DOLOMITES - Annexes 2-8 - Provincia di Udine

NOMINATION OF THE DOLOMITES FOR INSCRIPTION ON THE WORLD NATURAL HERITAGE LIST UNESCO
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(Kalke des Latemar, Richthofen 1860), representative of the internal platform deposits (well-stratified
micrites and calcarenites).
The prevalent lithologies on a regional scale are mainly white or light gray granular dolomites that
are re-crystallized, and to a much lesser extent limestones and white or light gray dolomitic limestone
(from the textural point of view: microbialitic boundstone associated with bio-intraclastic calcirudites
and calcarenites).
Start up and evolution of the pre-volcanic
Ladinian platforms and surrounding
basins and deep sea straits. The Anisian
platform of the Contrin Formation broke
down in blocks (A); some of those blocks,
slightly tilted, emerged from the water
and the lifted part suffered karst erosion
(B). While the all region is affected by a
strong subsidence, on the emerged or less
deep areas, took root organic communities
of corals, sponges and algae (C), whose
carbonate production it’s so abundant
to keep pace with the strong subsidence;
afterwards, when the subsidence rate
slowed down, the carbonate production
induced a lateral expansion (progradation)
on the surrounding basinal sediments of
the Buchenstein Formation (D). (Modified
from Bosellini, 1996).
Pervasive dolomitization processes that affected ‘Dolomia dello Sciliar’ make it difficult to recognize
the original sedimentary structures and textures. Where this doesn’t occur, and the original calcareous
lithology is preserved, one can still distinguish the different facies of the platform (e.g. M.
Coldai, Monte Cernera, Sass da Putia/Peitlerkofel, Gruppo del Latemar, Marmolada). It appears that
this area was a productive margin essentially dominated by microbialitic deposition, both in the form
of stromatolitic laminites and of trombolites, with an extreme abundance of early, fibrous cements;
in association, skeletal cyanobacteria, dasycladales, problematica (Tubiphytes sp.), skeletal metazoans
(prevalent sphinctozoan; rare colonial corals).
However, even where the original limestone lithology is not preserved, within the platform buildups,
three main areas based on depositional geometry can be distinguished (Bosellini, 1984): internal lagoon,
margin, and slope, developed diversely in the different carbonate buildups.
The inner lagoon facies are characterized by plane-parallel stratification; the sediments, where it is