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

Effects of lithospheric heterogeneities on the topographic evolution.Profiles of precipitation, erosion, topography, sedimentary thickness, crustal thickness, lithospheric mantle thickness, for the reference model setup MS0 and for a weaker rheology (MS1), at 30 and 60 My. A weaker lithosphere implies a further propagation of deformation towards the interior of the continent, imposing a more distant position of the Tarim basin. This in turn induces larger orographic effects in the strong-rheology setup: higher upwind precipitation in the left, and more pronounced rain shadow to the right.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132252.g006: Effects of lithospheric heterogeneities on the topographic evolution.Profiles of precipitation, erosion, topography, sedimentary thickness, crustal thickness, lithospheric mantle thickness, for the reference model setup MS0 and for a weaker rheology (MS1), at 30 and 60 My. A weaker lithosphere implies a further propagation of deformation towards the interior of the continent, imposing a more distant position of the Tarim basin. This in turn induces larger orographic effects in the strong-rheology setup: higher upwind precipitation in the left, and more pronounced rain shadow to the right.

Mentions: The lateral crustal and lithospheric contrasts cause in turn a differential isostatic adjustment via the flexure of the continent. Flexural basins form in areas of sharp contrast in lithospheric thickening (areas of little deformation near zones of intense thickening). One such area is the northern edge of the indenter. The foreland basin formed on the northern boundary of the indenter match to first degree the Cenozoic sedimentary thickness of the Indus and Ganges basins, with maximum values that change along the E-W strike from 2 to 7 km and a basin width ranging from 250 to 700 km (Figs 5a and 6). Another comparison that ensures that the surface processes are working at the right speed is the sediment thickness accumulated at the basin formed on the rigid block, ranging from 5 to 8 km (Figs 5 and 6), coinciding with observations compiled by [42]. Regional isostasy is responsible for most sediment accumulation within the continent (in both foreland or land-locked basins), by creating flexural basins next to areas of topography growth. Smaller sediment accumulation is predicted if the elastic thickness of the lithosphere is reduced (Fig 5). Also Te values significantly larger than 65 km imply smaller sediment accumulation within the continent, because the Te value adopted for the reference model optimizes the volume of accommodation space created by flexural isostasy.


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

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

Effects of lithospheric heterogeneities on the topographic evolution.Profiles of precipitation, erosion, topography, sedimentary thickness, crustal thickness, lithospheric mantle thickness, for the reference model setup MS0 and for a weaker rheology (MS1), at 30 and 60 My. A weaker lithosphere implies a further propagation of deformation towards the interior of the continent, imposing a more distant position of the Tarim basin. This in turn induces larger orographic effects in the strong-rheology setup: higher upwind precipitation in the left, and more pronounced rain shadow to the right.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132252.g006: Effects of lithospheric heterogeneities on the topographic evolution.Profiles of precipitation, erosion, topography, sedimentary thickness, crustal thickness, lithospheric mantle thickness, for the reference model setup MS0 and for a weaker rheology (MS1), at 30 and 60 My. A weaker lithosphere implies a further propagation of deformation towards the interior of the continent, imposing a more distant position of the Tarim basin. This in turn induces larger orographic effects in the strong-rheology setup: higher upwind precipitation in the left, and more pronounced rain shadow to the right.
Mentions: The lateral crustal and lithospheric contrasts cause in turn a differential isostatic adjustment via the flexure of the continent. Flexural basins form in areas of sharp contrast in lithospheric thickening (areas of little deformation near zones of intense thickening). One such area is the northern edge of the indenter. The foreland basin formed on the northern boundary of the indenter match to first degree the Cenozoic sedimentary thickness of the Indus and Ganges basins, with maximum values that change along the E-W strike from 2 to 7 km and a basin width ranging from 250 to 700 km (Figs 5a and 6). Another comparison that ensures that the surface processes are working at the right speed is the sediment thickness accumulated at the basin formed on the rigid block, ranging from 5 to 8 km (Figs 5 and 6), coinciding with observations compiled by [42]. Regional isostasy is responsible for most sediment accumulation within the continent (in both foreland or land-locked basins), by creating flexural basins next to areas of topography growth. Smaller sediment accumulation is predicted if the elastic thickness of the lithosphere is reduced (Fig 5). Also Te values significantly larger than 65 km imply smaller sediment accumulation within the continent, because the Te value adopted for the reference model optimizes the volume of accommodation space created by flexural isostasy.

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