Aspectos gerais da tectónica alpina no Algarve

Abstract

Key-words: Tectonic-Algarve-Portugal-Cenozoic. The study of the tectonic strutures affecting the mesozoic and cenozoic deposits of Algarve's basin allows us to recognize the following phases of the Alpine orogeny: Jurassic (Upper Triassic at least)-Lower Cretaceous N-S distension; N-S compression during the setting-up of the Monchique syenite dome at lhe uppermost Cretaceous; Paleogene compression (?) (only locally? - at lhe Albufeira salt dome); Lower Miocene N-S distension; Upper Burdigalian to Lower Langhian N-S and E-W distension; N -S or NNW -SSE compression after lhe Middle Miocene; E-W compression after the Upper Tortonian; N-S compression during the Quaternary. NE-SW fractures affecting the Paleozoic basement are related with lhe first distension phases. The mesozoic N-S distension are the main cause of the two E-W flexures so far recognized. A tectonic inversion event did occur after the setting-up of the Monchique syenite. If, the Lower Cretaceous Lower Miocene Albufeira's unconformity, is a local effect of halokinesis then, the true tectonic inversion of the Algarve basin, did occur in the Middle Miocene. These events correlate well with those knewn at Southern Spain and Morocco.