Structural evolution of the North Karakoram cover, north Pakistan

The oldest deformational structures recognized in the Karakoram sedimentary cover north of the Karakoram Axial Batholith (KAB) consist of an E-W deformed belt composed of Permian-early Cretaceous sediments. In the Chapursan Valley a complex and polyphase antiformal stack consisting of a Permian to Cretaceous succession was recognized. Post-Cretaceous northward and northeastward directions of transport are shown by slip vectors along thrust planes and by fold axes in the Chapursan Valley, whereas NW-SE-trending folds due to northeastward transport were observed in the Shimshal Valley. The last tectonic phase recognized in the Chapursan Valley caused the activation of an important set of E-W-orientated sinistral strike-slip faults. In the Shimshal Valley, large E-W sinistral and NW-SE dextral faults are present as well. The sedimentary cover of the Karakoram was deformed under anchimetamorphic conditions in the Chapursan Valley, whereas sericite to muscovite low-grade metapelites with occurrence of chloritoid, epidote and biotite are present in the lower Shimshal Valley. -from Author