Mesozoic fault systems, deformation and fault block rotation in the Andean forearc: a crustal scale strike-slip duplex in the Coastal Cordillera of northern Chile

摘要: Abstract In this paper we discuss the evolution and tectonic significance of Mesozoic trench-parallel fault systems which affected Coastal Cordillera their relation to magmatism crustal rotation. The oldest, extensional, system separates basement from rift-related Late Triassic younger sedimentary units. This [I] subsequently developed into a wider extensional acted as locus magma ascent emplacement Batholith during much Jurassic earliest Cretaceous period. defined forearc sliver period was consequence retreating subduction boundary. During Early (c. 132–125 Ma) kinematics changed transtension [II] accommodated major component left-lateral strike-slip motion, principal being Atacama Fault Zone along plutons continued be emplaced. final phase pluton within appears c. 106 Ma, after magmatic arc abandoned. An [III] some 20 Ma later located 50 km east in what is now Central Valley northern Chile. seeks show that deformed whole by formed crustal-scale transpressional duplex. deformation thermally weakened crust dissected series large-scale blocks bounded NW-trending faults merge NNE–SSW zone forms eastern boundary We term (CVFZ) together with defines duplex refer System (CCFS) [III]. have traced CCFS between 25°S 29°S suspect it continues northward. timing constrained post age abandonment, pre-Tertiary based on Zone. Palaeomagnetic data bound indicate 35°–45° post-Early clockwise rotation no substantial latitudinal motion. suggest observed are consistent model where rotations would occurred response transpression.