Multi-scale magnetic mapping of serpentinite carbonation

Area of Science:

• Geochemistry
• Geophysics
• Mineralogy

Background:

• Peridotite carbonation is key to the Earth's carbon cycle, sequestering atmospheric CO2.
• Understanding carbonation mechanisms is vital for climate change mitigation strategies.
• Bridging lab-scale findings to field-scale processes in ultramafic rocks is challenging.

Purpose of the Study:

• To conduct the first geophysical characterization of serpentinite carbonation.
• To investigate carbonation across multiple scales, from kilometers to sub-millimeters.
• To establish a correlation between magnetic mineralogy and carbonation extent.

Main Methods:

• Aeromagnetic surveys were employed for large-scale magnetic anomaly detection.
• Outcrop and thin-section magnetic mapping provided detailed, smaller-scale data.
• Analysis focused on magnetic anomalies at reaction fronts.

Main Results:

• Consistent changes in magnetic anomalies were observed at reaction fronts across all scales.
• Magnetic mineral abundance directly correlates with the progress of serpentinite carbonation.
• Variations in anomaly amplitude and wavelength reflect the degree of rock alteration.

Conclusions:

• Geophysical methods, particularly magnetic mapping, can effectively characterize ultramafic rock carbonation.
• The established correlation provides a foundation for assessing in situ carbonation extent and progress.
• This approach offers a novel way to monitor and understand geological carbon sequestration processes.