Brenna, M., Ubide, T., Nichols, A. R. L., Mollo, S., and Pontesilli, A. (2021). “Anatomy of Intraplate Monogenetic Alkaline Basaltic Magmatism,” in Crustal Magmatic System Evolution: Anatomy, Architecture, and Physico-Chemical Processes. AGU Geophysical Monograph. Editors M. Masotta, C. Beier, and S. Mollo, 264, 79–103. doi:10.1002/9781119564485.ch4

Anatomy of intraplate monogenetic alkaline basaltic magmatism: clues from magma, crystals and glass

Marco Brenna1,*, Teresa Ubide2, Alexander R. L. Nichols3, Silvio Mollo4, Alessio Pontesilli1

1 Geology Department, University of Otago, Dunedin, New Zealand 2 School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Australia 3 School of Earth and Environment, University of Canterbury, Christchurch, New Zealand 4 Dipartimento di Scienze della Terra, Sapienza Università di Roma, Rome, Italy * corresponding author: [email protected]

Abstract Intraplate basaltic systems, often occurring as fields of small monogenetic volcanoes, are dominated by eruption of alkaline basaltic rocks, ranging from nephelinite/basanite to transitional/subalkaline. Their generally primitive erupted compositions imply limited crustal modification, and hence they provide an important probe into deep, lithospheric mantle and partial melting processes. Partial melting and magmatic ascent processes can be investigated using the composition of crystals, glass and whole- rock, although a combination of these is preferable. The whole-rock chemical variability within single eruptions or over the temporal and spatial extent of a volcanic field is controlled by the characteristics of the primary melting source, as well as near source percolative/reaction processes. Coupled crystal- and -whole-rock detailed investigations are most promising to constrain the processes that modify primary melts into the primitive magmas that accumulate before ascent. Complex crystal textures and chemistry have so far demonstrated that basaltic magmas are principally processed and modified within the lithospheric mantle with minor modification en-route through the crust. Fractional crystallization and magma mixing modify melts throughout ascent, and can imprint secondary chemical intra-eruptive variability. Quantifiable temperature and pressure parameters based on crystal- melt compositions constrain the depth of formation, and hence provide information about the role of different mineral phases in deep versus shallow chemical evolution. Volatile components in the melt (e.g. H2O and CO2) can be quantified on glass and melt inclusions. These analyses, coupled with solubility models, may help to reconstruct initial dissolved volatile content to further constrain the source characteristics and magmatic ascent dynamics. Integrated studies of crystals and melt paint a picture of extended lithospheric mantle to minor crustal processing resulting from the complex deep plumbing of monogenetic basaltic systems. This highlights the need for improved resolution to characterize true primary signatures and hence elucidate the formation of intraplate alkaline basalts.

Keywords Intraplate basalt, alkaline, whole-rock composition, crystal composition, glass composition, magmatic volatiles

1. Introduction fundamental for developing our understanding of processes of magma formation and Basalt is the most common rock in the Earth’s evolution. Mid-Oceanic Ridge Basalts crust, although it is admittedly mostly (MORBs) are generated where tectonic plates submerged as the oceanic floor. Basalts (sensu diverge and new crust is formed. Melting in lato) also represent the compositions of partial these settings occurs by adiabatic melts forming in the mantle (Green, 1973), and decompression (Langmuir et al., 1992; hence primary magmas from which many Oxburgh and Turcotte, 1968), and despite local intermediate and silicic igneous rocks are and regional variability (Shimizu et al., 2016; derived. Basaltic rocks are therefore Wood, 1979), MORBs have a restricted compositional range compared to intraplate monogenetic magma batches with OIB-like Oceanic Island Basalts (OIBs) (e.g. Pilet, alkaline basalt/basanite associations. We will 2015). Despite the misleading appellation of extend the discussion to subalkaline basalts these latter magma types, rocks with OIB where they occur in the context of their alkaline characteristics occur in continental as well as correlatives. The rationale for focusing our oceanic settings. Our understanding of the attention on monogenetic alkaline basaltic generation of these intraplate rock suites, and rocks is that they generally provide a direct the associated mantle plume theory (Morgan, probe into the processes involved with magma 1971), was originally developed using intra- generation and evolution, and they are oceanic islands as type localities, notably ubiquitous in most continental intraplate Hawaii (Wilson, 1963), and hence the name. settings. Intraplate monogenetic alkaline OIBs are predominantly understood to be basalts often host inclusions of lithospheric produced by adiabatic decompression peridotite, indicative of their relatively rapid (Cawthorn, 1975; Green and Ringwood, 1967). ascent from the mantle (O’Reilly and Griffin, If exotic (metasomatic) amphibole and/or 2011; Spera, 1984). The lack of complex phlogopite are present, they may breakdown plumbing and storage has implications in terms and cause melting upon compression, such as of minimising the potential processes of during lithospheric delamination (Allen et al., magma modification en-route to the surface 2013). OIBs may also not be derived directly (McGee and Smith, 2016). The relatively from the partially molten portion of an limited crustal interaction makes monogenetic upwelling mantle diapir, with post-melting alkaline basaltic rocks a useful tool to processes such as chromatographic percolation, investigate deep processes of partial melting reactions with overlying lithosphere and re- and melt modification. Their generally melting due to thermal perturbation elementary crystal cargo, often consisting of contributing to final basalt magma formation only olivine and clinopyroxene is another (Godard et al., 1995; Harte et al., 1993; Mallik beneficial aspect to help the reconstruction of and Dasgupta, 2012; Menzies and Murthy, primitive and parental melt characteristics. 1980; Pilet, 2015). The wide compositional Occasional complex zonation patterns of spectrum (major and trace elements and crystals can help resolve deep to shallow isotopes) of OIBs implies that the process of plumbing processes (Coote and Shane, 2018; melting and melt modification through Duda and Schmincke, 1985; Jankovics et al., crystallization involve a greater number of 2013; Jankovics et al., 2016) and hence variables than those governing MORB improve the resolution of petrogenetic models. generation. As a consequence, the tectonic and Here we summarize current geochemical and petrogenetic processes of intraplate rock suites petrological tools employed in the are still hotly debated (Foulger and Jurdy, interpretation of continental alkaline basaltic 2007; Foulger et al., 2005; Herzberg, 2010; suites to elucidate the magmatic processes Pilet et al., 2008). within the plumbing system of intraplate monogenetic volcanoes. Systems with OIB-like characteristics are associated with magma spanning a broad 2. Origin of intraplate monogenetic basaltic compositional spectrum from subalkaline systems (tholeiitic) basalt to basanite/nephelinite (and Within the framework of the plate tectonic some lamprophyre), with rhyolite to phonolite theory, intraplate volcanoes erupt away from being their evolved derivatives. They also the direct influence of either convergent or occur in a variety of tectonic settings from divergent plate boundaries. In this context, oceanic and continental intraplate to some subduction-related and intraplate volcanoes back-arc environments. In this contribution we (Arc versus OIB magmas) bear distinct will focus particularly on continental intraplate chemical signatures (Pearce and Peate, 1995). basaltic suites consisting of multiple Due to the input of fluids and residual mineralogy from subducting slabs, the former Magmatic intraplate systems generally occur as are enriched in large ion lithophile elements fields of small monogenetic volcanoes on both (LILEs), depleted in high field strength continental and oceanic crust (Smith and elements (HFSEs) and have generally flat Németh, 2017). Because of the spatially and patterns of rare earth elements (REEs) (Elliott temporally dispersed nature of eruptions and et al., 1997; Hawkesworth et al., 1994; Kessel their relatively short duration (weeks to few et al., 2005; Tatsumi et al., 1986). In contrast, years), such systems do not generally construct magmas erupted in intraplate settings tend to be large volcanic edifices. The lack of burial of enriched in HFSEs and LILEs, also showing early eruptions means that field-scale eruptive relatively high light/heavy REE ratios histories can be investigated comprehensively (LREEs/HREEs), frequently interpreted to from the onset of activity (Condit and Connor, indicate residual garnet in the source of the 1996; Leonard et al., 2017), revealing changes melts (Clague and Frey, 1982; Floyd, 1991; occurring within the magma source area over Sun and McDonough, 1989). Where the spatial the lifetime of the volcanic field (Brenna et al., distinction between these different rock suites 2012a; Valentine and Perry, 2006). Individual is not obvious, the chemical characteristics small volcanoes often form single scoria or become paramount for interpreting their phreatomagmatic cones or maars with small genetic origins. For instance, intraplate alkaline lava fields (Valentine and Gregg, 2008) and volcanism due to variable asthenospheric flow erupted volumes <<1 km3 (Kereszturi et al., and decompression occurs in the immediate 2013), implying low magmatic flux from the vicinity of the volcanic arc in North Island, mantle (Valentine and Hirano, 2010; Valentine New Zealand (Briggs and McDonough, 1990; and Perry, 2007). Historical examples (with McGee et al., 2013; Smith et al., 1993), scientific reports) of monogenetic eruptions, Kyushu, Japan (Mahony et al., 2011; Mashima, albeit in arc settings, are the Ukinrek maars, 2009; Sakuyama et al., 2009), the trans- Aleutian arc, Alaska (Kienle et al., 1980), the Mexican volcanic belt (Ferrari et al., 2001; generation of Teishi Knoll during submarine Márquez et al., 1999), and the Cascades, eruptions off the Izu Peninsula, Japan western USA (Strong and Wolff, 2003). For the (Yamamoto et al., 1991), and the basaltic purpose of this contribution we consider andesite to andesite Paricutin cone and lava continental intraplate basalts (sensu lato) as field in the Trans-Mexican Volcanic Belt those rocks with the following chemical (Larrea et al., 2017; Segerstrom, 1966). Recent characteristics: examples of actual intraplate monogenetic 1) whole-rock compositions in the fields of basaltic eruptions, though without direct basalt-trachybasalt-basanite/tephrite plotted on observational records, include Laoheishan and the total-alkali versus silica (TAS) diagram (Le Huoshaoshan (1719-1721 AD), Wudalianchi Maitre et al., 2005), and Volcanic Field, China (Feng and Whitford- 2) lack of negative Nb-Ta anomalies on a trace Stark, 1986), Rangitoto (c. 1500 AD), element normalized diagram, otherwise Auckland Volcanic Field, New Zealand interpreted as direct subduction signatures (Sun (Needham et al., 2011) and the Al Madinah and McDonough, 1989). eruption (1256 AD), Kingdom of Saudi Arabia It is noteworthy that some continental intraplate (Camp et al., 1987). Due to the long recurrence suites occurring in association with OIB times, such eruptions are not perceived as volcanism display arc-like signature (e.g. Nb- major hazards, and hence human settlements Ta depletion) even when there is no proximal are constructed on volcanic fields (e.g. active subduction, thus revealing the Auckland). Nonetheless, even relatively small characteristics of lithologies involved in eruptions could result in considerable loss of magma-genesis (Menzies et al., 1991). life and infrastructure (McDonald et al., 2017). However, these are rare occurrences and will, therefore, not be treated in detail here. Alkaline basalts are not just a modern occurrence and have been erupted throughout Earth’s history (Manikyamba and Kerrich, orthopyroxene in peridotite. On the other hand, 2011). In the Archean, however, alkaline deep clinopyroxene crystallization during early basaltic rocks are less abundant than other magma ascent may generate trends towards an basaltic rock types (such as subalkaline, increasing apparent alkaline character tholeiites or rocks related to hydrous melting), (decreasing SiO2 and increasing Na2O and possibly due to poor preservation and/or non K2O) (Re et al., 2017; Smith et al., 2008). ideal mantle conditions for their generation, such as high mantle potential temperatures and high degrees of melting (Blichert-Toft et al., 1996). Mantle metasomatism (Menzies and Hawkesworth, 1986) derived from subduction and recycling of ancient crustal components is likely to be a prerequisite to form alkaline basalts because of their commonly enriched mantle isotopic signatures (Davies and Rawlinson, 2014; Menzies and Murthy, 1980; Wass and Roge, 1980), consequently explaining the paucity of such magma types early in the Precambrian. The origin of the recycled crustal component is still a matter of debate. It may either be linked to mantle cycling of subducted plates (Kogiso and Hirschmann, 2006; Xu, 2014) or delaminated lower crustal material (Homrighausen et al., 2018; Weiss et al., 2016), and is increasingly recognized to involve a carbonated component (Zeng et al., 2010). The mineralogical make-up of the melting material is another aspect that Figure 1. Summary of the solidus conditions has as yet not met consensus. This is in part due of different mantle lithologies. It should be to heterogeneities in chemical signatures that, emphasized that distinct lithologies have given the lack of well-constrained parameters very different melting temperatures and (such as modal mineralogy and partitioning pressures. In the absence of clear indicators values), can be accounted for by different of thermal anomalies (i.e., mantle plumes), models. Deep melting, reactions and or vigorous mantle convection or upwelling crystallization processes, which involve it is unlikely that unmetasomatized primitive principally pyroxenes and hydrous mineral mantle will partially melt because the base -2 phases (Condamine and Médard, 2014; of continental lithosphere (e.g. 60 mWm Robinson et al., 1998; Späth et al., 2001) geotherm) intersects the MOR (normal) produce competing chemical trends, and it may mantle adiabat at temperatures lower than the peridotite solidus. be impossible to distinguish them with confidence. For instance, Pilet (2015) proposed a model whereby primitive basanites/alkaline In addition to mantle metasomatism/reaction basalts melts are derived from the melting of and/or deep crystallization affecting the metasomatically-derived hornblendite and composition of primitive alkaline magmas, react with orthopyroxene in the lithosphere to other models advocate for melts derived from produce a trend towards subalkaline distinct lithologies and different degrees of compositions. Conversely, Mallik and partial melting within the Dasgupta (2012) formed alkaline compositions asthenosphere/lithosphere (Beccaluva et al., starting from eclogite-derived subalkaline 2007; Harangi et al., 2015; Kim et al., 2019; melts and through reaction-crystallization of McGee et al., 2013; Peters et al., 2008; Timm et al., 2010). There is general consensus that the asthenospheric shear (Conrad et al., 2011). mantle is heterogeneous on all scales. Distinct Alternative models require a multi-step lithologies, however, have very different process, whereby partial melts from the solidus curves, separated by several hundreds asthenosphere metasomatize the lower of temperature degrees (Brey et al., 2009; lithosphere, with subsequent thermodynamic Dasgupta and Hirschmann, 2006; Dasgupta et destabilization of the latter generating alkaline al., 2004; Kogiso and Hirschmann, 2006) (Fig. magmas (Pilet et al., 2008; Pilet et al., 2005; 1). For instance at 3 GPa, the solidus of Rooney et al., 2014). All models have their carbonated eclogite is at <1100 ºC, whereas merits and flaws, but they are mostly based on that of dry peridotite is >1400 ºC, and melting the chemical characteristics of the erupted would generate widely differing liquids lavas. The rheological and physical (Dasgupta et al., 2004). Therefore models mechanisms involved in the upwelling of advocating for melting of different lithologies mantle peridotite have also been broadly ought to be verified for consistency with the constrained and provide an additional petrological and thermodynamic properties of perspective to evaluate the feasibility of the lithologies involved, and whether these can melting models. For instance, upwelling rates melt contemporaneously (and to the required relating to continental intraplate volcanic areas degree) within a restricted spatial and temporal have been estimated to be <1 cm a-1 in eastern interval. Metasomatism and melt/mantle Australia, New Zealand and northeast China reactions may represent a continuum solution (Demidjuk et al., 2007; McGee et al., 2011; to explain distinct compositions (Pilet et al., Zou et al., 2008) and 10% partial melting of 2005), often erupted within single small- peridotite requires adiabatic decompression of volume monogenetic events (Brenna et al., ~35 km (Lee and Chin, 2014). Even conceding 2010; Needham et al., 2011). Uncertainty that alkaline basalts are likely to be generated remains large, and further and more advanced by only a small percentage of peridotite partial data-handling techniques may be necessary to melting, it would require >10 km upwelling produce models that can be applied generally. over >1 Myr to form an alkaline melt. These timeframes are longer than the lifetime of some The mechanisms responsible for the volcanic fields, and U-series indicate that destabilization of the mantle source and its partial melting is generally a fast process partial melting require further attention to (Bourdon et al., 2005; Cohen and O'Nions, better elucidate the origin of intraplate alkaline 1993; Williams and Gill, 1989), making basaltic systems. Often, decompression melting decompression melting an unlikely sole and is associated with upwelling in mantle plumes direct driver of intraplate volcanism. This is (Davies and Bunge, 2006; Kimura et al., 2018; further emphasized in the case of Ritter et al., 2001). Peridotite upwelling can contemporaneous eruption of alkaline and also result from other processes. For example, subalkaline magmas. Subalkaline magmas lithospheric delamination may lead to require greater degree of partial melting at a upwelling of asthenosphere, causing it to melt shallower level. If both compositions are (Hoernle et al., 2006; Lustrino, 2005). Edge erupted together (e.g. Brenna et al. 2010), it driven asthenospheric flow may cause implies that they had existed as independent localized upwelling and decompression magma batches for millions of years because melting (Ballmer et al., 2015; Demidjuk et al., fast contemporaneous melting is unlikely. In 2007) as could asthenospheric flow around slab the case of melts generated by delamination or tears (Rosenbaum et al., 2018). “Petit spots” edge driven flows, they imply some serious resulting from lithospheric flexures and irregularities (several 10s km) in the lower deformation could facilitate the ascent of lithosphere that ought to be reflected in surface existing asthenospheric melts (Harangi et al., topography. Hence, a robust model of the 2013; Hirano et al., 2006; Valentine and petrogenesis of intraplate alkaline basalts needs Hirano, 2010) potentially formed by Figure 2. a) TAS diagram with data from four representative intraplate basaltic volcanic fields (data from the GEOROC database: http://georoc.mpch-mainz.gwdg.de/georoc/). The illustrated portion of the TAS diagram is shown in the inset on top right. tb is trachybasalt, bta is basaltic trachyandesite, ba is basaltic andesite. The distinction between alkaline and subalkaline basalts and the field of overlap are as shown in Le Maitre et al. (2005) after Bellieni et al. (1983). b) Possible mechanisms related to the compositional variability within the basaltic spectrum. Hornblendite (hbl) partial melts and melt/peridotite reactions (Pilet, 2015; Pilet et al., 2008). Eclogite (ecl) partial melts and melt/peridotite reactions (Mallik and Dasgupta, 2012). High- pressure clinopyroxene (acmite, Cr-diopside and Al-augite) fractional crystallization (FC), compositional field from Duda and Schmincke (1985). Olivine fractional crystallization, Fo 85 is representative of olivine crystallizing in primitive basaltic magmas. c) and d) Compositional variation within single monogenetic eruptions: c) continuous trends from strongly alkaline to mildly alkaline or subalkaline compositions; and d) alkaline/subalkaline compositional bimodality. Pupuke data from McGee et al. (2013), Motukorea data from McGee et al. (2012), Kissomlyó data from Jankovics et al. (2015) Mount Rouse data from Boyce et al. (2015), Udo data from Brenna et al. (2010), Rangitoto data from Needham et al. (2011) and Mount Gambier data from Van Otterloo et al. (2014). to marry chemical signatures with physical and mineralogy and mechanics. Below we will timescale constraints. focus on interpreting these processes based on rock, mineral and glass chemistries. Primarily, the study of intraplate basalts has obvious practical ramifications for society and 3. Insights from whole-rock chemical data the economy, in terms of the potential hazards Intraplate alkaline basaltic rocks are the most associated with magma ascent and eruption. In common hosts of mantle xenoliths (Chen et al., this respect, post-sourcing differentiation 2007; Dalton et al., 2017; Pearson et al., 2003; processes have a more direct bearing on final Vaselli et al., 1995). Quantitative studies of eruption dynamics compared to the source magma ascent rates reveal that intraplate alkaline basalts rise from near-source mantle from foidite/nephelinite to subalkaline basalt, depths, where some storage may be involved, as exemplified by the Auckland Volcanic Field and ascend rapidly through the crust (Albert et (New Zealand; Fig. 2a). Not every volcanic al., 2015; Brenna et al., 2018; Demouchy et al., field, however, displays the same range and 2006; Harangi et al., 2013; Jankovics et al., distribution of erupted compositions, likely 2013). Consequently the effect of assimilation reflecting heterogeneities in the primary and crustal contamination do not generally melting mantle material, the degree of partial plague the interpretation of chemical signatures melting, the degree of percolative interaction in alkaline basalts, particularly those related to and the reacting lithologies. To constrain the small-volume eruptions (McGee and Smith, deep processes that are occurring, focusing on 2016). Far from being only dominated by near- single eruptions may facilitate greater sampling primary magmas, however, intraplate alkaline resolution and hence provide insightful systems have often undergone considerable information unattainable at the scale of entire magmatic evolution to form fields. trachyte/phonolite/rhyolite associations (Ablay et al., 1998; Brenna et al., 2012b; Crossingham The availability and interconnectivity of fertile et al., 2018; Harangi, 2001; Harangi et al., material to produce melt and allow melt to 1995; Melluso et al., 2018; Moufti et al., 2012). percolate and be extracted (Katz et al., 2006) Such magma compositions generally occur in influence the volumes of individual melt larger volume central volcanoes that are pockets that eventually coalesce to produce a associated with complex, multi-stage plumbing magma batch sufficient to sustain the opening systems and result from magma stalling and and propagation of a dyke to the surface evolving through fractional crystallization and (Rubin, 1995; Taisne and Tait, 2009). Such assimilation processes. Nevertheless, deep magma processing is recorded in the nominally evolved magmas, such as trachyte chemical composition of the eruption products. and phonolite, can form broadly For instance, it is not uncommon that single “monogenetic” eruptions, such as isolated monogenetic eruptions show a continuous domes, lava flows and pyroclastic cones transition from strongly alkaline compositions (Brenna et al., 2019; Paulick and Franz, 1997; (nephelinite/basanite) to mildly alkaline or Wörner and Schmincke, 1984). These could in subalkaline basalt, or subsets of this spectrum some cases result from direct extraction of (Fig. 2c). The extremes of the compositional lithospheric peridotite melts (Laporte et al., spectrum within these eruptions generally have 2014; Loges et al., 2019), particularly where distinct trace element and isotopic they host mantle xenoliths (Irving and Price, characteristics, as seen for instance at Mount 1981), although crustal storage and mixing may Rouse in the Newer Volcanic Province of also explain unusual associations (Abratis et Australia (Boyce et al., 2015) or Motukorea in al., 2015; Schmitt et al., 2017). Because of the the Auckland Volcanic Field (McGee et al., complexities introduced in the system by 2012). This has traditionally been interpreted to crustal storage, which end up obscuring indicate that two distinct primary magma primary magmatic signatures, we will not sources, such as peridotite and eclogite, or consider evolved intraplate alkaline series in lithospheric and asthenospheric, exist and this contribution. interact through mixing. However, the thermodynamics and thermal budget The total alkalis versus silica (TAS; Fig. 2) considerations involved in the independent diagram (Le Maitre et al., 2005) provides a first melting of distinct lithologies make such a order visualization of the whole-rock chemical process unlikely as noted earlier (Fig. 1). character of igneous suites. Considering single Instead, in a metasomatic percolation scenario intraplate volcanic fields as whole magmatic (Mallik and Dasgupta, 2012; Pilet, 2015), the entities, it is apparent that the range of erupted spectrum may indicate melt extraction from magmas spans a very broad spectrum, often porous mantle with interconnected melt channels. Complexly zoned olivine, cone and lava field (Jeju Island, Korea) and clinopyroxene and spinel phenocrysts and Rangitoto scoria cone and lava (Auckland xenocrysts of Kissomlyó (Pannonian Basin, Volcanic Field) are two emblematic examples, Hungary) (Jankovics et al., 2015) or olivine where early erupted alkaline basalt was xenocrysts at Pupuke, Auckland Volcanic Field followed by subalkaline basalt (Brenna et al., (Brenna et al., 2018), provide evidence that 2010; Needham et al., 2011). Mount Gambier melts with diverse alkaline affinities interacted. (Newer Volcanic Province, Australia) also These melts were proposed to have undergone erupted tephritic and trachybasaltic magmas different degrees of percolation and deep with a distinct compositional gap (Van Otterloo accumulation resulting in the broad et al., 2014). Such compositional records have compositional spectrum of those eruptions generally been interpreted in terms of two (Fig. 2c). The extreme case of compositional distinct magma sources being tapped. This diversity within monogenetic volcanoes is again raises the issue highlighted above of where two very distinct magma batches with implausible contemporaneous melting at a different degrees of alkalinity are erupted range of degrees forming magmas with a range within a single sequence (Fig. 2d). The Udo tuff of alkalinity. The spatial and temporal

Figure 3. Trends in whole-rock compositions of small-volume alkaline basaltic eruptions. a) Ilchulbong tuff cone (Jeju) was formed by three magma batches with analogous evolutionary trends (Sohn et al., 2012). b) Udo tuff cone and lava field (Jeju) erupted alkaline and subalkaline magmas (Brenna et al., 2010). c) Songaksan tuff ring, scoria and lava consist of individual magma batches with various degrees of evolution (Brenna et al., 2011). d) Motukorea (Auckland Volcanic Field) has constant variation from evolved to primitive compositions (McGee et al., 2012). Numbering 1 to 3 indicates eruption packages separated by collapse features, small erosional surfaces, or shifts in eruption styles. e) Summary and possible interpretation of observed trends. constraints imposed by sequential eruption in a volcanic particles (D'oriano et al., 2014; monogenetic eruption make a model involving Houghton and Smith, 1993). Particularly while melting of distinct portions of mantle or sampling in the field, dense crystalline or mud variable rates unlikely. Alternatively the coated clasts ought to be avoided as they likely bimodality in the composition of eruption represent recycled basement lithics or syn- products may indicate the existence of two eruptive reworked lapilli and bombs. distinct areas of accumulated melt that are more or less percolated and reacted, and hence more Identification of true chemical trends also or less alkaline in composition. One common require high-resolution sampling of as many characteristic of such bimodal systems is that eruptive beds as possible. Plotting of the more alkaline magma batch is erupted first, stratigraphically ordered compositions will followed by the less alkaline or subalkaline reveal whether consistent and systematic trends magma, likely indicating the opening of a path emerge (Fig. 3). Systematic trends imply that to the surface by the deeper-derived (less juvenile material was collected because percolated) alkaline melts (Brenna et al., 2010). sampling of recycled clasts would impose a It is also observed that the initial alkaline randomness to the compositional sequence. magma is erupted explosively Smooth changes in chemical composition (phreatomagmatic/Strombolian), whereas the indicate an eruption that was likely fed by a subsequent subalkaline magma is erupted single magma batch through one isolated dyke effusively with minor Strombolian activity or a set of interconnected dykes, such as Udo (Brenna et al., 2010, 2015). The overall (Jeju) and Motukorea (Auckland Volcanic compositional variation of small-volume Field; Fig. 3b, d, e) (Brenna et al., 2010; McGee eruptions can therefore provide a wealth of et al., 2012). Abrupt switches in chemical information on the deep (lithospheric mantle) composition may instead be indicative of plumbing architecture of monogenetic alkaline renewed magma feeding by distinct dykes, such system and could also be linked to shallow as at Ilchulbong and Songaksan (Jeju; Fig. 3a, eruption dynamics. c, e) (Brenna et al., 2011; Sohn et al., 2012). Such switches often occur in association with Intra-eruptive chemical variability is another lithic-rich horizons or evidence for brief aspect of monogenetic volcanoes that can eruption breaks or vent shifts. These events provide insights into magma processing and tend to be short lived recording single ascent dynamics (Blondes et al., 2008; Reiners, individual storm surges or tidal events, such as 2002). For such investigations, it is necessary at Songaksan (Sohn and Sohn, 2019). Irregular to know the stratigraphic order of collected or saw-toothed trends result from multiple sample suites, which is straightforward when dykes interacting in a chaotic fashion or sections are cut through cones by, for instance, alternatively that sampling included recycled wave erosion (Brenna et al., 2011; McGee et material or lithic fragments. al., 2012; Sohn et al., 2012) (Fig. 3). Stratigraphically ordered chemical variability A feature that is commonly observed in the can elucidate the sequence of magma input in chemical stratigraphy of individual eruptions is the shallow plumbing and conduit of the that the relatively more evolved magma (SiO2- ongoing eruption. Volcanic conduits are rich and MgO-poor) is ejected at the onset of nevertheless very dynamic environments, and the eruption, as pointed out by Smith et al. volcanic particles often fall back into the crater (2008) at Crater Hill (Auckland Volcanic area (Graettinger et al., 2016). Hence, Field). Data from Udo and Motukorea (Fig. 3b, distinguishing truly juvenile particles can be d) also show such a trend. This is likely to be challenging, particularly in phreatomagmatic related to the dynamics of dyke tapping during deposits. Even so, there are physical properties the eruption. The tip of the feeder dyke of lapilli and bombs that can be employed to undergoes high-degrees of crystallization due infer the degree of reworking and recycling of to strong undercooling associated with the opening of a path to the surface (Carrigan et al., LREEs/HREEs ratios can be changed, 1992). Because of this intra-dyke potentially imposing misleading “garnet differentiation and the resulting tapping signatures” on the melt (Bonadiman et al., dynamics, a variety of chemical trends can be 2005; Scott et al., 2016). In order to investigate imposed on the eruption products (Fig. 3e). true source signatures it is therefore essential to Relatively shallow effects on the magma unravel any near-source modification process, composition are, however, distinct from deep, and focus on primitive (high-MgO) samples near-source crystallization and fractionation. without crystal accumulation (Ubide et al., Clinopyroxene tends to be the stable liquidus 2014b). phase at lithospheric mantle depths, whereas olivine takes over in the crust (Bultitude and 4. Insights from crystal compositions Green, 1971; Jakobsson and Holloway, 1986). The relative contribution of The intra-suite variability of CaO, V and Sc melting/metasomatism and fractional (compatible in clinopyroxene but not in crystallization processes remains an enigmatic olivine) usually indicates the involvement of aspect of the chemical variability in basaltic clinopyroxene versus olivine fractionation. products. Early-formed phenocrysts, antecrysts Clinopyroxene fractionation may be cryptic in or xenocrysts, however, witnessed deep basalts with principally olivine phenocrysts. processes and hence provide a first-hand look This was observed at Crater Hill (Smith et al., at the plumbing system of basaltic volcanoes. 2008) and Udo (Brenna et al., 2010), where the Alkaline basaltic rocks are relatively simple chemical trends within the olivine basalt tuff petrographically, consisting principally of a have decreasing CaO, V and Sc, with macrocryst assemblage dominated by olivine + decreasing Mg# despite the lack of clinopyroxene in a microlitic groundmass of clinopyroxene as a phenocryst phase. In olivine + clinopyroxene + plagioclase + oxide. relatively hydrous alkaline melts, amphibole Amphibole and phlogopite require H2O-rich may also be involved in petrogenetic processes magmas, and with feldspathoids are confined to producing distinct chemical signatures, the SiO2-poor end of the spectrum, as shown in particularly in terms of the relative behaviour H2O-saturated experiments conducted on the of LILEs, LREEs and HFSEs (Francis and melanephelinite from Kakanui (Waiareka- Ludden, 1995; Mayer et al., 2014). Plagioclase Deborah Volcanics, New Zealand) (Merrill and tends to be a late crystallizing phase, generally Wyllie, 1975) and the nepheline mugearite of only forming groundmass microlites or The Anakies (Newer Volcanic Province, microphenocrysts upon cooling and eruption or Australia) (Irving and Green, 2008). Empirical else, if present as an important phenocryst hygrometry also suggests that H2O contents >3 phase, implies considerable crustal processing wt% are required for amphibole and mica to be (Giacomoni et al., 2014; Mollo et al., 2015; stable in the basanites and nephelinites with Ubide and Kamber, 2018). Early clinopyroxene lamprophyric affinities at Jagged Rock (Hopi and potentially amphibole fractionation implies Buttes Volcanic Field, USA) (Re et al., 2017) that those trace element ratios commonly and the Catalonian Coastal Range (Spain) employed to interpret source characteristics, (Ubide et al., 2014a). Plagioclase macrocrysts such as LREEs/HREEs, become unreliable. are prevalently segregated from SiO2 saturated HREEs partition into both phases preferentially (subalkaline) magmas, such as those erupted in compared to LREEs (refer to the GERM the Kaikohe-Bay of Island Volcanic Field partition coefficients database (New Zealand) (Coote et al., 2018). They also https://earthref.org/KDD/ for a comprehensive indicate relatively H2O-poor melts or shallow summary). The compositional changes that degassing and crustal processes, with deviation reflect clinopyroxene and amphibole from purely monogenetic basaltic systems crystallization play a major role in controlling (Crossingham et al., 2018; Giacomoni et al., the OIB signature of erupted magmas (Mollo et 2014). al., 2018; Scarlato et al., 2014). Primary Detailed studies of the crystal cargo of alkaline the development of sieve textured and partially basaltic rocks have, however, revealed a resorbed phenocrysts (Fig. 4b), are indicative complex textural architecture (Coote and of disequilibrium processes including magma Shane, 2018; Duda and Schmincke, 1985; recharge and mixing (de Maisonneuve et al., Jankovics et al., 2012; Jankovics et al., 2019; 2016; Streck, 2008; Ubide et al., 2014a; Ubide Re et al., 2017; Shane and Coote, 2018; Ubide and Kamber, 2018), whereas sector (hourglass) et al., 2014a). For example, the occurrence of zoning is a response to crystal growth rates and concentric zoning in clinopyroxene, as well as undercooling phenomena (Masotta et al., 2020;

Figure 4. Summary of zoning patterns on olivine and clinopyroxene crystals in monogenetic alkaline basaltic systems. a) Olivine textures and compositions indicative of complex magmatic processes involving diffusion and overgrowths (Shea et al., 2015). Greyscale olivine sketches indicate BSE response (dark = high Fo#, light = low Fo#). Compositional fields are from Jankovics et al. (2015) and Pupuke data are from Brenna et al. (2018). b) Clinopyroxene textures and compositions are clear indicators of the conditions of crystallization with spongy and green cores indicating crystal recycling and magma mixing (Duda and Schmincke, 1985; Ubide et al., 2014a) and sector zoning indicative of undercooling conditions (Masotta et al., 2020; Ubide et al., 2019). Ti and Al represent atoms per formula unit (considering 6 O). Pannonian Basin data from Jankovics et al. (2016), Jeju data from Brenna (2012). Clinopyroxene can be useful geobarometer indicative of crystallization at various levels within the lithosphere. Jagged Rock Complex (JRC) pressures from Re et al. (2017), Calatrava Volcanic Field (CVF) pressures from Villaseca et al. (2019), and Whangarei Volcanic Field (WVF) pressures from Shane and Coote (2018). Ubide et al., 2019). Concentric zonation can Most of the open-system processes that can take on very different forms, from normal significantly change the compositions of (more primitive core) to reverse (more evolved magmas by shifting them towards intermediate core), to oscillatory, patchy or stepped (Fig. 4). and evolved terms are confined to crustal This generally means that antecrysts (crystals depths. For example, in the monogenetic from preceding but genetically related magma volcanoes of the Kaikohe-Bay of Island batches) can be reincorporated and transported Volcanic Field, intra-crystal isotopic zoning multiple times by subsequent magmas during provides clues to the potential contribution of ascent, similar to occurrences at more complex crustal contamination during the geochemical polygenetic volcanoes (Davidson et al., 2007). evolution of magmas (Coote et al., 2018). Several detailed case studies have been Complexly zoned plagioclase testifies to a performed on the small alkaline volcanoes in crustal storage zone where assimilation the Carpathian-Pannonian Basin. Jankovics et occurred contaminating the Sr isotopic al. (2015; 2019) identified up to five different signature of the mantle-derived magma. This types of olivine based on compositions and can be compounded by mixing with stalled textures within single small eruptions. These batches of magma from preceding dyking were interpreted to represent crystal growth in events related to failed eruptions or unerupted storage areas within both the upper lithospheric magma from previous eruptions (Coote and mantle and the lower crust with subsequent Shane, 2018; Jankovics et al., 2019). Indeed, magma mixing and crystal recycling (Fig. 4a). such crustal processing may be a pre-condition Clinopyroxene crystals similarly display for the development of large volcanoes diverse zoning and distinct compositions (Fig. erupting trachytes and phonolites (Brenna et 4b) in the Pannonian Basin volcanoes al., 2012b). (Jankovics et al., 2016), as well as Eastern Austria (Dobosi et al., 1991), Jeju Island Different mineral phases have different (Brenna et al., 2012a), the Hopi Buttes stabilities in alkaline magmas, with Volcanic Field (USA) (Re et al., 2017) and the clinopyroxene, rather than olivine, being the Eifel Volcanic Field (Duda and Schmincke, liquidus phase at >1.5-2 GPa (Bultitude and 1985), for example. The occurrence of crystals Green, 1971; Irving and Green, 2008; derived from several levels within the Jakobsson and Holloway, 1986). This also plumbing systems, and that have interacted allows crystallization and fractionation within with diverse magma batches implies that the the lithospheric mantle to be distinguished from plumbing system of even small-volume crystallization and fractionation within the basaltic volcanoes is not as simple as the rock crust (Dobosi et al., 1991). For a more petrography may superficially suggest. quantitative approach concerning the depth of Compositionally distinct accumulation and crystallization there are now several updated storage zones call into question the literal thermometers, barometers and hygrometers “monogenetic” character of some basaltic calibrated specifically for alkaline/subalkaline volcanoes. The deep portions of these feeding basaltic systems (Table 1), which can assist in systems still require accurate investigation, in constraining the crystallization conditions of order to better resolve the different role played magmas and identifying potential depths of by partial melting and metasomatic source- magma storage. Several crystallization related processes. For this reason, integrated scenarios have been observed in intraplate studies dealing with bulk rock as well as monogenetic basaltic systems. Shane and phenocrysts and xenocrysts (or xenoliths) are Coote (2018) and Coote and Shane (2018) necessary to elucidate the complex interplay found that in the Whangarei and Kaikohe-Bay between the original genetic signature of of Islands volcanic fields clinopyroxene magmas and their differentiation through the crystallization occurs prevalently within the upper mantle and crust. crust (Fig. 4b). This is consistent with their investigation of plagioclase zoning, which also revealed a well-developed crustal storage mantles forming from mantle to crust, and system (Coote et al., 2018). However, in crystal rims formed within the crust. different systems storage and crystallization may occur over a variety of different levels. Such variability bears similarities with active Clinopyroxene thermobarometry revealed a composite volcanoes, for which most bimodal distribution in the Calatrava Volcanic thermobarometric models that apply to alkaline Field (Spain) (Villaseca et al., 2019). These basaltic systems have been developed. For authors interpreted the formation of cumulates example, Mt. Etna (Sicily, Italy) is one of the within the lithospheric mantle as well as most active and monitored volcanoes in the crystallization within the crust. Ubide et al. world, and although it is not sensu-stricto a (2014a) obtained similar results, with basaltic system (historically erupted principally two depths of storage within upper compositions range up to trachyte) (Ferlito and mantle and lower crust in lamprophyres from Lanzafame, 2010) its ongoing basalt- the Catalonian Coastal Range (Spain). Whereas dominated eruptions provide an outstanding in the Springerville Volcanic Field (USA), opportunity to probe the plumbing dynamics on Putirka and Condit (2003) found that human timescales. The present-day activity at clinopyroxene crystallization principally the volcano consists of trachybasaltic explosive occurred at two levels in the crust (lower and and effusive products sharing a common upper) reflecting density and rheology mineral assemblage of plagioclase + boundaries. Crystallization may also be clinopyroxene + olivine + titanomagnetite continuous during magma ascent from mantle (Mollo et al., 2015). Mantle-derived magmas depths, such as in the case of the Jagged Rock ascend towards shallower crustal reservoirs Complex, Hopi Buttes Volcanic Field (USA) through complex crystallization-recharge (Re et al., 2017). Here, clinopyroxene cores processes (Kahl et al., 2011; Ubide and mostly formed within the mantle, with crystal Kamber, 2018 and references therein). The

Figure 5. Clinopyroxene compositions from 2011-2013 trachybasaltic eruptions at Mt. Etna volcano, showing compositional changes in terms of a) cations and b) clinopyroxene components. Compositional variations record magma decompression and cooling (c), and degassing paths (d) (Mollo et al., 2018). crystallization of clinopyroxene is ubiquitous recorded by LREEs re-enrichment of REE within the entire plumbing system, recording depleted clinopyroxene in harzburgite and the entire decompression and cooling path of dunite xenoliths in the Dunedin Volcanic ascending magmas (Perinelli et al., 2018). On Group (Dalton et al., 2017), or explicitly such the other hand, the stability of olivine and as in metasomatized, amphibole-veined plagioclase is restricted to the shallower portion peridotite in Transylvania (Vaselli et al., 1995) of the plumbing system under the control of or Antarctica (Coltorti et al., 2004). Isotopic H2O-saturated melt conditions and further zoning in xenocrysts may indicate degassing mechanisms (Mollo et al., 2015; heterogeneities imposed by magmatic, hydro- Vetere et al., 2015), analogous to small-volume and carbothermal (CO2-dominated) fluid monogenetic basaltic centres in intraplate percolation. The refractive nature of zircon volcanic fields worldwide. Clinopyroxene makes it a useful tracer of such processes in the compositional changes are dominantly mantle over Myr-timescales (Siebel et al., controlled by the substitution of Mg + Fe2+ + 2009). However, with respect to the original Na with Ca + Fe3+ + Ti in octahedral sites, melting lithology, it is not clear how mantle accounting for the replacement of Si by TAl in metasomatic and chromatographic melt tetrahedral coordination (Fig. 5a). These percolation may change the isotopic signatures different crystallochemical configurations lead of magmas. Isotopic zoning within mantle to variable proportions of jadeite (Jd), diopside peridotite crystals, particularly clinopyroxene, (Di), hedenbergite (Hd) and Ca-Tschermak may help to unravel some of these processes (CaTs) components in clinopyroxene (Fig. 5b). but improved analytical techniques are required Importantly, Jd-melt, Jd-Di+Hd and CaTs- to pursue such an avenue. Di+Hd equilibria define P-T-H2O-sensitive exchange reactions governed by the Mantle-derived xenocrysts and deep plumbing physicochemical state of the system (Mollo et phenocrysts and antecrysts displaying al., 2018; Perinelli et al., 2016). Thus, the compositional zoning (elemental and/or geochemical evolution of clinopyroxene isotopic) can also provide clues on the enables accurate tracking of the dynamics of magma ascent (Jankovics et al., decompression, cooling and degassing paths of 2013; Oeser et al., 2015). For example, intra- mafic alkaline magmas rising from deep mantle crystal elemental diffusion modelling on regions to very shallow crustal levels (Fig. 5c- crystal cargoes (Costa and Morgan, 2011; d). Girona and Costa, 2013; Kahl et al., 2015) is a powerful tool to estimate the timescales of Mantle-derived xenoliths and xenocrysts magma residence and ascent of alkaline basalts provide information on the deep magma (Albert et al., 2015; Demouchy et al., 2006). dynamics of monogenetic volcanoes. These Timescales of ascent from the last storage site rock/crystal fragments inform on the within the upper mantle/lower crust for lithological properties of the lithospheric monogenetic basalts is generally estimated to mantle, testifying to heterogeneities on a range be on the order of few hours to days or weeks of scales. Mantle xenolith suites from broadly depending on the method applied (Jankovics et adjacent areas may have overall similar trace al., 2013; Ray et al., 2016). A word of caution element and isotopic characteristics, but is warranted here regarding the technique used. regional distinctions can be made, such as in Brenna et al. (2018) found that water diffusion north-east Asia, where there are spatial time estimates tend to be faster than elemental domains dominated by different types of (Fe-Mg) diffusion estimates, and attributed the enriched mantle (Choi et al., 2005). These discrepancy and fast time-scales in the water result from metasomatic re-enrichment of signature to shallow degassing. They proposed depleted mantle (DMM) from asthenosphere- that water loss from the melt starts the water derived fluids. The signature can be imposed diffusion chronometer instead of xenocryst cryptically, such as in the Zealandia lithosphere entrainment within the mantle. Beside attempting to quantify the rate of ascent of particular, is strongly dependent on single magma batches, one insight arising from composition in basaltic melts (Blank and diffusion studies is that not all magmas rise Brooker, 1994; Dixon, 1997; Holloway and from their source in one pulse. In the Perşani Blank, 1994). In alkaline basalts the solubility Volcanic Field (Romania), Harangi et al. of CO2 is higher (Dixon, 1997), meaning (2013) found short diffusion rims and a longer vapour-saturation occurs at lower pressures diffusion “mantles” in olivine xenocrysts. They compared to subalkaline melts with the same interpreted these to represent a protracted initial volatile contents. Dixon (1997) used a period (>1 year) of magma stalling within the seven component empirical parameter, termed mantle followed by rapid ascent (few days) P [-6.50´(Si+Al) + 20.17´(Ca + 0.8´K + through the crust. In the Auckland Volcanic 0.7´Na + 0.4´Mg + 0.4´Fe)], with each Field, Brenna et al. (2018) found hooked element in its molar concentration, to model the profiles in olivine xenocrysts, and implied that compositional dependence of H2O-CO2 interaction between magmas with different solubility. The calculations of mixed H2O-CO2 degrees of alkalinity occurred within the deep saturation pressures for basaltic melts in the plumbing also over protracted timeframes computer program VolatileCalc (Newman and (months-years) prior to final ascent (days). Lowenstern, 2002) are based on this solubility These case studies provide evidence for the model. This is to date the most widely used complex geometry of nominally simple deep program to calculate mixed H2O-CO2 plumbing systems. Undoubtedly, advances in saturation pressures in basalts and rhyolites, analytical resolution will open new largely owing to its ease of use, but it simplifies opportunities for multifaceted investigations the compositional parameter in basalts to just accounting for the compositional changes SiO2. However, neglecting the effect of alkalis recorded by the crystal cargo of intraplate on CO2 solubility has been shown to severely basaltic magmas. overestimate CO2 saturation pressures in alkaline basalts (Lesne et al., 2011; Vetere et 5. Insights from glass compositions al., 2011), making VolatileCalc not ideal for The last component of basalts that records intraplate alkaline basaltic systems. In response plumbing system and eruptive processes is to these discrepancies, Witham et al. (2012) volcanic glass, that is, the portion of magma developed the program SolEx to calculate H2O- that was still liquid and carrying solids (crystals CO2 solubilities and exsolved vapour and xenoliths) at the time of eruption (i.e. the compositions in basalts based on the silicate melt). Glass in volcanic products retains parameterisation of Dixon (1997), while also most of the physicochemical features of the adding the other volatiles S and Cl. This model melt, such as largely incompatible dissolved is calibrated for subalkaline basalts and alkaline volatile species (e.g. H2O, CO2, SO2, etc) that basalts to nephelinites (<52 wt% SiO2), and do not partition strongly into anhydrous requires the seven oxide components in P. minerals, thus concentrating in the melt. The solubility of volatiles in silicate liquids is An alternative solubility model developed by largely controlled by depth changes, as it Papale (1999) and Papale et al. (2006) is based decreases with decreasing pressure, but also on the multivariate regression of published H2O depends on composition and temperature. and CO2 solubility data, and produced a Different volatile species and different twenty-nine component compositional and P-T mixtures of volatiles have different solubilities. parameterization. This allows the major oxides For instance, CO2-bearing melts become SiO2, TiO2, Al2O3, Fe2O3, FeO, MnO, MgO, vapour-saturated at higher pressures than those CaO, Na2O and K2O to be varied. H2O in which CO2 is absent. The higher the initial solubilities are better constrained than CO2 or CO2 and H2O content, the deeper the pressure mixed solubilities in this model due to the at which vapour saturation will be achieved calibration dataset, and Moore (2008) (Dixon and Stolper, 1995). CO2 solubility, in concludes that while the Dixon (1997) model is the best option for tholeiitic melts, the Papale et amounts of H2O are present under moderately al. (2006) model works better for calc-alkaline reducing conditions from 790 to 1400 °C, melts. The Papale et al. (2006) model can also depending on composition and pressure up to deal with compositions that contain more than 300 MPa. Currently, the models for which links 52 wt.% SiO2 and agrees more closely with to the operating software are still active are high pressure data (>300 MPa) in alkaline VolatileCalc (Newman & Lowenstern, 2002, at basalts (Witham et al., 2012), although the https://volcanoes.usgs.gov/observatories/yvo/jl Dixon (1997) and Witham et al. (2012) owenstern/other/VolatileCalc_2.0.xls), the parameterization is better at lower pressures. Papale model (Papale et al., 2006, at Following similar principles to the Papale et al. http://melts.ofm- (2006) model, Duan (2014) developed a research.org/CORBA_CTserver/Papale/Papale thermodynamically based H2O-CO2 solubility .php) and D-Compress [Burgisser et al., 2015, model for silicate melts using the chemical at https://ars.els-cdn.com/content/image/1- potential of volatile species in the melt and s2.0-S0098300415000503-mmc5.zip vapour phases and the Duan and Zhang (2006) (Windows OS only)]. equation of state for the vapour phase. The model is compared to existing experimental Volatile exsolution and subsequent magma H2O and CO2 solubility data and calculates expansion contribute to explosivity during solubilities over a wide range of temperatures eruption. The melt loses most of its volatiles (660 to 1730 °C), pressures (up to 3 GPa) and during magma decompression and ascent prior compositions (ultramafic to silicic, to quenching to glass. Therefore, in most cases, metaluminous to peraluminous and subalkaline melt inclusions within host macrocrysts are to peralkaline). used to assess the volatile contents of melts prior to shallow degassing. Melt inclusions are Another H2O-CO2 solubility model developed portions of melts trapped during phenocryst around the same time as SolEx was presented growth at depth in the plumbing system. by Iacono-Marziano et al. (2012) who provided Volatile studies on alkaline basaltic rocks have experimental data on a range of mafic melts demonstrated that H2O and CO2 can be (alkaline basalt, lamproite and kamafugite) and dissolved at concentrations of several wt.% and used them to develop a semi-empirical model. thousands of ppm, respectively, together with They showed that alkalis bonded to non- other potentially important volatile species, bridging oxygens strongly enhance CO2 such as S and Cl (Kamenetsky and Clocchiatti, solubility and that CO2 solubility in mafic melts 1996; Spilliaert et al., 2006). There is is more strongly affected by melt composition nevertheless a paucity of quantitative studies of and silicate structure than H2O solubility, in the volatile content of alkaline basalt melt support of earlier studies (Blank and Brooker, inclusions in continental intraplate 1994; Dixon, 1997; Holloway and Blank, monogenetic systems. Rowe et al. (2015) found 1994). Most recently, Burgisser et al. (2015) <1 wt% H2O and S and <2000 ppm Cl and F developed the D-Compress software, which dissolved in alkaline to subalkaline basalt melt models the pressure control of volatiles (H2O, inclusions related to the Rio Grande Rift CO2 and S in the systems O–H, S–O–H, C–S– (USA). Cervantes and Wallace (2003) derived O–H, C–S–O–H–Fe, and C–O–H) in the similar concentrations (1.3 wt% H2O, <1000 vapour and melt phases. The model was ppm Cl and S, 370 ppm CO2) dissolved in melt calibrated for basaltic, phonolitic and rhyolitic inclusions from the monogenetic Xitle volcano, compositions. The major oxides can be varied which has OIB-like composition but sits within and the solubility laws depend on the pre- the supra-subduction Trans Mexican Volcanic defined (i.e., basalt, phonolite, rhyolite) Belt. Such volatile abundances are lower than composition selected. D-Compress is intended subduction related systems (Fig. 6), however it to be used to model the chemical evolution of is unclear to what degree these results represent vapour and fluids phases when significant partially degassed magmas. For example, Hidas et al. (2010) evaluated volatile content in Relying on the enhanced stability of olivine at melt inclusions hosted in clinopyroxenes from lower pressure in alkaline basaltic system, spinel lherzolite xenoliths from the Bakony– systematic melt inclusion studies can constrain Balaton Highland Volcanic Field, part of the the depth of magma storage and crystallization Pannonian Basin (western Hungary). They at shallow crustal levels (Spilliaert et al., 2006). calculated H2O contents of 3.1 – 4.5 wt% and This is made more effective by integrating CO2 contents of 9000 – 12000 ppm when whole-rock and melt inclusion data to provide considering the contribution of the vapour insights into magma source and crystallization bubble in addition to the volatiles dissolved in processes, such as in the Hainan (China) the surrounding glass of the silicate melt intraplate system (Liu et al., 2015). Rowe et al. inclusion. Such high volatile contents suggest (2011) identified shallow sedimentary entrapment and crystallisation under upper basement contamination in the monogenetic mantle conditions and reinforce that Dotsero volcano (USA), that shifted a basanitic metasomatism may be a precursor to intraplate magma composition (preserved in melt volcanism. More studies are required to inclusions) towards alkaline basalt bulk constrain recycled and metasomatic input in compositions. continental intraplate monogenetic basalts. Another aspect to consider when attempting Finally, the composition of glass shards in volatile species quantification from melt tephra samples is used as a tool for inclusions, is post-entrapment crystallization. fingerprinting tephra sources and cross- This can significantly affect their correlating eruptive records across individual concentrations with resulting discrepancies volcanic fields (Hopkins et al., 2015; Shane and between pressures determined by volatile and Smith, 2000). This method was successfully mineral-melt geobarometers (Maclennan, applied to provide a revised eruptive 2017). chronology in the Auckland Volcanic Field (Hopkins et al., 2017). In such investigations, comprehensive sampling and glass analyses are needed, given the potentially broad range of glass compositions found within single eruptive sequences, as in the case of Maungataketake, Auckland Volcanic Field (Agustín-Flores et al., 2014). The glass compositions tend to be broader than whole- rock analyses of analogous products, mostly due to shallow, syn-eruptive microlite crystallization (Verolino et al., 2018). Devitrification of older glass may also affect analytical precision. Figure 6. Volatile abundances in alkaline basalts related to monogenetic intraplate 6. Summary and concluding remarks systems in the Rio Grande Rift (Rowe et al., There is currently a breadth of knowledge that 2015) and Xitle volcano (Cervantes and enables us to paint a conceptual picture of the Wallace, 2003) tend to be lower than those complex plumbing architecture of continental in basalts from subduction arc systems intraplate monogenetic volcanic fields (Fig. 7). (Métrich and Wallace, 2008). Etna data The primary source area of magmatism is likely represent high-pressure, undegassed magma to contain fertile lithologies, such as recycled with >1000 ppm CO2 (Spilliaert et al., 2006). material from past subduction events or related to delamination. Localized slow upwelling due to broad asthenospheric circulation (or thermal anomalies) may cause these domains to partially melt. The derived fluids (silicate and fractionation processes) plumbing system and/or carbonate melts) migrate through the dynamics. lithospheric mantle and react, particularly with previously metasomatized domains. These processes cause the primary melts to undergo chemical contamination/differentiation through metasomatic/chromatographic processes altering their composition and alkaline character (Fig. 7). Melt aggregation areas may form at different levels within the lithosphere, thus controlling the overall alkaline signature of ensuing magma batches. These percolation/aggregation volumes match the low-velocity anomalies that are generally identified beneath monogenetic volcanic systems (e.g. Horspool et al., 2006). Magma batches can be extracted without further interaction, or may mix and mingle with coeval or previously injected magmas to form bimodal or broad chemical spectra within single monogenetic eruptive episodes (Fig. 7). Crustal involvement and contamination is essentially restricted to systems that show chemical evolution to intermediate compositions.

To better understand the origin and time/space evolution of monogenetic volcanoes, and their potential hazards, further constraints are needed, particularly regarding the deeper portion of the system and the percolation reactions that modify the sensu stricto primary partial melts. Magmas are complex mixtures of liquid, crystals and gases. It is only through the integration of detailed studies of all these components that we will be able to gain a comprehensive understanding of natural magmatic systems. Future studies will need to employ a holistic approach focusing on the physicochemical mechanisms controlling the final textures and compositions of crystals and their host rocks. Additional studies are also needed to better constrain the deep storage portions of the plumbing systems that, in turn, control the availability of magmas to feed Figure 7. Conceptual model of continental surface eruptions. In this context, the ensuing intraplate monogenetic basaltic plumbing eruption characteristics are the consequence of systems. In small volcanoes, the storage the close interplay between deep (magma areas are not necessarily connected to the generation, fluid percolation and surface by conduits. A large portion of metasomatism) and shallow (mixing, mingling generated magmas may not actually erupt. 7. Acknowledgements We thank Szabolcs Harangi and Abigail Barker for constructive reviews and Matteo Masotta for editorial handling.

8. References

Ablay, G., Carroll, M., Palmer, M., Martí, J., Sparks, R., Bindeman, I., 2008. Oxygen isotopes in mantle and 1998. Basanite–phonolite lineages of the Teide–Pico crustal magmas as revealed by single crystal analysis. Viejo volcanic complex, Tenerife, Canary Islands. Reviews in Mineralogy and Geochemistry 69, 445- Journal of Petrology 39, 905-936. 478. Abratis, M., Viereck, L., Pfänder, J.A., Hentschel, R., Blank, J.G., Brooker, R.A., 1994. Experimental studies 2015. Geochemical composition, petrography and 40 of carbon dioxide in silicate melts: solubility, Ar/39 Ar age of the Heldburg phonolite: implications speciation and stable isotope behavior. Reviews in on magma mixing and mingling. Int J Earth Sci (Geol Mineralogy and Geochemistry 30, 157-186. Rundsch) 104, 2033-2055. Blichert-Toft, J., Arndt, N.T., Ludden, J.N., 1996. Agustín-Flores, J., Németh, K., Cronin, S.J., Lindsay, Precambrian alkaline magmatism. Lithos 37, 97-111. J.M., Kereszturi, G., Brand, B.D., Smith, I.E.M., Blondes, M.S., Reiners, P.W., Ducea, M.N., Singer, 2014. Phreatomagmatic eruptions through B.S., Chesley, J., 2008. Temporal-compositional unconsolidated coastal plain sequences, trends over short and long time-scales in basalts of Maungataketake, Auckland Volcanic Field (New the Big Pine Volcanic Field, California. Earth and Zealand). Journal of Volcanology and Geothermal Planetary Science Letters 269, 140-154. Research 276, 46-63. Bonadiman, C., Beccaluva, L., Coltorti, M., Siena, F., Albert, H., Costa, F., Martí, J., 2015. Timing of 2005. Kimberlite-like metasomatism and ‘garnet Magmatic Processes and Unrest Associated with signature’in spinel-peridotite xenoliths from Sal, Mafic Historical Monogenetic Eruptions in Tenerife Cape Verde Archipelago: relics of a subcontinental Island. Journal of Petrology 56, 1945-1966. mantle domain within the Atlantic oceanic Allen, M., Kheirkhah, M., Neill, I., Emami, M., McLeod, lithosphere? Journal of Petrology 46, 2465-2493. C., 2013. Generation of arc and within-plate chemical Bourdon, B., Turner, S.P., Ribe, N.M., 2005. Partial signatures in collision zone magmatism: Quaternary melting and upwelling rates beneath the Azores from lavas from Kurdistan Province, Iran. Journal of a U-series isotope perspective. Earth and Planetary Petrology 54, 887-911. Science Letters 239, 42-56. Aryaeva, N., Koptev-Dvornikov, E., Bychkov, D., 2018. Boyce, J.A., Nicholls, I.A., Keays, R.R., Hayman, P.C., A Liquidus Thermobarometer for Modeling of the 2015. Variation in parental magmas of Mt Rouse, a Magnetite–Melt Equilibrium. Moscow University complex polymagmatic monogenetic volcano in the Geology Bulletin 73, 177-186. basaltic intraplate Newer Volcanics Province, Ballmer, M.D., Conrad, C.P., Smith, E.I., Johnsen, R., southeast Australia. Contributions to Mineralogy and 2015. Intraplate volcanism at the edges of the C Petrology 169, 11. olorado P lateau sustained by a combination of Brady, J.B., 1995. Diffusion data for silicate minerals, triggered edge-driven convection and shear-driven glasses, and liquids. Mineral Physics and upwelling. Geochemistry, Geophysics, Geosystems Crystallography: A Handbook of Physical Constants 16, 366-379. 2, 269-290. Beattie, P., 1993. Olivine-melt and orthopyroxene-melt Brenna, M., 2012. Geological evolution and magmatic equilibria. Contributions to Mineralogy and models for spatially and temporally variable modes Petrology 115, 103-111. of distributed volcanism, Jeju Island, Republic of Beccaluva, L., Bianchini, G., Bonadiman, C., Coltorti, Korea, Institute of Agriculture and Environment. M., Milani, L., Salvini, L., Siena, F., Tassinari, R., PhD Thesis, Massey University, Palmerston North, p. 2007. Intraplate lithospheric and sublithospheric 229. components in the Adriatic domain: Nephelinite to Brenna, M., Cronin, S.J., Németh, K., Smith, I.E.M., tholeiite magma generation in the Paleogene Veneto Sohn, Y.K., 2011. The influence of magma plumbing volcanic province, southern Alps. SPECIAL complexity on monogenetic eruptions, Jeju Island, PAPERS-GEOLOGICAL SOCIETY OF AMERICA Korea. Terra Nova 23, 70-75. 418, 131. Brenna, M., Cronin, S.J., Smith, I.E., Tollan, P.M., Scott, Bellieni, G., Justin Visentin, E., Le Maitre, R., Piccirillo, J.M., Prior, D.J., Bambery, K., Ukstins, I.A., 2018. E., Zanettin, B., 1983. Proposal for a division of the Olivine xenocryst diffusion reveals rapid basaltic (B) field of the TAS diagram. IUGS monogenetic basaltic magma ascent following subcommission on the Systematics of Igneous Rocks. complex storage at Pupuke Maar, Auckland Volcanic Circular. Field, New Zealand. Earth and Planetary Science Chen, Y., Zhang, Y., Graham, D., Su, S., Deng, J., 2007. Letters 499, 13-22. Geochemistry of Cenozoic basalts and mantle Brenna, M., Cronin, S.J., Smith, I.E.M., Maas, R., Sohn, xenoliths in Northeast China. Lithos 96, 108-126. Y.K., 2012a. How small-volume basaltic magmatic Choi, S.H., Kwon, S.T., Mukasa, S.B., Sagong, H., 2005. systems develop: a case study from the Jeju Island Sr-Nd-Pb isotope and trace element systematics of Volcanic Field, Korea. Journal of Petrology 53, 985- mantle xenoliths from Late Cenozoic alkaline lavas, 1018. South Korea. Chemical Geology 221, 40-64. Brenna, M., Cronin, S.J., Smith, I.E.M., Sohn, Y.K., Clague, D.A., Frey, F.A., 1982. Petrology and Trace Maas, R., 2012b. Spatio-temporal evolution of a Element Geochemistry of the Honolulu Volcanics, dispersed magmatic system and its implications for Oahu: Implications for the Oceanic Mantle below volcano growth, Jeju Island Volcanic Field, Korea. Hawaii. Journal of Petrology 23, 447-504. Lithos 148, 337-352. Cohen, A.S., O'Nions, R.K., 1993. Melting rates beneath Brenna, M., Cronin, S.J., Smith, I.E.M., Sohn, Y.K., Hawaii: evidence from uranium series isotopes in Németh, K., 2010. Mechanisms driving recent lavas. Earth and Planetary Science Letters 120, polymagmatic activity at a monogenetic volcano, 169-175. Udo, Jeju Island, South Korea. Contributions to Coltorti, M., Beccaluva, L., Bonadiman, C., Faccini, B., Mineralogy and Petrology 160, 931-950. Ntaflos, T., Siena, F., 2004. Amphibole genesis via Brenna, M., Németh, K., Cronin, S. J., Sohn, Y. K., metasomatic reaction with clinopyroxene in mantle Smith, I. E. & Wijbrans, J. 2015. Co-located xenoliths from Victoria Land, Antarctica. Lithos 75, monogenetic eruptions~ 200 kyr apart driven by 115-139. tapping vertically separated mantle source regions, Condamine, P., Médard, E., 2014. Experimental melting Chagwido, Jeju Island, Republic of Korea. Bulletin of phlogopite-bearing mantle at 1 GPa: implications of Volcanology 77, 43. for potassic magmatism. Earth and Planetary Science Brenna, M., Pontesilli, A., Mollo, S., Masotta, M., Letters 397, 80-92. Cronin, S.J., Smith, I.E., Moufti, M.R.H., Scarlato, Condit, C.D., Connor, C.B., 1996. Recurrence rates of P., 2019. Intra-eruptive trachyte-phonolite transition: volcanism in basaltic volcanic fields: An example Natural evidence and experimental constraints on the from the Springerville volcanic field, Arizona. role of crystal mushes. American Mineralogist 104, Geological Society of America Bulletin 108, 1225- 1750-1764. 1241. Brey, G.P., Bulatov, V.K., Girnis, A.V., 2009. Influence Conrad, C.P., Bianco, T.A., Smith, E.I., Wessel, P., of water and fluorine on melting of carbonated 2011. Patterns of intraplate volcanism controlled by peridotite at 6 and 10 GPa. Lithos 112, 249-259. asthenospheric shear. Nature Geoscience 4, 317. Briggs, R.M., McDonough, W.F., 1990. Coote, A., Shane, P., 2018. Open-system magmatic Contemporaneous convergent margin and intraplate behaviour beneath monogenetic volcanoes revealed magmatism, North Island, New Zealand. Journal of by the geochemistry, texture and thermobarometry of Petrology 31, 813-851. clinopyroxene, Kaikohe-Bay of Islands volcanic field Bultitude, R.J., Green, D.H., 1971. Experimental study (New Zealand). Journal of Volcanology and of crystal-liquid relationships at high pressure in Geothermal Research 368, 51-62. olivine nephelinite and basanite compositions. Coote, A., Shane, P., Stirling, C., Reid, M., 2018. The Journal of Petrology 12, 121-147. origin of plagioclase phenocrysts in basalts from Burgisser, A., Alletti, M., Scaillet, B., 2015. Simulating continental monogenetic volcanoes of the Kaikohe- the behavior of volatiles belonging to the C–O–H–S Bay of Islands field, New Zealand: implications for system in silicate melts under magmatic conditions magmatic assembly and ascent. Contributions to with the software D-Compress. Computers & Mineralogy and Petrology 173, 14. Geosciences 79, 1-14. Costa, F., Dohmen, R., Chakraborty, S., 2008. Time Camp, V.E., Hooper, P.R., Roobol, M.J., White, D.L., scales of magmatic processes from modeling the 1987. The Medinah eruption, Saudi Arabia: Magma zoning patterns of crystals. Reviews in Mineralogy mixing and simultaneous extrusion of three basaltic and Geochemistry 69, 545-594. chemical types. Bulletin of Volcanology 49, 489-508. Costa, F., Morgan, D., 2011. Time constraints from Carrigan, C.R., Schubert, G., Eichelberger, J.C., 1992. chemical equilibration in magmatic crystals, in: Thermal and dynamical regimes of single-and two- Dosseto, A., Turner, S.P., Van Orman, J.A. (Eds.), phase magmatic flow in dikes. Journal of Timescales of Magmatic Processes. Wiley- Geophysical Research: Solid Earth 97, 17377-17392. Blackwell, pp. 125-159. Cawthorn, R.G., 1975. Degrees of melting in mantle Crossingham, T., Ubide, T., Vasconcelos, P., Mallmann, diapirs and the origin of ultrabasic liquids. Earth and G., 2018. Parallel plumbing systems feeding a pair of Planetary Science Letters 27, 113-120. coeval volcanoes in eastern Australia. Journal of Cervantes, P., Wallace, P.J., 2003. Role of H2O in Petrology 59, 1035-1066. subduction-zone magmatism: new insights from melt D'oriano, C., Bertagnini, A., Cioni, R., Pompilio, M., inclusions in high-Mg basalts from central Mexico. 2014. Identifying recycled ash in basaltic eruptions. Geology 31, 235-238. Scientific reports 4, 5851. Dalton, H.B., Scott, J.M., Liu, J., Waight, T.E., Pearson, 2573.15 K: Molecular dynamics simulations with ab D.G., Brenna, M., Le Roux, P., Palin, J.M., 2017. initio potential surface. Geochimica et cosmochimica Diffusion-zoned pyroxenes in an isotopically acta 70, 2311-2324. heterogeneous mantle lithosphere beneath the Duda, A., Schmincke, H.-U., 1985. Polybaric Dunedin Volcanic Group, New Zealand, and their differentiation of alkali basaltic magmas: evidence implications for intraplate alkaline magma sources. from green-core clinopyroxenes (Eifel, FRG). Lithosphere 9, 463-475. Contributions to Mineralogy and Petrology 91, 340- Dasgupta, R., Hirschmann, M.M., 2006. Melting in the 353. Earth's deep upper mantle caused by carbon dioxide. Elliott, T., Plank, T., Zindler, A., White, W., Bourdon, Nature 440, 659. B., 1997. Element transport from slab to volcanic Dasgupta, R., Hirschmann, M.M., Smith, N.D., 2007. front at the Mariana arc. Journal of Geophysical Partial melting experiments of peridotite+ CO2 at 3 Research: Solid Earth 102, 14991-15019. GPa and genesis of alkalic ocean island basalts. Feng, M., Whitford-Stark, J., 1986. The 1719–1721 Journal of Petrology 48, 2093-2124. eruptions of potassium-rich lavas at Wudalianchi, Dasgupta, R., Hirschmann, M.M., Withers, A.C., 2004. China. Journal of volcanology and geothermal Deep global cycling of carbon constrained by the research 30, 131-148. solidus of anhydrous, carbonated eclogite under Ferlito, C., Lanzafame, G., 2010. The role of upper mantle conditions. Earth and Planetary Science supercritical fluids in the potassium enrichment of Letters 227, 73-85. magmas at Mount Etna volcano (Italy). Lithos 119, Davidson, J., Morgan, D., Charlier, B., Harlou, R., Hora, 642-650. J., 2007. Microsampling and isotopic analysis of Ferrari, L., Petrone, C.M., Francalanci, L., 2001. igneous rocks: implications for the study of magmatic Generation of oceanic-island basalt–type volcanism systems. Annu. Rev. Earth Planet. Sci. 35, 273-311. in the western Trans-Mexican volcanic belt by slab Davies, D.R., Rawlinson, N., 2014. On the origin of rollback, asthenosphere infiltration, and variable flux recent intraplate volcanism in Australia. Geology 42, melting. Geology 29, 507-510. 1031-1034. Floyd, P., 1991. Oceanic islands and seamounts, Oceanic Davies, J., Bunge, H.-P., 2006. Are splash plumes the Basalts. Springer, pp. 174-218. origin of minor hotspots? Geology 34, 349-352. Foley, S., 1991. High-pressure stability of the fluor- and de Maisonneuve, C.B., Costa, F., Huber, C., Vonlanthen, hydroxy-endmembers of pargasite and K-richterite. P., Bachmann, O., Dungan, M.A., 2016. How do Geochimica et Cosmochimica Acta 55, 2689-2694. olivines record magmatic events? Insights from Foulger, G.R., Jurdy, D.M., 2007. Plates, plumes, and major and trace element zoning. Contributions to planetary processes. Geological Society of America. Mineralogy and Petrology 171, 56. Foulger, G.R., Natland, J.H., Presnall, D.C., Anderson, Demidjuk, Z., Turner, S., Sandiford, M., George, R., D.L., 2005. Plates, plumes, and paradigms. Foden, J., Etheridge, M., 2007. U-series isotope and Geological Society of America. geodynamic constraints on mantle melting processes Francis, D., Ludden, J., 1995. The Signature of beneath the Newer Volcanic Province in South Amphibole in Mafic Alkaline Lavas, a Study in the Australia. Earth and Planetary Science Letters 261, Northern Canadian Cordillera. Journal of Petrology 517-533. 36, 1171-1191. Demouchy, S., Jacobsen, S.D., Gaillard, F., Stern, C.R., Giacomoni, P., Ferlito, C., Coltorti, M., Bonadiman, C., 2006. Rapid magma ascent recorded by water Lanzafame, G., 2014. Plagioclase as archive of diffusion profiles in mantle olivine. Geology 34, 429- magma ascent dynamics on “open conduit” 432. volcanoes: the 2001–2006 eruptive period at Mt. Dixon, J.E., 1997. Degassing of alkalic basalts. Etna. Earth-science reviews 138, 371-393. American Mineralogist 82, 368-378. Girona, T., Costa, F., 2013. DIPRA: A user-friendly Dixon, J.E., Stolper, E.M., 1995. An experimental study program to model multi-element diffusion in olivine of water and carbon dioxide solubilities in mid-ocean with applications to timescales of magmatic ridge basaltic liquids. Part II: applications to processes. Geochemistry, Geophysics, Geosystems degassing. Journal of Petrology 36, 1633-1646. 14, 422-431. Dobosi, G., Schultz-Güttler, R., Kurat, G., Kracher, A., Godard, M., Bodinier, J.-L., Vasseur, G., 1995. Effects 1991. Pyroxene chemistry and evolution of alkali of mineralogical reactions on trace element basaltic rocks from Burgenland and Styria, Austria. redistributions in mantle rocks during percolation Mineralogy and Petrology 43, 275-292. processes: a chromatographic approach. Earth and Duan, X., 2014. A general model for predicting the Planetary Science Letters 133, 449-461. solubility behavior of H2O–CO2 fluids in silicate Graettinger, A., Valentine, G., Sonder, I., 2016. melts over a wide range of pressure, temperature and Recycling in debris-filled volcanic vents. Geology compositions. Geochimica et Cosmochimica Acta 44, 811-814. 125, 582-609. Green, D., Ringwood, A., 1967. The genesis of basaltic Duan, Z., Zhang, Z., 2006. Equation of state of the H2O, magmas. Contributions to Mineralogy and Petrology CO2, and H2O–CO2 systems up to 10 GPa and 15, 103-190. Green, D.H., 1973. Experimental melting studies of a Upwelling induced by lithospheric removal. Earth model upper mantle composition at high pressure and Planetary Science Letters 248, 350-367. under water-saturated and water undersaturated Holloway, J.R., Blank, J.G., 1994. Application of conditions. Earth and Planetary Science Letters 19, experimental results to COH species in natural melts. 37-53. Reviews in mineralogy 30, 187-187. Green, D.H., 2015. Experimental petrology of Homrighausen, S., Hoernle, K., Hauff, F., Geldmacher, peridotites, including effects of water and carbon on J., Wartho, J.-A., van den Bogaard, P., Garbe- melting in the Earth’s upper mantle. Physics and Schönberg, D., 2018. Global distribution of the Chemistry of Minerals 42, 95-122. HIMU end member: Formation through Archean Harangi, S., 2001. Neogene magmatism in the Alpine- plume-lid tectonics. Earth-Science Reviews 182, 85- Pannonian Transition Zone-a model for melt 101. generation in a complex geodynamic setting. Acta Hopkins, J.L., Millet, M.-A., Timm, C., Wilson, C.J., Vulcanologica 13, 25-39. Leonard, G.S., Palin, J.M., Neil, H., 2015. Tools and Harangi, S., Jankovics, M.É., Sági, T., Kiss, B., Lukács, techniques for developing tephra stratigraphies in R., Soós, I., 2015. Origin and geodynamic lake cores: a case study from the basaltic Auckland relationships of the Late Miocene to Quaternary Volcanic Field, New Zealand. Quaternary Science alkaline basalt volcanism in the Pannonian basin, Reviews 123, 58-75. eastern–central Europe. Int J Earth Sci (Geol Hopkins, J.L., Wilson, C.J.N., Millet, M.-A., Leonard, Rundsch) 104, 2007-2032. G.S., Timm, C., McGee, L.E., Smith, I.E.M., Smith, Harangi, S., Sági, T., Seghedi, I., Ntaflos, T., 2013. E.G.C., 2017. Multi-criteria correlation of tephra Origin of basaltic magmas of Perşani volcanic field, deposits to source centres applied in the Auckland Romania: A combined whole rock and mineral scale Volcanic Field, New Zealand. Bulletin of investigation. Lithos 180, 43-57. Volcanology 79, 55. Harangi, S., Vaselli, O., Tonarini, S., Szabó, C., Harangi, Horspool, N., Savage, M., Bannister, S., 2006. R., Coradossi, N., 1995. Petrogenesis of Neogene Implications for intraplate volcanism and back-arc extension-related alkaline volcanic rocks of the Little deformation in northwestern New Zealand, from joint Hungarian Plain volcanic field (Western Hungary). inversion of receiver functions and surface waves. Acta Vulcanologica 7, 173-188. Geophysical Journal International 166, 1466-1483. Harte, B., Hunter, R., Kinny, P., 1993. Melt geometry, Houghton, B.F., Smith, R.T., 1993. Recycling of movement and crystallization, in relation to mantle magmatic clasts during explosive eruptions: dykes, veins and metasomatism. Philosophical estimating the true juvenile content of Transactions of the Royal Society of London. Series phreatomagmatic volcanic deposits. Bulletin of A: Physical and Engineering Sciences 342, 1-21. Volcanology 55, 414-420. Hawkesworth, C., Gallagher, K., Hergt, J., McDermott, Iacono-Marziano, G., Morizet, Y., Le Trong, E., F., 1994. Destructive plate margin magmatism: Gaillard, F., 2012. New experimental data and semi- Geochemistry and melt generation. Lithos 33, 169- empirical parameterization of H2O–CO2 solubility in 188. mafic melts. Geochimica et Cosmochimica Acta 97, Herzberg, C., 2010. Identification of source lithology in 1-23. the Hawaiian and Canary Islands: Implications for Irving, A.J., Green, D.H., 2008. Phase relationships of origins. Journal of Petrology 52, 113-146. hydrous alkalic magmas at high pressures: Hidas, K., Guzmics, T., Szabó, C., Kovács, I., Bodnar, production of nepheline hawaiitic to mugearitic R.J., Zajacz, Z., Nédli, Z., Vaccari, L., Perucchi, A., liquids by amphibole-dominated fractional 2010. Coexisting silicate melt inclusions and H2O- crystallization within the lithospheric mantle. Journal bearing, CO2-rich fluid inclusions in mantle of Petrology 49, 741-756. peridotite xenoliths from the Carpathian–Pannonian Irving, A.J., Price, R.C., 1981. Geochemistry and region (central Hungary). Chemical Geology 274, 1- evolution of Iherzolite-bearing phonolitic lavas from 18. Nigeria, Australia, East Germany and New Zealand. Hirano, N., Takahashi, E., Yamamoto, J., Abe, N., Ingle, Geochimica et Cosmochimica Acta 45, 1309-1320. S.P., Kaneoka, I., Hirata, T., Kimura, J.-I., Ishii, T., Jakobsson, S., Holloway, J.R., 1986. Crystal—Liquid Ogawa, Y., Machida, S., Suyehiro, K., 2006. experiments in the presence of a COH fluid buffered Volcanism in response to plate flexure. Science 313, by graphite+ iron+ wustite: experimental method and 1426-1428. near-liquidus relations in basanite. Journal of Hirschmann, M.M., 2000. Mantle solidus: Experimental Volcanology and Geothermal Research 29, 265-291. constraints and the effects of peridotite composition. Jankovics, M.É., Dobosi, G., Embey-Isztin, A., Kiss, B., Geochemistry, Geophysics, Geosystems 1. Sági, T., Harangi, S., Ntaflos, T., 2013. Origin and Hoernle, K., White, J.D.L., van den Bogaard, P., Hauff, ascent history of unusually crystal-rich alkaline F., Coombs, D.S., Werner, R., Timm, C., Garbe- basaltic magmas from the western Pannonian Basin. Schönberg, D., Reay, A., Cooper, A.F., 2006. Bulletin of Volcanology 75, 1-23. Cenozoic intraplate volcanism on New Zealand: Jankovics, M.É., Harangi, S., Kiss, B., Ntaflos, T., 2012. Open-system evolution of the Füzes-tó alkaline basaltic magma, western Pannonian Basin: slab-lithosphere interactions: Origin of the late constraints from mineral textures and compositions. Cenozoic intra-plate basalts on the East Eurasia Lithos 140, 25-37. margin. Lithos 300, 227-249. Jankovics, M.É., Harangi, S., Németh, K., Kiss, B., Kogiso, T., Hirschmann, M.M., 2006. Partial melting Ntaflos, T., 2015. A complex magmatic system experiments of bimineralic eclogite and the role of beneath the Kissomlyó monogenetic volcano recycled mafic oceanic crust in the genesis of ocean (western Pannonian Basin): evidence from mineral island basalts. Earth and Planetary Science Letters textures, zoning and chemistry. Journal of 249, 188-199. Volcanology and Geothermal Research 301, 38-55. Langmuir, C.H., Klein, E.M., Plank, T., 1992. Jankovics, M.É., Sági, T., Astbury, R.L., Petrelli, M., Petrological systematics of mid-ocean ridge basalts: Kiss, B., Ubide, T., Németh, K., Ntaflos, T., Harangi, Constraints on melt generation beneath ocean ridges. S., 2019. Olivine major and trace element Mantle Flow and Melt Generation at Mid-Ocean compositions coupled with spinel chemistry to Ridges 71, 183-280. unravel the magmatic systems feeding monogenetic Laporte, D., Lambart, S., Schiano, P., Ottolini, L., 2014. basaltic volcanoes. Journal of Volcanology and Experimental derivation of nepheline syenite and Geothermal Research 369, 203-223. phonolite liquids by partial melting of upper mantle Jankovics, M.É., Taracsák, Z., Dobosi, G., Embey-Isztin, peridotites. Earth and Planetary Science Letters 404, A., Batki, A., Harangi, S., Hauzenberger, C.A., 2016. 319-331. Clinopyroxene with diverse origins in alkaline Larrea, P., Salinas, S., Widom, E., Siebe, C., Abbitt, R.J., basalts from the western Pannonian Basin: 2017. Compositional and volumetric development of Implications from trace element characteristics. a monogenetic lava flow field: The historical case of Lithos 262, 120-134. Paricutin (Michoacan, Mexico). Journal of Kahl, M., Chakraborty, S., Costa, F., Pompilio, M., 2011. Volcanology and Geothermal Research 348, 36-48. Dynamic plumbing system beneath volcanoes Le Maitre, R.W., Streckeisen, A., Zanettin, B., Le Bas, revealed by kinetic modeling, and the connection to M., Bonin, B., Bateman, P., 2005. Igneous rocks: a monitoring data: An example from Mt. Etna. Earth classification and glossary of terms: and Planetary Science Letters 308, 11-22. recommendations of the International Union of Kahl, M., Chakraborty, S., Pompilio, M., Costa, F., 2015. Geological Sciences Subcommission on the Constraints on the nature and evolution of the magma Systematics of Igneous Rocks. Cambridge University plumbing system of Mt. Etna volcano (1991–2008) Press. from a combined thermodynamic and kinetic Lee, C.-T.A., Chin, E.J., 2014. Calculating melting modelling of the compositional record of minerals. temperatures and pressures of peridotite protoliths: Journal of Petrology 56, 2025-2068. Implications for the origin of cratonic mantle. Earth Kamenetsky, V., Clocchiatti, R., 1996. Primitive and Planetary Science Letters 403, 273-286. magmatism of Mt. Etna: insights from mineralogy Leonard, G.S., Calvert, A.T., Hopkins, J.L., Wilson, C.J., and melt inclusions. Earth and Planetary Science Smid, E.R., Lindsay, J.M., Champion, D.E., 2017. Letters 142, 553-572. High-precision 40Ar/39Ar dating of Quaternary Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The basalts from Auckland Volcanic Field, New Zealand, dynamics of melt and shear localization in partially with implications for eruption rates and molten aggregates. Nature 442, 676-679. paleomagnetic correlations. Journal of Volcanology Kereszturi, G., Németh, K., Cronin, S.J., Agustín-Flores, and Geothermal Research 343, 60-74. J., Smith, I.E.M., Lindsay, J., 2013. A model for Lesne, P., Kohn, S.C., Blundy, J., Witham, F., calculating eruptive volumes for monogenetic Botcharnikov, R.E., Behrens, H., 2011. Experimental volcanoes — Implication for the Quaternary simulation of closed-system degassing in the system Auckland Volcanic Field, New Zealand. Journal of basalt–H2O–CO2–S–Cl. Journal of Petrology 52, Volcanology and Geothermal Research 266, 16-33. 1737-1762. Kessel, R., Schmidt, M.W., Ulmer, P., Pettke, T., 2005. Liu, J.-Q., Ren, Z.-Y., Nichols, A.R., Song, M.-S., Qian, Trace element signature of subduction-zone fluids, S.-P., Zhang, Y., Zhao, P.-P., 2015. Petrogenesis of melts and supercritical liquids at 120–180 km depth. Late Cenozoic basalts from North Hainan Island: Nature 437, 724. Constraints from melt inclusions and their host Kienle, J., Kyle, P.R., Self, S., Motyka, R.J., Lorenz, V., olivines. Geochimica et Cosmochimica Acta 152, 89- 1980. Ukinrek Maars, Alaska, I. April 1977 eruption 121. sequence, petrology and tectonic setting. Journal of Loges, A., Schultze, D., Klügel, A., Lucassen, F., 2019. Volcanology and Geothermal Research 7, 11-37. Phonolitic melt production by carbonatite Mantle Kim, J.-I., Choi, S.H., Koh, G.W., Park, J.B., Ryu, J.-S., metasomatism: evidence from Eger Graben 2019. Petrogenesis and mantle source characteristics xenoliths. Contributions to Mineralogy and Petrology of volcanic rocks on Jeju Island, South Korea. Lithos 174, 93. 326, 476-490. Lustrino, M., 2005. How the delamination and Kimura, J.-I., Sakuyama, T., Miyazaki, T., Vaglarov, detachment of lower crust can influence basaltic B.S., Fukao, Y., Stern, R.J., 2018. Plume-stagnant magmatism. Earth-Science Reviews 72, 21-38. Maclennan, J., 2017. Bubble formation and decrepitation McGee, L.E., Smith, I.E., 2016. Interpreting chemical control the CO2 content of olivine-hosted melt compositions of small scale basaltic systems: A inclusions. Geochemistry, Geophysics, Geosystems review. Journal of Volcanology and Geothermal 18, 597-616. Research 325, 45-60. Mahony, S.H., Wallace, L.M., Miyoshi, M., Villamor, McGee, L.E., Smith, I.E.M., Millet, M.-A., Handley, P., Sparks, R.S.J., Hasenaka, T., 2011. Volcano- H.K., Lindsay, J.M., 2013. Asthenospheric Control tectonic interactions during rapid plate-boundary of Melting Processes in a Monogenetic Basaltic evolution in the Kyushu region, SW Japan. System: a Case Study of the Auckland Volcanic Geological Society of America Bulletin 123, 2201- Field, New Zealand. Journal of Petrology 54, 2125- 2223. 2153. Mallik, A., Dasgupta, R., 2012. Reaction between Melluso, L., Tucker, R., Cucciniello, C., le Roex, A., MORB-eclogite derived melts and fertile peridotite Morra, V., Zanetti, A., Rakotoson, R., 2018. The and generation of ocean island basalts. Earth and magmatic evolution and genesis of the Quaternary Planetary Science Letters 329, 97-108. basanite-trachyphonolite suite of Itasy (Madagascar) Manikyamba, C., Kerrich, R., 2011. Geochemistry of as inferred by geochemistry, Sr-Nd-Pb isotopes and alkaline basalts and associated high-Mg basalts from trace element distribution in coexisting phases. the 2.7Ga Penakacherla Terrane, Dharwar craton, Lithos 310, 50-64. India: An Archean depleted mantle-OIB array. Menzies, M., Hawkesworth, C., 1986. Mantle Precambrian Research 188, 104-122. metasomatism. Márquez, A., Oyarzun, R., Doblas, M., Verma, S.P., Menzies, M., Murthy, V.R., 1980. Mantle metasomatism 1999. Alkalic (ocean-island basalt type) and calc- as a precursor to the genesis of alkaline magmas- alkalic volcanism in the Mexican volcanic belt: A isotopic evidence. Am. J. Sci 280, 622-638. case for plume-related magmatism and propagating Menzies, M.A., Kyle, P.R., Jones, M., Ingram, G., 1991. rifting at an active margin? Geology 27, 51-54. Enriched and depleted source components for Mashima, H., 2009. A melting anomaly in Northwest tholeiitic and alkaline lavas from Zuni-Bandera, New Kyushu, Southwest Japan: A consequence of the Mexico: Inferences about intraplate processes and tectonic evolution of NW Kyushu and the origin of a stratified lithosphere. Journal of Geophysical pseudo hot spot in a convergent zone. Journal of Research: Solid Earth 96, 13645-13671. Volcanology and Geothermal Research 186, 195- Merrill, R., Wyllie, P., 1975. Kaersutite and kaersutite 209. eclogite from Kakanui, New Zealand—water-excess Masotta, M., Pontesilli, A., Mollo, S., Armienti, P., and water-deficient melting to 30 kilobars. Ubide, T., Nazzari, M., Scarlato, P., 2020. The role Geological Society of America Bulletin 86, 555-570. of undercooling during clinopyroxene growth in Métrich, N., Wallace, P.J., 2008. Volatile abundances in trachybasaltic magmas: Insights on magma basaltic magmas and their degassing paths tracked by decompression and cooling at Mt. Etna volcano. melt inclusions. Reviews in mineralogy and Geochimica et Cosmochimica Acta 268, 258-276. geochemistry 69, 363-402. Mayer, B., Jung, S., Romer, R., Pfänder, J., Klügel, A., Mollo, S., Blundy, J., Scarlato, P., De Cristofaro, S.P., Pack, A., Gröner, E., 2014. Amphibole in alkaline Tecchiato, V., Di Stefano, F., Vetere, F., Holtz, F., basalts from intraplate settings: implications for the Bachmann, O., 2018. An integrated P-T-H 2 O-lattice petrogenesis of alkaline lavas from the strain model to quantify the role of clinopyroxene metasomatised lithospheric mantle. Contributions to fractionation on REE+ Y and HFSE patterns of mafic Mineralogy and Petrology 167, 989. alkaline magmas: Application to eruptions at Mt. McDonald, G.W., Smith, N.J., Kim, J.-h., Cronin, S.J., Etna. Earth-Science Reviews. Proctor, J.N., 2017. The spatial and temporal ‘cost’ Mollo, S., Del Gaudio, P., Ventura, G., Iezzi, G., of volcanic eruptions: assessing economic impact, Scarlato, P., 2010. Dependence of clinopyroxene business inoperability, and spatial distribution of risk composition on cooling rate in basaltic magmas: in the Auckland region, New Zealand. Bulletin of implications for thermobarometry. Lithos 118, 302- Volcanology 79, 48. 312. McGee, L.E., Beier, C., Smith, I.E.M., Turner, S.P., Mollo, S., Giacomoni, P., Coltorti, M., Ferlito, C., Iezzi, 2011. Dynamics of melting beneath a small-scale G., Scarlato, P., 2015. Reconstruction of magmatic basaltic system: a U-Th-Ra study from Rangitoto variables governing recent Etnean eruptions: volcano, Auckland volcanic field, New Zealand. Constraints from mineral chemistry and P–T–fO2– Contributions to Mineralogy and Petrology 162, 547- H2O modeling. Lithos 212, 311-320. 563. Mollo, S., Putirka, K., Iezzi, G., Scarlato, P., 2013. The McGee, L.E., Millet, M.-A., Smith, I.E.M., Németh, K., control of cooling rate on titanomagnetite Lindsay, J.M., 2012. The inception and progression composition: implications for a geospeedometry of melting in a monogenetic eruption: Motukorea model applicable to alkaline rocks from Mt. Etna Volcano, the Auckland Volcanic Field, New Zealand. volcano. Contributions to Mineralogy and Petrology Lithos 155, 360-374. 165, 457-475. Moore, G., 2008. Interpreting H2O and CO2 contents in Volatile-Rich Magmas in the Shallow Plumbing melt inclusions: constraints from solubility System of Mt. Etna Volcano. Minerals 8, 482. experiments and modeling. Reviews in Mineralogy Perinelli, C., Mollo, S., Gaeta, M., De Cristofaro, S.P., and Geochemistry 69, 333-362. Palladino, D.M., Armienti, P., Scarlato, P., Putirka, Morgan, W.J., 1971. Convection plumes in the lower K.D., 2016. An improved clinopyroxene-based mantle. Nature 230, 42-43. hygrometer for Etnean magmas and implications for Moufti, M., Moghazi, A., Ali, K., 2012. Geochemistry eruption triggering mechanisms. American and Sr–Nd–Pb isotopic composition of the Harrat Al- Mineralogist 101, 2774-2777. Madinah Volcanic Field, Saudi Arabia. Gondwana Pertermann, M., Hirschmann, M.M., 2003. Partial Research 21, 670-689. melting experiments on a MORB-like pyroxenite Namur, O., Charlier, B., Toplis, M.J., Vander Auwera, between 2 and 3 GPa: Constraints on the presence of J., 2012. Prediction of plagioclase-melt equilibria in pyroxenite in basalt source regions from solidus anhydrous silicate melts at 1-atm. Contributions to location and melting rate. Journal of Geophysical Mineralogy and Petrology 163, 133-150. Research: Solid Earth 108. Neave, D.A., Putirka, K.D., 2017. A new clinopyroxene- Peters, T.J., Menzies, M., Thirlwall, M., Kyle, P.R., liquid barometer, and implications for magma storage 2008. Zuni–Bandera volcanism, Rio Grande, USA — pressures under Icelandic rift zones. American Melt formation in garnet- and spinel-facies mantle Mineralogist 102, 777-794. straddling the asthenosphere–lithosphere boundary. Needham, A.J., Lindsay, J.M., Smith, I.E.M., Lithos 102, 295-315. Augustinus, P., Shane, P.A., 2011. Sequential Pilet, S., 2015. Generation of low-silica alkaline lavas: eruption of alkaline and sub-alkaline magmas from a Petrological constraints, models, and thermal small monogenetic volcano in the Auckland Volcanic implications. Geological Society of America Special Field, New Zealand. Journal of Volcanology and Papers 514, SPE514-517. Geothermal Research 201, 126-142. Pilet, S., Baker, M.B., Stolper, E.M., 2008. Newman, S., Lowenstern, J.B., 2002. VolatileCalc: a Metasomatized lithosphere and the origin of alkaline silicate melt–H2O–CO2 solution model written in lavas. Science 320, 916-919. Visual Basic for excel. Computers & Geosciences 28, Pilet, S., Hernandez, J., Sylvester, P., Poujol, M., 2005. 597-604. The metasomatic alternative for ocean island basalt O’Reilly, S.Y., Griffin, W., 2011. Rates of magma chemical heterogeneity. Earth and Planetary Science ascent: Constraints from mantle-derived xenoliths. Letters 236, 148-166. Timescales of Magmatic Processes: From Core to Putirka, K., 1999. Clinopyroxene+ liquid equilibria to Atmosphere; Dosseto, A., Turner, S., van Orman, J., 100 kbar and 2450 K. Contributions to Mineralogy Eds, 116-124. and Petrology 135, 151-163. Oeser, M., Dohmen, R., Horn, I., Schuth, S., Weyer, S., Putirka, K., 2005. Igneous thermometers and barometers 2015. Processes and time scales of magmatic based on plagioclase + liquid equilibria: tests of some evolution as revealed by Fe–Mg chemical and existing models and new calibrations. American isotopic zoning in natural olivines. Geochimica et Mineralogist 90, 336-346. Cosmochimica Acta 154, 130-150. Putirka, K., 2016. Amphibole thermometers and Oxburgh, E.R., Turcotte, D., 1968. Mid-ocean ridges and barometers for igneous systems and some geotherm distribution during mantle convection. implications for eruption mechanisms of felsic Journal of geophysical research 73, 2643-2661. magmas at arc volcanoes. American Mineralogist Papale, P., 1999. Modeling of the solubility of a two- 101, 841-858. component H2O+ CO2 fluid in silicate liquids. Putirka, K., Condit, C.D., 2003. Cross section of a American Mineralogist 84, 477-492. magma conduit system at the margin of the Colorado Papale, P., Moretti, R., Barbato, D., 2006. The Plateau. Geology 31, 701-704. compositional dependence of the saturation surface Putirka, K.D., 2008. Thermometers and barometers for of H2O+ CO2 fluids in silicate melts. Chemical volcanic systems. Reviews in Mineralogy & Geology 229, 78-95. Geochemistry 69, 61-120. Paulick, H., Franz, G., 1997. The color of pumice: case Ray, A., Hatui, K., Paul, D.K., Sen, G., Biswas, S., Das, study on a trachytic fall deposit, Meidob volcanic B., 2016. Mantle xenolith-xenocryst-bearing field, Sudan. Bulletin of Volcanology 59, 171-185. monogenetic alkali basaltic lava field from Kutch Pearce, J.A., Peate, D.W., 1995. Tectonic implications of Basin, Gujarat, Western India: Estimation of magma the composition of volcanic arc magmas. Annu. Rev. ascent rate. Journal of Volcanology and Geothermal Earth Planet. Sci. 23, 251-285. Research 312, 40-52. Pearson, D., Canil, D., Shirey, S., 2003. Mantle samples Re, G., Palin, J.M., White, J.D.L., Parolari, M., 2017. included in volcanic rocks: xenoliths and diamonds. Unravelling the magmatic system beneath a Treatise on geochemistry 2, 568. monogenetic volcanic complex (Jagged Rocks Perinelli, C., Mollo, S., Gaeta, M., De Cristofaro, S., Complex, Hopi Buttes, AZ, USA). Contributions to Palladino, D., Scarlato, P., 2018. Impulsive Supply of Mineralogy and Petrology 172, 94. Reiners, P.W., 2002. Temporal-compositional trends in association with intraplate alkaline HIMU-like intraplate basalt eruptions: Implications for mantle magmatism. Journal of Petrology 57, 2053-2078. heterogeneity and melting processes. Geochemistry, Segerstrom, K., 1966. Paricutin, 1965–aftermath of Geophysics, Geosystems (G3) 3. eruption. Geological Survey Professional Paper 550, Ridolfi, F., Renzulli, A., 2012. Calcic amphiboles in 93. calc-alkaline and alkaline magmas: Shane, P., Coote, A., 2018. Thermobarometry of thermobarometric and chemometric empirical Whangarei volcanic field lavas, New Zealand: equations valid up to 1,130° C and 2.2 GPa. Constraints on plumbing systems of small Contributions to Mineralogy and Petrology 163, 877- monogenetic basalt volcanoes. Journal of 895. Volcanology and Geothermal Research 354, 130- Ritter, J.R.R., Jordan, M., Christensen, U.R., Achauer, 139. U., 2001. A mantle plume below the Eifel volcanic Shane, P., Smith, I., 2000. Geochemical fingerprinting of fields, Germany. Earth and Planetary Science Letters basaltic tephra deposits in the Auckland Volcanic 186, 7-14. Field. New Zealand Journal of Geology and Robinson, J.A.C., Wood, B.J., Blundy, J.D., 1998. The Geophysics 43, 569-577. beginning of melting of fertile and depleted peridotite Shea, T., Lynn, K.J., Garcia, M.O., 2015. Cracking the at 1.5 GPa. Earth and Planetary Science Letters 155, olivine zoning code: Distinguishing between crystal 97-111. growth and diffusion. Geology 43, 935-938. Rooney, T.O., Nelson, W.R., Dosso, L., Furman, T., Shimizu, K., Saal, A.E., Myers, C.E., Nagle, A.N., Hauri, Hanan, B., 2014. The role of continental lithosphere E.H., Forsyth, D.W., Kamenetsky, V.S., Niu, Y., metasomes in the production of HIMU-like 2016. Two-component mantle melting-mixing model magmatism on the northeast African and Arabian for the generation of mid-ocean ridge basalts: plates. Geology 42, 419-422. implications for the volatile content of the Pacific Rosenbaum, G., Sandiford, M., Caulfield, J., Garrison, upper mantle. Geochimica et Cosmochimica Acta J.M., 2018. A trapdoor mechanism for slab tearing 176, 44-80. and melt generation in the northern Andes. Geology Siebel, W., Schmitt, A.K., Danišík, M., Chen, F., Meier, 47, 23-26. S., Weiß, S., Eroǧlu, S., 2009. Prolonged mantle Rowe, M.C., Lassiter, J.C., Goff, K., 2015. Basalt residence of zircon xenocrysts from the western Eger volatile fluctuations during continental rifting: An rift. Nature Geoscience 2, 886. example from the R io G rande R ift, USA. Smith, I., Németh, K., 2017. Source to surface model of Geochemistry, Geophysics, Geosystems 16, 1254- monogenetic volcanism: a critical review. Geological 1273. Society, London, Special Publications 446, 1-28. Rowe, M.C., Peate, D.W., Newbrough, A., 2011. Smith, I.E.M., Blake, S., Wilson, C.J.N., Houghton, B.F., Compositional and thermal evolution of olivine- 2008. Deep-seated fractionation during the rise of a hosted melt inclusions in small-volume basaltic small-volume basalt magma batch: Crater Hill, eruptions: a “simple” example from Dotsero Auckland, New Zealand. Contributions to Volcano, NW Colorado. Contributions to Mineralogy Mineralogy and Petrology 155, 511-527. and Petrology 161, 197-211. Smith, I.E.M., Okada, T., Itaya, T., Black, P.M., 1993. Rubin, A.M., 1995. Propagation of magma-filled cracks. Age relationship and tectonic implications of the Annu. Rev. Earth Planet. Sci. 23, 287-336. Cenozoic basaltic volcanism in Northland, New Sakuyama, T., Ozawa, K., Sumino, H., Nagao, K., 2009. Zealand. New Zealand Journal of Geology and Progressive melt extraction from upwelling mantle Geophysics 36, 385-393. constrained by the Kita-Matsuura basalts in NW Sohn, C., Sohn, Y.K., 2019. Volcaniclastic tide- Kyushu, SW Japan. Journal of Petrology 50, 725- modulated tempestite in a coastal tuff ring, Jeju 779. Island, Korea. Scientific reports 9, 3561. Scarlato, P., Mollo, S., Blundy, J., Iezzi, G., Tiepolo, M., Sohn, Y.K., Cronin, S.J., Brenna, M., Smith, I.E.M., 2014. The role of natural solidification paths on REE Németh, K., White, J.D.L., Murtagh, R.M., Jeon, partitioning between clinopyroxene and melt. Y.M., Kwon, C.W., 2012. Ilchulbong tuff cone, Jeju Bulletin of volcanology 76, 810. Island, Korea, revisited: A compound monogenetic Schmitt, A.K., Klitzke, M., Gerdes, A., Schäfer, C., volcano involving multiple magma pulses, shifting 2017. Zircon Hafnium–Oxygen isotope and trace vents, and discrete eruptive phases. Geological element petrochronology of intraplate volcanic rocks Society of America Bulletin 124, 259-274. from the Eifel (Germany) and implications for mantle Späth, A., Le Roex, A.P., Opiyo-Akech, N., 2001. versus crustal origins of zircon megacrysts. Journal Plume–lithosphere interaction and the origin of of Petrology 58, 1841-1870. continental rift-related alkaline volcanism—the Scott, J.M., Brenna, M., Crase, J.A., Waight, T.E., van Chyulu Hills Volcanic Province, southern Kenya. der Meer, Q.H., Cooper, A.F., Michael Palin, J., Le Journal of Petrology 42, 765-787. Roux, P., Münker, C., 2016. Peridotitic lithosphere Spera, F.J., 1984. Carbon dioxide in petrogenesis III: role metasomatized by volatile-bearing melts, and its of volatiles in the ascent of alkaline magma with special reference to xenolith-bearing mafic lavas. Contributions to Mineralogy and Petrology 88, 217- (North America) and northwest Pacific Ocean. 232. Geology 38, 55-58. Spilliaert, N., Allard, P., Métrich, N., Sobolev, A., 2006. Valentine, G.A., Perry, F.V., 2006. Decreasing Melt inclusion record of the conditions of ascent, magmatic footprints of individual volcanoes in a degassing, and extrusion of volatile-rich alkali basalt waning basaltic field. Geophysical Research Letters during the powerful 2002 flank eruption of Mount 33, L14305. Etna (Italy). Journal of Geophysical Research: Solid Valentine, G.A., Perry, F.V., 2007. Tectonically Earth 111. controlled, time-predictable basaltic volcanism from Streck, M.J., 2008. Mineral textures and zoning as a lithospheric mantle source (central Basin and Range evidence for open system processes. Reviews in Province, USA). Earth and Planetary Science Letters Mineralogy and Geochemistry 69, 595-622. 261, 201-216. Strong, M., Wolff, J., 2003. Compositional variations Van Otterloo, J., Raveggi, M., Cas, R., Maas, R., 2014. within scoria cones. Geology 31, 143-146. Polymagmatic activity at the monogenetic Mt Sun, S.S., McDonough, W.F., 1989. Chemical and Gambier Volcanic Complex in the Newer Volcanics isotopic systematics of oceanic basalts: implications Province, SE Australia: new insights into the for mantle composition and processes, in: Saunders, occurrence of intraplate volcanic activity in A.D., Norry, M.J. (Eds.), Magmatism in the Ocean Australia. Journal of Petrology 55, 1317-1351. Basins. Geological Society, London, pp. 313-345. Vaselli, O., Downes, H., Thirlwall, M., Dobosi, G., Taisne, B., Tait, S., 2009. Eruption versus intrusion? Coradossi, N., Seghedi, I., Szakacs, A., Vannucci, R., Arrest of propagation of constant volume, buoyant, 1995. Ultramafic xenoliths in Plio-Pleistocene alkali liquid-filled cracks in an elastic, brittle host. Journal basalts from the Eastern Transylvanian Basin: of Geophysical Research 114, B06202. depleted mantle enriched by vein metasomatism. Tatsumi, Y., Hamilton, D., Nesbitt, R., 1986. Chemical Journal of Petrology 36, 23-53. characteristics of fluid phase released from a Verolino, A., White, J., Brenna, M., 2018. Eruption subducted lithosphere and origin of arc magmas: dynamics at Pahvant Butte volcano, Utah, western evidence from high-pressure experiments and natural USA: insights from ash-sheet dispersal, grain size, rocks. Journal of Volcanology and Geothermal and geochemical data. Bulletin of Volcanology 80, Research 29, 293-309. 81. Timm, C., Hoernle, K., Werner, R., Hauff, F., den Vetere, F., Botcharnikov, R.E., Holtz, F., Behrens, H., Bogaard, P.v., White, J., Mortimer, N., Garbe- De Rosa, R., 2011. Solubility of H2O and CO2 in Schönberg, D., 2010. Temporal and geochemical shoshonitic melts at 1250 C and pressures from 50 to evolution of the Cenozoic intraplate volcanism of 400 MPa: implications for Campi Flegrei magmatic Zealandia. Earth-Science Reviews 98, 38-64. systems. Journal of Volcanology and Geothermal Ubide, T., Gale, C., Arranz, E., Lago, M., Larrea, P., Research 202, 251-261. 2014a. Clinopyroxene and amphibole crystal Vetere, F., Mollo, S., Giacomoni, P., Iezzi, G., Coltorti, populations in a lamprophyre sill from the Catalonian M., Ferlito, C., Holtz, F., Perugini, D., Scarlato, P., Coastal Ranges (NE Spain): a record of magma 2015. Experimental constraints on the origin of history and a window to mineral-melt partitioning. pahoehoe “cicirara” lavas at Mt. Etna Volcano Lithos 184, 225-242. (Sicily, Italy). Bulletin of Volcanology 77, 44. Ubide, T., Galé, C., Larrea, P., Arranz, E., Lago, M., Villaseca, C., Dorado, O., Orejana, D., 2019. Mineral 2014b. Antecrysts and their effect on rock chemistry of megacrysts and associated compositions: the Cretaceous lamprophyre suite in clinopyroxenite enclaves in the Calatrava volcanic the Catalonian Coastal Ranges (NE Spain). Lithos field: crystallization processes in mantle magma 206, 214-233. chambers. Journal of Iberian Geology. Ubide, T., Kamber, B.S., 2018. Volcanic crystals as time Wass, S.Y., Roge, N., 1980. Mantle metasomatism— capsules of eruption history. Nature communications precursor to continental alkaline volcanism. 9, 326. Geochimica et Cosmochimica Acta 44, 1811-1823. Ubide, T., Mollo, S., Zhao, J.-x., Nazzari, M., Scarlato, Waters, L.E., Lange, R.A., 2015. An updated calibration P., 2019. Sector-zoned clinopyroxene as a recorder of of the plagioclase-liquid hygrometer-thermometer magma history, eruption triggers, and ascent rates. applicable to basalts through rhyolites. American Geochimica et Cosmochimica Acta. Mineralogist 100, 2172-2184. Ustunisik, G., Kilinc, A., Nielsen, R.L., 2014. New Weiss, Y., Class, C., Goldstein, S.L., Hanyu, T., 2016. insights into the processes controlling compositional Key new pieces of the HIMU puzzle from olivines zoning in plagioclase. Lithos 200, 80-93. and diamond inclusions. Nature 537, 666. Valentine, G.A., Gregg, T.K.P., 2008. Continental Williams, R.W., Gill, J.B., 1989. Effects of partial basaltic volcanoes - Processes and problems. Journal melting on the uranium decay series. Geochimica et of Volcanology and Geothermal Research 177, 857- Cosmochimica Acta 53, 1607-1619. 873. Wilson, J.T., 1963. A possible origin of the Hawaiian Valentine, G.A., Hirano, N., 2010. Mechanisms of low- Islands. Canadian Journal of Physics 41, 863-870. flux intraplate volcanic fields--Basin and Range Witham, F., Blundy, J., Kohn, S.C., Lesne, P., Dixon, J., Evidence, provenance and significance. Geochimica Churakov, S.V., Botcharnikov, R., 2012. SolEx: A et Cosmochimica Acta 143, 49-67. model for mixed COHSCl-volatile solubilities and Yamamoto, T., Soya, T., Suto, S., Uto, K., Takada, A., exsolved gas compositions in basalt. Computers & Sakaguchi, K., Ono, K., 1991. The 1989 submarine Geosciences 45, 87-97. eruption off eastern Izu Peninsula, Japan: ejecta and Wood, D.A., 1979. A variably veined suboceanic upper eruption mechanisms. Bulletin of Volcanology 53, mantle—genetic significance for mid-ocean ridge 301-308. basalts from geochemical evidence. Geology 7, 499- Zeng, G., Chen, L.-H., Xu, X.-S., Jiang, S.-Y., Hofmann, 503. A.W., 2010. Carbonated mantle sources for Cenozoic Wörner, G., Schmincke, H.-U., 1984. Petrogenesis of the intra-plate alkaline basalts in Shandong, North China. zoned Laacher See tephra. Journal of Petrology 25, Chemical Geology 273, 35-45. 836-851. Zou, H., Fan, Q., Yao, Y., 2008. U-Th systematics of Wyllie, P.J., 1995. Experimental petrology of upper dispersed young volcanoes in NE China: mantle materials, processes and products. Journal of Asthenosphere upwelling caused by piling up and Geodynamics 20, 429-468. upward thickening of stagnant Pacific slab. Chemical Xu, Y.-G., 2014. Recycled oceanic crust in the source of Geology 255, 134-142. 90–40Ma basalts in North and Northeast China:

Table 1. Use of different minerals in alkaline basaltic rocks to interpret magmatic processes.

Mineral Technique Interpretable mechanisms References Olivine Thermometry Crystallization temperature Beattie (1993), Putirka (2008) Diffusion Timing of crystallization and Costa et al. (2008), Girona residence, magma ascent rates and Costa (2013) Mineral/melt Estimate equilibrium melt GERM partition coefficients partitioning compositions database Oxygen isotopes Magma genesis, ascent and timing Bindeman (2008) Clinopyroxene Thermobarometry Crystallization temperature and Putirka (2008), Neave and pressure Putirka (2017), Mollo et al. (2018) Hygrometry Magma water content Perinelli et al. (2016) Diffusion Timing of crystallization Brady (1995) and references therein Zoning Magma mixing, crystallization Streck (2008), Ubide and dynamics Kamber (2018) Mineral/melt Estimate equilibrium melt GERM partition coefficients partitioning compositions database, Mollo et al (2010), Putirka (1999) Plagioclase Thermometry Crystallization temperature Putirka (2005, 2008) Hygrometry Magma water content Waters and Lange (2015) Zoning Magma mixing, assimilation, Ustinisik et al. (2014), Coote crystallization dynamics et al. (2018) Mineral/melt Estimate equilibrium melt GERM partition coefficients partitioning compositions database, Namur et al. (2012) Amphibole Thermobarometry Crystallization temperature and Ridolfi and Renzulli (2012), pressure Putirka (2016) Hygrometry Magma water content Ridolfi and Renzulli (2012), Putirka (2016) Mineral/melt Estimate equilibrium melt GERM partition coefficients partitioning compositions database, Putirka (2016) Ti-magnetite Thermometry Crystallization temperature Aryaeva et al. (2018) Oxy-barometry Magma oxygen fugacity Aryaeva et al. (2018) Geospeedometry Cooling rates during crystallization Mollo et al. (2013)