Neogene Paleostress and Structural Evolution of Trinidad: Rotation, Strain Partitioning, and Strike-slip Reactivation of an Obliquely Colliding Thrust Belt

Jean-Claude Hippolyte (1) , Paul Mann

1 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

Kinematic analysis of faults in Trinidad reveal three main stages of the tectonic evolution of the southeastern Caribbean-South American plate boundary. During Stage 1, folds and thrusts identified on seismic lines and capped by a middle Miocene angular unconformity formed. They have been related by previous workers to the initial, oblique collision of the Great Arc of the Caribbean with the passive margin of South America. We propose that middle Miocene east-northeast-trending compression identified in this study initially had a more northwest-southeast direction and has been rotated in a clockwise direction during this collision. This tectonic stage may have resulted in clockwise rotation of structures along the southeastern Caribbean plate margin within a broad, right-lateral, strike-slip zone. During Stage 2 in the late Miocene and middle Pliocene, south-southeasttrending contraction uplifted the Central Range, formed the prominent south-vergent thrusts, bounded by oblique ramps such as the Los Bajos right-lateral strike-slip fault and formed piggy-back basins. This north-northwest-south-southeast trend of compression is compatible with coeval right-lateral shear on the El Pilar fault zone in Trinidad. We interpret this pattern of thrusts and strike-slip faults as the result of strain partitioning. In Stage 3 during the late Pliocene-Quaternary, east-southeast-trending compression reactivated previous thrusts with strike-slip motion, such as the Central Range fault. It deactivated previous, east-west-trending, strike-slip faults such as the El Pilar extension into Trinidad. The polyphase evolution of Trinidad results from the eastward motion of the Caribbean arc and the propagation of the southern Subduction-Transform Edge Propagator (STEP) fault of the Caribbean subduction.

Mots clés: plate tectonics, carbbean, Trinidad, paleostress, partitioning, fault, Central Range fault, El Pilar fault; plate tectonics, carbbean, Trinidad, paleostress, partitioning, fault, Central Range fault, El Pilar fault

Domaines: Tectonique; Stratigraphie; Géomorphologie

Jean-Claude Hippolyte, Paul Mann. Neogene Paleostress and Structural Evolution of Trinidad: Rotation, Strain Partitioning, and Strike-slip Reactivation of an Obliquely Colliding Thrust Belt. C. Bartolini. AAPG Memoir 123: South America–Caribbean–Central Atlantic plate boundary: Tectonic evolution, basin architecture, and petroleum systems: Tectonic evolution, basin architecture, and petroleum systems, C. Bartolini, ed.,, 123, The American Association of Petroleum Geologists, pp.317 - 346, 2021, AAPG Memoir, ⟨10.1306/13692249m1233851⟩. ⟨hal-03663812⟩