Enhanced buckling due to river incision:the Oxaya Antiform, northern ChileGerold Zeilinger, Fritz Schlunegger, Univ. BernGuy Simpson, ETH Zurich

OutlineIntroductionExamples of transverse rivers intersecting anticlines in compressional beltsCan incision amplify buckling also in active continental margins?

OutlineIntroductionStudy areaGeographical positionTectonic frameStratigraphy of important units Geological overview

OutlineIntroductionStudy areaAnticline structureOxaya Anticline geometry Basement Tertiary units unconformityTertiary units fold geometry Spatial distribution of structures

OutlineIntroductionStudy areaAnticline structureInterpretationTiming of anticline growth (River incision history)(Regional compression)

OutlineIntroductionStudy areaAnticline structureInterpretationConclusion Does the incision of the studied valleys influence the deformation of the surrounding Oxaya Anticline?

Worldwide examplesIntroduction

Worldwide examplesPyrenees: Segre River at Oliana AnticlineIntroduction

Worldwide examplesPyrenees: Segre River at Oliana AnticlineSwiss Alps: Reuss above Lake LucerneIntroduction

Worldwide examplesPyrenees: Segre River at Oliana AnticlineSwiss Alps: Reuss above Lake LucerneFrench Alps: Fier river at Val du FierIntroduction

Worldwide examplesPyrenees: Segre River at Oliana AnticlineSwiss Alps: Reuss above Lake LucerneFrench Alps: Fier river at Val du FierHimalaya: Arun riverIntroduction

Worldwide examplesPyrenees: Segre River at Oliana AnticlineSwiss Alps: Reuss above Lake LucerneFrench Alps: Fier river at Val du FierHimalaya: Arun riverApennine: Fold-thrust belt of the UmbriaMarche ApenninesIntroduction

LocationStudy area

LocationStudy area

LocationStudy area

LocationStudy area

StratigraphyStudy area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

StratigraphyStudy area

Study area

Simplified Geological Map (after Uhlig, 1999 and Garcia, 2003 unpublished)Study area

Simplified Geological Map (after Uhlig, 1999 and Garcia, 2003 unpublished)Study area

Schematic ProfilesStudy area

Oxaya Anticline GeometryAnticline structure

Oxaya Anticline GeometryAnticline structure

Basement Tertiary units unconformityAnticline structureEW

Basement Tertiary units unconformityAnticline structureImage by Michi StrasserWE

Tertiary units fold geometryAnticline structureEWEWAzapa ValleyLluta Valley

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Spatial distribution of structuresAnticline structure

Timing of anticline growth Interpretation

Timing of anticline growth Interpretation

Timing of anticline growth Interpretation

Timing of anticline growth Interpretation

Conclusion

The Formation of the Oxaya Anticline was enhanced by the incision of the studied valleys.Incision amplified buckling occurs also in regions not representing fold and thrust belts.The Oxaya Anticline is coherent with the results of numerical modelling of transverse rivers.Existing deformation can be substantially enhanced by surface processes

Thank you!

Geographical position of the area Tectonic frameStratigraphic of important units Geological OverviewTopographic geometry Basement Tertiary strata unconformityTertiary stratas fold geometry Spatial distribution of structuresGeographical position of the area Tectonic frameStratigraphic of important units Geological OverviewTopographic geometry Basement Tertiary strata unconformityTertiary stratas fold geometry Spatial distribution of structuresGeographical position of the area Tectonic frameStratigraphic of important units Geological OverviewTopographic geometry Basement Tertiary strata unconformityTertiary stratas fold geometry Spatial distribution of structuresGeographical position of the area Tectonic frameStratigraphic of important units Geological OverviewTopographic geometry Basement Tertiary strata unconformityTertiary stratas fold geometry Spatial distribution of structuresGeographical position of the area Tectonic frameStratigraphic of important units Geological OverviewTopographic geometry Basement Tertiary strata unconformityTertiary stratas fold geometry Spatial distribution of structures