We examined an alkaline ring complex in the Eastern Desert of Egypt, Wadi Dib (WDRC), to understand formation mechanisms intimately related structure and chemical diversity. The WDRC consists multiple circular rings oldest volcanic units, middle-stage plutonic unit, youngest dike these units show overlapping whole-rock major element compositions. compositional variation can be accounted for by ...

The eruptions of Campi Flegrei (Southern Italy), one the most studied and dangerous active volcanic areas world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte phonotrachyte. Petrological investigations carried out in past decades on rocks provide crucial information for understanding differentiation processes its magmatic system. However, compositional features a palim...

Many volcanoes have the ability to impact human infrastructure with explosive activity and understanding processes of magma generation conditions storage in these systems remains a priority. The Sete Cidades volcano on island São Miguel, Azores archipelago is exactly such lying only 12 km from island's capital city Ponta Delgada has been repeatedly active during Holocene. westernmost central Mi...

Abstract The Quaternary Tarosero volcano is situated in the East African Rift of northern Tanzania and mainly consists trachyte lavas some trachytic tuffs. In addition, there are minor occurrences extrusive basalts, andesites latites, as well peralkaline trachytes, olivine trachytes phonolites. Some phonolites contain interstitial eudialyte, making one few known for agpaitic rocks. This study i...

Ignimbrites are relatively uncommon on ocean island volcanoes and yet they constitute a significant portion of the stratigraphy Terceira Island (Azores). The Lajes-Angra Ignimbrite Formation (ca. 25 cal ka BP) contains youngest ignimbrites records two ignimbrite-forming eruptions Pico Alto volcano that occurred closely spaced in time. Here, we present first detailed lithofacies analysis archite...

Abstract Magma mixing is a widespread magmagenic process. However, its significance in the formation of ultrapotassic magmas has been largely overlooked so far as they are commonly thought to originate directly from mantle and ascend rapidly through crust. The Hezhong lavas Western Yunnan (SW China) (basaltic) trachy-andesitic composition. These rocks display porphyritic textures with olivine, ...

Unlike their silicic counterparts, mafic eruptions are known for being on the low-end of explosivity spectrum with eruption styles commonly ranging from effusive to Hawaiian fire fountaining. However, there increasing discoveries large Plinian eruptions, sometimes generating ignimbrites, suggesting that this phenomenon might not be so uncommon. So, what processes lead a magma fragment violently...