Crustal structure of the eastern part of the Maya Terrane from magnetic anomalies and magnetic power spectrum inversion

Abstract

We interpret a new compilation of total-field magnetic anomaly data from the eastern part of the Maya Terrane, comprising aeromagnetic data for the Yucatan Peninsula and marine magnetic data for its northern and eastern continental margins. Qualitatively, on the basis of amplitude, shape; and horizontal extent of the magnetic anomalies and their correlation with available geologic and geophysical information we infer that the eastern part of the Maya Terrane can be divided at least in four tectonic blocks. We model the radially-averaged power-density spectrum of the magnetic anomalies from the northern continental margin of the Yucatan peninsula by the superposition of functions that statistically describe the depth to the top and the thickness and horizontal dimensions of an ensemble of uniformly magnetized prisms. The results are portrayed as contour maps which show depth to basement and thickness of the crustal magnetic layer. The magnetic basement is found at an average depth of 1.8 km below sea level and shows some agreement with the character of magnetic and gravity anomalies, as well as seismic and drillhole data. The basal depth of the crustal magnetic layer varies from 15 to 35 km below sea level, in agreement with the presence or absence of long-wavelength magnetic and gravity anomalies. This interpretation suggests that locally the Moho is the magnetic boundary.