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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

Model set-up and other boundary conditions.The tectonic boundary conditions (black) consist of a 50 mm/yr indentation of a rigid block at the southern boundary and fixed (vx = vy = 0) elsewhere. Vertical isostatic motions are allowed at the entire boundary (zero slope and zero momentum across the boundary). The harder block in red has 3 times higher viscosity than the rest of the model domain. The orographic precipitation model is controlled by a constant velocity and direction of incoming humid air (blue arrows). The initial topography is set flat and 35 m above sea level, with an additional random noise between ±5 m. In the text, the positive-y direction is referred to as ‘north’, and the positive-x direction is named ‘east’.
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pone.0132252.g002: Model set-up and other boundary conditions.The tectonic boundary conditions (black) consist of a 50 mm/yr indentation of a rigid block at the southern boundary and fixed (vx = vy = 0) elsewhere. Vertical isostatic motions are allowed at the entire boundary (zero slope and zero momentum across the boundary). The harder block in red has 3 times higher viscosity than the rest of the model domain. The orographic precipitation model is controlled by a constant velocity and direction of incoming humid air (blue arrows). The initial topography is set flat and 35 m above sea level, with an additional random noise between ±5 m. In the text, the positive-y direction is referred to as ‘north’, and the positive-x direction is named ‘east’.

Mentions: For the initial set-up of the reference model (MS0; parameters in Table 1), we predefine an initially flat continent at an elevation of 35 m, with a 32 km-thick crust and a base of the lithosphere located at a depth of 133 km. The boundaries of 3 distinctive domains in this continent are inspired by the India-Eurasia collision (Fig 2): 1) Indenter (completely rigid, representing India); 2) An intracontinental rigid domain (with a vertically-averaged viscosity 3 times higher than the rest of the model domain, representing the Tarim block); and 3) The rest of the model domain, representing Asia.


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

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

Model set-up and other boundary conditions.The tectonic boundary conditions (black) consist of a 50 mm/yr indentation of a rigid block at the southern boundary and fixed (vx = vy = 0) elsewhere. Vertical isostatic motions are allowed at the entire boundary (zero slope and zero momentum across the boundary). The harder block in red has 3 times higher viscosity than the rest of the model domain. The orographic precipitation model is controlled by a constant velocity and direction of incoming humid air (blue arrows). The initial topography is set flat and 35 m above sea level, with an additional random noise between ±5 m. In the text, the positive-y direction is referred to as ‘north’, and the positive-x direction is named ‘east’.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132252.g002: Model set-up and other boundary conditions.The tectonic boundary conditions (black) consist of a 50 mm/yr indentation of a rigid block at the southern boundary and fixed (vx = vy = 0) elsewhere. Vertical isostatic motions are allowed at the entire boundary (zero slope and zero momentum across the boundary). The harder block in red has 3 times higher viscosity than the rest of the model domain. The orographic precipitation model is controlled by a constant velocity and direction of incoming humid air (blue arrows). The initial topography is set flat and 35 m above sea level, with an additional random noise between ±5 m. In the text, the positive-y direction is referred to as ‘north’, and the positive-x direction is named ‘east’.
Mentions: For the initial set-up of the reference model (MS0; parameters in Table 1), we predefine an initially flat continent at an elevation of 35 m, with a 32 km-thick crust and a base of the lithosphere located at a depth of 133 km. The boundaries of 3 distinctive domains in this continent are inspired by the India-Eurasia collision (Fig 2): 1) Indenter (completely rigid, representing India); 2) An intracontinental rigid domain (with a vertically-averaged viscosity 3 times higher than the rest of the model domain, representing the Tarim block); and 3) The rest of the model domain, representing Asia.

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