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Abstract: Peruvian Foothills, A Key for Future Exploration in a Frontier Area

Alain Villien, Armando Telles Jr.

Within the 1700 km Peruvian foothills, several units can be identified with different types of thrust belt geometry reflecting pre-Andean sedimentary history and structural framework.

In the northern part, the Santiago area shows several "en echelon" fault bounded folds separated from the main sub-Andean Maranon basin by an elongated thrusted arch. Locally, limited Late Tertiary inversion has preserved halokinetic structures initiated from Late Mesozoic to Early Tertiary.

In the central part, the Huallaga area appears controlled by an inherited framework including NW-SE and ENE-WSW paleozoic trends. Furthermore Lower Mesozoic evaporites and associated deposits have acted as preferential decollement levels giving large hanging wall anticlines and several thrust slices at the leading edge.

In the southern part, the Ene-Camisea-Madre de Dios area shows a major WNW-ESE trend intersected by NE-SW paleozoic arches present in the Ucayali and Madre de Dios basins. Thrust belt geometry differs from basement involved structures to typical ramp-flat geometry with transverse features acting as transfer zones.

Structural analysis reveals piggy-back and overstep sequences of thrusting, and besides the classical late Miocene phase, a Plio-Pleistocene neotectonic event caused major uplift in the southern Peruvian foothills.

Petroleum systems include several source rocks and reservoirs nevertheless, parameters such as recent structural inversion may affect reservoir quality in the North.

To the South, with Devonian, Carboniferous and Permian source rocks, some of them showing adequate maturity level for oil generation, precise knowledge of migration events and influence of recent uplift on frozen kitchens are key factors for exploration.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France