Viscosity of the atlantic ocean bottom

Area of Science:

• Geophysics
• Oceanography
• Solid Earth Science

Background:

• Understanding the viscosity of the Earth's mantle is crucial for comprehending tectonic plate movement and geological processes.
• Previous viscosity measurements have been conducted on continental regions, such as the Fennoscandian Uplift.
• The Mid-Atlantic Ridge provides a unique oceanic setting to investigate mantle viscosity due to active seafloor spreading.

Purpose of the Study:

• To determine the viscosity of the oceanic lithosphere and upper mantle beneath the Mid-Atlantic Ridge.
• To compare viscosity values obtained from an oceanic spreading center with those from a continental uplift region.
• To assess the influence of horizontal scale on viscosity measurements.

Main Methods:

• Analysis of two bathymetric profiles across the Mid-Atlantic Ridge.
• Modeling of viscous creeping of seafloor features under gravitational stress.
• Assumption of a constant sea floor spreading rate of 2 cm/year.

Main Results:

• Viscosity values were successfully determined for the analyzed profiles.
• The obtained viscosity values showed good agreement with previously published results from the Fennoscandian Uplift.
• This agreement was observed despite significant differences in the horizontal dimensions of the geological features between the two regions.

Conclusions:

• Mantle viscosity beneath the Mid-Atlantic Ridge is comparable to that of the Fennoscandian Uplift.
• The horizontal scale of geological relief does not appear to significantly affect the determined viscosity values in these contrasting settings.
• These findings contribute to a more unified understanding of mantle rheology across different tectonic environments.