The Walpole-Nornalup Inlets System, Western Australia: A case study of a potential estuarine geopark

Unlike other estuaries Nationally in Australia, the Walpole-Nornalup Inlets is unique complex twin-basin ria estuary in the most humid part of Western Australia. The estuary fronts the oceanographically-dynamic Southern Ocean and, with the high annual rainfall, it provides a range of estuarine landforms, estuarine peripheral wetlands, a dynamic sand barrier that records climate changes and, with its microtidal setting, it provides examples of complex riverine-to-marine dynamics such as intra-basinal gyring. A range of geological to estuarine features that are of geoheritage significance and available for exploration and explanation as geotrails include: (1) the Precambrian geology, (2) the stratigraphy of the Cainozoic Werillup Formation, (3) Cainozoic weathering, sedimentation, and climate history, with a very wet climate to produce erosionally-resistant quartz grain lags, (4) Cainozoic to Quaternary formation of a rock tombolo, (5) the complex estuarine shorelines and history, and (6) complex estuarine processes and history. As an ensemble of geological and other natural history features, Walpole-Nornalup Inlets system also provides a case study of a systematic approach, using the Geoheritage Tool-kit, of identifying and evaluating different natural values. This forms the foundation for to baseline monitoring (for environmental management) and tourism to explore through geological time the natural history of this geologically and biologically rich location

The Archaean to Proterozoic igneous rocks of the Pilbara region, Western Australia –internationally significant geology of a globally unique potential geopark

The Pilbara region of Western Australia, covering some 500 km × 500 km, provides a diversity of Archaean to Proterozoic igneous rocks in a relatively compact area that records a younging southward crustal history of igneous activity, sedimentation, early life, tectonics, and metamorphism from the Archaean (3.6–2.7 Ga) to Proterozoic (2.5–1.8 Ga). The igneous rocks are variable in age, types of rocks, and mode of occurrence and, throughout the Precambrian, record varying igneous rock activity that appear related to several age-related geological settings: to north, the Archaean Pilbara Craton consists of a granitoid-and-greenstone complex; in the central region, there are Proterozoic sequences of volcanic rock, volcaniclastic rock, ironstone, chert, dolomite, shale, and intrusive dolerite sills and cross-cutting dolerite dykes; to the south, there are Proterozoic shale, dolomite, and chert with isolated granitic batholiths. Igneous activity begins in the Archaean with mafic and ultramafic volcanism alternating with sedimentation, and then granitoid cratonisation. This was followed by Proterozoic volcanic crustal accretion with mafic volcanic and volcaniclastic rocks, and by dolerite and gabbro sill and dyke intrusions, ending with isolated granite batholithic intrusions. Igneous rocks in the Pilbara region are diverse: komatiite; mafic volcanic/volcaniclastic rocks; basalt; tuff/volcanic breccia/accretionary lapilli; dolerite, gabbro, leucogabbro, pegmatitic gabbro, granite, and adamellite; xenolithic dolerite/gabbro; andesite, dacite, rhyodacite, rhyolite; granitoids: adamellite, monzogranite, syenogranite, granodiorite, tonalite, granite; granophyre; felsic dykes; and felsic porphyry. They are expressed as granitoid batholiths, komatiite and basalt sheets/lenses, mafic volcanic/volcaniclastic rocks in sheets, sills of dolerite, gabbro, ultramafic rocks, and diorite, dykes of dolerite, gabbro, and felsic rocks, structurally-oriented dolerite dyke swarms, tuff/volcanic breccia/accretionary lapilli in sheets/lenses, sheets of dacite, rhyodacite, rhyolite, and andesite, gabbroic plugs, apophyses, and a variety of host-rock to xenolith relationships. Today, the Pilbara region is arid, hence outcrop is excellent and many of these geological features are well exposed. The diversity of Archaean to Proterozoic igneous rocks in a relatively compact and well-exposed area and qualifies it as a globally unique potential Precambrian igneous-rock geopark

The Holocene Becher Point Cuspate Foreland, Western Australia – An internationally significant and globally unique potential geopark

Located in south-western Australia in a distinctive setting sedimentologically, oceanographically, climatically, biologically, and sea-level history context, the Becher Point Cuspate Foreland is globally unique, and is a site of International Geoheritage Significance that has the potential to be developed as a Geopark. The cuspate foreland is part of an extensive shore-parallel Holocene coastal sand system that forms the seaward edge of the Swan Coastal Plain and eastern border of the Rottnest Shelf. It is the largest cuspate foreland complex in Western Australia and one of the largest in the World. Sedimentary accretion in the region began some 7000 years BP with a sea level + 2 m AHD. Since then, attended by a progressive climate change, sea level has steadily fallen to its present position, and sedimentation has built a coastal plain of low beach ridges with wetlands in the swales. Sedimentologically and stratigraphically, the cuspate foreland developed by seagrass bank accretion shoaling to the strand to form beach and beach-ridge/dune deposits capped in the swales by wetland deposits. Key features of the Cuspate Foreland are (1) the accreted Holocene beach-ridge plain, (2) the evolution of Holocene swale wetlands, (3) the Holocene sea level history, (4) Holocene climate history as recorded in the wetlands, and (5) a host of small-scale geological phenomena. The complex of beach ridges and swale wetlands is the basis of a geopark in which coastal plain evolution, wetland evolution, Holocene sea level history, and Holocene climate changes can be explored and explained essentially in an outdoor Museum. To illustrate the richness of the natural history information, from macroscale to microscale, embedded in the Becher Point Cuspate Foreland, we choose, as case studies, two aspects of the area and describe them in a holistic and multi-scalar manner for education and research, and potential thematic geotours

A Globally Significant Potential Megascale Geopark: The Eastern Australian Mantle Hotspot Interacting with a North-Migrating Heterogeneous Continental Plate Creating a Variety of Volcano Types, Magmas, Xenoliths, and Xenocrysts

Australia commenced separating from Antarctica some 85 million years ago, finally separating about 33 million years ago, and has been migrating northwards towards the Eurasian plate during that time. In the process, Australia, on its eastern side, progressively passed over a mantle hotspot. A magma plume intersected a variable lithocrust with various lithologic packages such as Phanerozoic sedimentary basins, fold belts and metamorphic terranes, and Precambrian rocks. As such, there was scope for compositional evolution of magmas through melting and assimilation, as well as plucking of host rocks to include xenoliths, and xenocrysts. The volcanic chain, volcanoes, and lava fields that are spread latitudinally along 2000 km of eastern Australia present a globally-significant volcanic system that provides insights into magma and crust interactions, into the variability of xenoliths and xenocrysts, into magma evolution dependent on setting, and into the mantle story of the Earth. The Cosgrove Volcano Chain is an example of this, and stands as a globally-unique potential megascale geopark

Coastal geoheritage: A hierarchical approach to classifying coastal types as a basis for identifying geodiversity and sites of significance in Western Australia

Identifying sites of coastal geoheritage significance begins with classification of coastal geology and geomorphology. However, classifying coasts for purposes of geoheritage is made difficult due to the complexity, intergradation, and different scales at which coastal features are expressed, with variation potentially present locally or regionally. Also, geoheritage must address geological content as well as coastal geomorphology expressed erosionally and/or sedimentologically, and Earth history as manifested in coastal erosional and stratigraphic products. While geological and environmental settings play important roles in determining regional variation in coastal form and coastal products, or expression of geological content, coasts at the local scale commonly are expressions of one or more of the main processes of (marine) inundation, erosion, and deposition, and/or of subdominant processes of biogenic activity and diagenesis. To address this coastal geodiversity for geoheritage and geoconservation in Western Australia, a three-level scalar hierarchical approach is used. Level 1 identifies the regional geological and environmental setting, i.e., recognising major cratons and basins, and the climatic/oceanographic setting of a coast, which determine regional coastal forms. Level 2 identifies the main coastal types developed by coastforming processes (e.g., marine inundation of pre-existing landforms; coastal erosion; exhuming of older landforms; construction by Holocene sedimentation, coasts formed biogenically, amongst others), as well as coastal types that illustrate Holocene history geomorphically or stratigraphically, or manifest pre-Holocene rock sequences in sea cliffs. Level 3 identifies finer-scale characteristics particular to any coast within its regional setting to develop an inventory of features providing data within the context of the coastal types for comparative geoconservation purposes. All three levels need to be applied to fully categorise coasts for assessing geoheritage values and for geoconservation

The Onshore Southern Carnarvon Basin in Coastal Western Australia during the Quaternary: Tectonic Setting and Facies-Complicated Heterogeneous Stratigraphic Patterns

The onshore southern Carnarvon Basin in Western Australia, in existence since the early Palaeozoic, has a history during the Palaeozoic and Tertiary of relatively uniform sedimentary styles with thick laterally-extensive sequences of sediment. Its sedimentary history became more complicated in the Quaternary period with complex tectonics and arrays of sedimentary facies and packages and basin complexity over relatively short distances, with several regions that are sedimentologically and stratigraphically distinct related to the factors of physiographic and geological setting, riverine input, arid climate, migrating climate, tectonism, and degree of protection from open ocean. For the Pleistocene and Holocene epoch, there are distinct north-trending stratigraphic packets, each with their environmentally distinctive shoaling facies sharply juxtaposed against each other or separated by Pleistocene non-marine sediments; in geographic order, from south to north, these are: a limestone aeolianite barrier along western Shark Bay; pocket seagrass bank carbonate complexes of central western Shark Bay that are nestled in the northerly-oriented inter-dune depressions developed as swales of the north-trending parabolic dunes deriving from the limestone aeolianite barrier; an aeolian red sand shoestring of the north-trending Peron Peninsula longitudinally bisecting central Shark Bay; metahaline to hypersaline shoaling carbonate sedimentary packages of south-eastern Shark Bay that fringe Hamelin Pool; the Wooramel delta, a wave-dominated delta composed of quartz sand and locally-generated carbonate sediment; the Wooramel seagrass bank (an extensive shore-parallel wedge of seagrass bank carbonate sequence along the eastern coast, central to northern Shark Bay); metahaline carbonate and quartz sand platforms fringing both sides of the red-sand Peron Peninsula; metahaline to hypersaline carbonate sediments that underlie the deeper-water axially-oriented embayments of Shark Bay; the Boodalia Pleistocene reddened (quartzose) deltaic sediment sequence; the Gascoyne Delta and laterally equivalent beach-ridge complex, the former comprising subtidal quartz-dominated sand capped by tidal sand-and-mud sequences, and the latter comprising subtidal quartz-dominated sand capped by beach-to-beach-ridge deposits; the Lake MacLeod evaporite basin filled with a shoaling sequence of carbonate sediments, halite, and gypsite; Tertiary limestone and Pleistocene aeolian sediments acting as a barrier to Lake McLeod; and the uplifted Tertiary limestone barrier of Cape Range that is fringed by Holocene coral complexes of the Ningaloo Reef. The coastal and onshore near-coastal southern Carnarvon Basin is an example of a complex sedimentary basin, where sedimentary packages can be markedly different over short distances, and illustrates the complexities a geologist would face if analyzing such a basin in the stratigraphic column. This feature of extreme diversity of sedimentary facies and packages within and between separate contemporaneous ‘sedimentary basins’ is the theme of this contribution

Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large to Small Scale

Across the globe, volcanoes and volcanic terrains present one of the most complex geological systems on Earth that, depending on magma type, viscosity, and water and gas content, form a diverse range of products in terms of geomorphology, lithologic suites, structures, and stratigraphy. In broad terms, magmas, with their diagnostic composition, derive from specific tectonic settings, e.g., basalt-dominated oceanic crusts, acidic magma from continental plates, and andesitic convergent-plate margins. In addition to magma composition and volcanic rock types, there is a wide range of volcanic products, manifest at all scales, dependent on how magma interacts with the Earth’s surface, varying, for instance, from lava flows such as vesicular lava beds and flow-banded to flow-laminated lava beds, to breccias, tephra (ejecta) deposits, and bombs, amongst others, each commonly with their diagnostic small-scale lithological/structural features. This wealth of rock types, stratigraphy, and structures linked to geologic setting, potentially has geoheritage significance, and we provide here methods tailored for volcanoes and volcanic rocks of identifying, classifying and evaluating the complex and heterogeneous nature of volcanoes so that the full complement of their geology for a given region can be appreciated and incorporated into thematic geoparks, Nature Reserves and protected areas. For sites of geoheritage significance, we present (1) a globally-applicable Geoheritage Tool-kit to systematically identify volcanic geoheritage sites, (2) a technique to classify/categorise geoheritage sites, and (3) a semi-quantitative method to evaluate the geoheritage significance of volcanic sites

Introducing New Guidelines on Geoheritage Conservation in Protected and Conserved Areas

The Cultural Heritage Administration, Republic of Korea, funded the design and publication of the Guidelines on which this paper is based.This paper introduces newly published guidelines on geoheritage conservation in protected and conserved areas within the “IUCN WCPA Best Practice Guidelines” series. It explains the need for the guidelines and outlines the ethical basis of geoheritage values and geoconservation principles as the fundamental framework within which to advance geoheritage conservation. Best practice in establishing and managing protected and conserved areas for geoconservation is described with examples from around the world. Particular emphasis is given to the methodology and practice for dealing with the many threats to geoheritage, highlighting in particular how to improve practice for areas with caves and karst, glacial and periglacial, and volcanic features and processes, and for palaeontology and mineral sites. Guidance to improve education and communication to the public through modern and conventional means is also highlighted as a key stage in delivering effective geoconservation. A request is made to geoconservation experts to continue to share best practice examples of developing methodologies and best practice in management to guide non-experts in their work. Finally, a number of suggestions are made on how geoconservation can be further promoted.Publisher PDFPeer reviewe

Principles and tools for conserving sites of geoheritage significance on the Western Australian coast

The focus of this Thesis is geoheritage of the coastal zone, and thus coastal geoheritage. The coast is one of the most complex environments on the Earth’s surface being a zone of intersection and interaction between land, sea, groundwater, and atmosphere. The geodiversity developed along the coast is variable depending on parent rock types, sediments and other materials, local biodiversity, hydrochemical effects, and diagenesis, and variable according to environmental setting and climate. As such, the coastal zone presents complicated products of erosion, sedimentation, biogenesis, and diagenesis, and well-exposed wave-washed, sediment-scoured, and salt-weathered rock sequences. With its complexity and variability, the coastal zone lends itself to developing principles, classifications, and procedures for geoheritage, geoconservation, and policy to protect sites of geoheritage significance. The coastline of Western Australia is an ideal starting point for the development of a classification of coastal types and for the development of principles for coastal geoheritage because it manifests a wide variety of coastal forms along its 6000 km length and 22° of latitudinal range. It transcends a diverse range of geological regions and several climate zones (from tropical to near-temperate, and humid to arid), encompassing large tracts that are rocky and erosional versus sedimentary and depositional, and fronts various oceanographic and coastal settings (from macrotidal to microtidal, from wave-dominated to tide-dominated to protected, to wind-dominated). The approach in this Thesis is original in that, for the first time, there is a holistic study that identifies the significance of the coast for its geoheritage values. From forty-four sites described along the Western Australian coast, as well as information from literature review, a new coastal classification was developed, tailored for purposes of comparative geoconservation. Twelve coastal types were identified, categorised as inundational, erosional, depositional, biogenic, and diagenetic types, and their combinations. In addition, a Geoheritage Tool-kit was developed to establish a category-based inventory for identifying and assessing sites of geoheritage significance. The Geoheritage Tool-kit is applied to a selection of four large-scale and four small-scale sites. Outcomes of this study resulted in the development of concepts, principles, approaches and methods, and classifications with the objectives of identifying, selecting, and assessing coastal sites of geoheritage significance within Western Australia. Within a National legislative framework in Australia that is biocentric, and a Draft National Heritage Strategy that does not encompass geoheritage, policy specific to Western Australia and the coastal zone was developed in this Thesis. This policy incorporated overall themes and philosophy of geoconservation with principles and criteria adapted from overseas. More specific policy/policies were designed, tailored to site-specific geological regions, local geomorphology, and hazards resulting from oceanographic and biogeographic setting

King sound and the tide-dominated delta of the Fitzroy river: Their geoheritage values

There are numerous geological and geomorphic features in King Sound and the tide-dominated delta of the Fitzroy River that are of International to National geoheritage significance. Set in a tropical semiarid climate, the delta of the Fitzroy River has the largest tidal range of any tide-dominated delta in the World. Within King Sound, the Quaternary stratigraphy, comprised of early Holocene gulf-filling mud formed under mangrove cover and followed by middle to late Holocene deltaic sedimentation, and the relationship between Pleistocene linear desert dunes and Holocene tidal flat sediment are globally unique and provide important stratigraphic and climate history models. The principles of erosion, where sheet, cliff and tidal creek erosion combine to develop tidal landscapes and influence (mangrove) ecological responses also provide a unique global classroom for such processes. The high tidal parts of the deltaic system are muddy salt flats with groundwater salinity ranging up to hypersaline. Responding to this, carbonate nodules of various mineralogy are precipitated. Locally, linear sand dunes discharge freshwater into the hypersaline salt flats. With erosion, there is widespread exposure along creek banks and low tidal flats of Holocene and Pleistocene stratigraphy, and development of spits and cheniers in specific portions of the coast