A9: ITALY

This page authored by Richard Twitchett.


This page gives details of Griesbachian (earliest Triassic) microbialites in the Werfen Formation at L’Uomo, Passa San Pellegrino, northern Italy, N46 deg, 23’42.6”; E011 deg, 47’55.2”. Samples come from a single bed, 10.5 - 11 m above base of Werfen Formation (i.e. the base of the section here) at only this site.


Not observed this structure anywhere else in Werfen Fm. Microbialite is on top of an oolite, which itself overlies a vuggy, yellow-coloured, bedded dolomitic unit (?peritidal). These beds are interpreted as representing a local sea-level fall within an otherwise transgressive sequence (Tesero Member through to Mazzin Member).

Note: although the stratigraphic height would indicate that this bed belongs to the lower Mazzin Member, the presence of an oolite could, depending on the lithostratigraphic definitions, be used to infer that this was uppermost Tesero Member. The Tesero/Mazzin contact has been described by some workers as being “transitional” at this locality.


CREDITS:

All images and descriptive text on this page provided by Richard.

Photos taken June 2008.


Coin in photos: 20 mm diameter

 
Go to Microbialite Atlas Contents PageGA3_Microb_Contents.htmlGA3_Microb_Contents.htmlshapeimage_1_link_0
Go to PTB map pageGA5_P-T_Boundary.htmlGA5_P-T_Boundary.htmlshapeimage_2_link_0

Outcrop view, showing dipping beds of the microbialite.

View of microbial structures in the microbialite bed.

View of microbial structures in the microbialite bed.

View of microbial structures in the microbialite bed.