Fast and slow spreading ridges: Structure and hydrothermal activity, ultramafic topographic highs, and CH4 output
作者： Henri Bougault , Jean-Luc Charlou , Yves Fouquet , Hubert D. Needham , Nathalie Vaslet
DOI: 10.1029/93JB00508
关键词:
摘要: Different parts of the world ridge system have quite different morphologies, which reflect constructional processes. It appears that hydrothermal circulation at all spreading centers is an important exchange process between ocean and newly formed oceanic crust. This may vary according to morphology crustal composition also affect The TAG (26°N) Snake Pit (23°N) sites on Mid-Atlantic Ridge (MAR) display Mn/CH4 ratios in overlying seawater similar those nonsedimented East Pacific Rise sites, i.e., about 0.2 mol/L. In contrast, large methane anomalies with very low 0.005 mol/L are associated ultramafic topographic highs near 15°N, close axis walls rift valley. association bodies CH4 indicates active serpentinization produced during Fisher Tropsch reaction (Charlou et al., 1991). Many rock assemblages been sampled MAR away from fracture zones, particular by Deep Sea Drilling Project. Changes mechanical properties density uplifted deep material accreting plate boundary zone caused play role construction slow ridges.
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