Precise U–Pb dating of Paleoproterozoic mafic dyke swarms of the Dharwar craton, India: Implications for the existence of the Neoarchean supercraton Sclavia

Constraining atmospheric oxygen and seawater sulfate concentrations during Paleoproterozoic glaciation: In situ sulfur three-isotope microanalysis of pyrite from the Turee Creek Group, Western Australia

“…Thick flood basalt sequences of this age are recorded from Western Australia (2209 ± 15 Ma Cheela Springs Basalt; Martin et al, 1998) and South Africa (2222 ± 12 Ma Hekpoort and Ongeluk lavas; Cornell et al, 1996;Dorland, 2004). Equivalent intrusive rocks from North America include the extensive 2219 ± 3 to 2210 ± 3 Ma Nipissing diabase intrusions (Corfu and Andrews, 1986;Noble and Lightfoot, 1992) and Seneterre dykes (2216 + 8/À4 Ma; in Buchan et al, 1996), as also recorded in India (French and Heaman, 2010), and in China (2199 ± 11 Ma gneisses and 2193 ± 15 Ma gabbros; Zhao et al, 2008;Wang et al, 2010).…”

The Basement of the Deccan Traps and Its Madagascar Connection: Constraints from Xenoliths

“…Juxtaposition of India and Madagascar at 120 Ma and suggested correlation of shear zones and tectonic units, as proposed by Ishwar Kumar et al (2013). The published ages of the crustal units in western India and northcentral Madagascar are shown (age data compiled from Balasubramanian et al 1978;Swami Nath and Ramakrishnan 1981;Naqvi and Rogers 1987;Gupta et al 1988;Agarwal et al 1992;Jayananda et al 1995Jayananda et al , 2000Peaucat et al 1995;Russel et al 1996;Tucker et al 1999bTucker et al , 2011bTucker et al , 2014Chawwick et al 2000;Paquette et al 2003;Ghosh et al 2004;French and Heaman 2010;Schofield et al 2010;Ishwar Kumar et al 2013;Rekha et al 2013). A major part of the Peninsular Indian basement along the Konkan coast is covered and hidden by volcanic rocks of the Deccan Traps, making reliable correlations with Madagascar difficult.…”

“…It is tentatively correlated with thermal metamorphism associated with the emplacement of the oldest set of mafic dyke swarm within the Dharwar craton at ca. 2.37 Ga (French et al 2010).…”

2.24 Ga mafic dykes from Taihua Complex, southern Trans-North China Orogen, and their tectonic implications

“…The high Fe contents can be obtained from: (1) up-welling mantle plume (Gibson et al, 2000); (2) garnet-bearing lherzolite (Takahahshi et al, 1998); (3) mantle-wedge metasomatized by slab-derived fluids/melts (Leybourne et al, 1999); (4) garnet-free refractory mantle (Hanski and Smolkin, 1995). Although mafic dyke swarms dated at ∼2.2 Ga were found globally in recent years and perhaps were related with mantle plumes (French and Heaman, 2010), the genesis of the Zhaiwa mafic dykes was unlikely to be associated with mantle plumes, because: (1) the Zhaiwa mafic dykes are only sparsely distributed, inconsistent with the widespread mafic rocks associated with mantle plumes; (2) plume-related basalts are generally enriched in Nb, Ta and have high Ce/Pb ratios (Callegaro et al, 2013), which is inconsistent with the Zhaiwa mafic dykes; (3) the calculated mantle potential temperatures (Tp) via the formula Tp = 1463 + 12.74MgO-2924/MgO (MgO in wt%) range 722-1135 • C (Herzberg et al, 2007;Herzberg and Asimow, 2008;Herzberg and Gazel, 2009), which is clearly lower that that related to mantle plume (i.e., 1560-1620 • C for the Galapagos mantle plume; Herzberg and Asimow, 2008). (Shaw, 1970) of a lherzolitic mantle source.…”