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Since ~ 25 Ma ago the plate margin between the Australian plate and the Philippine Sea and Pacific-Caroline plates in northwestern New Guinea has been undergoing oblique convergence and resulted in various uplifts and compressional deformation in the Bird's Head Peninsula. These reflect partitioning into north-northeast compression and east-west sinistral strike-slip faulting analogous to that in the Sumatran active margin. We present new data on the provenance of the upper Miocene to lower Pliocene succession in the northeastern Bird's Head Peninsula and its structure that has enabled a new tectonic synthesis. Initiation of oblique convergence resulted in development of the sinistral strike-slip Sorong Fault and docking of the Oligocene Arfak Volcanics from the southern Philippine Sea Plate. At ~ 15–12 Ma the compressional component initiated 40 km of dextral offset of the Sorong Fault along the northwest-trending Ransiki Fault. Subsequently, sinistral movement along the Sorong Fault was impeded by formation of a restraining bend at the Ransiki Fault, with uplift shown by the provenance of the local upper Miocene to lower Pliocene conglomerates. Further compressional deformation in the late Pliocene to Pleistocene caused widespread uplift and folding in the adjacent upper Miocene to lower Pliocene succession. [ABSTRACT FROM AUTHOR]

Slab rollback during subduction plays a key role in controlling continental growth at convergent plate boundaries. The dynamics of currently subducting slabs can be precisely constrained using geophysical techniques. In contrast, ancient episodes of slab rollback can be difficult to constrain, yet are critical to unlocking the tectonic evolution of long‐lived orogens such as the Phanerozoic Australian Tasmanides of eastern Gondwana. Recognition of ancient slab rollback relies on the identification of the progressive migration of magmatic arcs. Here, we investigate the timing and isotopic variation of ∼90 km of the trans‐orogen migration of the Carboniferous Bathurst Batholith as a potential indicator of slab rollback. U–Pb–Hf isotopes, combined with a regional zircon Hf isotope data set, suggest that the eastward migration of the batholith over ∼18 Myr, from 340.1 to 322.4 Ma, records a maximum slab steepening rate of ∼0.6–1.2° Myr−1 in a relatively stable trench setting. These results provide a magmatic record of Carboniferous slab rollback and establish a missing link between the long‐lived Lachlan and New England orogens of the eastern Gondwanan Tasmanides. Plain Language Summary: Slab rollback occurs at convergent plate boundaries, which is key to understanding the evolution of subduction processes. However, for ancient subduction zones where the geometry of long since subducted slabs no longer exists, the evolution of slab dynamics remains unclear. Occasionally though, the progressive migration of magmatic trends is observable and provides constraints on slab rollback, which aid in reconstructing the tectonic evolution of long‐lived orogens, such as the Phanerozoic orogens of eastern Australia. Here, we focus on how the unique magmatism of the Carboniferous Bathurst Batholith progressively migrated in the direction of the trench and analyze and interpret the geochronological and geochemical evolution of the batholith to better constrain subduction dynamics. We find that the Bathurst Batholith records the Carboniferous slab rollback of eastern Gondwana and reveals the relationship between the two key orogens of eastern Australia. Thus, the migration of magmatism in convergent settings can be used to track the slab rollback processes and evolution of the long‐lived orogens. Key Points: The Bathurst Batholith is part of a Carboniferous continental arc formed as a result of westward subduction in eastern GondwanaEastward migration of the batholith over ∼18 Myr recorded a maximum slab steepening rate of ∼0.6–1.2° Myr−1 in a stable trench settingThe batholith as a trans‐orogen "missing link" reveals continental arc magmatism extended across the Lachlan and New England orogens [ABSTRACT FROM AUTHOR]

The Sanandaj-Sirjan Zone is a basement culmination northeast of the Neo-Tethys suture in Iran. In this zone near Azna, granite has a magmatic zircon U-Pb age of 568 ± 11 Ma, with 900-800, ca. 2400, and ca. 3600 Ma inherited cores. The ca. 3600 Ma inherited zircon is the oldest crustal component yet detected in Iran. Near Chadegan, orthogneiss has a magmatic zircon U-Pb age of 637 ± 15 Ma, and carries ca. 1000 and 2000 Ma inherited zircons. Inherited 900-1000 Ma zircons have juvenile initial [ζ.sub.Hf] values of ca. +8 to +9, whereas the younger 630 and 568 Ma magmatic zircons show lower initial [ζ.sub.Hf] values; however, the 3600 Ma core has initial [ζ.sub.Hf] = 0.0. A Neoproterozoic rim on the inherited 3600 Ma core has the most extreme initial [ζ.sub.Hf] value of -18. The Hf isotopic data indicates generation of the magmatic protoliths from a mixture of juvenile Neoproterozoic and Archean sources. Previous studies showed that in Turkey the Central Anatolian Crystalline Complex is underlain by Neo-Eoarchean rocks, the Menderes Massif contains Neoproterozoic granitoids, and that central Iran's basement and the northern Sanandaj-Sirjan Zone contain Neoproterozoic granitic rocks. This basement terrane is from Gondwana, and was transferred across Paleo-Tethys to dock against Eurasia's southern margin. Occurrence in Iran and Turkey of Eoarchean crust raises the possibility of sinistral migration of this terrane in the closure of Tethys because the nearest known early Archean crust occurs in northeast India. La zone Sanandaj-Sirjan constitue un bombement du socle au nord-est de la suture de l'ocean Neotethys en Iran. Dans cette zone a proximite d'Azna, le granite a un age magmatique (U-Pb sur zircon) de 568 ± 11 Ma, avec des noyaux herites de 900-800, ~2400 et ~3600 Ma. Le zircon herite d'environ 3600 Ma est le plus ancien composant de la croute detecte a ce jour en Iran. A proximite de Chadegan, un orthogneiss a un age magmatique (U-Pb sur zircon) de 637 ± 15 Ma et comporte des zircons herites d'environ 1000 et 2000 Ma. Les zircons herites ages de 900-1000 Ma ont des valeurs juveniles initiales [ζ.sub.Hf] d'environ +8 a +9, alors que les zircons magmatiques plus jeunes, 630 et de 568 Ma, montrent des valeurs [ζ.sub.Hf] initiales inferieures et que le noyau de 3600 Ma a une valeur initiale [ζ.sub.Hf] de 0,0. Une bordure neoproterozoique sur le noyau herite de 3600 Ma a la valeur initiale [ζ.sub.Hf] la plus extreme, soit de -18. Les donnees isotopiques Hf indiquent une generation de protolites magmatiques a partir d'un melange de sources juveniles proterozoiques et archeennes. Des etudes anterieures ont montre que le complexe cristallin de l'Anatolie centrale en Turquie repose sur des roches neo-eoarcheennes, que le massif Menderes contient des granitoides neoproterozoiques et que le socle du centre de l'Iran ainsi que la zone Sanandaj-Sirjan nord contiennent des roches granitiques neoproterozoiques. Ce terrane de socle provient de Gondwana et il a ete deplace a travers la Paleotethys pour s'amarrer a la bordure sud de l'Eurasie. La presence en Iran et en Turquie d'une croute eoarcheenne souleve la possibilite d'une migration senestre de ce terrane lors de la fermeture de l'ocean Tethys; la croute archeenne la plus proche se trouve en effet dans le nord-est de l'Inde. [Traduit par la Redaction], Introduction The cratons are the traditional hunting ground for early Precambrian crust, with most revealing histories dating back to 3.4 Ga or earlier (e.g., Nutman et al. 1996). However, serendipitous [...]