LASI 1 was an international workshop on the physical geology of subvolcanic systems, promoted by Chris Breitkreuz and Nick Petford. LASI 1 was held at TU Bergakademie, Freiberg, Germany in 2002. The two-day workshop and one-day field trip led by Chris Breitkreutz and Alex Mock attracted 40 participants from 10 countries who presented papers covering a range of topics relevant to the geology and emplacement of high-level intrusions. Fourteen of the papers were subsequently published as a Geological Society Special Publication (Breitkreuz and Petford, Geological Society, London, Special Publication 234).

LASI 2 helped discover how the study of high-level magmatic systems developed over the four years since the previous meeting. Ken Thomson(†) and Nick Petford brought together workers in physical geology, igneous petrology, volcanology, structural geology, crustal mechanics and geophysics to discuss all aspects relating to the shallow emplacement of magma. The workshop was structured into two days with fourty-three oral presentations followed by a one-day field trip led by Donny Hutton and Ken Thomson to classic Palaeocene sill complexes of the Isle of Skye. Several papers presented at the workshop have been submitted for publication in a Geological Society, London, Special Publication (Thomson and Petford, Geological Society, London, Special Publication 302).

LASI 3 continued and updated the discussion of emplacement mechanisms of shallow tabular intrusions, and also extended the discussion to magma chemistry and the relationships between intrusive history and regional geology. The two-day field trip was devoted to two of the youngest (late Miocene) plutonic-subvolcanic complexes in Europe. Participants visited a nested felsic Christmas-tree laccolith complex, a major sheeted pluton, a mafic dyke swarm, and a felsic-aplitic dyke swarm coupled with classical ore mineral deposits. Several papers presented at the workshop are being submitted for publication in a Geosphere Themed Volume "Magma Pulses and Sheets in Tabular Intrusions" (Rocchi, Dini, Mazzarini, Westerman Editors).

LASI 4 is intended to continue the discussion about the emplacement processes, petrogenesis, magma system dynamics, fabric analysis, and geologic setting of shallow level magma emplacement. The two-day field trip will be devoted to the Henry Mountains, which are the type locality for the term ‘laccolith’ and have superb three-dimensional exposures of many forms of intrusions.  Field trips will document the incremental growth of a large intrusion from sill, to sheeted laccolith, to bysmalith (pluton). We will also examine evidence for assembly of intrusions through emplacement of multiple magma pulses (sheets).