Carbon flux metasomatism in the subduction environment is an important process, but it remains poorly understood. The paucity of exposed lower crust and upper mantle rocks in continental arcs renders xenoliths a major target for studying the slab-derived carbon cycle. This study of the carbonate phases in volcanic rocks from three drill cores in Ulleung Island, South Korea, sheds light on the interaction of carbon flux in the upper mantle and lower crust in a back-arc setting. The volcanic rocks from Ulleung Island range in composition from trachybasalt to trachyte and contain abundant euhedral pseudomorphic carbonate grains, ulvöspinel-hosted and biotite-hosted carbonate-silicate melt inclusions, and irregular carbonate globules. Integrated petrographic and geochemical studies of a variety of phenocrysts, carbonate phases, and carbonate-silicate inclusions in biotite and ulvöspinel indicate that recharging of carbon flux affected magma evolution. Carbon and oxygen isotopes of the pseudomorphic carbonate grains overlap with mantle values, indicating a carbonatite-like origin of the carbonate phases. The (MgO, FeO, CaO)-rich silicates in ulvöspinel-hosted silicate inclusions and pseudomorphic carbonate grains likely represent a primary melt, which formed from the partial melting of carbonated eclogite of the subducted slab within the mantle wedge beneath Ulleung Island. A petrogenetic model is proposed to illustrate that the crystal mush in the magma chamber was intruded by carbonate-rich liquids and caused alteration of cumulate crystals to generate the euhedral pseudomorphic carbonate grains. The extrusive magma captured those pseudomorphic grains and erupted to form the trachybasalt-trachyte units. The observed carbonate phases and their geochemical characteristics indicate that carbon flux metasomatism played a fundamental role in this back-arc magmatism.

中文翻译：

---

碳通量和碱性火山活动：来自韩国郁陵岛粗面岩中的类碳酸盐碳酸盐矿物的证据

俯冲环境中的碳通量交代作用是一个重要的过程，但仍知之甚少。大陆弧中暴露的下地壳和上地幔岩石的缺乏使得捕虏体成为研究板片衍生碳循环的主要目标。这项对韩国郁陵岛三个钻芯的火山岩碳酸盐相的研究揭示了弧后环境中上地幔和下地壳中碳通量的相互作用。郁陵岛火山岩的成分范围从粗面玄武岩到粗面岩，并含有丰富的自面体假形碳酸盐颗粒、以绿尖晶石和黑云母为主体的碳酸盐-硅酸盐熔体包裹体，以及不规则的碳酸盐球。对各种斑晶、碳酸盐相、黑云母和硫绿尖晶石中的碳酸盐-硅酸盐包裹体表明碳通量的补给影响了岩浆演化。假形碳酸盐颗粒的碳和氧同位素与地幔值重叠，表明碳酸盐相的碳酸盐类起源。富含 (MgO, FeO, CaO) 的硅酸盐包裹体和假形碳酸盐颗粒中的硫黄尖晶石包裹体和假相碳酸盐颗粒可能代表了一次熔体，它是由郁陵岛下方地幔楔内俯冲板片的碳酸盐榴辉岩部分熔融形成的。提出了岩石成因模型，说明岩浆房中的结晶糊被富含碳酸盐的液体侵入，导致堆积晶体发生蚀变，产生自面体假相碳酸盐颗粒。喷出的岩浆捕获了这些假相颗粒并喷发形成粗面玄武岩-粗面岩单元。观察到的碳酸盐相及其地球化学特征表明，碳通量交代作用在这种弧后岩浆作用中发挥了基础性作用。