The significance of switch in convergence direction in the Alborz Mountains, northern Iran: insights from scaled analogue modelling
2017 (English)In: Interpretation, ISSN 2324-8858, E-ISSN 2324-8866, Vol. 5, no 1, SD81-SD98 p.Article in journal (Refereed) Epub ahead of print
The switch in direction of convergence between Central Iran and the Eurasian plate isbelieved to have a significant impact on the structural style in the Alborz Mountains, in northof Iran. To understand the deformation pattern and investigate the influence of the SouthCaspian Basin (SCB) kinematics since the middle Miocene on the structural styles and activetectonics of the Alborz Mountains, a series of scaled analogue models were prepared, wherepassively layered loose sand simulating the sedimentary units were subjected toorthogonal and subsequently oblique shortening by a rigid indenter. Model resultsshow that during the shortening an arcuate-shape foreland-vergent imbricate stack forms infront of the indenter. The orthogonal shortening is characterized by a prevailing right-lateraland left-lateral oblique-slip motion in the east and west of the model, respectively. This shiftin kinematics contradicts the proposed pre-neotectonic (orthogonal) model of the Alborz.However, during oblique shortening, model results show that deformation is mainlyaccommodated by left-lateral transpression within the sand wedge and by its internaldeformation. Oblique shortening is consistently accommodated by continued left-lateralmotion on the WNW-trending oblique thrusts, whereas the east-west trending thrusts and thepre-existing ENE-trending right-lateral oblique thrusts reactivate as left-lateral oblique faults.Precise monitoring of the model surface also illustrates partitioning of shortening into theforeland-vergent left-lateral thrusting in the south and hinterland-vergent back thrusting in thenorth. These model results are generally consistent with field observations and GPS data ofstructure and kinematics of the Alborz Mountains.
Place, publisher, year, edition, pages
2017. Vol. 5, no 1, SD81-SD98 p.
Crustal deformation, Tectonics, Alborz Mountains, Iran, Analogue modeling
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:hig:diva-23006DOI: 10.1190/INT-2016-0117.1OAI: oai:DiVA.org:hig-23006DiVA: diva2:1055065