Middle Pennsylvanian vegetation of the San Giorgio Basin, southern Sardinia (Italy)

Abstract

The small, intramontane San Giorgio Basin in southwestern Sardinia has yielded plant macrofossils dominated by sphenophytes, but with subsidiary pteridosperms, ferns, (?)noeggerathians and cordaitanthaleans. They belong to the upper part of the Crenulopteris acadica Zone or possibly the Odontopteris cantabrica Zone, indicating a late Asturian or Cantabrian (≡ late Moscovian) age. They therefore correlate with the post-Leonian deposits in northern Spain, the Nýřany Member in Western and Central Bohemia, and the Llantwit Beds in South Wales. The presence of post-tectonic deposits of this age is further evidence of the widespread influence of the Leonian Phase of tectonic activity in middle Asturian times, whose effect can be observed across Europe. The San Giorgio Basin is therefore a late Variscan rather than post-Variscan basin.