Mount Etna: Variations in its internal plumbing

On the basis of historical records of eruptions and the results of recent volcanological, petrological and geophysical investigations, a model for the internal plumbing of Etna is proposed. It is argued that, over about the last 200 years, hawaiite magma has been fed from a deep-seated crustal reservoir at about 20 km depth to be erupted at the surface with no long term high level storage. This is quite a different model for basaltic plumbing from that suggested for Kilauea Volcano on Hawaii. However, the presence on Etna of ignimbrites, more evolved lavas of mugearite and benmoreite composition, calderas and thick pyroclastic sequences indicates that, at times in the prehistoric past, the style of volcanic activity was different to that of the present. At these times there must have been substantial high level storage of magma in the volcano. It is apparent that the internal plumbing of Etna has varied during the history of the volcano. It is considered that the deep seated crustal reservoir plays an important role in the differentiation of the primitive primary magma.Paper presented at the Symposium Volcanoes of the Earth and Planets, held at the University of Lancaster, March 17, 1981.     

The last 5000 years of activity at Sete Cidades volcano (São Miguel Island,Azores): Implications for hazard assessment

Sete Cidades is a central volcano with a summit caldera at the western end of São Miguel Island, Azores. Its stratigraphy comprises two main geological groups: the Inferior Group, the units of which date from more than 200 000 years ago through to 36 000 years before present, consisting of thick lava flows and subaerial volcaniclastic deposits that built the base of the central volcano; and the Superior Group which comprises all the activity from the last 36 000 years, including pumice and scoria fallout and PDC deposits with minor lava flows. The volcanostratigraphy is divided into six main formations — Risco, Ajuda, Bretanha, Lombas, Santa Bárbara and Lagoas, each defined by different activity phases in the volcano's evolution.     

Scientific rationale for the D-CIXS X-ray spectrometer on board ESA's SMART-1 mission to the Moon

The D-CIXS X-ray spectrometer on ESA's SMART-1 mission will provide the first global coverage of the lunar surface in X-rays, providing absolute measurements of elemental abundances. The instrument will be able to detect elemental Fe, Mg, Al and Si under normal solar conditions and several other elements during solar flare events. These data will allow for advances in several areas of lunar science, including an improved estimate of the bulk composition of the Moon, detailed observations of the lateral and vertical nature of the crust, chemical observations of the maria, investigations into the lunar regolith, and mapping of potential lunar resources. In combination with information to be obtained by the other instruments on SMART-1 and the data already provided by the Clementine and Lunar Prospector missions, this information will allow for a more detailed look at some of the fundamental questions that remain regarding the origin and evolution of the Moon.