Understanding Earth surface responses in terms of sediment dynamics to climatic variability and tectonics forcing is hindered by limited ability of current models to simulate long-term evolution of sediment transfer and associated morphological changes. This paper presents pyBadlands, an open-source python-based framework which computes over geological time (1) sediment transport from landmasses to coasts, (2) reworking of marine sediments by longshore currents and (3) development of coral reef systems. pyBadlands is cross-platform, distributed under the GPLv3 license and available on GitHub (http://github.com/badlands-model). Here, we describe the underlying physical assumptions behind the simulated processes and the main options already available in the numerical framework. Along with the source code, a list of hands-on examples is provided that illustrates the model capabilities. In addition, pre and post-processing classes have been built and are accessible as a companion toolbox which comprises a series of workflows to efficiently build, quantify and explore simulation input and output files. While the framework has been primarily designed for research, its simplicity of use and portability makes it a great tool for teaching purposes.

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Recent studies of the past eastern Australian landscape from present-day longitudinal river profiles and from mantle flow models suggest that the interaction of plate motion with mantle convection accounts for the two phases of large-scale uplift of the region since 120 Ma. We coupled the dynamic topography predicted from one of these mantle flow models to a surface process model to study the evolution of the eastern Australian landscape since the Jurassic Period. We varied the rainfall regime, erodibility, sea level variations, dynamic topography magnitude, and elastic thickness across a series of experiments. The approach accounts for erosion and sedimentation and simulates catchment dynamics. Despite the relative simplicity of our model, the results provide insights on the fundamental links between dynamic topography and continental-scale drainage evolution. Based on temporal and spatial changes in longitudinal river profiles as well as erosion and deposition maps, we show that the motion of the Australian plate over the convecting mantle has resulted in significant reorganization of the eastern Australian drainage. The model predicts that the Murray river drained eastward between 150 and $120 Ma, and switched to westward draining due to the tilting of the Australian plate from $120 Ma. First order comparisons of eight modeled river profiles and of the catchment shape of modeled Murray-Darling Basin are in agreement with presentday observations. The predicted denudation of the eastern highlands is compatible with thermochronology data and sedimentation rates along the southern Australian margin are consistent with cumulative sediment thickness.Continental-scale landscape dynamics, sediment erosion, and transport in response to long-wavelength dynamic topography occurring over hundreds to thousands of kilometers and tens of million years (i.e., Key Points: We simulate the role of mantle flow on eastern Australia drainage evolution over the last 150 Ma Distinct features of present-day landscape (river longitudinal profiles, Murray-Darling basin shape) are reproduced by the model The model predicts the drainage reversal of proto-Murray river driven by the Cretaceous phase of eastern Highland uplift Correspondence to: T. Salles, We reconstruct past mantle flow by driving CitcomS [Zhong et al., 2008] incompressible convection models with plate velocities as time-dependent boundary conditions and progressively assimilating the thermal structure of the lithosphere and of shallow slabs [Bower et al., 2015] derived in 1 million year intervals from a plate reconstruction. This semiempirical modeling is guided by the current intractability of computing timedependent models of the plate-mantle system with a resolution sufficient to dynamically obtain tectonic-like features, including one-sided subduction [Stadler et al., 2010]. The approach allows us to reconstruct past mantle flow for times before 100 Ma, and it ensures the computations follow Earth's imposed tectonic history.The model consists of 1283128364312 % 12:6310...

Landscapes in actively developing rifts respond to tectonic forcing over a similar time scale to that of fault array evolution (i.e., 10 5 -10 6 yr). Consequently transient landscapes (i.e., not in topographic steady state) predominate, characterized by focused incision along extensional fault scarps and regional tectonic tilting of surface slopes across strike. Using a field-calibrated numerical model to explore the controls on landscape evolution across the Corinth rift, central Greece, we demonstrate that this tilting, although subtle, leads to a shift in dominant source area as well as a shift toward sediment-starved conditions within the basin. We show, by comparing model runs with and without imposing tectonic forcing, that the impact of active faulting on relief development along the most active Corinth rift margin locally increases erosion rates and footwall incision. However, the overall sediment flux from this margin is reduced because back-tilting lowers erosion rates in catchment headwaters. Conversely, the hanging-wall side of the rift, as it is downwarped, supplies relatively more sediment as rift-directed channel slopes increase even though the relief is decreasing. In summary, we show that tilting plays a key role in controlling the syn-rift sediment flux and, in a counterintuitive way, modifies the relationship between topographic relief and catchmentaveraged erosion rates. Our results provide a new perspective on the origin and timing of sediment starvation relative to structural development in rifts. 1GSA Data Repository item 2019094, Table DR1 (model input), Table DR2 (uplift/subsidence rates), Table DR3 (model calibration and sensitivity tests), Table DR4 (erosion rate data), Figure DR1 (displacement map), Figure DR2 (bedrock erodibility), and Figure DR3 (erosion rate analysis),

The Bayesian paradigm is becoming an increasingly popular framework for estimation and uncertainty quantification of unknown parameters in geophysical inversion problems. Badlands is a landscape evolution model for simulating topography evolution at a broad range of spatial and temporal scales. Our previous work presented Bayeslands that used the Bayesian inference for estimating unknown parameters in the Badlands model using Markov chain Monte Carlo sampling. Bayeslands faced challenges in terms of computational issues and convergence due to multimodal posterior distributions. Parallel tempering is an advanced Markov chain Monte Carlo method suited for irregular and multimodal posterior distributions. In this paper, we extend Bayeslands using parallel tempering with high‐performance computing to address previous limitations in Bayeslands. Our results show that parallel tempering Bayeslands not only reduces the computation time‚ but also provides an improvement in sampling multimodal posterior distributions, which motivates future application to continental scale landscape evolution models.

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Bayesian inference provides a principled approach towards uncertainty quantification of free parameters in geophysical forward models. This provides advantages over optimization methods that provide single point estimates as solutions, which lack uncertainty quantification. Badlands (basin and landscape dynamics model) is geophysical forward model that simulates topography development at various space and time scales. Badlands consists of a number of geophysical parameters that need to be estimated with appropriate uncertainty quantification, given the observed ground truth such as surface topography, sediment thickness and stratigraphy through time. This is challenging due to the scarcity of data, sensitivity of the parameters and complexity of the Badlands model. In this paper, we take a Bayesian approach to provide inference using Markov chain Monte Carlo sampling (MCMC). Hence, we present BayesLands, a Bayesian framework for Badlands that fuses information obtained from complex forward models with observational data and prior knowledge. As a proof-of-concept, we consider a synthetic and real-world topography with two free parameters, namely precipitation and erodibility, that we need to estimate through BayesLands. The results of the experiments shows that BayesLands yields a promising distribution of the parameters. Moreover, the challenge in sampling due to multi-modality is presented through visualizing a likelihood surface that has a range of suboptimal modes.

Understanding the effects of climatic variability on sediment dynamics is hindered by limited ability of current models to simulate long-term evolution of sediment transfer from source to sink and associated morphological changes. We present a new approach based on a reduced-complexity model which computes over geological time: sediment transport from landmasses to coasts, reworking of marine sediments by longshore currents, and development of coral reef systems. Our framework links together the main sedimentary processes driving mixed siliciclastic-carbonate system dynamics. It offers a methodology for objective and quantitative sediment fate estimations over regional and millennial time-scales. A simulation of the Holocene evolution of the Great Barrier Reef shows: (1) how high sediment loads from catchments erosion prevented coral growth during the early transgression phase and favoured sediment gravity-flows in the deepest parts of the northern region basin floor (prior to 8 ka before present (BP)); (2) how the fine balance between climate, sea-level, and margin physiography enabled coral reefs to thrive under limited shelf sedimentation rates after ~6 ka BP; and, (3) how since 3 ka BP, with the decrease of accommodation space, reduced of vertical growth led to the lateral extension of reefs consistent with available observational data.