(Supplement S1) Silicon oxide and Potassium + Sodium oxide from the PACManus hydrothermal area

This study presents a systematic analysis and interpretation of autonomous underwater vehicle-based microbathymetry combined with remotely operated vehicle (ROV) video recordings, rock analyses and temperaturemeasurements within the PACManus hydrothermal area located on Pual Ridge in the Bismarck Sea of eastern Manus Basin. The data obtained during research cruise Magellan-06 and So-216 provides a framework for understanding the relationship between the volcanism, tectonismand hydrothermal activity. PACManus is a submarine felsic vocanically-hosted hydrothermal area that hosts multiple vent fields locatedwithin several hundredmeters of one another but with different fluid chemistries, vent temperatures and morphologies. The total area of hydrothermal activity is estimated to be 20,279m**2. Themicrobathymetrymaps combinedwith the ROV video observations allow for precise high-resolution mapping estimates of the areal extents of hydrothermal activity.We find the distribution of hydrothermal fields in the PACManus area is primarily controlled by volcanic features that include lava domes, thick andmassive blocky lava flows, breccias and feeder dykes. Spatial variation in the permeability of local volcanic facies appears to control the distribution of venting within a field.We define a three-stage chronological sequence for the volcanic evolution of the PACManus based on lava flow morphology, sediment cover and lava SiO2 concentration. In Stage-1, sparsely to moderately porphyritic dacite lavas (68-69.8 wt.% SiO2) erupted to form domes or cryptodomes. In Stage-2, aphyric lava with slightly lower SiO2 concentrations (67.2-67.9 wt.% SiO2) formed jumbled and pillowed lava flows. In the most recent phase Stage-3, massive blocky lavaswith 69 to 72.5wt.% SiO2were erupted throughmultiple vents constructing a volcanic ridge identified as the PACManus neovolcanic zone. The transition between these stages may be gradual and related to progressive heating of a silicic magma following a recharge event of hot, mantle-derived melts.

本研究针对位于马努斯盆地东部俾斯麦海保尔山脊（Pual Ridge）的PACManus热液区，开展了基于自主水下航行器的微地形测深（microbathymetry）结合遥控水下机器人（Remotely Operated Vehicle, ROV）视频记录、岩石分析与温度测量的系统性分析与解译。科考航次Magellan-06与So-216期间获取的数据集，为厘清火山作用、构造作用与热液活动间的内在关联提供了研究框架。PACManus是一处长英质海底火山赋存型热液区，区内分布多个喷口场，彼此间距仅数百米，但流体化学组成、喷口温度与地貌形态均存在显著差异。热液活动总面积估算为20279平方米。结合ROV视频观测的微地形测深图，可实现热液活动分布范围的高精度高分辨率制图估算。研究发现，PACManus区热液场的分布主要受火山构造特征控制，包括熔岩穹丘、厚层块状熔岩流、角砾岩与补给岩脉。局部火山岩相的渗透率空间差异，似乎控制了单个热液场内喷口的分布格局。基于熔岩流形态、沉积物覆盖度与熔岩二氧化硅（SiO₂）含量，本研究构建了PACManus火山演化的三阶段时间序列。第一阶段：稀疏至中等斑状英安岩（二氧化硅含量68~69.8 wt.%）喷发形成穹丘或隐伏穹丘；第二阶段：二氧化硅含量略低（67.2~67.9 wt.%）的无斑熔岩形成杂乱堆积的枕状熔岩流；第三阶段为最新阶段：二氧化硅含量69~72.5 wt.%的块状熔岩经多个喷口喷发，形成被命名为PACManus新火山带的火山脊。各阶段间的过渡可能是渐进的，与幔源热熔体补给事件后长英质岩浆的持续升温过程相关。