The Cadomian and Variscan record of the Gondwana margin in Israel: Protracted Crustal Evolution between the Arabian-Nubian Shield and multiple Tethyan Oceans

The northern extent of the supercontinent Gondwana in the late Neoproterozoic-Cambrian is not well defined. In most localities the continental margin is covered by thick sedimentary successions, formed following the successive rifting of Tethyan Oceans that episodically detached continental terranes from the edge of the supercontinent. East of the Mediterranean, despite the continental continuity between the Arabian-Nubian-Shield (ANS) and the Tauride block (a Cadomian terrane), the original transition between the two crustal domains is inaccessible and remains obscured. In Israel, investigations of Late Ediacaran, late-stage igneous intrusions of the ANS in the South, together with granulite xenoliths from the lower crust in the North, allow us to probe into the North-Gondwana edge in the late Neoproterozoic and envisage its transition towards the peri-Gondwana Cadomian realm, as well as the evolution of the North Gondwana crust subsequently to the Neoproterozoic. Geochronology and isotopic geochemistry of alkaline intrusions in the Amram massif (southern Israel) as well as doleritic intrusions in the late Neoproterozoic Zenifim Formation (subsurface of south-central Israel) has revealed an igneous and thermal imprint at ca. 550 Ma recorded by the reset of apatite U-Pb ages, together with additional apatite U-Pb dates taken to represent crystallization. Nd and Hf isotopes in apatite, zircon and whole rock also show the ca. 550 Ma intrusions are isotopically distinct from the ANS and resemble Cadomian magmatism in the Taurides. Granulite xenoliths from the lower crust under the lower Galilee (North Israel) contain abundant zircons of distinct U-Pb-Hf properties. These include detrital grains remnant of Neoproterozoic sediment that was subducted and relaminated to the lower crust, late Carboniferous zircons (peaking at 300 Ma) with contrasting εHf_(t) signatures, some of which represent syn-Variscan magmatism, and zircons with the age of the host Pliocene basalt. We demonstrate that the Cadomian (ca. 550 Ma) igneous and thermal imprint on the North ANS may have been driven by proto-Tethys subduction that brought about sediment relamination to the North Gondwana lower crust in the latest Neoproterozoic. The late Carboniferous ages recorded in the xenoliths involve both the reworking of depleted ANS basement as well as the relaminated sediment in the means of metamorphism and minor magmatism. Carboniferous thermal disturbance was associated with the formation of continental scale basin and swell architecture across present-day N Africa, Arabia and Iran, and the development of ‘Hercynian unconformities’ in these areas, that were located at the time south of the passive(?) margin of Paleo-Tethys.