Large Ra excesses in a number of mafic arc magmas, and geophysical observations of earthquake hypocenters locations, indicate that mafic melts can get transferred from source to surface within days to ~1 kyr. Decreasing Ra–Th disequilibria with increasing SiO2 in co-magmatic suites of individual arc volcanoes suggest that magma differentiation often occurs on timescales of a few thousand years ...

The behavior of nickel (Ni) isotopes during magmatic differentiation is not adequately explored. Here, we find that tholeiitic rocks in the Kīlauea Iki (KI) lava lake, Hawai'i, show progressively lighter Ni isotopic compositions with increasing differentiation, whereas calc-alkaline from thick Kamchatka arc (30–45 km), located at convergent boundary Eurasian and Pacific plates isotope values as...

The Pirrit Hills are located in the Ellsworth–Whitmore Mountains of West Antarctica. granite exhibits significant negative Eu anomalies (Eu/Eu* = 0.01~0.25) and a REE tetrad effect indicating intensive magmatic differentiation. Whole-rock Rb-Sr Sm-Nd geochronologic analysis gave respective ages 172.8 ± 2.4 Ma with initial 87Sr/86Sr 0.7065 0.0087 169 12 144Nd/143Nd 0.512207 0.000017. isotopic ra...

The Wadi Dib magmatic complex is the oldest known alkaline ring complex in the Egyptian part of the Pan-African orogenic belt. Rb-Sr isotope data for seven samples suggest a Vendian age of 578=k16 Ma, and a 87Sr/S6Sr initial ratio of 0.7048±0.0010. The igneous complex has a diameter of 2 km and was emplaced within granodioritic Pan-African host rocks at the intersection of two faults. It shows ...