Publication Date:
2022-05-26
Description:
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Marine Geology 355 (2014): 98-114, doi:10.1016/j.margeo.2014.05.011.
Description:
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 temperature measurements 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, tectonism and hydrothermal activity. PACManus is a submarine felsic vocanically-hosted hydrothermal area that hosts multiple vent fields located within several hundred meters of one another but with different fluid chemistries, vent temperatures and morphologies. The total area of hydrothermal activity is estimated to be 20,279 m2. The microbathymetry maps combined with 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 and massive 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 lavas with 69 to 72.5 wt. % SiO2 were erupted through multiple 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.
Description:
The RV Melville work was funded by a combination of the US National Science Foundation grant OCE-0327448 and a collaborative research funding grant from Nautilus Minerals for the ABE surveys. The RV Sonne research cruise was funded through the BMBF (Grant G03216a). Additional funding, including salary support for JT, was provided by the German DFG Research Centre/Excellence Cluster “The Ocean in the Earth System”. WB acknowledges support from DFG research grant BA1605/4-1.
Keywords:
PACManus
;
Submarine volcanism
;
Manus Basin
;
Hydrothermal vent
;
ROV
;
Black smoker
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
Format:
video/mp4
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