Spinotti Formation

The Spinotti Formation can be subdivided into three units: Unit 1, a lower massive stromatoporoid and crinoid-rich bioclastic limestone (from the onset of massive limestone below the ladder at 1880 m to elevation 1970 m at Sentiero Spinotti; elevation 1840-1860 m at Seekopf base), followed by Unit 2, a thick-bedded to massive light gray grainstone to rudstone. Beds are two to three meters thick with thin (25-30 cm) dolomitic interbeds. Higher up section the bed thickness decreases to 0.5-1 m and dolomite beds become more prevalent. Components are largely peloids and intraclasts comparable to the Eiskar Limestone described by Kreutzer (1990, 1992a). Unit 3 is characterized by bedded limestone with well-developed birdseye structures from elevation 2020 m to 2200 m. Dark limestones with Amphipora become more common in this upper part. Above the trail at 2120 m are bedded limestones with Stringocephalus exposed. This unit also contains many gastropods and amphipores. Bandel (1972: 30) observed stringocephalids in the area called “dolines” beyond Costone Stella at elevation 2180 m. These cannot be correlated with the ones at 2120 m and must belong to a higher stratigraphic unit, suggesting that the Eifelian-Givetian boundary is located approximately in the middle of the section.