The thesis presents research on recent hydrothermal discharge features in a shallow marine hydrothermal system. It aims to clarify their occurrence, genesis, and preservation potential. A facies model is developed, being based on the processes involved in the formation and the prevailing lithofacies. It describes six major groups: channels, fractures, tubes, cones, bowls, and lineaments. Each of these groups subdivides into numerous facies types according to the cements or mineral precipitates prevailing. To clarify the rather complex formation processes of hydrothermal discharge features, genetic models for each facies are proposed. An integrated evolutionary model is developed considering the temporal evolution of the major types of hydrothermal discharge features in the Panarea system and their preservation potential. Confirming presumptions of former, preliminary data, the first documentation of secure paleo-evidences of such hydrothermal discharge features is presented.:1. Introduction ....11 1.1. Preamble .....11 1.2. Research questions, objectives, and hypotheses ......................................... 12 2. State of research - seafloor hydrothermal systems ................................ 15 2.1. Hydrothermal deposits in general ................................................................. 15 2.2. Deep-sea environments ............................................................................... 16 2.3. Shallow-water systems and their preservation potential ............................... 17 3. Panarea Island - the area of investigation ................................................ 20 3.1. The hydrothermal system of Panarea Island ................................................ 20 3.2. Fluid discharge features in Panarea ............................................................. 30 3.3. Study sites .................................................................................................... 34 4. Materials and methods ............................................................................... 40 4.1. Underwater research .................................................................................... 40 4.2. Field methods ............................................................................................... 41 4.3. Laboratory methods ..................................................................................... 44 5. Results ........................................................................................................ 47 5.1. Prevailing lithologies ..................................................................................... 47 5.1.1. Hardrocks ..................................................................................................... 47 5.1.2. Sedimentary rocks ........................................................................................ 51 5.1.3. Sediments .................................................................................................... 54 5.1.4. Cements ....................................................................................................... 58 5.2. Underwater investigation sites and findings ................................................. 66 HYDROTHERMAL FLUID DISCHARGE FEATURES IN PANAREA, ITALY PAGE 10 | 174 5.2.1. Area 26 ......................................................................................................... 66 5.2.2. Basiluzzo ...................................................................................................... 75 5.2.3. Black Point ................................................................................................... 77 5.2.4. Bottaro North ................................................................................................ 79 5.2.5. Bottaro West ................................................................................................. 81 5.2.6. Cave ............................................................................................................. 84 5.2.7. Fumarolic Field ............................................................................................. 87 5.2.8. Hot Lake ....................................................................................................... 89 5.2.9. La Calcara .................................................................................................... 92 5.2.10. Point 21 ........................................................................................................ 98 5.2.11. Subaerial locations ..................................................................................... 100 5.3. Summarizing tables .................................................................................... 104 6. Interpretation ............................................................................................ 106 6.1. Discharge features and secondary processes ............................................ 106 6.1.1. Complex genesis and development of discharge features and their occurrence throughout the system ............................................................. 119 6.1.1.1. Cones, bowls, and lineament structures ..................................................... 119 6.1.1.2. Tubes ......................................................................................................... 128 6.2. Preservation potential and paleo-record ..................................................... 138 7. Conclusion and Discussion .................................................................... 141 7.1. General context of the formation of hydrothermal discharge features in Panarea ...................................................................................................... 141 7.2. Evolution of hydrothermal discharge features in Panarea .......................... 142 7.3. Comprehensive summary ........................................................................... 145