DOLOMITES - Annexes 2-8 - Provincia di Udine

NOMINATION OF THE DOLOMITES FOR INSCRIPTION ON THE WORLD NATURAL HERITAGE LIST UNESCO
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(Moena), suggested the Triassic age of the basaltic volcanites and suggested that the faults and folds
spectacularly visible in the area were the result of tangential compressive forces more than the product
of the vertical displacement suggested by the von Buch’s Erhebungs theory. Wilhelm Fuchs, Agordo
Mine geologist, published (1814) a synthesis of the northern Dolomites (Badia Valley) geology
and a first accurate geological map of the area. Graf Georg zu Münster (1776-1844) described the
faunae of the argillaceous limestones from the San Cassiano Formation (1834, 1841), revealing the
apparently bottomless richness of this late Ladinian-early Carnian basinal formation.
Palaeontology works put the base of the modern ammonoid and pelagic pelecypods based biostratigraphy
of the Tethyan Triassic.
At the publication time of these contributions, major developments in the genetic understanding of
the carbonate platforms were developing. The German geologist Ferdinand von Richthofen (1833-
1905) at the age of 26, interpreted the Dolomites platforms as organic coral reefs from ancient tropical
seas (1860), drew accurate geological profiles of the western Dolomites platform and inferred
the role of the subsidence in the accumulation of thick piles of shallow water carbonates. An further
milestone in the Earth Science development was the publication, by Johan August Edmund von Mojsisovics
(1839-1907) of “Die Dolomitriffe von Südtirol und Venetien” (1879), a book illustrated by
some of the first spectacular photographs of the region and by an accurate geological map at the 1:75
000 scale. The nobleman confirmed the accuracy of von Richthofen interpretation and synthesised
an accurate interpretation of the depositional geometry and stratigraphic architectures of the platforms,
largely accepted even today. He interpreted the horizontally bedded nuclei of platforms as aggrading
lagoon, shallow-water, algal-rich sediments, flanked by massive reefs bodies and by large volumes
of slope brecciae. Despite lacking any knowledge of the modern tropical slopes, he brilliantly
interpreted the steep clinostratifications as Ueberguss-Schichten (primarily inclined beds), associated
to the slope growth. Against the accepted wisdom, he clearly stated that coeval, adjacent platform
and basinal deposits can have very different facies (Facies Heteropie). He subdivided the large carbonate
platform bodies according to the interfingering ammonoid-bearing basinal units. What we now
consider as Anisian-Ladinian pre-volcanic platforms were named Buchensteiner Riff, from the coeval
Buchenstein Formation (Livinallongo Fm). The syn-early post volcanic platform were named Wengener
Riff, the younger Cassianer, according to their interfingering with the San Cassiano basinal
formation. From a structural point of view, he considered the Southern Alps as a stair like systems of
brittle basement blocks, separated by high angle faults, lowering the southerner portion. High angle
faults is often what you can actually see in the field, even if now we recognize a number of important
Historical geological cross-section from the Sciliar/Schlern area to the left to the Sella by F. von Richthofen, 1860.