Glaciovolcanic deposits at Tongariro and Ruapehu volcanoes, New Zealand, represent diverse styles of interaction between wet-based glaciers and andesitic lava. There are iceconfined lavas, and also hydroclastic breccia and subaqueous pyroclastic deposits that formed during effusive and explosive eruptions into meltwater beneath the glacier; they are rare among globally reported products of andesitic glaciovolcanism. The apparent lack of hydrovolcanically fragmented andesite at ice-capped volcanoes has been attributed to a lack of meltwater at the interaction sites because either the thermal characteristics of andesite limit meltwater production or meltwater drains out through leaky glaciers and down steep volcano slopes. We used published field evidence and novel, dynamic andesite-ice experiments to show that, in some cases, meltwater accumulates under glaciers on andesitic volcanoes and that meltwater production rates increase as andesite pushes against an ice wall. We concur with models for eruptions beneath ice sheets showing that the glacial conditions and pre-eruption edifice morphology are more important controls on the style of glaciovolcanism and its products than magma composition and the thermal properties of magmas. Glaciovolcanic products can be useful proxies for paleoenvironment, and the range of andesitic products and the hydrological environments in which andesite erupts are greater than hitherto appreciated.Currently, 254 Holocene volcanoes host glacial ice, 72% of which are arc volcanoes, and numerous high-latitude and high-altitude intermediate-composition (hereafter termed “andes-itic”) stratovolcanoes were glaciated during the Pliocene–Pleistocene (Edwards et al., 2020). Ice-confined lava is a well-documented product of andesitic glaciovolcanism, formed when a glacier physically confines lava to high inter-fluves, and little to no hydrovolcanic fragmentation takes place (e.g., Lescinsky and Fink, 2000; Kelman et al., 2002; Conway et al., 2015). The rarity of reported andesitic glaciovolcanic clastic products (Kelman et al., 2002) has been taken to indicate that fragmentation is rare at glaciated arc volcanoes. Lower eruption temperatures have been suggested to reduce the rate of ice melting for intermediate-silicic lavas compared with basalts, so that meltwater is driven out by positive pressures in the englacial vault, impeding hydrovolcanic fragmentation (Höskuldsson and Sparks, 1997; Kelman et al., 2002; cf. Stevenson et al., 2009). No observational or experimental data have been published, however, to support an entirely compositional control on a lava's ability to melt ice. Field observations and experiments with basaltic lava show that ice melting rates increase when flow or inflation rate is low, and that melting is faster when lava directly contacts ice, rather than snow or a cara-pace of breccia (Edwards et al., 2013, 2015). The only experiments to date with broadly andes-itic melts showed heat fluxes similar to basalts (Oddsson et al., 2016b). Low calculated heat fluxes and a lack of subaqueous deposits at the Table, an andesitic lava–dominated tuya in British Columbia (Canada), were explained by low effusion rates, a carapace of insulating breccia, and meltwater drainage on steep slopes (Wilson et al., 2019). In addition, the range of clastic and coherent glaciovolcanic products from basaltic and rhyolitic volcanoes indicates production of varied volumes of meltwater by both magma types (e.g., Smellie and Skilling, 1994; Stevenson et al., 2006; Tuffen et al., 2008; McGarvie, 2009; Smellie, 2018). The apparent lack of hydroclastic rocks at many andesitic edifices arguably results from poor meltwater retention at arc volcanoes, due to steep terrain and thin, permeable glaciers (Lescinsky and Fink, 2000; Stevenson et al., 2009). There are far fewer published studies of andesitic glaciovolcanism than for basalt and rhyolite. Also, volcaniclastic products from explosive eruptions that land on snow or ice of a cone's slopes are not preserved on the edifice, leading to a preservation and publication bias toward ice-confined lavas (Kelman et al., 2002).We identified distinct styles of glaciovolcanism at andesitic volcanoes capped by wet-based glaciers using evidence published from Tongariro and Ruapehu volcanoes, New Zealand (Conway et al., 2015, 2016; Cole et al., 2018, 2020). The examples given represent styles of glaciovolcanism that may have occurred at many ice-capped andesitic edifices worldwide, and there is also overlap with volcano-ice interactions under large ice sheets (e.g., Stevenson et al., 2009).New molten andesite-ice deformation experiments, building on static experiments by Oddsson et al. (2016b), tested rates of heat flux and meltwater production during dynamic lava-ice interaction. Active pushing of lava against ice has not been considered before, but it probably occurs in most natural lavas as they flow or inflate against an ice barrier or roof. Our results suggest that this dynamic influence on the heat transfer is significant. Understanding the thermodynamics of intermediate-composition lava-ice interaction is important for assessing emplacement of glaciovolcanic products, and for forecasting whether meltwater may cause flooding and/or influence explosive activity (Major and Newhall, 1989; Lescinsky and Fink, 2000).Three types of glaciovolcanic products are preserved on Tongariro and Ruapehu volcanoes (Fig. 1; Conway et al., 2015; Townsend et al., 2017; Cole et al., 2018, 2020), recording diverse glaciovolcanic styles from magmas of similar composition. Approximately 90% of analyzed lavas from Ruapehu are basalticandesite or andesite (Price et al., 2012; Conway et al., 2016), and 77% of visible, edifice-forming units at Tongariro are andesite, while 23% are basaltic-andesite (Pure et al., 2020). Temperatures of most historic eruptions at Ruapehu have been estimated at 950–1050 °C (Kilgour et al., 2013). Russell et al. (2014) defined nine types of tuya based on eruption style and glacio-hydro-logical conditions, all independent of magma composition. On a smaller scale, we suggest that different glacio-hydrological conditions on an ice-capped volcano can yield at least three distinct glaciovolcanic products from three pairings of eruptive style with environmental conditions (Fig. 2):(1) Effusive and subaqueous. Effusive eruptions into ponded water lead to nonexplosive, quench fragmentation forming massive hyaloclastic/hydroclastic breccias (Figs. 1A and 1B; Cole et al., 2020). Meltwater accumulation has led to similar deposits at volcanoes in large ice sheets across the range of magma compositions (e.g., Smellie and Skilling, 1994; McGarvie et al., 2007; Stevenson et al., 2009). In glacial periods, multivent composite volcanoes have supported glaciers a few hundred meters thick within valleys, or on an irregular summit topography (Eaves et al., 2016; Cole et al., 2018, 2020). Thick ice combined with confining topography enables meltwater to pond locally, even at generally steep-sided volcanoes, influencing glaciovolcanic interaction (Fig. 2).(2) Explosive and subaqueous. Deposits of aqueous pyroclastic currents formed from explosive eruptions into meltwater (Figs. 1C, 1D, and 2) are emplaced either by meltwater draining through a subglacial channel, or by currents moving through accumulated water, such as an englacial lake. Deposition from eruption-fed currents in either setting produces similar features, but with different implications for glacial hydrology (Smellie and Skilling, 1994; White, 2000). Based on the surrounding topography at Tongariro, the deposits are inferred to have been emplaced in meltwater channels along an ice-capped ridgeline (ice ≤150 m thick; Fig. 2; Cole et al., 2018). Comparable deposits have formed in Iceland, where ice >550 m thick is inferred to have overwhelmed topography (Stevenson et al., 2009).(3) Effusive and ice-confined. Ridge-capping lava flows form from effusive eruptions but represent a different style of glaciovolcanism to hydroclastic breccia. Their overthickened forms and the orientation of marginal cooling joints indicate that lava was physically confined by the glacier (Figs. 1E and 1F). Meltwater is produced and contributes to cooling and fracturing in these settings, but the lavas are not emplaced in ponded water. At Tongariro and Ruapehu (Conway et al., 2015; Cole et al., 2018), and other stratovolcanoes globally (Lescinsky and Sisson, 1998; Lescinsky and Fink, 2000), ice-confined lavas are perched at high elevations on steep terrain. They erupted alongside thin, fractured alpine glaciers that allowed meltwater to drain freely from the site of interaction. In ice sheets, lava-dominated products cap edifices that became emergent or form entire edifices where glacial conditions permit efficient drainage (Smellie and Skilling, 1994; Tuffen et al., 2002; Stevenson et al., 2006; Russell et al., 2014; Wilson et al., 2019).The distinct deposit types (1–3) represent andesitic lava–ice interaction under different hydrological conditions on ice-capped volcanoes, but there is considerable overlap with products at basaltic and rhyolitic edifices, and also beneath thick ice sheets (Smellie and Skilling, 1994; Stevenson et al., 2006, 2009; Tuffen et al., 2008; McGarvie, 2009; Russell et al., 2014; Smellie, 2018). We concur that glacio-volcanic interaction at ice-capped volcanoes is controlled by meltwater availability and glacial hydrology, as functions of the glacier characteristics and edifice morphology (Fig. 2).We conducted novel experiments to investigate how much meltwater can be produced when andesitic lava flows against a glacier. We selected lava younger than 5 ka (Conway et al., 2016; Townsend et al., 2017) in Ruapehu's Whangaehu Valley for its apparent freshness. X-ray fluorescence analysis (at the University of Waikato, New Zealand) confirmed an andesitic composition (60 wt% SiO2 and 5.1 wt% Na2O + K2O with loss on ignition [LOI] at −0.15; the full major-element data set is given in the Supplemental Material1). For each experiment, we melted 60–100 g of granulated andesite in a crucible at 1250 °C using an induction furnace. The experimental melt temperature higher than that of erupting andes-ite (T ≈1000 °C; Harris and Rowland, 2015) counterbalanced the loss of viscosity-reducing volatiles by outgassing during emplacement of the natural lava (Zimanowski et al., 1991). This overheating precluded direct comparison of ice-melt rates with those during emplacement of natural andesite, but it allowed the andesite to be deformed against ice, which was the focus of these experiments. Despite the high melt temperature, the andesite was much more viscous than remelted basalt. A squeeze apparatus was designed consisting of two wooden paddles attached to scissored arms. The andesite melt was pressed against an ice block frozen to one of the paddles, and pressure sensors attached to the arms of the apparatus recorded the pressure applied during deformation (Fig. 3A). A calorimeter beneath collected meltwater. Water mass and temperature were measured during the experiments. Two additional experimental runs were performed with andesite melt placed on top of an ice block, one resting under gravity only, and the other being pushed into the ice (Fig. 3B). For these runs, only the mass of the meltwater was measured.The molten andesite was easily squeezed against the ice block, melting a cavity in the ice that was only slightly wider than the andes-ite and of comparable shape. A widening glassy crust progressed across the melt sample from the margin in direct contact with the ice, while meltwater drained down from the andesite-ice interface. During the runs in which the molten andesite was placed on top of an ice block, a cavity formed beneath the andesite and partially filled with meltwater. The meltwater formed a channel that breached the edge of the ice block seconds after the start of the experiment and ran down the side, carving a vertical chute. Some meltwater refroze to the ice before reaching the calorimeter, but the majority was collected. Details of the experimental procedure and heat flux calculations and photos are provided in the Supplemental Material.The overall heat fluxes from each experiment were between 186 and 250 kW m−2, consistent with published observational and experimental values obtained for andesitic lava from Eyjafjallajökull, Iceland (Oddsson et al., 2016a, 2016b), and basaltic lava effusions (Allen, 1980; Höskuldsson and Sparks, 1997; Edwards et al., 2013). The fluxes are much lower than the 500–600 kW m−2 estimated during the 1996 Gjálp eruption, Iceland (Gudmundsson, 2003), and an order of magnitude lower than the 1–4 MW m−2 estimated from ice melting during the explosive phase of the 2010 Eyjafjallajökull eruption (Magnússon et al., 2012). This difference is expected because virtually no fragmentation took place during the experiments. Our calculated heat fluxes are higher than those calculated for the emplacement of the Table in British Columbia, where endogenous emplacement within an enclosing carapace of breccia is inferred to have insulated the hot interior from surrounding ice (Wilson et al., 2019). We note that unlike a natural lava flow, the volume of andesite in the experiments was small and not replenished by continued feeding from a vent. More fragmentation would be expected in a natural lava as it cools, forms a crust, and is fractured by quenching and dynamic stressing. Heat transfer and meltwater production would be prolonged by continued feeding. If issues associated with the high viscosity of remelted andesite can be overcome, large-scale experiments with greater volumes of melt that remain molten for longer (e.g., Edwards et al., 2013) to determine heat transfer while measuring flow or strain rate would provide results more easily scalable to natural lava emplacement in ice.Our attempt to recreate the dynamic interaction between ice and deforming lava produced transient increases in heat flux of up to an order of magnitude, following increases in applied force, causing temporary rises in melt-water production (Fig. 3A). Compared with static molten andesite-ice interaction, meltwater was produced at a higher rate and in greater volume when the andesite melt was pressed into the ice (Fig. 3B). The increases in heat flux and meltwater production from deforming melt are inferred to have resulted from advection of heat to the melt-ice interface, an increased interface area from lateral spreading of the deforming melt, and the formation of cracks in the solidifying andesite due to the applied force. The offset in time of a few seconds between the increase in applied force and increase in meltwater production is expected due to the time taken for ice melting, the time required for the meltwater to fall into the calorimeter, and the delay in mass recording due to inertia of the balance. Overall, results from additional experimental runs and the limitations of our experimental procedure, which could be developed further, are given in the Supplemental Material.We found that meltwater production increases when lava flows, or inflates, against a glacier, as would occur during emplacement of ice-confined lava of any composition. An area where the deformation simulated in these experiments is likely to be most significant is at the flow front of a lava flow, where it presses against the glacier with the force of the remaining flow behind the front. The effect on meltwater production from dynamic lava-ice interaction should be included in theoretical and experimental models to fully understand the ice-melting potential of different lavas. Lava flow rate, contact area, and contact geometry with ice, and the rate and geometry of surface crust fracturing during flow or extrusion, as well as the ability of meltwater to drain away, are probably more important than magma composition in controlling glaciovolcanic interaction style and products.Andesite is able to generate enough melt-water during eruptions at ice-capped volcanoes to form subaqueous lithofacies. Further, heat transfer and meltwater production increase during dynamic interactions when lava flows or inflates against glacial ice. This dynamic effect should be considered in models for meltwater production from ice-confined lava, and large-scale experiments undertaken to better quantify this effect. The dominance of ice-confined lavas in known intermediate-composition glaciovolcanic sequences probably reflects preservation bias or meltwater drainage in leaky systems. Meltwater retention controlled by glacial hydrology plays a more significant role in volcano-ice interaction style than compositionally controlled differences in rates of meltwater production.R.P. Cole received funding from the Geological Society of New Zealand Wellman Research Award and the University of Otago Polar Environments Research Theme. The New Zealand Department of Conservation provided logistical assistance in the field. Brent Pooley and Luke Easterbrook assisted with making the experimental apparatus. Matteo Demurtas helped Cole in using MatLab. Kelly Russell, John Smellie, and Alison Graettinger provided constructive reviews.

中文翻译：

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野外和实验研究对冰盖火山安山岩火山作用的控制

新西兰汤加里罗 (Tongariro) 和鲁阿佩胡 (Ruapehu) 火山的冰川火山沉积物代表了湿基冰川和安山岩熔岩之间不同类型的相互作用。有冰封的熔岩，以及在冰川下方融水的喷发和爆炸性喷发过程中形成的水​​力碎屑角砾岩和水下火山碎屑沉积物；它们在全球报道的安山冰川作用产物中很少见。冰盖火山中明显缺乏水火山碎裂的安山岩归因于相互作用地点缺乏融水，因为安山岩的热特性限制了融水的产生，或者融水通过泄漏的冰川和陡峭的火山斜坡排出。我们使用已发表的现场证据和新颖的动态安山岩冰实验来表明，在某些情况下，融水在安山岩火山的冰川下积聚，随着安山岩推向冰墙，融水的产生率会增加。我们同意冰盖下喷发的模型，表明冰川条件和喷发前建筑物形态是对冰川火山作用及其产物类型的更重要控制，而不是岩浆成分和岩浆的热性质。冰川火山产物可以作为古环境的有用代理，安山岩产物的范围和安山岩喷发的水文环境比迄今为止所认识的要大。 目前，254座全新世火山有冰川冰，其中72%是弧形火山，和许多高纬度和高海拔中间成分（以下称为“安山岩”）层状火山在上新世-更新世期间被冰川化（Edwards 等，2020）。冰封熔岩是安山岩火山作用的有据可查的产物，当冰川将熔岩物理地限制在高的河流间并且几乎没有发生水火山碎裂时形成（例如，Lescinsky 和 ​​Fink，2000 年；Kelman 等人，2002 年） ；康威等人，2015 年）。已报告的安山岩冰川火山碎屑产物的稀有性（Kelman 等，2002）表明冰川弧火山很少发生碎裂。与玄武岩相比，较低的喷发温度被认为可以降低中硅质熔岩的冰融化速度，从而使融水被冰川穹窿中的正压排出，阻止水火山碎裂（Höskuldsson 和 Sparks，1997 年；Kelman 等人，2002 年；参见 Stevenson 等人，2009 年）。然而，没有发表任何观察或实验数据来支持对熔岩融化冰的能力的完全成分控制。对玄武岩熔岩的实地观察和实验表明，当流动或膨胀率较低时，冰融化速度会增加，而当熔岩直接接触冰而不是雪或角砾岩的角砾岩时，融化速度会更快（Edwards 等，2013， 2015）。迄今为止，对广泛的安山岩熔体进行的唯一实验显示出类似于玄武岩的热通量（Oddsson 等人，2016b）。计算出的低热通量和表中缺乏水下沉积物，即不列颠哥伦比亚省（加拿大）以安山岩熔岩为主的 tuya，可以用低渗出率、绝缘角砾岩的甲壳、和陡坡上的融水排放（Wilson 等人，2019 年）。此外，玄武质和流纹质火山的碎屑和连贯冰川火山产物的范围表明两种岩浆类型产生了不同体积的融水（例如，Smellie 和 Skilling，1994 年；Stevenson 等人，2006 年；Tuffen 等人，2008 年；麦加维，2009 年；斯梅利，2018 年）。许多安山岩建筑物明显缺乏水碎屑岩，这可以说是由于弧形火山的融水滞留能力差，原因是地形陡峭，冰川薄而可渗透（Lescinsky 和 ​​Fink，2000 年；Stevenson 等人，2009 年）。与玄武岩和流纹岩相比，已发表的关于安山冰川火山作用的研究要少得多。此外，爆炸性喷发的火山碎屑产物落在锥体斜坡的雪或冰上，不会保留在建筑物上，导致对冰封熔岩的保存和出版偏见（Kelman 等人，2002 年）。我们使用新西兰汤加里罗和鲁阿佩胡火山发表的证据，确定了被湿冰川覆盖的安山岩火山的不同类型的冰川作用（Conway 等人， al., 2015, 2016; Cole et al., 2018, 2020)。给出的例子代表了可能发生在世界范围内许多被冰盖的安山岩建筑物上的冰川火山作用的类型，并且还与大冰盖下的火山-冰相互作用重叠（例如，Stevenson 等，2009）。新的熔融安山岩-冰变形实验，基于 Oddsson 等人的静态实验。(2016b)，在动态熔岩冰相互作用期间测试了热通量和融水产生的速率。以前没有考虑过将熔岩主动推向冰层，但它可能发生在大多数天然熔岩中，因为它们在冰障或屋顶上流动或膨胀。我们的结果表明，这种对传热的动态影响是显着的。了解中间成分熔岩-冰相互作用的热力学对于评估冰川火山产物的就位以及预测融水是否会导致洪水和/或影响爆炸活动很重要（Major 和 Newhall，1989 年；Lescinsky 和 ​​Fink，2000 年）。三种类型在汤加里罗和鲁阿佩胡火山上保存了大量冰川火山产物（图 1；Conway 等人，2015 年；Townsend 等人，2017 年；Cole 等人，2018 年，2020 年），记录了来自相似成分的岩浆的不同冰川火山类型。大约 90% 的鲁阿佩胡分析熔岩是玄武岩或安山岩（Price 等人，2012 年；Conway 等人，2016 年），汤加里罗 77% 的可见建筑物形成单元是安山岩，而 23% 是玄武岩安山岩（Pure 等，2020）。鲁阿佩胡历史上大多数火山喷发的温度估计为 950–1050 °C（Kilgour 等，2013）。拉塞尔等人。(2014) 根据喷发方式和冰川水文条件定义了九种类型的图雅，它们都与岩浆成分无关。在较小的范围内，我们认为冰盖火山上不同的冰川水文条件可以从三种喷发方式与环境条件的配对中产生至少三种不同的冰川火山产物（图 2）：（1）喷发和水下。涌入池水中的喷发导致非爆炸性的骤冷破碎，形成巨大的透明碎屑/水碎屑角砾岩（图 1A 和 1B；Cole 等人，2020 年）。融水积聚导致在岩浆成分范围内的大型冰盖火山中的类似沉积物（例如，Smellie 和 Skilling，1994 年；McGarvie 等人，2007 年；Stevenson 等人，2009 年）。在冰川时期，多喷口复合火山在山谷内或不规则的山顶地形上支撑了数百米厚的冰川（Eaves 等人，2016 年；Cole 等人，2018 年，2020 年）。厚冰加上受限制的地形使融水能够在局部积聚，即使在一般陡峭的火山中，影响冰川火山相互作用（图 2）。(2) 爆炸性和水下。由爆炸性喷发进入融水形成的含水火山碎屑流沉积物（图 1C、1D 和 2）被融水通过冰下通道排出，或由流经积水的水流形成，比如冰川湖。两种环境中喷发馈流的沉积都会产生相似的特征，但对冰川水文具有不同的影响（Smellie 和 Skilling，1994 年；White，2000 年）。根据汤加里罗周围的地形，推断沉积物沿着冰盖的山脊线（冰 ≤150 m 厚；图 2；Cole 等人，2018 年）位于融水通道中。冰岛也形成了类似的沉积物，据推测，那里的冰 > 550 m 厚，具有压倒性的地形（Stevenson 等人，2009 年）。(3) 喷流和冰封。山脊熔岩流形成于喷发喷发，但代表了不同类型的冰川火山作用和碎屑角砾岩。它们过厚的形式和边缘冷却接头的方向表明熔岩被冰川物理限制（图 1E 和 1F）。在这些环境中，会产生融水并有助于冷却和压裂，但熔岩不会被放置在积水中。在汤加里罗和鲁阿佩胡（Conway 等人，2015 年；Cole 等人，2018 年）以及全球其他层状火山（Lescinsky 和 ​​Sisson，1998 年；Lescinsky 和 ​​Fink，2000 年），冰封熔岩栖息在陡峭地形的高海拔地区. 它们与薄而破碎的高山冰川一起喷发，使融水从相互作用的地点自由流出。在冰盖中，熔岩占主导地位的产物覆盖了浮出水面的建筑物或在冰川条件允许有效排水的地方形成完整的建筑物（Smellie 和 Skilling，1994 年；Tuffen 等人，2002 年；Stevenson 等人，2006 年；Russell 等人，2014 年） ；威尔逊等人，2019 年）。不同的沉积类型 (1-3) 代表了冰盖火山在不同水文条件下的安山岩熔岩-冰相互作用，但与玄武岩和流纹岩建筑物以及厚冰盖下的产物有相当大的重叠（Smellie 和 Skilling，1994 ；Stevenson 等人，2006、2009；Tuffen 等人，2008 年；McGarvie，2009 年；Russell 等人，2014 年；Smellie，2018 年）。我们同意冰盖火山的冰川 - 火山相互作用受融水可用性和冰川水文控制，作为冰川特征和建筑物形态的函数（图 2）。我们进行了新的实验来研究安山岩时可以产生多少融水熔岩流向冰川。我们在 Ruapehu' 中选择了小于 5 ka 的熔岩（Conway 等人，2016 年；Townsend 等人，2017 年）s Whangaehu Valley 因其明显的新鲜度。X 射线荧光分析（在新西兰怀卡托大学）证实了安山岩成分（60 wt% SiO2 和 5.1 wt% Na2O + K2O，烧失量 [LOI] 为 -0.15；完整的主要元素数据集是补充材料 1) 中给出。对于每个实验，我们使用感应炉在 1250 °C 的坩埚中熔化 60–100 g 粒状安山岩。实验熔体温度高于喷发的安山岩（T ≈ 1000 °C；Harris 和 Rowland，2015 年），抵消了天然熔岩侵位过程中因放气而降低粘度的挥发物的损失（Zimanowski 等人，1991 年）。这种过热排除了冰融化速率与天然安山岩就位期间的直接比较，但它允许安山岩在冰上变形，这是这些实验的重点。尽管熔体温度很高，但安山岩比重熔玄武岩粘稠得多。设计了一个挤压装置，由两个连接在剪断臂上的木桨组成。安山岩熔体被压在冰块上，冰块冻结在其中一个桨上，连接到设备臂上的压力传感器记录变形过程中施加的压力（图 3A）。收集的融水下方的热量计。在实验期间测量水的质量和温度。将安山岩熔体放置在冰块顶部进行了两次额外的实验运行，一次仅在重力作用下休息，另一次被推入冰中（图 3B）。对于这些运行，只测量了融水的质量。熔融的安山岩很容易被冰块挤压，融化冰中的一个空洞，该空洞仅比安山岩稍宽且形状相似。加宽的玻璃状外壳从与冰直接接触的边缘穿过熔体样品，而融水从安山岩-冰界面向下排出。在将熔化的安山岩放置在冰块顶部的运行过程中，安山岩下方形成了一个空洞，部分充满了融水。融水形成了一条通道，在实验开始几秒钟后就突破了冰块的边缘，并沿着侧面流下，形成了一个垂直的斜槽。一些融水在到达热量计之前重新冻结成冰，但大部分被收集了。补充材料中提供了实验程序和热通量计算和照片的详细信息。每个实验的总热通量在 186 到 250 kW m-2 之间，与从冰岛埃亚菲亚德拉冰盖 (Oddsson et al., 2016a, 2016b) 和玄武岩熔岩喷流 (Allen, 1980；Höskuldsson 和 Sparks，1997；Edwards 等，2013）。通量远低于 1996 年冰岛 Gjálp 喷发期间估计的 500-600 kW m-2（Gudmundsson，2003），并且比爆炸期间冰融化估计的 1-4 MW m-2 低一个数量级2010 年 Eyjafjallajökull 火山喷发的阶段（Magnússon 等，2012）。这种差异是预料之中的，因为在实验过程中几乎没有发生碎片。我们计算出的热通量高于为不列颠哥伦比亚省表中就位计算的热通量，推断角砾岩封闭甲壳内的内源性侵位使高温内部与周围冰隔离（Wilson 等人，2019 年）。我们注意到，与天然熔岩流不同，实验中安山岩的体积很小，并且不会通过来自通风口的持续进料来补充。当天然熔岩冷却、形成地壳并通过淬火和动态应力破裂时，预计会出现更多碎裂。继续喂食会延长传热和融水的产生。如果可以克服与重熔安山岩的高粘度相关的问题，则在测量流量或应变率的同时，使用更大体积的熔体进行更长时间的大规模实验（例如，Edwards 等人，2013 年）来确定热传递将提供结果更容易扩展到冰中的天然熔岩位置。我们试图重建冰和变形熔岩之间的动态相互作用，在施加的力增加后，导致热通量瞬时增加一个数量级，导致融水产量暂时增加（图 3A）。与静态熔融安山岩-冰相互作用相比，当安山岩熔体被压入冰中时，融水以更高的速率和更大的体积产生（图 3B）。变形熔体产生的热通量和融水产量的增加被推断是由于热量平流到融冰界面，变形熔体横向扩展导致界面面积增加，以及凝固的安山岩中裂纹的形成导致施加的力。由于冰融化所需的时间、融水落入量热计所需的时间以及质量记录的延迟，预计在施加的力的增加和融水产量的增加之间存在几秒钟的时间偏移。天平的惯性。总体而言，补充材料中给出了额外实验运行的结果和我们实验程序的局限性（可以进一步开发）。任何成分的冰封熔岩。在这些实验中模拟的变形可能最显着的区域是熔岩流的流动前沿，在那里它通过前沿后面的剩余流动的力压在冰川上。动态熔岩-冰相互作用对融水产生的影响应包含在理论和实验模型中，以充分了解不同熔岩的融冰潜力。熔岩流速、接触面积和与冰的接触几何形状，流动或挤压过程中地壳破裂的速率和几何形状，以及融水流失的能力，在控制冰川火山相互作用方式方面可能比岩浆成分更重要和产品。安山岩能够在冰盖火山喷发期间产生足够的融水以形成水下岩相。此外，当熔岩在冰川上流动或膨胀时，热传递和融水产生会在动态相互作用中增加。在从冰封熔岩生产融水的模型中应考虑这种动态效应，并进行了大规模实验以更好地量化这种影响。在已知的中间成分冰川火山序列中，冰封熔岩的主导地位可能反映了泄漏系统中的保存偏差或融水排水。冰川水文控制的融水滞留在火山-冰相互作用方式中比融水产生率的成分控制差异更重要。RP Cole 获得了新西兰地质学会威尔曼研究奖和奥塔哥大学极地环境研究主题的资助. 新西兰环境保护部在该领域提供了后勤援助。Brent Pooley 和 Luke Easterbrook 协助制作了实验装置。Matteo Demurtas 帮助 Cole 使用 MatLab。凯利·拉塞尔，约翰·斯梅利