Spherulites as Recorders of Multi-batch Felsic Magma Transport and Time Scales: A Case Study from Southeast of China.

This article focuses on using spherulites—spherical mineral aggregates formed by immiscible felsic magma—as natural recorders to reconstruct the ascent, transport, and emplacement processes of felsic magma within crustal magma plumbing systems. Through petrographic, geochemical, and microscopic analyses of spherulitic rhyolite porphyry dikes from the Late Jurassic–Early Cretaceous volcanic region in southeastern China, the study identifies three generations of spherulites that correspond to magma residence in three distinct magma chambers during episodic ascent. By applying measured natural spherulite growth rates, the authors estimate a total magma chamber residence time of about 90 days, revealing a pulsed magma transport mechanism with increasing frequency near the surface. This spherulite-based geochronological method offers a novel, quantitative approach to tracking magma migration paths, compositional evolution, and time scales, with potential applicability to other felsic volcanic regions and implications for understanding volcanic activity and mineralization processes.