Jurassic guyots on the Southern Iberian Continental Margin: a model of isolated carbonate platforms on volcanic submarine edifices

During the middle Jurassic on the Southern Iberian Continental Margin (at the westernmost end of the northern Tethys) isolated carbonate platforms developed over volcanic edifices, forming guyots. The volcanic edifices were composed of K-rich pillow-lavas and pyroclastic rocks with a radiometric age ≈ 170 Myr. Such phenomena have not been described until now in this continental margin nor in other passive continental margins of Alpine domains. The presence of a shallowing-upward megasequence (Bajocian–Bathonian) with hummocky cross- stratification strata below oolitic shoals, shows that very shallow isolated carbonate platforms developed above the volcanic edifices, with similar facies to those recognized in other guyots, but with a different age and geodynamic context.