Hydrothermal activity is abundant at volcanic structures in subduction zones, including those associated with young volcanism in back-arc regions. Fluid boiling is a common process in these environments, but its fractionation and precipitation effects on trace metals and metalloids are still poorly constrained. The submarine back-arc hydrothermal system of Nifonea caldera hosts two recently discovered active vent sites with sulphide-sulphate chimneys showing a diverse mineralogy and chemistry. The focused discharge of fluids with temperatures (up to 368 °C) near the seawater boiling curve at ~ 1860 m water depth and “jets of steam” emitted from the chimney structures suggest fluid boiling. Fluid processes, as well as metal and metalloid deposition vary on a relatively small spatial-scale (<0.5 km²) and coincide with changes in sulphide-sulphate mineralogy and texture between different chimneys with zoning and dendritic intergrowths, indicating temperature gradients and fluid boiling. Boiling-induced precipitation, together with seawater mixing in the sub-seafloor led to a depletion of Zn, Ga, Ge, Ag, Cd, Sb, Au and Pb in the discharging fluids and their precipitates at the main compared to the northern vent site, also resulting in a depleted trace element signature with respect to most other back-arc hydrothermal systems in the Pacific Ocean. A magmatic-hydrothermal signature (high ${\mathrm{S}\mathrm{O}}_4^{2-}$) in some of the discharging fluids propose a weak magmatic volatile influx to the Nifonea caldera hydrothermal system. However, S isotope data provides no evidence for a magmatic volatile component and rather suggests, in combination with the sulphide-sulphate (Zn, Ge, Se, Ag, Cd, Sb, Ba, Au and Pb) and fluid data (high K) that the Nifonea caldera hydrothermal system is dominantly controlled by a combination of boiling, mixing and water–rock interaction.

在俯冲带的火山构造中，包括与后弧地区年轻火山爆发有关的火山构造中，热液活动丰富。在这些环境中，流体沸腾是一个常见的过程，但是它对痕量金属和准金属的分馏和沉淀作用仍然很难控制。尼福尼亚破火山口的海底弧热液系统有两个最近发现的活跃的通风口，硫化物-烟囱烟囱显示出多种多样的矿物学和化学。在大约1860 m的水深处，靠近海水沸腾曲线的温度（最高368°C）的流体的集中排放和从烟囱结构发出的“蒸汽喷射”表明流体沸腾。流体过程以及金属和准金属的沉积在相对较小的空间尺度（<0.5 km ²），并且与不同烟囱之间的硫化物-硫酸盐矿物学和质地变化（具有分区和树突状共生体）相吻合，表明温度梯度和流体沸腾。沸腾引起的降水以及海底混合海水导致排泄液中Zn，Ga，Ge，Ag，Cd，Sb，Au和Pb的消耗以及与北部排放点相比主要排放物中的沉淀，这也导致了太平洋中大多数其他背弧热液系统的痕量元素签名减少。岩浆热液特征（高${\mathrm{小号}\mathrm{Ø}}_4^{\mathrm{2个}--}$）在某些排放流体中，提出了一种弱的岩浆挥发物涌入Nifonea破火山口的热液系统。但是，S同位素数据没有提供岩浆挥发性成分的证据，而是建议与硫化物硫酸盐（Zn，Ge，Se，Ag，Cd，Sb，Ba，Au和Pb）和流体数据（高K）结合使用Nifonea破火山口的热液系统主要受沸腾，混合和水-岩相互作用的控制。