ICE 2022


The Boomerang Hills is an important prospective area located in front of the Bolivian Andes, close to the Bolivian Orocline. This region has been explored for more than fifty years what have resulted on the acquisition of multiple 2D and 3D seismic surveys, as well as the drilling of hundreds of wells. With the aid of 2 2D and 2 3D seismic surveys and 31 wells we were able to create cross sections, maps, a 3D geological model, a velocity model and decompaction curves. Two different structural and stratigraphic regions may be separated within the area: the southern Boomerang Hills representing the buried frontal part of the Andes and the northern Boomerang Hills that correspond to the Beni-Chaco Plain. The main features of the southern unit are: dominant thin-skinned contractional structures of Late Cenozoic age, with N-directed thrust emanating from a basal detachment level situated close to the Silurian base; and an angular unconformity at the base of the Mesozoic that erodes Silurian to Carboniferous rocks, progressively younger towards the S-SW. The northern domain key characteristics are: frequent thick-skinned extensional faults of pre-Andean age (Paleozoic, Mesozoic and Early Cenozoic); and a Mesozoic sequence lying mostly directly on top of the pre-Silurian basement. The boundary between these two zones is approximately defined by the tipline of the basal detachment level. One remarkable structural feature of the Boomerang Hills is that its structures tend to show E-W strikes, in contrast with the general orientation of the Andean Cordillera, mostly NW-SE to WNW-ESE. The two main reasons for that would be: the pre-Silurian inherited basement configuration and the distribution of the cover rocks (Silurian to Cenozoic). The sequential restoration of a cross section and the 3D backstripping of the geological model should help to decipher the evolution of the area since Paleozoic times.