--> --> Apatite Fission Track Thermochronology in 2-D Basin Modeling - A Case Study of a Frontier Basin in a Fold and Thrust Belt

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Apatite Fission Track Thermochronology in 2-D Basin Modeling - A Case Study of a Frontier Basin in a Fold and Thrust Belt

Abstract

A clear understanding of the structural and sedimentary evolution of a petroleum basin is fundamental in calibrating 2D models of porosity, pressure, temperature, and thermal maturity in frontier petroleum plays. Modeling petroleum plays hosted in fold and thrust belts is particularly challenging due to composite in-sequence and out-of-sequence thrusting events, interconnected with a complex burial history. This study presents a 2D- basin model approach that uses apatite fission track analysis to constrain uplift, erosion, and temperature history of a frontier onshore petroleum system in western Newfoundland. The basin is situated at the structural front of the Canadian Appalachian and represents an ideal place to study a petroleum system hosted in a fold and thrust belt. The complex geologic history of western Newfoundland has significant implications for the petroleum system. In order to model its evolution, we collected siliciclastic and crystalline rocks at 11 locations along the hanging and footwalls of the deformational front for apatite fission track analysis. Apatite fission track thermochronology relies on ionization damage in the crystal lattice, which is generated by the flight paths of 238U fission fragments. Subsequent annealing of the damage tracks is temperature-dependent and reveals the thermal history of a mineral. The annealing temperature depends on the chlorine content in the apatite mineral, which is accounted for in the time-temperature solutions of the annealing modeling. Calibrating the uplift and erosion history of the basin to the annealing model enables the basin-model to predict the minimum amount of deposition and denudation of sediments. Apatite annealing models identify three distinct cooling events in the Carboniferous, Jurassic, and Cenozoic. The associated minimum amount of erosion for these events is modeled to be 1.6 miles (2.5 km) in the Carboniferous, and 0.6 miles (1 km) each in the Jurassic and Cenozoic. For this petroleum system model the apatite fission track thermochronology offers essential calibration parameters for the thermal and sedimentary evolution of the basin where a lack of rock record prohibited this in previous studies. The AFTA data provides, in conjunction with basin modeling, additional insight into the maturity development of the hanging and footwalls during the Carboniferous and sheds light on the possible reactivation of migration pathways during Jurassic and Cenozoic cooling events.