Figure F22. Schematic interpretation of the eruptive setting of the volcaniclastic rocks at Site 1184. These reworked pyroclastic deposits probably formed on top of a large seamount as it grew to within ~200 m of the sea surface. The presence of basalt at depth is conjectural. Letters A through F identify features for which we have evidence in the volcaniclastic rocks. A: The presence of blocky, nonvesicular glass shards suggests fragmentation of rapidly quenched magma in hydromagmatic eruptions under shallow water; abundant tachylite clasts in parts of the succession suggest that this process occurred in an environment that was at times subaerial. B: Accretionary and armored lapilli form in the atmosphere, in steam-rich columns of volcanic ash. C: The absence of blocks, bombs, or lapilli >20 mm suggests that the primary pyroclastic deposits formed several kilometers from the eruption center(s). D: Wood fragments found at the bases of four of the five subunits indicate proximity to land. E: Deposition or redeposition of the volcaniclastic material in a marine setting is indicated by the presence of nannofossils throughout the unit. F: Redeposition by turbidity currents is suggested by the presence of rip-up clasts and broken accretionary lapilli and by the absence of the layering that would be expected from material settling through water.

Figure F22. Schematic interpretation of the eruptive setting of the volcaniclastic rocks at Site 1184. These reworked pyroclastic deposits probably formed on top of a large seamount as it grew to within ~200 m of the sea surface. The presence of basalt at depth is conjectural. Letters A through F identify features for which we have evidence in the volcaniclastic rocks. A: The presence of blocky, nonvesicular glass shards suggests fragmentation of rapidly quenched magma in hydromagmatic eruptions under shallow water; abundant tachylite clasts in parts of the succession suggest that this process occurred in an environment that was at times subaerial. B: Accretionary and armored lapilli form in the atmosphere, in steam-rich columns of volcanic ash. C: The absence of blocks, bombs, or lapilli >20 mm suggests that the primary pyroclastic deposits formed several kilometers from the eruption center(s). D: Wood fragments found at the bases of four of the five subunits indicate proximity to land. E: Deposition or redeposition of the volcaniclastic material in a marine setting is indicated by the presence of nannofossils throughout the unit. F: Redeposition by turbidity currents is suggested by the presence of rip-up clasts and broken accretionary lapilli and by the absence of the layering that would be expected from material settling through water.