scholarly journals Geodynamic diagnostics, scientific visualisation and StagLab 3.0

Author(s):  
Fabio Crameri

Abstract. Today's Geodynamic models can, often do, and sometimes have to become very complex. Their underlying, increasingly elaborate numerical codes produce a growing amount of raw data. Post-processing such data becomes therefore more and more challenging and time consuming. In addition, visualising processed data and results has, in times of coloured figures and a wealth of half-scientific software, become one of the weakest pillars of science, widely mistreated and ignored. Efficient and automated Geodynamic diagnostics and sensible, scientific visualisation, preventing common pitfalls, is thus more important than ever. Here, a collection of numerous diagnostics for plate tectonics and mantle dynamics is provided and a case for truly scientific visualisation is made. Amongst other diagnostics are a most accurate and robust plate-boundary identification, slab-polarity recognition, plate-bending derivation, surface-topography component splitting and mantle-plume detection. Thanks to powerful image processing tools and other elaborate algorithms, these and many other insightful diagnostics are conveniently derived from only a subset of the most basic parameter fields. A brand-new set of scientifically proof, perceptually uniform colour maps including "devon", "davos", "oslo" and "broc" is introduced and made freely available. These novel colour maps bring a significant advantage over misleading, non-scientific colour maps like "rainbow"', which is shown to introduce a visual error to the underlying data of up to 7.5 %. Finally, StagLab (http://www.fabiocrameri.ch/software) is introduced, a software package that incorporates the whole suite of automated Geodynamic diagnostics and, on top of that, applies state-of-the-art, scientific visualisation to produce publication-ready figures and movies, all in a blink of an eye, all fully reproducible. StagLab, a simple, flexible, efficient and reliable tool, made freely available to everyone, is written in MatLab and adjustable for use with Geodynamic mantle-convection codes.

2018 ◽  
Vol 11 (6) ◽  
pp. 2541-2562 ◽  
Author(s):  
Fabio Crameri

Abstract. Today's geodynamic models can, often do and sometimes have to become very complex. Their underlying, increasingly elaborate numerical codes produce a growing amount of raw data. Post-processing such data is therefore becoming more and more important, but also more challenging and time-consuming. In addition, visualising processed data and results has, in times of coloured figures and a wealth of half-scientific software, become one of the weakest pillars of science, widely mistreated and ignored. Efficient and automated geodynamic diagnostics and sensible scientific visualisation preventing common pitfalls is thus more important than ever. Here, a collection of numerous diagnostics for plate tectonics and mantle dynamics is provided and a case for truly scientific visualisation is made. Amongst other diagnostics are a most accurate and robust plate-boundary identification, slab-polarity recognition, plate-bending derivation, surface-topography component splitting and mantle-plume detection. Thanks to powerful image processing tools and other elaborate algorithms, these and many other insightful diagnostics are conveniently derived from only a subset of the most basic parameter fields. A brand new set of scientific quality, perceptually uniform colour maps including devon, davos, oslo and broc is introduced and made freely available (http://www.fabiocrameri.ch/colourmaps, last access: 25 June 2018). These novel colour maps bring a significant advantage over misleading, non-scientific colour maps like rainbow, which is shown to introduce a visual error to the underlying data of up to 7.5 %. Finally, StagLab (http://www.fabiocrameri.ch/StagLab, last access: 25 June 2018) is introduced, a software package that incorporates the whole suite of automated geodynamic diagnostics and, on top of that, applies state-of-the-art scientific visualisation to produce publication-ready figures and movies, all in the blink of an eye and all fully reproducible. StagLab, a simple, flexible, efficient and reliable tool made freely available to everyone, is written in MATLAB and adjustable for use with geodynamic mantle convection codes.


2020 ◽  
Author(s):  
Fabio Crameri

<p>Advances in numerical modelling of geological processes are based upon, and driven by, diagnosing models. Such model diagnostics are often performed by hand, by eye, or else, by individually written routines that are neither tested or testable, nor reproducible.</p><p>Collecting geodynamic diagnostics, automating them in a robust manner to be applied to the multitude of different geodynamic models and codes, and providing them back to the community can foster additional progress within the modelling community.</p><p>In this presentation, I introduce the latest version of StagLab (Crameri 2018; <strong>www.fabiocrameri.ch/StagLab</strong>; currently version 5.0), which is a growing resource of geodynamic diagnostics, openly available, and easy to use. StagLab works seamlessly with StagYY (Tackley 2008) and can be made compatible with any other mantle convection code, if the respective developers start to provide machine-readable and documented output. Moreover, StagLab represents model data fairly to its users and to the readers of their papers. StagLab allows its users, whether professional or beginner, to produce state-of-the-art post-processing of geodynamic models, and publication-ready figures and movies, in a blink of an eye; all fully tested, testable and reproducible.</p><p> </p><p><em>Crameri (2018), Geodynamic diagnostics, scientific visualisation and StagLab 3.0, Geosci. Model Dev., http://dx.doi.org/10.5194/gmd-11-2541-2018</em></p><p><em>Tackley (2008), Modelling compressible mantle convection with large viscosity contrasts in a three-dimensional spherical shell using the Yin-Yang grid, PEPI, http://dx.doi.org/10.1016/j.pepi.2008.08.005.</em></p>


10.1144/sp470 ◽  
2019 ◽  
Vol 470 (1) ◽  
pp. NP-NP

Fifty years ago, Tuzo Wilson published his paper asking ‘Did the Atlantic close and then re-open?’. This led to the ‘Wilson Cycle’ concept in which the repeated opening and closing of ocean basins along old orogenic belts is a key process in the assembly and breakup of supercontinents. The Wilson Cycle underlies much of what we know about the geological evolution of the Earth and its lithosphere, and will no doubt continue to be developed as we gain more understanding of the physical processes that control mantle convection, plate tectonics, and as more data become available from currently less accessible regions.This volume includes both thematic and review papers covering various aspects of the Wilson Cycle concept. Thematic sections include: (1) the Classic Wilson v. Supercontinent Cycles, (2) Mantle Dynamics in the Wilson Cycle, (3) Tectonic Inheritance in the Lithosphere, (4) Revisiting Tuzo's question on the Atlantic, (5) Opening and Closing of Oceans, and (6) Cratonic Basins and their place in the Wilson Cycle.


Author(s):  
Bradford J. Foley

For plate tectonics to operate on a planet, mantle convective forces must be capable of forming weak, localized shear zones in the lithosphere that act as plate boundaries. Otherwise, a planet's mantle will convect in a stagnant lid regime, where subduction and plate motions are absent. Thus, when and how plate tectonics initiated on the Earth is intrinsically tied to the ability of mantle convection to form plate boundaries; however, the physics behind this process are still uncertain. Most mantle convection models have employed a simple pseudoplastic model of the lithosphere, where the lithosphere ‘fails’ and develops a mobile lid when stresses in the lithosphere reach the prescribed yield stress. With pseudoplasticity high mantle temperatures and high rates of internal heating, conditions relevant for the early Earth, impede plate boundary formation by decreasing lithospheric stresses, and hence favour a stagnant lid for the early Earth. However, when a model for shear zone formation based on grain size reduction is used, early Earth thermal conditions do not favour a stagnant lid. While lithosphere stress drops with increasing mantle temperature or heat production rate, the deformational work, which drives grain size reduction, increases. Thus, the ability of convection to form weak plate boundaries is not impeded by early Earth thermal conditions. However, mantle thermal state does change the style of subduction and lithosphere mobility; high mantle temperatures lead to a more sluggish, drip-like style of subduction. This ‘sluggish lid’ convection may be able to explain many of the key observations of early Earth crust formation processes preserved in the geologic record. Moreover, this work highlights the importance of understanding the microphysics of plate boundary formation for assessing early Earth tectonics, as different plate boundary formation mechanisms are influenced by mantle thermal state in fundamentally different ways.This article is part of a discussion meeting issue ‘Earth dynamics and the development of plate tectonics’.


Author(s):  
Jun Korenaga

Resolving the modes of mantle convection through Earth history, i.e. when plate tectonics started and what kind of mantle dynamics reigned before, is essential to the understanding of the evolution of the whole Earth system, because plate tectonics influences almost all aspects of modern geological processes. This is a challenging problem because plate tectonics continuously rejuvenates Earth's surface on a time scale of about 100 Myr, destroying evidence for its past operation. It thus becomes essential to exploit indirect evidence preserved in the buoyant continental crust, part of which has survived over billions of years. This contribution starts with an in-depth review of existing models for continental growth. Growth models proposed so far can be categorized into three types: crust-based, mantle-based and other less direct inferences, and the first two types are particularly important as their difference reflects the extent of crustal recycling, which can be related to subduction. Then, a theoretical basis for a change in the mode of mantle convection in the Precambrian is reviewed, along with a critical appraisal of some popular notions for early Earth dynamics. By combining available geological and geochemical observations with geodynamical considerations, a tentative hypothesis is presented for the evolution of mantle dynamics and its relation to surface environment; the early onset of plate tectonics and gradual mantle hydration are responsible not only for the formation of continental crust but also for its preservation as well as its emergence above sea level. Our current understanding of various material properties and elementary processes is still too premature to build a testable, quantitative model for this hypothesis, but such modelling efforts could potentially transform the nature of the data-starved early Earth research by quantifying the extent of preservation bias.This article is part of a discussion meeting issue ‘Earth dynamics and the development of plate tectonics’.


2020 ◽  
Vol 42 (3) ◽  
pp. 271-282
Author(s):  
OLEG IVANOV

The general characteristics of planetary systems are described. Well-known heat sources of evolution are considered. A new type of heat source, variations of kinematic parameters in a dynamical system, is proposed. The inconsistency of the perovskite-post-perovskite heat model is proved. Calculations of inertia moments relative to the D boundary on the Earth are given. The 9 times difference allows us to claim that the sliding of the upper layers at the Earth's rotation speed variations emit heat by viscous friction.This heat is the basis of mantle convection and lithospheric plate tectonics.


2020 ◽  
Vol 224 (2) ◽  
pp. 961-972
Author(s):  
A G Semple ◽  
A Lenardic

SUMMARY Previous studies have shown that a low viscosity upper mantle can impact the wavelength of mantle flow and the balance of plate driving to resisting forces. Those studies assumed that mantle viscosity is independent of mantle flow. We explore the potential that mantle flow is not only influenced by viscosity but can also feedback and alter mantle viscosity structure owing to a non-Newtonian upper-mantle rheology. Our results indicate that the average viscosity of the upper mantle, and viscosity variations within it, are affected by the depth to which a non-Newtonian rheology holds. Changes in the wavelength of mantle flow, that occur when upper-mantle viscosity drops below a critical value, alter flow velocities which, in turn, alter mantle viscosity. Those changes also affect flow profiles in the mantle and the degree to which mantle flow drives the motion of a plate analogue above it. Enhanced upper-mantle flow, due to an increasing degree of non-Newtonian behaviour, decreases the ratio of upper- to lower-mantle viscosity. Whole layer mantle convection is maintained but upper- and lower-mantle flow take on different dynamic forms: fast and concentrated upper-mantle flow; slow and diffuse lower-mantle flow. Collectively, mantle viscosity, mantle flow wavelengths, upper- to lower-mantle velocities and the degree to which the mantle can drive plate motions become connected to one another through coupled feedback loops. Under this view of mantle dynamics, depth-variable mantle viscosity is an emergent flow feature that both affects and is affected by the configuration of mantle and plate flow.


2021 ◽  
Vol 379 (4) ◽  
Author(s):  
Pavlo O. Dral ◽  
Fuchun Ge ◽  
Bao-Xin Xue ◽  
Yi-Fan Hou ◽  
Max Pinheiro ◽  
...  

AbstractAtomistic machine learning (AML) simulations are used in chemistry at an ever-increasing pace. A large number of AML models has been developed, but their implementations are scattered among different packages, each with its own conventions for input and output. Thus, here we give an overview of our MLatom 2 software package, which provides an integrative platform for a wide variety of AML simulations by implementing from scratch and interfacing existing software for a range of state-of-the-art models. These include kernel method-based model types such as KREG (native implementation), sGDML, and GAP-SOAP as well as neural-network-based model types such as ANI, DeepPot-SE, and PhysNet. The theoretical foundations behind these methods are overviewed too. The modular structure of MLatom allows for easy extension to more AML model types. MLatom 2 also has many other capabilities useful for AML simulations, such as the support of custom descriptors, farthest-point and structure-based sampling, hyperparameter optimization, model evaluation, and automatic learning curve generation. It can also be used for such multi-step tasks as Δ-learning, self-correction approaches, and absorption spectrum simulation within the machine-learning nuclear-ensemble approach. Several of these MLatom 2 capabilities are showcased in application examples.


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