original geoform, exposing the near-vent12 tuff of 25 ring successions provides a great opportunity to preserve those remaining sections for scientific research and geoeducation.

FigureFigure 8. 8. BasaltBasalt quarrying at at Wiri Wiri Mountain Mountain over over a century a century has has exposed exposed superb superb quarry quarry walls walls as key as geosites valuable to understanding the evolution of volcanoes of Auckland. (A) Unconformity sur- key geosites valuable to understanding the evolution of volcanoes of Auckland. (A) Unconformity faces between phreatomagmatic tuff rings and capping magmatic pyroclastic and coherent lava surfacesflow units between are important phreatomagmatic locations to tuff depict rings geolog andical capping conditions magmatic where pyroclastic such eruption and style coherent changes lava ﬂowoccurred. units are(B) importantBasalt tuff locations ring succession to depict is geological informative conditions for understanding where such the eruption pyroclastic style changesdensity occurred. (B) Basalt tuff ring succession is informative for understanding the pyroclastic density current operating in that stage of the volcano growth. Note that the black rectangle corresponds to the ﬁeld of view shown in Figure8A. ( C) Long, continuous outcrops exposed by quarrying are rare and important sites; however, urban expansion and high demand for raw materials threaten their preservation. (D) The numbers refer to distinct pyroclastic units: (1) lithic-rich pyroclastic density current deposited succession, (2) lithic-rich pyroclastic density current deposit with increasing amount of juvenile pyroclasts, (3) poorly sorted, massive pyroclastic density current deposited unit, (4) bedded, juvenile-rich pyroclastic density current deposit, and (5) coarse grained thickly bedded, massive pyroclastic density current deposited unit.

Scoria units can be seen having abruptly developed on the tuff ring succession (Figure8A ). The base of the section is more spatter dominated agglutinate with large cm-to-m-size bed flattened blobs of basalt (Figure9A–C). This basal magmatic unit is covered by a more scoria lapilli-rich dark red unit with more distinct elongated lavas commonly exhibiting clastogenic texture (Figure9B–D). The third unit is a more typical well packed scoria lapilli succession that is slightly bed-flattened. The entire magmatic cap is covered by a succession of lava flows that show clastogenic texture (Figure9D–F) and some flattened and broken basalt lapilli (Figure9C). The entire section is perfectly exposed by quarrying, allowing a unique view into the proximal half section of an evolving scoria cone that extruded lava out in its final eruptive phase (Figure9D). On the far side (in the NE), the lava flows are also half sectioned by some long quarry cut surfaces, providing opportunities to observe the lava unit textural evolution up-section (Figure9E). In this side of the former volcanic edifice, a long lava tube of (cave) about 200 m length is known to lie just a few meters below the surface. The urban development at the NE side of the remaining edifice is currently lies only a few tens of meters away from the location of the lava tube. Sustainability 2021, 13, x FOR PEER REVIEW 13 of 26

current operating in that stage of the volcano growth. Note that the black rectangle corresponds to the field of view shown in Figure 8A. (C) Long, continuous outcrops exposed by quarrying are rare and important sites; however, urban expansion and high demand for raw materials threaten their preservation. (D) The numbers refer to distinct pyroclastic units: (1) lithic-rich pyroclastic density current deposited succession, (2) lithic-rich pyroclastic density current deposit with increasing amount of juvenile pyroclasts, (3) poorly sorted, massive pyroclastic density current deposited unit, (4) bedded, juvenile-rich pyroclastic density current deposit, and (5) coarse grained thickly bedded, massive pyroclastic density current deposited unit.

Wiri Mountain also has a unique and complex magmatic capping unit forming the upper part of the volcanic succession (Figure 9). While the section itself is not significantly different from other complex and large volume monogenetic geoforms, the significance Sustainability 2021, 13, 6549 of the Wiri Mountain capping section lays in the fact that it is well exposed due 13to ofthe 25 quarrying, and displays a threefold pyroclastic unit indicating long lasting and gradually changing explosive phases in the final stage of the edifice growth (Figure 9A,B).

FigureFigure 9. 9.Wiri Wiri Mountain Mountain quarrying quarrying exposedexposed thethe upper,upper, magmaticmagmatic cappingcapping successions of the former complex volcano, showing multiple layers of scoria and spatter successions marked as S1, S2, and complex volcano, showing multiple layers of scoria and spatter successions marked as S1, S2, and S3 units below the capping lava flows (A–D). Arrows on the (A,D,E,F) mark the location of the entry S3point units of below the lava the tube capping of Wiri lava Mountain. flows (A The–D). expo Arrowssed sections on the ( provideA,D–F) marksuperb the examples location of of magmatic the entry pointexplosive of the and lava effusive tube of processes Wiri Mountain. (B,C), Thebut they exposed are gradually sections provide diminishing superb due examples to urbanization of magmatic and explosiveraw material and effusiveneeds (E processes,F). The black (B,C rectangles), but they on are (A gradually,F) mark the diminishing same area due shown to urbanization in (B,C). and raw material needs (E,F). The black rectangles on (A,F) mark the same area shown in (B,C). Scoria units can be seen having abruptly developed on the tuff ring succession 3.2.2.(Figure Urbanization 8A). The base and of Quarrying the section at is Wiri more Mountain spatter dominated Region agglutinate with large cm- to-m-sizeRapid bed urbanization flattened blobs and extractionof basalt (Figure of raw 9A–C). materials This has basal had magmatic a significant unit impactis covered on theby Wiria more Mountain scoria lapilli-rich region. This dark issue red has unit been with voiced more through distinct variouselongated blog lavas posts commonly (https:// aotearoarocks.blogspot.com/2018/01/part-1-of-disappearing-maunga-of.htmlexhibiting clastogenic texture (Figure 9B–D). The third unit is a more typical well, accessed packed 1 Junescoria 2021; lapilli https://aotearoarocks.blogspot.com/2018/01/part-2-of-disappearing-maunga- succession that is slightly bed-flattened. The entire magmatic cap is covered of.htmlby a succession, accessed of 1 Junelava flows 2021). that A visual show narrativeclastogenic over texture the vanishing (Figure 9D–F) Wiri and Mountain some flat- has alsotened been and published broken basalt via lapilli web-based (Figure resources 9C). The entire (https://aotearoarocks.blogspot.com/20 section is perfectly exposed by quar- 18/08/guest-post-by-david-fraser-standing-up.htmlrying, allowing a unique view into the proximal half, section accessed of 1an June evolving 2021). scoria One of cone the mostthat notableextruded drivers lava out of in removal its final oferuptive thesevolcanoes phase (Figure is rapid 9D). expansionOn the far side of the (in road the NE), and train network and the emergence of warehouses covering large surface areas. Through this process, large earthworks have cut and removed many volcanic sites. The north- easternmost eruption center in the volcanic chain that Wiri Mountain belongs to is Ash Hill. Once a small volcanic cone with a pronounced crater [78], by 2019 it had been completely removed and currently its remaining volcanic deposits lie under roading and large distribution warehouses (Figure 10). The former cone had a small, swampy crater section in its interior closely resembling a small tuff ring less than 200 m across its base. While the site has not been studied, photo records from 2005 show typical phreatomagmatic tuff breccia outcrops nearby [35], indicating that it was formed by what may have been the shortest eruption event of the AVF. What was the smallest tuff ring is now gone completely. Aerial photographs from the mi-20th century show a rural countryside (Figure 10) with a very low-density road network. Besides agricultural activity, the region had a low density of housing with natural vegetation along stream networks. Wiri Mountain was the main source of aggregate for the region, and the quarry could be accessed from the main north- south railway trunkline by a branch sideline (Figure 10A). As early quarrying exposed the interior of the volcano, it became evident that the edifice has some sort of low rimmed tuff Sustainability 2021, 13, 6549 14 of 25

ring filled with a magmatic cap and topped by a steep sided lava spatter-dominated cone with rugged lava flow surfaces. These features are typical of basaltic volcanoes erupting low viscosity magma over gradually steepened cone surfaces (Figure 10A). On the original and near-intact landscape, it is clearly visible that the Puhinui Creek followed the margin of the terminus of a lava flow field, likely formed as a combination of the effusive eruptions from the Wiri Mountain volcano chain (Figure 10B). In the SW end of the volcano chain, the McLaughlins (Matukutureia) volcano seems to form a similar volcanic massif as the Wiri Mountain itself (Figure 10B,C). While the center part of the McLaughlins Mountain has been heavily altered by quarrying, some morphological evidence suggests the presence of Sustainability 2021, 13, x FOR PEER REVIEWa single explosion crater in its SW extremity; however, no direct evidence through15 preserve of 26

pyroclastic successions is known from the region yet [35].

FigureFigure 10.10. WiriWiri MountainMountain quarryingquarrying exposed the upper, magmatic capping successions successions of of the the forformer mer complex volcano, showing multiple layers of scoria and spatter successions. The exposed sec- complex volcano, showing multiple layers of scoria and spatter successions. The exposed sections tions superb to explain the magmatic explosive and effusive processes but they are gradually di- superbminishing to explain due to thethe magmaticurbanization explosive and raw and material effusive needs. processes In each but frame, they arethe graduallyred lines mark diminishing the duesame to road the urbanization for better orientation. and raw materialIn (A,C), needs.blue lines In eachalso frame,represen thet corresponding red lines mark roads. the same In (A road,B), for betterRed arrows orientation. point Into (theA,C same), blue tree lines line also on representeach image corresponding for better orientation. roads. In The (A,B base), Red of arrowsthe Wiri point tocone the samecomplex tree coincides line on each roughly image with for the better area orientation. captured by The the base blue of and the Wirired roads cone complexon (A) and coincides the roughlydisturbed with (quarried) the area area captured that mark by more the blueor less and the redmain roads part of on the (A cone.) and Aerial the disturbed photographs (quarried) are from Auckland Museum collections. area that mark more or less the main part of the cone. Aerial photographs are from Auckland Museum collections. Following land coverage changes through the historic data set of GoogleEarth Pro sinceFollowing 2005), it becomes land coverage apparent changes that the throughWiri Mountain the historic complex data went set through of GoogleEarth dramatic Pro sincechanges 2005), (Figure it becomes 10). After apparent complete that removal the Wiri of the Mountain capping complex scoria cone went and through proximal dramatic lava changesflows that (Figure filled 10the). Aftercrater completewith high removal quality dense of the cappinglava material, scoria quarrying cone and went proximal on to lava flowsexploit that the filledcore of the the crater volcanic with cone. high As qualitya result, densethe open lava pit material, quarry removed quarrying rock went formed on to exploitby the ponded the core and of the degassed volcanic lava, cone. with As a ahigh result, economic the open value pit quarryas dense removed (low vesicularity) rock formed basalts. This left behind the tuff ring and proximal magmatic explosive caping units by the ponded and degassed lava, with a high economic value as dense (low vesicularity) (Figure 11). It is apparent that the quarry pit rapidly filled with water in the early 2010s, basalts. This left behind the tuff ring and proximal magmatic explosive caping units and subsequently filled with debris from the 2015s onward, creating land for an industrial (Figure 11). It is apparent that the quarry pit rapidly filled with water in the early 2010s, storage yard. From 2017 onwards the quarry was transformed completely, continuing to and subsequently filled with debris from the 2015s onward, creating land for an industrial function as a dumping area in its center but gradually expanding as a storage yard. From storage yard. From 2017 onwards the quarry was transformed completely, continuing to 2019, a significant activity can be observed to “tidy” up the site and develop it as suitable functionland for a as shared a dumping storage area facility in its for center a range but of gradually vehicles and expanding industrial as equipment a storage yard.provid- From 2019,ers. Similar a significant trends activitycan be observed can be observed in other South to “tidy” Auckland up the former site and quarry develop sites. it By as early suitable land2020, for through a shared this storage process facility of incremental for a range encroachment of vehicles and and industrial destruction, equipment the main providers. tuff Similarring section trends in the can west be observed had been innearly other completely South Auckland removed. former quarry sites. By early Sustainability 2021, 13, 6549 15 of 25

Sustainability 2021, 13, x FOR PEER2020, REVIEW through this process of incremental encroachment and destruction, the main16 of tuff 26 ring section in the west had been nearly completely removed.

Figure 11. Wiri Mountain outcrop changes over time due to quarrying. Images were captured from GoogleEarth Pro His- Figure 11. Wiri Mountain outcrop changes over time due to quarrying. Images were captured from GoogleEarth Pro toric Database. Blue arrows point to the same roads and red arrows to the same train tracks for better orientation. Yellow Historicstar Database.marks the Wiri Blue Mountain arrows point lava tocave the entry same point. roads Image and reddates arrows (day, month to the sameand year) train are: tracks (A)—31 for betterDecember orientation. 2005; (B)— Yellow star marks7 April the 2010; Wiri (C Mountain)—22 July 2015; lava cave(D)—4 entry January point. 2017; Image (E)—5 dates October (day, 2018; month (F)—14 and year) February are: (2019;A)—31 (G)—24 December January 2005; 2020; (B )—7 April(H 2010;)—21 ( CDecember)—22 July 2020. 2015; (D)—4 January 2017; (E)—5 October 2018; (F)—14 February 2019; (G)—24 January 2020; (H)—21 December 2020. 3.2.3. Loss of Volcanic Geoheritage in the Wiri Region 3.2.3. LossThe loss of Volcanic of volcanic Geoheritage geoheritage in at the Wiri Wiri Mountain Region can be observed through satellite imagery and through direct on-ground observation. Two site visits occurring in 2017 (FigureThe loss12) and ofvolcanic 2019 (Figure geoheritage 13) observed at Wiri dramatic Mountain changes can in bethe observed quarry walls. through In 2017 satellite it imagerywould have and throughbeen possible direct to “rescue” on-ground the observation.scientifically important Two site tuff visits ring occurring sections, con- in 2017 (Figuretact exposure 12) and 2019sections (Figure and the13) observedmagmatic dramaticinfill sections changes (Figure in the12). quarry However, walls. by In2019 2017 it wouldnothing have remained been possible of these to features “rescue” at thethese scientiﬁcally locations. On important the image tuff dated ring 28 sections, November contact exposure2017, we sections can clearly and see the the magmatic long continuous inﬁll sections tuff ring (Figure section 12 forming). However, a type by of 2019 natural nothing remainedbarrier between of these the features quarry site at theseand encroa locations.ching urban On the development image dated (Figure 28 November 12A). How- 2017, weever, can by clearly 2019 seethe same the long feature continuous had been tuffcompletely ring section removed. forming Unfortunately, a type of naturalthis would barrier betweenhave been the the quarry best exposure site and encroachingof a proximal urbantuff ring development succession of(Figure the active 12 A).monogenetic However, by 2019 the same feature had been completely removed. Unfortunately, this would have been Sustainability 2021, 13, 6549 16 of 25

Sustainability 2021, 13, x FOR PEER REVIEW 17 of 26

Sustainability 2021, 13, x FOR PEER REVIEW 17 of 26 the best exposure of a proximal tuff ring succession of the active monogenetic volcanic ﬁeldvolcanic of Auckland. field of Auckland. Thankfully, Thankfully, sampling sampling was completed was completed prior to prior removal, to removal, hence somehence data some data will likely be available soon, but it cannot be revisited, restudied, and, most willvolcanic likely field be availableof Auckland. soon, Thankfully, but it cannot sampling be revisited, was completed restudied, prior and, to removal, most importantly, hence usedimportantly, for geoeducation used for geoeducation purposes. purposes The remaining. The remaining section section can be can accessed be accessed from from a public somea public data road will outside likely bethe available quarry; however,soon, but outcrops it cannot are be overgrownrevisited, restudied, and not asand, well-ex- most roadimportantly, outside used the quarry; for geoeducation however, purposes outcrops. The are remaining overgrown section and not can asbe well-exposedaccessed from and self-explanatoryposed and self-explanatory as those accessed as those from accessed the quarry from garden the directionquarry garden (Figure 13direction). (Figurea public 13E). road outside the quarry; however, outcrops are overgrown and not as well-exposed and self-explanatory as those accessed from the quarry garden direction (Figure 13E).

Figure 12. The changes of Wiri Mountain due to quarrying and damping activity shown well on Figure 12. The changes of Wiri Mountain due to quarrying and damping activity shown well on these images taken on 28 November 2017.A section of a tuff ring is still preserved (A), exposing theseFigurevaluable images 12. contact The taken changes between on 28of basal Wiri November tuffMountain ring 2017.A and due capping to section quarrying magmatic of a tuffand explosive ringdamping is still and activity preserved effusive shown units (A well), (B exposing, Con). valuableThethese quarry images contact wall taken betweenwas on still 28 accessibleNovember basal tuff and ring2017.A clean, and se cappingctionproviding of a magmatic tuff perfect ring locations is explosive still preserved for and visitors effusive (A ),(D exposing,E units). Red ( B,C). Thevaluablestars quarry mark contact the wall same wasbetween locations still accessiblebasal on tuff (A ,ring andB,D ,and clean,E). capping providing magmatic perfect explosive locations and for effusive visitors units (D,E ).(B Red,C). stars markThe quarry the same wall locations was still onaccessible (A,B,D, Eand). clean, providing perfect locations for visitors (D,E). Red stars mark the same locations on (A,B,D,E).

Figure 13. By 22 November 2019, the majority of the tuff ring section was barricaded by container

and car storage (A,B). The tuff ring section became difficult to access (B–D) and a long section was Figure 13. By 22 November 2019, the majority of the tuff ring section was barricaded by container Figureremoved 13. completelyBy 22 November in the south 2019, (E the). Red majority stars in of each the frame tuff ring represent section the was same barricaded location. by container and car storage (A,B). The tuff ring section became difficult to access (B–D) and a long section was andremoved car storage completely (A,B ).in Thethe south tuff ring (E). sectionRed stars became in each difﬁcult frame represent to access the (B same–D) and location. a long section was removed completely in the south (E). Red stars in each frame represent the same location. Sustainability 2021, 13, 6549 17 of 25 Sustainability 2021, 13, x FOR PEER REVIEW 18 of 26

In addition to the physical loss, the quarry has been used in a very intrusive way from In addition2019 to onward the physical as more loss, and the more quarry businesses has been have used taken in a advantagevery intrusive of the way newly reclaimed from 2019 onwardland, utilizingas more and the more site as businesses various “depot” have taken or storageadvantage facility. of the Asnewly a result, re- in 2019, the claimed land,site utilizing had been the site ﬁlled as various with a large“depot” number or storage of containers, facility. As making a result, it in nearly 2019, impossible to the site had beenaccess filled or clearlywith a seelarge the number remaining of containers, geosites exposing making it the nearly contact impossible between to the phreatomag- access or clearlymatic see tuffthe remaining ring succession, geosites the exposing transitional the contact pyroclastic between zone the andphreatomag- the capping lava ﬂows matic tuff ring(Figure succession, 13A–D). the transitional pyroclastic zone and the capping lava flows (Figure 13A–D). 3.2.4. Broader South Auckland Context 3.2.4. Broader SouthIf weAuckland expand Context our observations across the broader region of South Auckland, we can If we expandobserve our losses observations occurring across over the the broader same time region period of South (Figure Auckland, 14). GoogleEarth we can Pro historic observe lossessatellite occurring imagery over the reveals same thattime the period Wiri (Figure Mountain 14). volcanicGoogleEarth chain Pro has historic lost the majority of satellite imagerythe reveals key geosites. that the This Wiri is Mountain demonstrated volcanic by chain the complete has lost the removal majority of of Ash the Hill and rapid key geosites. developmentThis is demonstrated at McLaughlins by the complete Mountain, removal resulting of Ash in Hill a dramatic and rapid loss devel- of volcanic geology opment at McLaughlinsinformation Mountain, [35]. resulting in a dramatic loss of volcanic geology information [35].

Figure 14. HistoricFigure GoogleEarth 14. Historic Pro GoogleEarth images showing Pro images the dramatic showing pr theessure dramatic of urbanization pressure ofon urbanization the broader Wiri on the Mountain broader Wiri Mountain region. In eachregion. frame, InWiri each Mountain frame, Wiri is mark Mountained by a is red marked circle. byNu ambers red circle. in each Numbers frame (A in–H each) show frame the ( Asituations–H) show from the situations from older to youngerolder times. to younger Time format times. is Timeday, formatmonth and is day, year month in each and frame. year in each frame. SustainabilitySustainability2021 2021, 13, 13, 6549, x FOR PEER REVIEW 1819 of of 25 26

4.4. Discussion—Urbanization Discussion—Urbanization and and Geoheritage Geoheritage Loss Loss in in the the Greater Greater Auckland Auckland Region Region WhileWhile Wiri Wiri Mountain Mountain is is clearly clearly at at the the frontline frontline of of urban urban development development in in South South Auck- Auck- land,land, similar similar losses losses of of volcanic volcanic geoheritage geoheritage can can be be seen seen elsewhere elsewhere in in critical critical sites sites of of the the AucklandAuckland Volcanic Volcanic Field. Field. WeWe definedefine critical sites in in the the context context of of Auckland Auckland volcanism volcanism as asthose those that that provide provide the the most most complex complex geological geological information information andand displaying displaying the full the spec- full spectrumtrum of volcanic of volcanic processes processes responsible responsible for their fortheir formation. formation. The AVF The is AVF a relatively is a relatively young youngvolcanic volcanic field where field where most most of the of geosites the geosites have have been been obscured, obscured, modified, modified, or ordestroyed destroyed by byurbanization urbanization occurring occurring since since the the earliest earliest days days of ofEuropean European settlement. settlement. Accessible Accessible sites sites al- allowinglowing observation observation of of the the full section of pyroclasticpyroclastic successionssuccessions fromfrom thethe basebase to to the the top top areare rare. rare. Most Most of of these these sites sites are are associated associated with wi formerth former or current or current quarry quarry sites. sites. While While it may it bemay inevitable be inevitable that extraction that extraction of raw of materials raw materials such assuch scoria as scoria and basalt and basalt will modify will modify and damageand damage original original landscape landscape features, features, we recognize we recognize these locationsthese locations as providing as providing invaluable inval- opportunitiesuable opportunities to observe to observe volcanic volcanic successions successions that would that otherwise would otherwise remain buried remain deep buried be- neathdeep ourbeneath feet. Thisour feet. is particularly This is particularly the case in the young case volcanicin young fields. volcanic Many fields. young Many volcanic young fieldsvolcanic across fields Europe across utilize Europe their utilize abandoned their abandoned quarries of monogeneticquarries of monogenetic volcanoes as volcanoes their key geoeducationas their key geoeducation spots [79–83]. spots By interlinking [79–83]. By interlinking young andold young monogenetic and old monogenetic volcanic fields vol- andcanic cross-communicating fields and cross-communicating the information the information made accessible, made we accessible, can maximize we can education maximize andeducation community and community engagement engagement opportunities opportunities at these sites. at these In the sites. case In of the Auckland, case of Auck- the greatestland, the volcanic greatest hazard volcanic is expectedhazard is toexpected be phreatomagmatic to be phreatomagmatic in nature. in Although nature. Although we may observewe may basal observe pyroclastic basal pyroclastic rocks formed rocks during formed initial during phreatomagmatic initial phreatomagmatic explosive phases explosive at manyphases locations at many in locations the AVF, in the the South AVF, Auckland the South region Auckland is the region most complex is the most in this complex respect, in providingthis respect, a wealth providing of locations a wealth readily of locations accessible readily for accessible research (Figure for research 15). In (Figure addition 15). to In Wiri Mountain, we define here four key locations clearly demonstrating the unstructured addition to Wiri Mountain, we define here four key locations clearly demonstrating the approach to mitigating effects of quarrying and preserving geoheritage value these sites unstructured approach to mitigating effects of quarrying and preserving geoheritage may offer (Figures 15 and 16). value these sites may offer (Figures 15 and 16).

Figure 15. Time frames from GoogleEarth Pro historic satellite imagery shows the dramatic changes Figure 15. Time frames from GoogleEarth Pro historic satellite imagery shows the dramatic changes of key geosites with high scientific values. (A–D) show the Maungataketake tuff ring from the recent of key geosites with high scientiﬁc values. (A–D) show the Maungataketake tuff ring from the recent times back to 2005. (E–H) frames show Crater Hill in roughly the same time slices as Maunga- timestaketake. back ( toI– 2005.L) show (E– Hthe) frameslandform show changes Crater of Hill Pukewairiki/Highbrook in roughly the same time Park. slices as Maungataketake. (I–L) show the landform changes of Pukewairiki/Highbrook Park. Sustainability 2021, 13, 6549 19 of 25 Sustainability 2021, 13, x FOR PEER REVIEW 20 of 26

FigureFigure 16. 16. DramaticDramatic changeschanges on the Pukewairiki/HighbrooksPukewairiki/Highbrooks Park Park tuff tuff ring ring due due to to urban urban develop- devel- ment within a 15-year-long time frame. GoogleEarth Pro historic satellite imagery shows the situa- opment within a 15-year-long time frame. GoogleEarth Pro historic satellite imagery shows the tion from 2020 (A), 2017 (B), 2007 (C) and 2005 (D) situations. The dates on each image are in year, situation from 2020 (A), 2017 (B), 2007 (C) and 2005 (D) situations. The dates on each image are in month, and day format. Red stars in (A–D) mark the same location in each frame that is also cap- year,tured month, in a temporarily and day format. opened Red outcrop stars of in fantastic (A–D) mark base the surge same dune location beds ( inE). each An impact frame thatsag in is also(E) is capturedmarked by in aa temporarilycircle, suggesting opened transportation outcrop of fantastic direction base from surge the dune west. beds Base ( Esurge). An dunes impact (arrow) sag in ( Eare) iswell marked preserved by a circle, despite suggesting that the pyroclastic transportation rocks direction are altered. from Yellow the west. lines Basein (A surge) mark dunes the view (arrow) angle areshown well in preserved (F). despite that the pyroclastic rocks are altered. Yellow lines in (A) mark the view angle shown in (F). One of the only still active quarries is located at Maungataketake (also known as El- let’sOne Mountain), of the only where still a deep active pit quarries has clearly is located exposed at the Maungataketake internal structure (also of known a complex as Ellet’sphreatomagmatic Mountain), where to magmatic a deep pitexplosive has clearly and effusive exposed volcano the internal (Figure structure 15A–D). of a From complex 2005 phreatomagmaticto 2020, development to magmatic of the quarry explosive pit is clea andrly effusive visible, volcanoand once(Figure extraction 15A–D). of raw From mate- 2005rial was to 2020, complete development the pit was of theinfilled quarry with pit waste. is clearly The visible,quarry andremains once inaccessible extraction ofto rawvisi- materialtors, including was complete scientists, the with pit wasall attempts infilled withat engagement waste. The with quarry the remainsowners to inaccessible gain access tounsuccessful. visitors, including Although scientists, the site with is one all of attempts the best atexposed engagement locations with of thethe ownersshallow tosubsur- gain accessface architecture unsuccessful. of a Although wet volcano, the siteit has is onenot been of the scientifically best exposed studied locations to any of the degree shallow and subsurfaceremains unlikely architecture to be ofin athe wet near volcano, future. it hasIn contrast, not been a scientificallypublicly accessible studied coastal to any site degree that andis part remains of the unlikely same volcanic to be in thecomplex near future. provides In contrast, an excellent a publicly 1 km accessiblelong tuff ring coastal section site thatwhere is part the ofvisitor the same can follow volcanic the complex proximal provides to distal an section excellent of 1base km longsurge tuff dominated ring section tuff wherering succession. the visitor Being can follow able to the research proximal these to distal sites sectionin parallel of basewould surge result dominated in a scientific tuff ringoverview succession. of the Beinggrowth able of the to researchvolcano throug these sitesh proximal in parallel and wouldcrater-filling result successions, in a scientific as overviewwell as providing of the growth opportunities of the volcano for education through and proximal engagement and crater-filling with visitors successions, to the area. as well as providing opportunities for education and engagement with visitors to the area. A similar scenario has been played out at Crater Hill (Figure 15E–H), with a distinct A similar scenario has been played out at Crater Hill (Figure 15E–H), with a distinct difference that this site provided one of the first and best geochemical reference sites to difference that this site provided one of the first and best geochemical reference sites to document chemical variations occurring during the eruption of a small wet monogenetic document chemical variations occurring during the eruption of a small wet monogenetic volcano. After the quarry ceased active operations, key sites rapidly filled with waste. volcano. After the quarry ceased active operations, key sites rapidly filled with waste. After a long-lasting Environmental Court action, an agreement was reached to restore the Sustainability 2021, 13, 6549 20 of 25

After a long-lasting Environmental Court action, an agreement was reached to restore the site to its original landscape appearance (similar to how some maar craters were recreated in the Vulkaneifel in Germany—http://www.globalgeopark.org/news/news/5934.htm, accessed 1 June 2021), recreating a tuff ring partially filled with scoria and spatter cones, and retaining a crater lake in its center. While we acknowledge this as a positive outcome from an aesthetic and geoform perspective, the fact that the key sites of scientific study of geochemical stratigraphy [84,85] have been destroyed, has resulted in an irreversible scientific loss. This situation also reflects an expensive and time-consuming legal strategy that is reactive and unlikely to be sustainable in the long-term against well-resourced commercial developers and landowners. The third location is the Waitomokia (also known as Mount Gabriel) tuff ring complex, composed of a large tuff ring with a shallow maar crater that was partially occupied with at least three scoria cones and some short lava flows (Figure 15I–L). The site is now occupied by a winery operated by the Villa Maria Estate, which have made significant investments in making the site a recreational center based on food and wine. The Fourth International Maar Conference in 2012 hosted its conference dinner in the recreational facilities, with aspirations for future collaborations between the winery and the scientific community with the area acknowledged as the center of several volcanic geosites. While this idea remains to be fully realized, the site appears to have been subject to similar degradational processes as others in the area with little to no action taken on facilitating the necessary processes to make the aspiration a reality. Once-free access to key proximal phreatomagmatic explosion breccia exposures has become incorporated into a restricted operations area. Over time we have observed that once access is restricted by commercial operations, this process is highly unlikely to be reversed without significant and complex negotiations requiring time, effort, and financial input. Therefore, we can confidently say that the loss of public access to these sites facilitated by an active operating business is likely to be permanent. The fourth location that demonstrates an ad hoc and reactive approach to acquiring geological information is Pukewairiki (Highbrook Park) (Figure 16). The location was well known as a tuff ring and appeared in the early geological maps; however, the lack of outcrops prevented acquisition of more detailed information about the volcano. The geoform was covered by grass and due to its location adjacent to the Tamaki Estuary es- caped encroachment from urban expansion until 2005 (Figure 16A–D). From 2005 onwards, rapid construction of large warehouses and retail centers commenced in the region. During the initial development phase large warehouses were planned for the northern crater rim with earthworks likely to dissect the tuff ring and expose its interior. As expected, around 2007–2008 the tephra rings had been cross-cut in several locations, providing superb exposure of altered fine grained dune-bedded pyroclastic surge beds (Figure 16E,F). However, with development in the area complete, these exposures are now covered and inaccessible. They are lost for future research or utilization for geoeducation, in spite of their significant scientific value demonstrating a perfect longitudinal and cross-sectional view of pyroclastic surge deposits from one of most hazardous volcanic processes likely to occur in the future across the low lands of South Auckland [86]. Overall, if we compare the documented volcanic sites in Auckland for their geoheritage and geoeducation potential of what remains of volcanic features, the huge information loss and underutilization of these sites becomes obvious. In addition, urbanization is inevitable in a rapidly growing city like Auckland, especially during housing and transportation crises in a post-pandemic time. We note the seeming lack of vision for preservation of volcanic geoheritage and geoeducation in the context of volcanic hazard resilience. While scientific programs such as the Determining Volcanic Risk in Auckland (DEVORA) (https://www.devora.org.nz/, accessed 1 June 2021) have made a huge impact on linking end-users and the scientific community, and collating information to form a coherent model for understanding volcanic hazard of Auckland, it has had little direct impact on at least slowing rapid information loss or offering an alternative model to utilize these values. Sustainability 2021, 13, 6549 21 of 25

The Bakony–Balaton UNESCO Global Geopark (http://www.geopark.hu/en/, accessed 1 June 2021), as a well-resourced and well-supported geopark, provides an example of the importance of volcanic geoheritage in regions where no active volcanism is recorded, and most of the geosites are coincident with or resulted from raw material exploitation. Such a trend is clear across the geopark programs in many regions, mostly in the continental Europe (such as the Vulcania volcano theme park in France— https://www.vulcania.com/en/, accessed 1 June 2021), and we suggest this as a potential model for Auckland in the future. The Bakony–Balaton UNESCO Global Geopark to some extent similar (volcano type, geotectonic setting, eruption styles, number of volcanoes, etc.) to the Auckland Volcanic Field, could provide a model in terms of geoeducation and geoconservation of volcanic landscapes for Auckland. The Hungarian examples show clearly that volcanic geoheritage can play a main driving force to develop a sustainable geoconservation strategy. However, the Hungarian case may only indirectly be useful for modeling a solution for problems typical of the AVF such as rapidly accelerating urbanization and exploitation of volcanic geosites for short-term benefits. The foundation of a geopark with UNESCO status could be seen as the ultimate outcome reconciling conflicting and often opposing values and needs in terms of usage of volcanic landscapes. We suggest that such a concept needs to be researched and developed in Auckland urgently. In this concept, ideas such as the Vulcania volcano theme park in France might be a potential model for Auckland in the future. However, development of such geoeducational centers is unlikely to halt urbanization but could reduce it to a sustainable level and in parallel change local governments and community’s attitudes towards supporting conservation and accessibility of key geosites. We acknowledge these as hypothetical and largely aspirational ideas in the current socio- economic climate, underlain by a housing crisis, the COVID-19 pandemic, and growth of Auckland as the largest population center in the country. Nonetheless, we suggest that strategic planning to preserve significant abiotic aspects of the environment on an equal footing with its biotic aspects, is likely to be the only way forward for sustainable evolution of the wider Auckland region. Overall, we have highlighted markers of insufficient care for the conservation of volcanic heritage in the Auckland area. We suggest an important area of research should address reasons behind the apparent lack of effective geopreservation policy in the largest urban center of New Zealand. Questions that remain unexplored and unanswered are: Is this only due to physical proximity to the city? How does Auckland compare with other cities with similar types of volcanic geoheritage? Could the relative ubiquity of volcanic geoforms in New Zealand contribute to bias within conservation strategies and general attitudes toward volcanic geoheritage? Attitudes to volcanic landforms in this country can be contrasted to Central Europe, where remnants of volcanism are considered special or even unique, in that regions in question have no active volcanism and active volcanoes are rare and may be considered “mystic” natural phenomena for most of the people. Such relative perspective might be the reason why various regions act differently toward geopreservation of their volcanic geoheritage.

5. Conclusions In this semiquantitative study, we provided observation-based data from satellite imagery, historic photos, and direct observations on the rapid speed of geoheritage site loss in the greater Auckland urban area. We argued that geoheritage values of monogenetic volcanic ﬁelds are important in facilitating volcanic hazard resilience programs. This is especially important in regions like the active Quaternary Auckland Volcanic Field. We also acknowledged that raw material needs are increasing hence quarrying is inevitable in rapidly growing urban areas like Auckland. However, the resulting quarries could be used in a far more effective, logical, and visionary way for sustainable urban growth demonstrated through our case-studies. The examples we presented from western Hungary demonstrated general geoconservation aspects of abandoned quarries across continental Sustainability 2021, 13, 6549 22 of 25

Europe, which could provide viable links in developing programs within Auckland. The interlinking of volcanic ﬁelds composed of young and largely intact geoforms with those of similar origin but older, hence eroded, or intensively quarried and deeply exposed volcanic ﬁelds through geoheritage programs is considered a cost-effective and very natural pro- gram to follow, suggested here as valuable for the future development of geoconservation and geoheritage ventures in Auckland.

Author Contributions: Conceptualization, K.N. and I.G.; methodology, B.N. and K.N.; validation, K.N., I.G. and B.N.; investigation, K.N. and B.N.; resources, I.G. and B.N.; data curation, I.G.; writing— original draft preparation, K.N.; writing—review and editing, I.G. and K.N. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by Earthquake Commission of New Zealand AND Auckland Regional Council titled as “DEVORA—Investigate how geoheritage values in Auckland may be incorporated in planning and public education”, grant number GNS-EQC00046. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Acknowledgments: The authors are thankful for the support provided by EQC–ARC–DEVORA to pursue this research. We are grateful for all the fruitful discussions with Peter Crossley (Lave Cave research and field work) and Bruce Hayward (Auckland geoheritage, Wiri Mountain, Crater Hill geopreservation). We also thank the four anonymous reviewers whose formal reviews improved the quality of the manuscript significantly. Conflicts of Interest: The authors declare no conflict of interest.

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