Giencias da,Terra c0N!.-) pp .. 289·296 .2 Figs., I :rab. High-resolution correlation of coastal cliff sections in the Lagos- Portimao Formation (Lower - Middle Miocene, central Algarve, Portugal) Markus H. Forst<l), Thomas C. Brachert<l,J) & Joiio Pais(l) I - Institul nu- Geowisscnscllaften, Palaonlologic, Johanncs GUlcnberg· Univcrsillu Mainz, 0-55099 Mainz, Germany (
[email protected]·mainz.dc) 2 • Ccntro de Estudos GeoI6gieos, Faculdade de Ciencias e Tecnologia, Quinta da Torre, 2S25 - 114 Caparica, Portugal (
[email protected]). 3 · Present adress: Inslitul und Museum flir GeoIoSic und Paliontologie, Georg-Augusl-UniveniUit, GoldschmidlStr. 3, [)"17077 GMingen, Gcnnany (
[email protected]). ABSTRACT Keywords: Bed·by-bed correlation; outcrop gamma ray logging; biofacies analysis; Miocenc; Algarve; S-Portugal. This paper describes a high-resolution stratigraphic correlation scheme for the early to middle Miocene Lagos-Portimao Fonnation of central Algarve, southern Portugal. The Lagos Portimio·Formation ofcentral Algarve is a 60 m thick package of horizontally bedded siliciclastics and carbonates. The bryozoan and mollusc dominated biofacies is typical of a shallow marine, wann-lemperate climatic environment. We define four strati graphic marker beds based on biofacies, lithology, and gamma-ray signatures. Marker bed I is a reddish shell bed composed predominantly of bivalve shells in various stages of fragmentation. Marker bed 2 is a fossilifcrous sandstone J sandy rudstone characterized by bryozoan masses. Marker bed 3 is also a fossiliferous sandstone with abundant larger foramin ifers and foliate bl)'ozoans. Marker bed 4 is composed ofthree distinct layen: two fossiliferous sandstones with an intercalated shell bed.