Publication: Spatial variations of effective elastic thickness of the lithosphere in Central America and surrounding regions
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Publication Date
2014
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Elsevier Science B.V., Amsterdam
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Abstract
As a proxy for long-term lithospheric strength, the effective elastic thickness (Te) can be used to
understand the relationship between lithospheric rheology and geodynamic evolution of complex tectonic
settings. Here we present, for the first time, high-resolution maps of spatial variations of Te in Central
America and surrounding regions from the analysis of the coherence between topography and Bouguer
gravity anomaly using multitaper and wavelet methods. Regardless of the technical differences between
the two methods, there is a good overall agreement in the spatial variations of re recovered from both
methods. Although absolute re values can vary in both maps, the qualitative re structure and location
of the main re gradients are very similar. The pattern of the re variations in Central America and
surrounding regions agrees well with the tectonic provinces in the region, and it is closely related
to major tectonic boundaries, where the Middle American and Lesser Antilles subduction zones are
characterized by a band of high Te on the downgoing slab seaward of the trenches. These high re values
are related to internal loads (and in the case of the southernmost tip of the Lesser Antilles subduction
zone also associated with a large amount of sediments) and should be interpreted with caution. Finally,
there is a relatively good correlation, despite some uncertainties, between surface heat flow and our
re results for the study area. These results suggest that although this area is geologically complex, the
thermal state of the lithosphere has profound influence on its strength, such that re is strongly governed
by thermal structure.