Surface deformation induced by pluton emplacement: The case of Amiata (Italy)

The Amiata area was uplifted during the Pliocene as a consequence of pluton emplacement in an extensional setting. In the Middle Pleistocene, a fissur al eruption filled a depression within the uplifted area. Field analysis an d analogue models are integrated to study the surface deformation induced b y the emplacement of the buried pluton. Field work recognized a domed overb urden, approximate to2.5 km high and 35 x. 50 km wide. Analogue models of p luton emplacement show three stages at the surface, which consist of: domin g, development of a crestal depression and apical extrusion. Theoretical ca lculations suggest that the bending stresses and the stretching of the brit tle layer during doming induce the development of the apical depression in experiments and nature. This, in turn, is responsible fur a localized decom pression, enhancing extrusion. The integrated data suggests that doming, cr estal depression and fissural volcanism at Amiata are sequential features d ue to pluton emplacement in an extensional setting. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.