Monogenetic volcanic fields: Origin, sedimentary record, and relationship with polygenetic volcanism

Abstract

Monogenetic volcanism is commonly represented by evolution of clusters of individual volcanoes. Whereas the eruption duration of an individual volcano of a volcanic field is generally short, the life of the entire volcanic field is longer than that of a composite volcano (e.g., stratovolcano). The magmatic output of an individual center in a volcanic field is 1–3 orders of magnitude less than that of a composite volcano, although the total field may be of the same volume as a composite volcano in any composition. These features suggest that the magma source feeding both monogenetic volcanic fields and composite volcanoes are in the same range. Monogenetic volcanic fields therefore are an important and enigmatic manifestation of magmatism at the Earth's surface. The long eruption duration for an entire volcanic field makes this type of volcanism important for understanding sedimentary basin evolution. Accumulated eruptive products may not be significant from a single volcano, but the collective field may contribute significant sediment to a basin. The eruptive history of volcanic fields may span millions of years, during which dramatic climatic and paleoenvironmental changes can take place. Through systematic study of individual volcanoes in a field, detailed paleoenvironmental reconstructions can be made as well as paleogeographic evaluations and erosion-rate estimates. Monogenetic volcanoes are typically considered to erupt only once and to be short-lived; recent studies, however, demonstrate that the general architecture of a monogenetic volcano can be very complex and exhibit longer eruption durations than expected. In this way, monogenetic volcanic fields should be viewed as a complex, long-lasting volcanism that in many respects carries the basic characteristics similar to those known from composite volcanoes.