Approccio micropaleontologico disciminante per riconoscere la provenienza alpina o appenninica della Scaglia Rossa (Italia centro-settentrionale)

The Scaglia rossa is one of the best known geological formations to archaeologists who study the petrography of lithic industries in Central and Northern Italy. It is constituted by upper Cretaceous to middle Eocene reddish to whitish hemipelagic micritic limestones containing reddish to yellowish brown chert nodules and lenses mainly distributed in specific stratigraphic layers. Together with the lower Cretaceous Biancone (Prealps) and the Maiolica / Calcari a Calpionelle formations (Apennines) the Scaglia Rossa chert constituted one of the main provisioning resources for the prehistoric groups living and moving in a wide area spread from the southern slope of the Alps to the northern and central Apennines. The basin where the Scaglia deposited was quite large going from Trentino in the north to Lazio in the south and from Lombardia in the west to Friuli in the east and the chert is widespread: samples look very similar in color and texture. It has long been unsuccessfully discussed as to whether there are any criteria which could allow the identification of the cherts, in particular the ones cropping up in two different chains like the Prealps and the Appennines. As this article highlights, a micropaleontological approach makes it possible to distinguish most of the apennine cherts from the alpine ones as they date back to different ages.