To test vicariant speciation hypotheses derived from geological evidence of the closing of the Tethys Sea, we reconstruct phylogenetic relationships of the predominantly fresh-water killifish genus Aphanius using 3263 aligned base pairs of mitochondrial DNA from samples representing 49 populations of 13 species. We use additional 11 cyprinodontid species as outgroup taxa. Genes analysed include...

Turbiditic sandstones from the mid–Late Cretaceous Tianba Flysch sequence are well exposed near Tianba in the north Nieru Valley, southern Tibet, and contain significant amounts of chrome-rich spinels. Microprobe results show that the spinels have a well-developed Fe-Ti trend and have Cr/( ) 0.4–0.65, Mg/( ) 0.3–0.9, and TiO2 2 Cr Al Mg Fe 11%. The occurrence of melt inclusions, and well above ...

Ocean basins are formed when continents are broken apart. Adiabatic melt generation that is driven by rifting of continental lithosphere is strongly dependent on the rate of extension. Slow extension results in conductive heat loss from the upwelling mantle, whereas cooling is limited during fast extension and can result in the geotherm intersecting the peridotite solidus. However, there are fe...

Several pairs of solar system satellites occupy mean motion resonances (MMRs). We divide these into two groups according to their proximity to exact resonance. Proximity is measured by the existence of a separatrix in phase space. MMRs between Io–Europa, Europa–Ganymede, and Enceladus–Dione are too distant from exact resonance for a separatrix to appear. A separatrix is present only in the phas...

The hypothesis that the origin of the resonances among Saturn's satellites is due to orbital evolution is critically reviewed. It is concluded that the hypothesis provides a plausible explanation of the origin of the Mimas-Tethys resonance, but it is unsatisfactory for Bnceladus-Dione, since their resonance is having little effect on the relative evolution rate of these satellites at present.

Abstract In the Gasht-Masuleh area in Alborz Mountains, gabbroic magma intruded Palaeozoic metasediments and Mesozoic sediments crystallised as isotropic cumulate gabbros. LREE enrichment points to relatively low degrees of mantle melting depletion Ti, Nb Ta relative primitive an arc related component magma. Clinopyroxene compositions indicate MORB signatures. U–Pb zircon crystallisation ages 9...