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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

Effect of climatic parameters and isostasy on the final topography, precipitation, drainage, and sediment distribution.a) the reference orographic precipitation setting (reference setup MS0), b) changing wind direction (SE instead of NW, setup MS3). Numbers in red indicate lake evaporation rates. c) In absence of evaporation (MS4); and d) a model under local isostasy (Te = 0; MS5). The red shading shows areas where precipitation is higher than 0.4 m/yr. The setups implying a wetter climate in the plateau region (MS3, MS4), show less sediment accumulation than the drier ones (MS0, MS5), because they inhibit endorheism and thus part of the sediments are drained out of the model boundaries. The absence of flexural isostasy in MS5 causes a smaller amount of sediment accumulation in all basins.
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pone.0132252.g005: Effect of climatic parameters and isostasy on the final topography, precipitation, drainage, and sediment distribution.a) the reference orographic precipitation setting (reference setup MS0), b) changing wind direction (SE instead of NW, setup MS3). Numbers in red indicate lake evaporation rates. c) In absence of evaporation (MS4); and d) a model under local isostasy (Te = 0; MS5). The red shading shows areas where precipitation is higher than 0.4 m/yr. The setups implying a wetter climate in the plateau region (MS3, MS4), show less sediment accumulation than the drier ones (MS0, MS5), because they inhibit endorheism and thus part of the sediments are drained out of the model boundaries. The absence of flexural isostasy in MS5 causes a smaller amount of sediment accumulation in all basins.

Mentions: The final topography at t = 50 My, (Figs 4d and 5a) shows a relative similitude to the Tibetan plateau, with a 3000x1200 km region above an elevation of 3 km. The topography in this region is underestimated by about 1 km, but this was expected because processes such as lithospheric mantle removal have been previously pointed as responsible for a substantial part of the Tibetan Plateau elevation [19], [46], [47]. Again we have opted for not incorporating further complexity in our tectonic setting because we want to focus on the understanding of the process interplay rather than reproducing all the available observables of the Himalayan-Indian system. Another feature of the calculated topography that shows the limitations of our modeling approach is the elevation maximum, located in the southern flank of the Tarim block, instead of the southern flank of the plateau. Overall, the final topography is reflecting the large lateral variations of the thickened crust and lithospheric mantle, as displayed in Fig 4. The thickness of the crust and the lithosphere remains nearly unchanged (32 and 130 km respectively) in the most distal parts of the model domain and in the rigid Tarim block. In contrast, both thicknesses have more than doubled in the southern flank of the plateau, reaching maximum values of 80 and 290 km respectively in the syntaxes.


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

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

Effect of climatic parameters and isostasy on the final topography, precipitation, drainage, and sediment distribution.a) the reference orographic precipitation setting (reference setup MS0), b) changing wind direction (SE instead of NW, setup MS3). Numbers in red indicate lake evaporation rates. c) In absence of evaporation (MS4); and d) a model under local isostasy (Te = 0; MS5). The red shading shows areas where precipitation is higher than 0.4 m/yr. The setups implying a wetter climate in the plateau region (MS3, MS4), show less sediment accumulation than the drier ones (MS0, MS5), because they inhibit endorheism and thus part of the sediments are drained out of the model boundaries. The absence of flexural isostasy in MS5 causes a smaller amount of sediment accumulation in all basins.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132252.g005: Effect of climatic parameters and isostasy on the final topography, precipitation, drainage, and sediment distribution.a) the reference orographic precipitation setting (reference setup MS0), b) changing wind direction (SE instead of NW, setup MS3). Numbers in red indicate lake evaporation rates. c) In absence of evaporation (MS4); and d) a model under local isostasy (Te = 0; MS5). The red shading shows areas where precipitation is higher than 0.4 m/yr. The setups implying a wetter climate in the plateau region (MS3, MS4), show less sediment accumulation than the drier ones (MS0, MS5), because they inhibit endorheism and thus part of the sediments are drained out of the model boundaries. The absence of flexural isostasy in MS5 causes a smaller amount of sediment accumulation in all basins.
Mentions: The final topography at t = 50 My, (Figs 4d and 5a) shows a relative similitude to the Tibetan plateau, with a 3000x1200 km region above an elevation of 3 km. The topography in this region is underestimated by about 1 km, but this was expected because processes such as lithospheric mantle removal have been previously pointed as responsible for a substantial part of the Tibetan Plateau elevation [19], [46], [47]. Again we have opted for not incorporating further complexity in our tectonic setting because we want to focus on the understanding of the process interplay rather than reproducing all the available observables of the Himalayan-Indian system. Another feature of the calculated topography that shows the limitations of our modeling approach is the elevation maximum, located in the southern flank of the Tarim block, instead of the southern flank of the plateau. Overall, the final topography is reflecting the large lateral variations of the thickened crust and lithospheric mantle, as displayed in Fig 4. The thickness of the crust and the lithosphere remains nearly unchanged (32 and 130 km respectively) in the most distal parts of the model domain and in the rigid Tarim block. In contrast, both thicknesses have more than doubled in the southern flank of the plateau, reaching maximum values of 80 and 290 km respectively in the syntaxes.

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