Open Access

Lava identification by paleomagnetism: a case study and some problems surrounding the 1631 eruption of Mount Vesuvius, Italy

Earth, Planets and Space200658:BF03352611

https://doi.org/10.1186/BF03352611

Received: 7 February 2005

Accepted: 7 March 2006

Published: 16 September 2006

Abstract

Detailed rock magnetic, paleomagnetic and absolute paleointensity studies of lava flows from the disputed 1631 Mount Vesuvius eruption are reported. The magnetic carrier consists of pseudo-single domain state Ti-poor titanomagnetites. Characteristic magnetization directions determined from detailed stepwise alternating field and thermal demagnetizations provide four new well-defined flow unit mean directions, with α95 ranging from 0.7° to 2.6°. Paleodirections for 11 lava flows from 24-four flows studied previously appear to be related to the 1631 eruption, as indicated by their correlation to the early 17th century segment of the Italian paleosecular variation reference curve. This provides new evidence supporting the conclusion that the 1631 episode was an explosive-effusive eruption. The paleointensity results obtained from this study are the first to be published for Mount Vesuvius, with virtual dipole moments of 9.24±1.8 × 1022 and 13.5±0.4 × 1022 Am2 higher than the present-day geomagnetic field strength.

Key words

Paleosecular variation Vesuvius volcano 1631 eruption paleointensity Italy