Study of elastic thickness from seamount loading of old oceanic lithosphere: implications for lithosphere stability

The PLATE (Pacific Lithosphere Anisotropy and Thickness Experiment) study will employ several marine geophysical methods to investigate the natural and undisturbed growth of the lithosphere. The field area was chosen in order to obtain an ideal location where minimal volcanic and tectonic activity had occurred. However, during the field work for the project, several seamounts were found within the area using high resolution shiptrack bathymetry, suggesting volcanic activity. Determining the timing of these volcanic events is crucial to understand the stability over time of the lithosphere. Calculations from twelve seamounts in the area yielded elastic thicknesses that range from 1.5 to 3.5 km. These elastic thicknesses (Te) were used to estimate the age of the seafloor at the time in which the seamounts formed. I obtained a lithosphere age of less than10 m.y. at time of seamount loading. The abyssal hill geomorphology and magnetic lineations provide further support for these results and suggest no major tectonic event. The early loading of the seamounts supports the idea that the lithosphere has grown in a normal undisturbed fashion consistent with conductive cooling for the past 140 Ma, making it an ideal location to study lithospheric growth and test the conductive cooling model in old seafloor. This study provides support for the field area’s integrity.