Deep Electrical Resistivity Investigation across the Rennick Graben and Oates Land by Geomagnetic Depth Sounding

E. Armadillo*, E. Bozzo & G. Caneva

Dipartimento per lo Studio del Territorio e delle sue Risorse, Università di Genova, V.le Benedetto XV 5,
16132 Genova – Italy

Received 25 March 2003; accepted in revised form 19 September 2003
 

Abstract - A geomagnetic depth sounding investigation in the period range 20 - 250 s has been carried out along the Oates Coast and across the Rennick Graben (RG) to get geophysical independent constraints on the deep structure of the Oates Land. Along the former profile the coast effect hinders structural interpretation; on the contrary, the latter profile across the RG shows a well characterized regional bidimensional pattern with induction arrows trend perpendicular to the graben and the main structural lineaments. Interpretations by induction arrows analysis and 2D inversion suggest a clear differentiation of the investigated area in three crustal blocks separated by the Daniels Range and the Bowers Mts., in close relation with main known structural lineaments. The thickening of the shallow resistivity layer from the East to the West of the RG could indicate a thickening of the resistive upper crust which usually overlays the enhanced conductive layer in the lower continental crust. At depth over 15 km, two electrical conductivity anomalies are located at both the sides of the RG which on the contrary is not affected by electrical conductivity enhancement, suggesting a recent reactivation of the shoulders rather than of the graben itself.  A shallow conductivity anomaly below

 
*Corresponding author (egidio@dipteris.unige.it)