Regional Variations in the Spreading‐Rate Dependence of Abyssal Hill Roughness as Indicators of Mantle Heterogeneity

Abstract

Abstract Abyssal hills are potential proxy records of mid‐ocean ridge faulting and volcanism, as well as the spreading rates and mantle properties that influence these processes. Satellite gravity‐based global prediction of abyssal hill root‐mean‐square (RMS) heights could provide such a proxy, but are broadly influenced off‐axis by pelagic sediment cover, which can lower their values by preferentially filling lows. Here I formulate a sediment‐corrected RMS height prediction by estimating an empirical relationship between mean RMS and sediment thickness as a function of spreading rate. I utilize these values to investigate regional variations in the spreading‐rate dependence of mean RMS across eight regions world‐wide, focusing on half spreading rates <40 mm/yr where spreading rate dependence is strongest. I find that regional variations in this relationship are significant, likely indicating heterogeneity in mantle properties between the different regions.

Keywords

• seafloor roughness
• mid‐ocean ridge
• seafloor spreading
• satellite gravity