Mechanisms for phosphorus fluctuation in Phanerozoic volcanic rocks

Abstract

Phosphorus (P) is one of the most critical limiting nutrients for biological evolution, and volcanic rocks are a crucial source of available P for terrestrial ecosystems. Volcanic-sedimentary records indicate that massive volcanism on the North China Craton in the late Mesozoic supported the evolution of terrestrial biotas. The variation of P content in the Mesozoic mafic volcanics mainly results from melt-garnet reactions during lithospheric thinning. The high P contents in most mafic volcanics worldwide could be related to the contents of olivine and clinopyroxene. In contrast, P variation in felsic volcanics could depend on apatite saturation. In the Phanerozoic volcanics, P content increases with the decrease of rock ages, resulting from the Earth's cooling. The contents of P and SiO 2 in these Phanerozoic volcanics have similar variation trends. However, this is not the case for intrusive rocks, which could have experienced more complex and protracted magmatism. Therefore, deep processes and associated magmatism control the variation of P in volcanics, ultimately reflected in the evolution of surface ecosystems. • Late Mesozoic volcanic P supply supported the evolution of terrestrial biotas. • Melt-garnet reactions affected mafic volcanic P variation with lithospheric thinning. • Olivine and clinopyroxene contributed to P variation in mafic volcanic rocks. • Apatite saturation resulted in P variation in felsic volcanic rocks. • The P content in the Phanerozoic volcanic rocks increased with Earth's cooling.