Abstract

GIAMPAOLI, Pablo. Caracterización de sistemas de fallas extensionales utilizando perfiles y mapas de desplazamiento: ejemplos del cretácico de la cuenca del golfo San Jorge. Rev. Asoc. Geol. Argent. [online]. 2015, vol.72, n.1, pp.107-119. ISSN 0004-4822.

Displacement profiles and maps were used in the subsurface of the Golfo San Jorge Basin in the Manantiales Behr region to analyze the factors affecting fault growth and propagation, the kinematic evolution of the extensional system and the migration and trapping of hydrocarbons. Two types of faults were recognized: faults that deform the basement and the sedimentary cover, and faults that involve only the sedimentary cover. The vertical growth of the faults within the sedimentary cover was restricted by lithologic variations and the intersection with the free surface. Faults involving the basement are syn-sedimentary and show Dmax/L relationships and aspect ratios that allow the distinction between this type of faults and shallower fault planes. The geometric coherence shown in the aggregated displacement profile and map suggests a synchronous kinematic evolution of the faults in the sedimentary cover. The relationship between the observed fault sizes could be indicative of an early linkage of fault segments and a later increase of throw. Reactivation of the pre-existent basement fabric had little influence on the development of faulting in the sedimentary cover because the Pozo D-129 Formation acted as a structural decoupling level. The low degree of connection between the shallow and deep fault zones disregards the hypothesis of hydrocarbon charge from a local deep ktichen. The mapping of fault segments with higher values of displacement and the recognition of transfer zones may help to locate and delineate hydrocarbon traps in the footwall blocks.

Keywords : Normal faults; Kinematic; Migration; Trapping; Golfo San Jorge Basin.

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