Abstract The Archean age granite gneiss basement along the Prydz Bay coastline in East Antarctica hosts north–south-, east–west-, NE–SW- and NW–SE-trending mafic dyke swarms in the Vestfold Hills region that intruded between 2420 and 1250 Ma. The orientations of dykes do not show a direct correlation with the dyke geochemistry. Instead the dykes can be broadly discriminated into high-Mg and Fe-rich tholeiites. The former type is more siliceous, large ion lithophile elements (LILEs), high field strength elements (HFSEs) and light REEs enriched crystallized from a fractionated melt with a notable crustal component or fluid enrichment through the previous subduction process. The Fe-rich tholeiites are less siliceous, have lower abundances of LILEs and REEs, that indicates derivation from an undifferentiated, primitive melt. The geochemical characteristics of both types underline a shallow level and a high degree of melting in the majority of cases, and a broadly island arc basalt (IAB) affinity. Palaeomagnetic analysis of hand samples shows directional groups consistent with geochemical groupings. The Vestfold Hills dykes show a possible linkage with the coeval mafic dykes in the Eastern Dharwar and Bastar cratons of the South Indian Block, based on the similarity in the Paleoproterozoic palaeolatitudes.

Abstract In this short paper, we outline the potential links between India and the East Antarctica region from Enderby Land to Princess Elizabeth Land using the Mesozoic East Gondwana configuration as a starting point. Palaeomagnetic data indicate that East Gondwana did not exist prior to the Ediacaran–Cambrian. Early Neoproterozoic (1050–950 Ma) deformation in East Antarctica and along the Eastern Ghats Province in India marks the initial contact between the two regions. Volcanism in the Kerguelen hotspot led to final break-up of India and East Antarctica in the Cretaceous. Although connections between the Archaean and Proterozoic provinces of India and East Antarctica have been proposed, the current record of large igneous provinces (or dyke swarms), palaeomagnetic data and geochronology do not show a consistently good match between the two regions.

Abstract The Precambrian geological history of Peninsular India covers nearly 3.0 Ga. The Peninsula is an assembly of five different cratonic nuclei known as the Aravalli–Bundelkhand, Eastern Dharwar, Western Dharwar, Bastar and Singhbhum cratons along with the Southern Granulite Province. Final amalgamation of these elements occurred either by the end of the Archaean (2.5 Ga) or by the end of the Palaeoproterozoic ( c. 1.6 Ga). Each of these nuclei contains one or more sedimentary basins (or metasedimentary basins) of Proterozoic age. This chapter provides an overview of each of the cratons and a brief description of the Precambrian sedimentary basins in India that form the focus of the remainder of this book. In our view, it appears that basin formation and subsequent closure can be grossly constrained to three separate intervals that also broadly correspond to the assembly and disaggregation of the supercontinents Columbia, Rodinia and Gondwana. The oldest Purana-I basins developed during the 2.5–1.6 Ga interval, Purana-II basins formed during the 1.6–1.0 Ga interval and the Purana-III basins formed during the Neoproterozoic–Cambrian interval.

Abstract Northern Ethiopia is marked by a fanning system of thrust planes with NW-dipping structures in the east and southeast-dipping in the west. The central zone of this large-scale (200 km long) structure is formed by a c. 10 km wide zone of localized strain and amphibolites facies metamorphic conditions (680 °C and 3.4 kbar) referred to as the Central Steep Zone (CSZ). The CSZ comprises a mafic rock assemblage of amphibolite, serpentinite showing ocean-floor characteristics and calc-silicate schist. A monzonite intrusion in the central part of the CSZ post-dates the deformation and is related to partial melting of the mafic rocks. Magnetic fabric measurements reveal NE-trending (043°) steep foliations in the CSZ with vertical orientation of lineation, parallel to the axes of micro-folds. This high-strain zone is interpreted as central zone of a positive flower structure on the basis of simultaneous flattening and shear movement, typical for transpressive kinematics. The CSZ has a northern continuation into the Nafka terrane of Eritrea where it can be traced over a distance of 200 km. This high-strain belt forms a major structure in the context of Arabian–Nubian Shield (ANS) collision tectonics during the closure of the Mozambique Ocean and assembly of Gondwana.