Changes

===Norian (about 205 Ma)===

===Norian (about 205 Ma)===

The Norian represents a key interval in the evolution of the Paleo-Tethys Ocean ([[:file:M106Ch01Fig07.jpg|Figure 7]]). During this stage the first evidence for the closure of the Paleo-Tethys Ocean was recorded by the onset of the Cimmerian orogeny along the southern margin of Asia, due to the collision of the Iran blocks with the active margin of Turan. This collisional episode is known as the “Eocimmerian” event, which was followed during Jurassic time by additional collisions of other microplates (Zanchi et al., 2009).

The Norian represents a key interval in the evolution of the Paleo-Tethys Ocean ([[:file:M106Ch01Fig07.jpg|Figure 7]]). During this stage the first evidence for the closure of the Paleo-Tethys Ocean was recorded by the onset of the Cimmerian orogeny along the southern margin of Asia, due to the collision of the Iran blocks with the active margin of Turan. This collisional episode is known as the “Eocimmerian” event, which was followed during Jurassic time by additional collisions of other microplates.<ref name=Zanchietal_2009>Zanchi, A., Zanchetta, S., Berra, F, Mattei, M., Garzanti, E., Molyneux, S., Nawab, A., and Sabouri, J., 2009, The Eo-Cimmerian (Late? Triassic) orogeny in North Iran, in M.-F. Brunet, M. Wilmsen, and J. W. Granath, eds., South Caspian to Central Iran Basins: GSL Special Publications, 312, p. 31–56.</ref>

All the microplates that detached from Gondwana were approaching Southern Asia, which was an active margin situated above a north-dipping subduction zone. The Neo-Tethys Ocean was widely open. The paleogeographic situation is clear in the central part of the Tethyan Gulf, but the geodynamic setting was extremely complex close to the triple junction located in the western part of the Tethys. Intense extensional to strike slip tectonics (likely transtension) was recorded along the southern margin of Europe, close to the future axis of the Alpine Tethys. This tectonic activity was connected westward with the Central Atlantic, where rift basins were forming during Norian time (Newark Basins). Among the different small plates in the Mediterranean region (Apulia, Greece, Turkey), minor deep-water seaways, partly floored with oceanic crust, have been recognized. Northern Africa and Arabia acted as the southern passive margin of the Neo-Tethys, with extensional basins in Lybia and Egypt (Schandelmeier and Reynolds, 1997). Extensional tectonics (Palmiryde Basin) was recorded along the Lebanon-Northern Israel shelf. Emplacement of basalts, probably related to local rifting, is documented in Israel. Intraplate alkaline magmatic activity (intrusive and subvolcanic) occurred in Sudan and S-E Egypt (Schandelmeier and Reynolds, 1997).

All the microplates that detached from Gondwana were approaching Southern Asia, which was an active margin situated above a north-dipping subduction zone. The Neo-Tethys Ocean was widely open. The paleogeographic situation is clear in the central part of the Tethyan Gulf, but the geodynamic setting was extremely complex close to the triple junction located in the western part of the Tethys. Intense extensional to strike slip tectonics (likely transtension) was recorded along the southern margin of Europe, close to the future axis of the Alpine Tethys. This tectonic activity was connected westward with the Central Atlantic, where rift basins were forming during Norian time (Newark Basins). Among the different small plates in the Mediterranean region (Apulia, Greece, Turkey), minor deep-water seaways, partly floored with oceanic crust, have been recognized. Northern Africa and Arabia acted as the southern passive margin of the Neo-Tethys, with extensional basins in Lybia and Egypt (Schandelmeier and Reynolds, 1997). Extensional tectonics (Palmiryde Basin) was recorded along the Lebanon-Northern Israel shelf. Emplacement of basalts, probably related to local rifting, is documented in Israel. Intraplate alkaline magmatic activity (intrusive and subvolcanic) occurred in Sudan and S-E Egypt (Schandelmeier and Reynolds, 1997).