Limits...
Topographic Evolution and Climate Aridification during Continental Collision: Insights from Computer Simulations.

Garcia-Castellanos D, Jiménez-Munt I - PLoS ONE (2015)

Bottom Line: For this purpose, we combine in a single computer program: 1) a thin-sheet viscous model of continental deformation; 2) a stream-power surface-transport approach; 3) flexural isostasy allowing for the formation of large sedimentary foreland basins; and 4) an orographic precipitation model that reproduces basic climatic effects such as continentality and rain shadow.At the continental scale, however, the overall distribution of topographic basins and ranges seems insensitive to climatic factors, despite these do have important, sometimes counterintuitive effects on the amount of sediments trapped within the continent.These complex climatic-drainage-tectonic interactions make the development of steady-state topography at the continental scale unlikely.

View Article: PubMed Central - PubMed

Affiliation: Group of Dynamics of the Lithosphere, Instituto de Ciencias de la Tierra Jaume Almera (ICTJA-CSIC), Barcelona, Spain.

ABSTRACT
How do the feedbacks between tectonics, sediment transport and climate work to shape the topographic evolution of the Earth? This question has been widely addressed via numerical models constrained with thermochronological and geomorphological data at scales ranging from local to orogenic. Here we present a novel numerical model that aims at reproducing the interaction between these processes at the continental scale. For this purpose, we combine in a single computer program: 1) a thin-sheet viscous model of continental deformation; 2) a stream-power surface-transport approach; 3) flexural isostasy allowing for the formation of large sedimentary foreland basins; and 4) an orographic precipitation model that reproduces basic climatic effects such as continentality and rain shadow. We quantify the feedbacks between these processes in a synthetic scenario inspired by the India-Asia collision and the growth of the Tibetan Plateau. We identify a feedback between erosion and crustal thickening leading locally to a <50% increase in deformation rates in places where orographic precipitation is concentrated. This climatically-enhanced deformation takes place preferentially at the upwind flank of the growing plateau, specially at the corners of the indenter (syntaxes). We hypothesize that this may provide clues for better understanding the mechanisms underlying the intriguing tectonic aneurisms documented in the Himalayas. At the continental scale, however, the overall distribution of topographic basins and ranges seems insensitive to climatic factors, despite these do have important, sometimes counterintuitive effects on the amount of sediments trapped within the continent. The dry climatic conditions that naturally develop in the interior of the continent, for example, trigger large intra-continental sediment trapping at basins similar to the Tarim Basin because they determine its endorheic/exorheic drainage. These complex climatic-drainage-tectonic interactions make the development of steady-state topography at the continental scale unlikely.

No MeSH data available.


Related in: MedlinePlus

Topographic evolution of the reference setup MS0 at t = 10, 20, 30, and 40 Myr.A complete animation of the topographic evolution is available in the multimedia repository. Red shading shows areas where precipitation is higher than 0.4 m/yr. Note that the y-direction axis is the location relative to the indenter, so the rigid block appears to move southwards. Note the changes in drainage connectivity (captures) promoted by the tectonic growth of the plateau. The early endorheic plateau is captured by a northern river after 24 Myr which is in turn captured by the Tarim-like closed basin at t = 36 Myr, favoured by the lack of thickening of that block and its strong isostatic subsidence of over 8 km.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526229&req=5

pone.0132252.g003: Topographic evolution of the reference setup MS0 at t = 10, 20, 30, and 40 Myr.A complete animation of the topographic evolution is available in the multimedia repository. Red shading shows areas where precipitation is higher than 0.4 m/yr. Note that the y-direction axis is the location relative to the indenter, so the rigid block appears to move southwards. Note the changes in drainage connectivity (captures) promoted by the tectonic growth of the plateau. The early endorheic plateau is captured by a northern river after 24 Myr which is in turn captured by the Tarim-like closed basin at t = 36 Myr, favoured by the lack of thickening of that block and its strong isostatic subsidence of over 8 km.

Mentions: For computing-efficiency reasons (to keep the modelling domain small and around the area of deformation), the modelling domain is shifted northwards together with the indenter (technique used also in [19]). Thus, in the planform views in Fig 3 and in the S1 video the continent appears to move southwards, while the velocity arrows at the indenter and at the growing plateau (Fig 4) have a northward direction. Keeping this in mind, the upper, right, and left boundaries of the model are locked ( velocity), while the indenter moves towards the north at 50 mm/yr. While the model setup could be easily adapted to reproduce more closely the Himalayan collision and the formation of the Tibetan Plateau (for instance, the right boundary could allow the exit of rock to reproduce the eastwards lateral extrusion reflected in GPS measurements in the Tibet, [41]), we opt here for keeping the model simple and focus on identifying process interactions rather than on finding geodynamic implications for the Himalayas-Tibetan Plateau region. Keeping this in mind, we will refer to the positive y direction as North (N) and the positive x as East (E), and we will use the terms Tarim and India to refer to the rigid block and the indenter, respectively.


Topographic Evolution and Climate Aridification during Continental Collision: Insights from Computer Simulations.

Garcia-Castellanos D, Jiménez-Munt I - PLoS ONE (2015)

Topographic evolution of the reference setup MS0 at t = 10, 20, 30, and 40 Myr.A complete animation of the topographic evolution is available in the multimedia repository. Red shading shows areas where precipitation is higher than 0.4 m/yr. Note that the y-direction axis is the location relative to the indenter, so the rigid block appears to move southwards. Note the changes in drainage connectivity (captures) promoted by the tectonic growth of the plateau. The early endorheic plateau is captured by a northern river after 24 Myr which is in turn captured by the Tarim-like closed basin at t = 36 Myr, favoured by the lack of thickening of that block and its strong isostatic subsidence of over 8 km.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526229&req=5

pone.0132252.g003: Topographic evolution of the reference setup MS0 at t = 10, 20, 30, and 40 Myr.A complete animation of the topographic evolution is available in the multimedia repository. Red shading shows areas where precipitation is higher than 0.4 m/yr. Note that the y-direction axis is the location relative to the indenter, so the rigid block appears to move southwards. Note the changes in drainage connectivity (captures) promoted by the tectonic growth of the plateau. The early endorheic plateau is captured by a northern river after 24 Myr which is in turn captured by the Tarim-like closed basin at t = 36 Myr, favoured by the lack of thickening of that block and its strong isostatic subsidence of over 8 km.
Mentions: For computing-efficiency reasons (to keep the modelling domain small and around the area of deformation), the modelling domain is shifted northwards together with the indenter (technique used also in [19]). Thus, in the planform views in Fig 3 and in the S1 video the continent appears to move southwards, while the velocity arrows at the indenter and at the growing plateau (Fig 4) have a northward direction. Keeping this in mind, the upper, right, and left boundaries of the model are locked ( velocity), while the indenter moves towards the north at 50 mm/yr. While the model setup could be easily adapted to reproduce more closely the Himalayan collision and the formation of the Tibetan Plateau (for instance, the right boundary could allow the exit of rock to reproduce the eastwards lateral extrusion reflected in GPS measurements in the Tibet, [41]), we opt here for keeping the model simple and focus on identifying process interactions rather than on finding geodynamic implications for the Himalayas-Tibetan Plateau region. Keeping this in mind, we will refer to the positive y direction as North (N) and the positive x as East (E), and we will use the terms Tarim and India to refer to the rigid block and the indenter, respectively.

Bottom Line: For this purpose, we combine in a single computer program: 1) a thin-sheet viscous model of continental deformation; 2) a stream-power surface-transport approach; 3) flexural isostasy allowing for the formation of large sedimentary foreland basins; and 4) an orographic precipitation model that reproduces basic climatic effects such as continentality and rain shadow.At the continental scale, however, the overall distribution of topographic basins and ranges seems insensitive to climatic factors, despite these do have important, sometimes counterintuitive effects on the amount of sediments trapped within the continent.These complex climatic-drainage-tectonic interactions make the development of steady-state topography at the continental scale unlikely.

View Article: PubMed Central - PubMed

Affiliation: Group of Dynamics of the Lithosphere, Instituto de Ciencias de la Tierra Jaume Almera (ICTJA-CSIC), Barcelona, Spain.

ABSTRACT
How do the feedbacks between tectonics, sediment transport and climate work to shape the topographic evolution of the Earth? This question has been widely addressed via numerical models constrained with thermochronological and geomorphological data at scales ranging from local to orogenic. Here we present a novel numerical model that aims at reproducing the interaction between these processes at the continental scale. For this purpose, we combine in a single computer program: 1) a thin-sheet viscous model of continental deformation; 2) a stream-power surface-transport approach; 3) flexural isostasy allowing for the formation of large sedimentary foreland basins; and 4) an orographic precipitation model that reproduces basic climatic effects such as continentality and rain shadow. We quantify the feedbacks between these processes in a synthetic scenario inspired by the India-Asia collision and the growth of the Tibetan Plateau. We identify a feedback between erosion and crustal thickening leading locally to a <50% increase in deformation rates in places where orographic precipitation is concentrated. This climatically-enhanced deformation takes place preferentially at the upwind flank of the growing plateau, specially at the corners of the indenter (syntaxes). We hypothesize that this may provide clues for better understanding the mechanisms underlying the intriguing tectonic aneurisms documented in the Himalayas. At the continental scale, however, the overall distribution of topographic basins and ranges seems insensitive to climatic factors, despite these do have important, sometimes counterintuitive effects on the amount of sediments trapped within the continent. The dry climatic conditions that naturally develop in the interior of the continent, for example, trigger large intra-continental sediment trapping at basins similar to the Tarim Basin because they determine its endorheic/exorheic drainage. These complex climatic-drainage-tectonic interactions make the development of steady-state topography at the continental scale unlikely.

No MeSH data available.


Related in: MedlinePlus