Ordovician mafic magmatism in an Ediacaran arc complex, Sibak, NE Iran: the eastern tip of the Rheic Ocean

The assembly of Gondwana in the Ediacaran was concluded by extensive arc magmatism along its northern margin. Extensional events in the Early Paleozoic led to rifting and the eventual separation of terranes which were later assimilated in different continents and orogens. The Sibak area of northeastern Iran records these events, including Late Precambrian volcanic-sedimentary processes, metamorphism, and magmatism. A granite at Chahak in the Sibak Complex yields a zircon U-Pb age of 548.3 Âą 1.1 Ma whereas a spatially associated gabbro has an age of 471.1 Âą 0.9 Ma. The latter corresponds to the earliest stages of rifting in the nearby Alborz domain with the deposition of clastic sedimentary sequences, basaltic volcanism, and, as indicated by indirect evidence, coeval granitic plutonism. The Chahak gabbro is thus one of earliest witnesses of the rifting processes which eventually led to the development of the Rheic Ocean, and were indirectly linked to subduction of Iapetus at the Laurentian margin and the early development of the Appalachian orogen.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author