**2. What is Geoheritage and how does it relate to volcanoes?**

Geoheritage, and its sister endeavour, geoconservation, are concerned with the identification, categorisation, and preservation of significant Earth geological features, and are recognised globally as important, as reflected in

**335**

**Figure 6.**

*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large…*

various international and intra-national bodies set up for conservation, with agreements, conventions, and inter-governmental initiatives [17, 19–24]. Both endeavours are integral components of the preservation of geological features, geo-education, geotourism, planning and environmental management globally

*diameter) that was buried by vesicular lava (north island New Zealand).*

*Illustration of a selection of volcanic features at Jeju Island that are of geoheritage significance (photographs also are annotated). A & B. Various interlayered vesicular and massive basalt (coins for scale). C. Vesicular lava filling a small-scale fissure. D. Carbonate stalactites and stalagmites formed by dripping groundwater in a lava tube. E. A complex arrangement of vesicle types (large, medium and small) in basalt. F. Layered tephra with various brown and black lithoclasts in laminated tephra (walking stick is 1 m long). G. Tree trunk (30 cm* 

*DOI: http://dx.doi.org/10.5772/intechopen.97928*

*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large… DOI: http://dx.doi.org/10.5772/intechopen.97928*

### **Figure 6.**

*Updates in Volcanology – Transdisciplinary Nature of Volcano Science*

**2. What is Geoheritage and how does it relate to volcanoes?**

Geoheritage, and its sister endeavour, geoconservation, are concerned with the identification, categorisation, and preservation of significant Earth geological features, and are recognised globally as important, as reflected in

*Illustration of a selection of volcanic features at Jeju Island that are of geoheritage significance (photographs also are annotated). A. Bombs and dropstone structures in finer-grained tephra. B. Surge structures of megaripples and ripples in tephra. C & D. Polygonal (hexagonal) columnar jointing in basalt.*

**334**

**Figure 5.**

*Illustration of a selection of volcanic features at Jeju Island that are of geoheritage significance (photographs also are annotated). A & B. Various interlayered vesicular and massive basalt (coins for scale). C. Vesicular lava filling a small-scale fissure. D. Carbonate stalactites and stalagmites formed by dripping groundwater in a lava tube. E. A complex arrangement of vesicle types (large, medium and small) in basalt. F. Layered tephra with various brown and black lithoclasts in laminated tephra (walking stick is 1 m long). G. Tree trunk (30 cm diameter) that was buried by vesicular lava (north island New Zealand).*

various international and intra-national bodies set up for conservation, with agreements, conventions, and inter-governmental initiatives [17, 19–24]. Both endeavours are integral components of the preservation of geological features, geo-education, geotourism, planning and environmental management globally

### **Figure 7.**

*Illustration of a selection of volcanic features in the Canary Islands (A, B, C) and at Bali (D, E, F, G) that are of geoheritage significance (photographs also are annotated). A. Complex tephra layering overlying basement rocks. B. Exotic xenoliths in vesicular lava (coin for scale). C. Simple laminated ash with lapilli laminae (lens cap for scale). D. The fan-shaped volcanic deposit emanating from Mt Batur is the 1974 eruption. E. The edge of the 1974 eruption, and the breccia nature of the eruption. E & F. Breccia and mega breccia comprising the rocks of the 1974 eruption (stick in foreground of E is 0.5 m long).*

under the World Heritage Convention (and especially in the United Kingdom and in Pan-Europe, *i.e.*, Continental Europe), and across the Globe under various national instrumentalities [19]. Of the large range of geological phenomena that can be assigned to sites of geoheritage significance listed in Table 1 of

**337**

of geoheritage.

products.

**Figure 8.**

*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large…*

Brocx & Semeniuk [17], three of the most complex are coastal zones, volcanoes, and caves in that they encompass a plethora of large-scale to small-scale features. Volcanoes are particularly important in that various types of magma erupting at the Earth's surface interact with water, atmosphere, and (pre-existing) rocks, and result in a large variety of volcanic products - this Chapter is focused on the geoheritage significance of volcanoes and their associated diverse geological

*geothermal spring, and closeup of three laminated siliceous sinters.*

*Illustration of a selection of volcanic features at Rotorua, New Zealand. The Rotorua volcanic area presents a complex of rhyolitic lavas and ignimbrites (including dacitic and andesitic lavas), with development of a large caldera and a series of smaller geothermal springs; these images focus on the active geothermal springs and their associated laminated siliceous sinters and sulphurous deposits. Annotated images show geothermal lakes, layered siliceous sinter lining edges of lakes, microbreccia of fragmenting sinter, sulphurous deposit precipitating from a* 

In an overview, Geoheritage encompasses the legacy of global, national, state-wide, and local features of geology, at all scales from mountain ranges and island arcs to crystals, that are important intrinsically, scientifically, historically, or culturally, offering information or insights into the evolution of the Earth, or into the history of Science, or that can be used for research, education/teaching of geological science, or used for reference [17]. As geoheritage focuses on features that are geological, the scope and scale of what constitutes Geology will determine what is included under the umbrella term 'geoheritage'. The discipline of Geology includes igneous, metamorphic, and sedimentary rocks, stratigraphy, structural geology, geochemistry, fossils and other aspects of palaeontology, geomorphology, soils and pedology, and hydrogeology/ hydrology (as listed in Table 1 of Brocx & Semeniuk [17]). From there, all that is encompassed by the discipline of Geology can be included under the umbrella

The many-and-diverse large- to small-scale features of volcanoes hold potential to be of geoheritage significance particularly as they present diverse magmas,

*DOI: http://dx.doi.org/10.5772/intechopen.97928*

*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large… DOI: http://dx.doi.org/10.5772/intechopen.97928*

### **Figure 8.**

*Updates in Volcanology – Transdisciplinary Nature of Volcano Science*

under the World Heritage Convention (and especially in the United Kingdom and in Pan-Europe, *i.e.*, Continental Europe), and across the Globe under various national instrumentalities [19]. Of the large range of geological phenomena that can be assigned to sites of geoheritage significance listed in Table 1 of

*of the 1974 eruption (stick in foreground of E is 0.5 m long).*

*Illustration of a selection of volcanic features in the Canary Islands (A, B, C) and at Bali (D, E, F, G) that are of geoheritage significance (photographs also are annotated). A. Complex tephra layering overlying basement rocks. B. Exotic xenoliths in vesicular lava (coin for scale). C. Simple laminated ash with lapilli laminae (lens cap for scale). D. The fan-shaped volcanic deposit emanating from Mt Batur is the 1974 eruption. E. The edge of the 1974 eruption, and the breccia nature of the eruption. E & F. Breccia and mega breccia comprising the rocks* 

**336**

**Figure 7.**

*Illustration of a selection of volcanic features at Rotorua, New Zealand. The Rotorua volcanic area presents a complex of rhyolitic lavas and ignimbrites (including dacitic and andesitic lavas), with development of a large caldera and a series of smaller geothermal springs; these images focus on the active geothermal springs and their associated laminated siliceous sinters and sulphurous deposits. Annotated images show geothermal lakes, layered siliceous sinter lining edges of lakes, microbreccia of fragmenting sinter, sulphurous deposit precipitating from a geothermal spring, and closeup of three laminated siliceous sinters.*

Brocx & Semeniuk [17], three of the most complex are coastal zones, volcanoes, and caves in that they encompass a plethora of large-scale to small-scale features. Volcanoes are particularly important in that various types of magma erupting at the Earth's surface interact with water, atmosphere, and (pre-existing) rocks, and result in a large variety of volcanic products - this Chapter is focused on the geoheritage significance of volcanoes and their associated diverse geological products.

In an overview, Geoheritage encompasses the legacy of global, national, state-wide, and local features of geology, at all scales from mountain ranges and island arcs to crystals, that are important intrinsically, scientifically, historically, or culturally, offering information or insights into the evolution of the Earth, or into the history of Science, or that can be used for research, education/teaching of geological science, or used for reference [17]. As geoheritage focuses on features that are geological, the scope and scale of what constitutes Geology will determine what is included under the umbrella term 'geoheritage'. The discipline of Geology includes igneous, metamorphic, and sedimentary rocks, stratigraphy, structural geology, geochemistry, fossils and other aspects of palaeontology, geomorphology, soils and pedology, and hydrogeology/ hydrology (as listed in Table 1 of Brocx & Semeniuk [17]). From there, all that is encompassed by the discipline of Geology can be included under the umbrella of geoheritage.

The many-and-diverse large- to small-scale features of volcanoes hold potential to be of geoheritage significance particularly as they present diverse magmas, occur in a vast range of Earth-surface settings and, depending on what materials they interact with, present a large variety of lithologies, structures, and geological relationships between volcanic materials and country rock. Further, volcanoes and volcanic sequences, depending on setting, often present an ensemble of inter-related geological features. For instance, while there may be a degree of structural and volcanic-stratigraphic overlap, the volcanic rock associations, lithologies, and structures of basaltic volcanoes in a submarine and emergentvolcanic-island settings are different to those of andesitic settings to those of rhyolitic settings.

Volcanoes and volcanic geology have existed from Precambrian times to the present, but the emphasis in this Chapter, for purposes of addressing geoheritage values, is on modern and sub-recent examples (*i.e.*, the latter Cainozoic to the latter Quaternary - older volcanic deposits carry with them the complication of imprints and overprints of geomorphic modification, sedimentary reworking, epigenesis, pedogenesis, metamorphism, and structural modifications [18, 25], and thus are outside the scope of this Chapter. However, the principles developed in this Chapter can be applied to these older deposits.

While many sites and features of geoheritage significance can be an isolated geological phenomenon or a stand-alone isolated feature (*e.g.*, Mato Tipila [The Devils Tower] in Wyoming [26–28], a volcanic feature appearing to be related to monogenetic volcanism [28]; or Pamukkale [the Cotton Castle in Turkey] [29]), the same perspective also applies to some aspects of volcanic geology. However, more typically, the majority of volcanic features occur as ensembles of geological phenomena. Thus, a volcano can carry with it several or many of the following that can be (in isolation or collectively) of geoheritage significance: 1. geomorphic form; 2. lithology-specific volcanic form; 3. internal layering of a volcanic cone; 4. complex stratigraphic layering and relationships internal to the volcano; 5. layering of distally-dispersed tephra (*e.g.*, fine-grained ejecta); 6. tephra that is lithologically and granulometrically diverse; 7. tephra with diverse structures (*e.g.*, surge structures, drop-stones structures); 8. tephra interlayered with lahar (water-saturated mudflow or debris flow composed of pyroclastic material and rocky debris); 9. rocks of diverse lithology, such as lavas, plugs, dykes, sills, and diatremes associated with volcanoes; 10. breccia and mega-breccia; 11. lapilli and accretionary lapilli; 12. lava-filled, or empty fumarolic vents (mostly small-scale fissures that are venting gases); 13. dykes (concordant to discordant to volcano layering); 14. lava tubes; 15. lenses/wedges of slumps/avalanches deriving from and inter-layered with fine-grained tephra; and 16. rain-induced mobilisation of tephra forming lenses/wedges of reworked material.

For sites of geoheritage significance, Brocx & Semeniuk designed a globallyapplicable Geoheritage Tool-kit to identify geoheritage sites [17, 30, 31] (that is currently recommended by the IUCN [20] and, using Brocx & Semeniuk, the Geological Society of Australia [31]), presented this Tool-kit to categorise geoheritage sites [17]), and a semi-quantitative method to evaluate them [17]. Modified versions of these procedures, tailored for volcanoes and volcanic rocks, are illustrated here in **Figures 1** and **2**. The techniques for classifying/categorising sites of geoheritage significance are applied (following Brocx & Semeniuk [17]) in **Table 1** to four relatively geologically simple localities: 1. bomb-rich tephra, Jeju Island, 2. grainsize-graded tephra, Bali, 3. basement disconformity influencing tephra layering, Canary Islands, and 4. rhyolitic geothermal springs and sinters, Rotorua, New Zealand. Further examples of systematically evaluating levels of significance of geoheritage sites are provided in Tables 1-3 in Brocx & Semeniuk [30].

**339**

**Geological feature**

**Jeju Island (Figures 5** and **6)**: a regional framework of mainly Pleistocene to Holocene basaltic to trachyandesite to andesite (lavas, tephra, ignimbrites), with lapilli-rich layers alternating with lapilli-

depauperate layers, alternating with bomb-rich layers; bomb-rich sequence with local deformation structures of dropped bombs; surge structures (megaripple and ripple lamination) [32]

**Bali (Figure 7)**: a regional framework of basaltic to dacitic volcanism (lavas, tephra, ignimbrites), a layered deposit of relatively fine-

grained tephra (ash), overlain by coarse grained ejecta (lapilli), in turn overlain by bomb-sized and block-size ejecta [33, 34]

**Canary Islands (Figure 7)**: within a framework of diverse volcanic

rocks ranging from basalt and basanite to trachyte to trachyandesite

in which are recognised five developmental stages, there are local

occurrences of basement topographic highs which influenced layering

**Rotorua (Figure 8)**: a framework of rhyolitic lavas and ignimbrites

(including dacitic and andesitic lavas) forming a large caldera and a

series of smaller geothermal springs; active geothermal springs are

forming laminated siliceous sinters and sulphurous deposits [39, 40]

**Table 1.**

*Features of geoheritage significance Jeju Island, Bali, Canary Iislands, and Rotorua, and the rationale for the assessment.*

in deposition of tephra [35–38]

Though the volcanoes of Bali represent active geological sites, the cliff illustrated in **Figure**

is a geohistorical site; medium scale to small scale; also can be reference site for the graded upward coarsening of tephra deposits

Ancient geohistorical site; medium scale to

National

small scale; can be reference site for the effect of

basement rock topography on tephra layering

Active volcanic site; medium scale to small

International

Well-exposed site of rhyolitic rocks and

ignimbrites, geothermally-derived siliceous

sinters, active geothermal springs; useful for

research, education and geotourism

scale; plethora of surface features and derivative

products from siliceous sinter (*e.g.*, microbreccia

of fragmenting sinter)

 **7B**

State-wide to Regional

Well-exposed cliff site of grain-size-graded ejects grading from relatively fine-grained to block-sized showing a history of increasing intensity of volcanic activity; useful for research, education and geotours

Geohistorical site; medium scale to small scale; also can be reference site for (1) the variety of tephra deposits, (2) the dropstone effects of bombs, and (3) the stratigraphic/structural record of surges

**Type of site, and its scale (category of site from Figure 1)**

**Significance (based on criteria of Figure 2)** International

**Rationale for assigning the level of significance**

*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large…*

Well-exposed site of Cainozoic tephra with

complex lensoid layering above a basement

topographic high followed by horizontal

tephra layering; useful for research, education

and geotourism

*DOI: http://dx.doi.org/10.5772/intechopen.97928*

Well-exposed cliff site of multi-lithologic sequence of tephra types and, in particular, the deformation effects of bombs as drop stones and the evidence of surge deposits as ripple lamination and megaripple lamination; useful for research, education and geotours



*Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large… DOI: http://dx.doi.org/10.5772/intechopen.97928*

*Updates in Volcanology – Transdisciplinary Nature of Volcano Science*

rhyolitic settings.

can be applied to these older deposits.

occur in a vast range of Earth-surface settings and, depending on what materials they interact with, present a large variety of lithologies, structures, and geological relationships between volcanic materials and country rock. Further, volcanoes and volcanic sequences, depending on setting, often present an ensemble of inter-related geological features. For instance, while there may be a degree of structural and volcanic-stratigraphic overlap, the volcanic rock associations, lithologies, and structures of basaltic volcanoes in a submarine and emergentvolcanic-island settings are different to those of andesitic settings to those of

Volcanoes and volcanic geology have existed from Precambrian times to the present, but the emphasis in this Chapter, for purposes of addressing geoheritage values, is on modern and sub-recent examples (*i.e.*, the latter Cainozoic to the latter Quaternary - older volcanic deposits carry with them the complication of imprints and overprints of geomorphic modification, sedimentary reworking, epigenesis, pedogenesis, metamorphism, and structural modifications [18, 25], and thus are outside the scope of this Chapter. However, the principles developed in this Chapter

While many sites and features of geoheritage significance can be an isolated geological phenomenon or a stand-alone isolated feature (*e.g.*, Mato Tipila [The Devils Tower] in Wyoming [26–28], a volcanic feature appearing to be related to monogenetic volcanism [28]; or Pamukkale [the Cotton Castle in Turkey] [29]), the same perspective also applies to some aspects of volcanic geology. However, more typically, the majority of volcanic features occur as ensembles of geological phenomena. Thus, a volcano can carry with it several or many of the following that can be (in isolation or collectively) of geoheritage significance: 1. geomorphic form; 2. lithology-specific volcanic form; 3. internal layering of a volcanic cone; 4. complex stratigraphic layering and relationships internal to the volcano; 5. layering of distally-dispersed tephra (*e.g.*, fine-grained ejecta); 6. tephra that is lithologically and granulometrically diverse; 7. tephra with diverse structures (*e.g.*, surge structures, drop-stones structures); 8. tephra interlayered with lahar (water-saturated mudflow or debris flow composed of pyroclastic material and rocky debris); 9. rocks of diverse lithology, such as lavas, plugs, dykes, sills, and diatremes associated with volcanoes; 10. breccia and mega-breccia; 11. lapilli and accretionary lapilli; 12. lava-filled, or empty fumarolic vents (mostly small-scale fissures that are venting gases); 13. dykes (concordant to discordant to volcano layering); 14. lava tubes; 15. lenses/wedges of slumps/avalanches deriving from and inter-layered with fine-grained tephra; and 16. rain-induced mobilisation of tephra forming lenses/wedges of reworked

For sites of geoheritage significance, Brocx & Semeniuk designed a globallyapplicable Geoheritage Tool-kit to identify geoheritage sites [17, 30, 31] (that is currently recommended by the IUCN [20] and, using Brocx & Semeniuk, the Geological Society of Australia [31]), presented this Tool-kit to categorise geoheritage sites [17]), and a semi-quantitative method to evaluate them [17]. Modified versions of these procedures, tailored for volcanoes and volcanic rocks, are illustrated here in **Figures 1** and **2**. The techniques for classifying/categorising sites of geoheritage significance are applied (following Brocx & Semeniuk [17]) in **Table 1** to four relatively geologically simple localities: 1. bomb-rich tephra, Jeju Island, 2. grainsize-graded tephra, Bali, 3. basement disconformity influencing tephra layering, Canary Islands, and 4. rhyolitic geothermal springs and sinters, Rotorua, New Zealand. Further examples of systematically evaluating levels of significance of geoheritage sites are provided in Tables 1-3 in Brocx

**338**

& Semeniuk [30].

material.
