The triple orogenic junction of central Gondwana

The Neoproterozoic tectonic evolution of central Gondwana involved three successive continental collisions, associated with the East African Orogeny (late Cryogenian), the Kirwan Orogeny (early Ediacaran), and the Kuunga Orogeny (late Ediacaran). The interactions between these orogenies produced extensive reactivation of Archean to Mesoproterozoic basement rocks, as well as deformation and metamorphism in the Neoproterozoic cover sequences. To unravel the geological history of central Gondwana, we compiled zircon and monazite U-Pb ages (from igneous, detrital, and metamorphic rock samples), Sm-Nd and Lu-Hf isotope data, and thermobarometric P-T peak estimates from 19 tectonic terranes. The dataset, which encompasses the regions of eastern Africa, southern India, central-southern Madagascar, Sri Lanka, and East Antarctica, enables us to reconstruct the history of these three orogenies. The analysis of 2208 concordant U-Pb metamorphic zircon ages, ranging from 700 to 450 Ma, indicates that a peak metamorphic event occurred at ~ 550 Ma. Our dataset allows us to identify records of similar tectonic events amongst different terranes, thus demonstrating correlations between the multiple terranes of central Gondwana. A reassessment of previous tectonic reconstructions is discussed based on geochronological and isotopic data from a potentially contiguous province named TNASH (Trivandrum and Nagercoil terranes in southern India, Androyen and Anosyen terranes in southwestern Madagascar, Skallevikshalsen terrane in East Antarctica, and Highland Province in Sri Lanka). These Paleoproterozoic terranes exhibit comparable U-Pb igneous ages, isotopic signatures (Lu-Hf and Sm-Nd), and metamorphic conditions. Our study provides an extensive review into the complex tectonic history of central Gondwana, and a better understanding of the strengths and limitations of previous hypotheses.

We present a compilation of U-Pb ages and isotopic data from 19 central Gondwana terranes.
Our dataset includes 2208 metamorphic concordant U-Pb zircon and monazite ages (700–450 Ma).
The data allow us to characterize the Kirwan Orogeny.
Alternative hypotheses for the Neoproterozoic assembly of central Gondwana are reviewed.

We present a compilation of U-Pb ages and isotopic data from 19 central Gondwana terranes.
Our dataset includes 2208 metamorphic concordant U-Pb zircon and monazite ages (700–450 Ma).
The data allow us to characterize the Kirwan Orogeny.
Alternative hypotheses for the Neoproterozoic assembly of central Gondwana are reviewed.