Late Miocene to Quaternary slip history across the Qiulitag anticline in the southern Tianshan piedmont

Julien Charreau (1) , Amandine Sartégou (2, 1) , Dimitri Saint-Carlier (1) , Jérôme Lavé (1) , Pierre-Henri Blard (1) , Stéphane Dominguez (3) , Sheng Li Wang (4) , Gang Rao (5) , A.S.T.E.R. Team (2) , Georges Aumaitre (2) , Didier Bourles (2) , Karim Keddadouche (2)

1 CRPG - Centre de Recherches Pétrographiques et Géochimiques
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
3 Géosciences Montpellier
4 SESE - NUIST - School of Environmental Science and Engineering [Nanjing University]
5 School of Earth Sciences [Hangzhou]

In this study, we reconstruct the Miocene to Quaternary shortening history across the Qiultag anticline, a complex fault-bend fold located in southern Tianshan. We studied the Yaha and Kuche sections, where we combined surface structural measurements and seismic imaging to model the stratigraphic horizons. The history of folding was reconstructed based on magnetostratigraphic analyses and eight cosmogenic burial ages in Kuche. Pleistocene deformation rates were also quantified in Yaha based on a deformed fluvial terrace that we dated to ~67 ka using a cosmogenic depth profile. Our results suggest that the fold grew at a mean slip rate of 0.9-1.3 mm/a in both sections but accelerated to ~2.5 mm/a during the Pleistocene in Kuche. These results support a migration of the deformation toward the basin during the Pleistocene and suggest that most of the present deformation of the Tianshan is accommodated across the external structures of the range.

Domaines: Tectonique; Géochimie; Géomorphologie; Stratigraphie

Julien Charreau, Amandine Sartégou, Dimitri Saint-Carlier, Jérôme Lavé, Pierre-Henri Blard, et al.. Late Miocene to Quaternary slip history across the Qiulitag anticline in the southern Tianshan piedmont. Terra Nova, 2019, ⟨10.1111/TER.12439⟩. ⟨hal-02344058⟩