Dome and basin refolding and transpressive inversion along the Karatau Fault System, southern Kazakstan

The Karatau Fault System of southern Kazakstan forms a crustal-scale zone o f strike-slip dominated transpressional tectonics which has undergone multi ple phases and styles of deformation during a protracted history of reactiv ation from the Neoproterozoic to the Cenozoic. Ductile fabrics associated w ith dextral kinematic indicators are present in amphibolites along the Main Karatau Fault. The ages of the (possibly ophiolitic) protoliths and the du ctile fabrics are not well constrained, but they are plausibly pre-late Rip hean. Late Ordovician granites stitch thrusts and folds which deform late R iphean to Llanvirn clastics, preserved beneath a regional Late Devonian ang ular unconformity. This deformation may be related to a contemporary contin ental collision NE of the Karatau. Two phases of late Palaeozoic deformatio n affected the Upper Devonian and Carboniferous carbonate succession. The f irst phase is related to sinistral transpression along the Karatau Fault Sy stem, the second to dextral transpressional reactivation. The combination o f these events produced a regional-scale dome-and-basin fold interference p attern. Similar polyphase deformation appears to have affected large areas of Central Asia and was possibly caused by the late Palaeozoic orogenies at Asia's margins, such as the accretion of Tarim and the East European Crato n to Asia, and the closure of the Kazakstan Orocline. Normal faults in the Karatau are related to the formation of the Leontiev Graben, South Turgay B asin and the Yarkand-Fergana Basin in the Early to Mid-Jurassic, during ren ewed dextral slip along the Karatau/Talas-Fergana Fault. Late Cenozoic defo rmation is minor, and resulted in the uplift and incision of a Cretaceous-P alaeogene peneplain without a major tectonic overprint. Reversals in the se nse of strike-slip dominated transpressive deformation across major fault s ystems results in transpressive inversion. This represents an ideal process with which to generate overprinting orthogonal fold systems, resulting in classic dome and basin interference patterns on a regional scale.