Depth to sources and Bouguer density determination of the Merida Andes, Venezuela, by means of a fractal analysis of gravity data

Abstract:

The objective of this research, done in the scope of the GIAME (Integrated Geosciences of the Merida Andes) project, was to contribute to the determination of the crustal structure of the mountain chain, and its relation to the development of the adjacent sedimentary basins by means of fractal analysis of gravity data. In order to determine the Bouguer density and the depth of the bodies responsible for the observed anomalies, an improved method of spectral analysis was applied to study the self-affinity of the data. Since the conception of self-similar forms with fractional dimension, significant improvements in the analysis of gravimetric data using fractal geometry have been reported. Such method has not been applied before in Venezuela for this kind of problems. The most striking result was the depth values obtained which differ significantly from earlier interpretations. In general, the Bouguer density obtained with this method for the entire study area was 2.5 g/cm³, whereas for one local scale study, that covers the Merida Andes, the density was 2.9 g/cm³. Both values are substantially different from the value of the average cortical density of 2.67 g/cm³ considered by several authors in previous studies. The depths obtained for the anomalies of different structures in the whole area were less than 5-km, so much smaller than those founded through traditional spectral analysis. This suggests that the depths could be overestimated in those models where the degree of correlation (scaling factor) is not considered.

Año de publicación:

2017

Keywords:

Fuente:

scopus