Comment on “Timing and nature of the Xinlin–Xiguitu Ocean: constraints from ophiolitic gabbros in the northern Great Xing’an Range,eastern Central Asian Orogenic Belt” by Feng et al. (2016)

International Journal of Earth Sciences - We disagree the transitional supra-subduction zone model of Feng et al. (Int J Earth Sci (Geol Rundsch) 105:491–505, 2016) for the tectonic setting...     

Comment on: “Enriched mantle – Dupal signature in the genesis of the Jurassic Ferrar tholeiites from Prince Albert Mountains (Victoria Land, Antarctica)” by Antonini P. et al. (Contributions to Mineralogy and Petrology 136, 1–19; 1999)

18 O values, the magmas retain initial ⁸⁷Sr/⁸⁶Sr Compositions of greater than 0.709 (e.g. Hoefs et al. 1980). Consistent with this is the lack of a radiogenic Os isotope signature in these rocks (e.g. Molzahn et al. 1996) as would be expected with assimilation of continental crust. Comments here are not concerned with the AFC calculations employed to describe the variations within the suite of samples from the Prince Albert mountains studied by Antonini et al., but rather, the extrapolation of these to more primitive compositions. Antonini et al. have revived the possibility that the unusual chemical features of the least evolved low Ti continental flood basalts of the Ferrar Province reflect a crustal-level interplay between mantle-derived magmas and the continental crust. It is argued here that they have not demonstrated their claim. Received: 7 October 1999 / Accepted: 25 January 2000