Timing, styles, and kinematics of Cambro–Ordovician extension in the Teplá–Barrandian Unit, Bohemian Massif, and its bearing on the opening of the Rheic Ocean

摘要: This paper describes late Cambrian dikes and Early Ordovician volcano-sedimentary successions of the Prague Basin, Bohemian Massif, to discuss timing kinematics breakup northern margin Gondwana. Andesitic indicate minor E–W crustal extension in Cambrian, whereas Tremadocian Dapingian lithofacies distribution linear array depocenters suggest opening this Rheic Ocean rift-related basin during NW–SE pure shear-dominated extension. kinematic change was associated with onset basic submarine volcanism, presumably resulting from decompression mantle melting as amount increased. We conclude these inferences a comparison other Avalonian–Cadomian terranes that rifting along Gondwana two-stage process involving one major pulse terrane detachment early Ordovician. While geodynamic cause for former phase remains unclear, but still may include effects Cadomian subduction (roll-back, slab break-off), isostatic rebound, or plume, incipient stage latter have been triggered by Iapetus at around 510 Ma, followed advanced broadly coeval (Tremadocian Darriwilian) large portions belt. Unequal amounts resulted separation drift some terranes, while belt remained adjacent