Unraveling subsidence and heat flow in poly-phase tectonic basins

North Carolina State University, Raleigh NC

Investigators

Abstract

Poly-phase sedimentary basins are those that have undergone multiple phases of deformation and subsidence. Such basins are ubiquitous and increasingly important for hydrocarbon and geothermal resource development. However, traditional modeling methods often fall short in classifying the drivers of subsidence, thermal evolution, resource prospectivity and maturity, and general geometry of poly-phase basins. This research focuses on developing novel modeling methods for unraveling subsidence in poly-phase sedimentary basins, with a focus on the Arctic Alaska basin. This research will develop a numerical modeling code in Matlab that incorporates backstripping, flexural isostasy, and depth-dependent extension in three-dimensions to investigate and segregate multiple subsidence events in the Arctic Alaska basin. Research goals will be accomplished by leveraging an exceptional dataset including seismic data, wells, thermochronology data, and thermal maturity indicators. The model will ultimately be disseminated to the public in a user-friendly package that can be applied to sedimentary basins globally. This research will foster new collaborations between the PI who is an early career female, the USGS, and the data science academy at NCSU. As part of this work the team will develop a short course intended for undergraduate to post-graduate attendees to be run at national conferences free of charge. Traditional subsidence analyses (flexural backstripping, McKenzie stretching) are prolific in basin research, but when used independently these techniques can be insufficient and misleading in poly-phase basins, where overlapping subsidence events convolute the subsidence signal. A growing set of observations in basins worldwide indicate multi-phase, poly-phase, or hybrid basins are commonly mischaracterized. The Brooks Range and Arctic Alaska basin collectively form an ideal location for investigating poly-phase sedimentary basins due to nearly overlapping extensional and convergent tectonism. Despite huge efforts by the USGS to collect data on the Arctic Alaska basin, the relationship between extension and convergence with respect to basin subsidence and heat flow is not clear, and has major implications for thermal evolution, hydrocarbon maturity, geothermal energy prospectivity, source-to-sink dynamics, and interpretations of lithospheric structure. The primary goal of this proposal is to quantify and characterize the spatio-temporal evolution of subsidence and heat flow in the Arctic Alaska basin from the Jurassic to the present. The research will utilize publicly available subsurface and thermal data to constrain a new exportable numerical modeling workflow for investigating poly-phase sedimentary basins that incorporates flexural loading, depth-dependent thermal subsidence, and backstripping. This project will deliver 1) a comprehensive study of subsidence drivers in the resource-rich Arctic Alaska basin and 2) an exportable and user-friendly numerical modeling workflow for poly-phase basins that will facilitate comprehensive subsidence analyses of basins worldwide. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.