| Abstrakt: |
The sinking of a deep drill hole (3003.5 m) for geothermal exploration in the eastern part of the Piton de la Fournaise volcano on Réunion Island has revealed the underlying lithostratigraphy. Six principal sequences have been distinguished: (a) 0–440 m, subaerial basaltic flows; (b) 440–556 m, a transitional series characterized by an alternation of subaerial basalts and submarine deposits (vitric basalt and hyaloclastic breccia); (c) 556–616 m, submarine basalts (lavas and hyaloclastites); (d) 616–890 m, subaerial basalts; (e) 890–1010 m, submarine basaltic deposits with abundant argillized hyaloclastites; (f) 1010–3003.5 m a layered intrusive complex comprising: 1010–1129 m, sheets of gabbro injected into the lavas and hyaloclastites; 1129–1920 m, a zoned intrusion of olivine gabbro and dolerite; 1920–3003.5 m, stratified cumulate gabbro-wehrlite-dunite. |
