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The package PbIso is a free and open R toolbox for commonly used calculations and plots of Pb–Pb isotope data and for generating Pb evolution models. In this paper, we review Pb isotope systematics and the calculations that are commonly used, such as model age, model source μ (238U/204Pb), time-integrated κ (232Th/238U), and initial Pb isotope ratios. These equations are implemented into R functions in the package PbIso. In addition, functions are provided for generating Pb evolution models, paleoisochrons, and isochrons. This allows users to apply calculations to their data in a straightforward way while providing transparency and flexibility of the calculations used. We have implemented some basic features of the PbIso package into an online shiny R application (see https://shereearmistead.github.io/software/pbiso), which makes it easy for users without any R experience to use these calculations with their own data and to generate plots. We have provided a case study from the Superior Province in Canada, showing how different Pb evolution models can be generated in PbIso and compared to Pb isotope data. [ABSTRACT FROM AUTHOR]

• Reappraised sedimentology and stratigraphy of the Palaeoproterozoic Nonacho Basin. • Evidence of marine deposition first recognized in the Nonacho Basin. • Depositional history records basin inception, expansion, and rejuvenation. • Basin related to crustal relaxation and flexure, rather than strike-slip, at ~1.9 Ga. • New testable hypotheses for correlation with nearby basins are proposed. The synoptic analysis of coeval orogens and sedimentary basins is crucial to our understanding of Earth's crustal and surface processes. The Nonacho Group (Northwest Territories, Canada) is a major and yet enigmatic clastic sedimentary unit part of a basin system preserved over >2300 km along its original continental-sloping direction. This basin system records crustal sagging, relaxation, and flexure at ~2.3–1.9 Ga in the Rae Craton, one of the main building blocks of ancestral North America. Correlations between the Nonacho Group and coeval supracrustal assemblages in the Rae Craton has posed challenges. The group has been hitherto related to continental deposition at ~1.9 Ga, in a regime of sinistral strike-slip linked to the collision of the Rae and adjoining Slave cratons. We reappraise the Nonacho Group by means of facies analysis, stratigraphic logging, and palaeocurrent-data collection at key sites. Record of marine deposition is inferred based on the cumulative thickness of shoreface strata, an inference corroborated by sedimentological indicators such as wave- and bimodal-ripple, hummocky-cross, and flaser stratification. The alluvial to marine stratigraphy of the lower and middle parts of the Nonacho Group records basin inception and expansion in a regime of crustal relaxation. Topographic rejuvenation and deposition of younger alluvial to marine strata floored by an unconformity (upper Nonacho Group) followed in a regime of crustal flexure and renewed extension. These stratigraphic trends are tentatively related to broadly contemporaneous tectono-depositional events in the Rae Craton, including crustal thickening and ensuing extensional collapse of the bounding Thelon-Taltson and Snowbird orogens. By these means, we provide new testable hypotheses of a pan-continental tectono-sedimentary system developed during the Palaeoproterozoic amalgamation of the Canadian Shield. [ABSTRACT FROM AUTHOR]