Page 247 - Carbonate Facies in Geologic History

234 Permo-Triassic Buildups and Late Triassic Ecologic Reefs

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Fig. VIII-lO. Location map of the Dolomites of the southern Tyrol, Italy showing the location
of the major Triassic carbonate banks. After an index map of Bosellini and Rossi (1974,
Fig. 1). Hachured lines indicate platform edges marked by inclined foreslope beds and talus.
Location of banks from Leonardi (1967)

important fault zone. The great thickness of the carbonate buildups and the
effusive basic volcanic sediments which filled in around them indicates geosyn-
clinal subsidence on the outer continental margin (Bernoulli, 1972). This subsid-
ing area block-faulted during Triassic time and carbonate banks developed exten-
sively along it.
The area of the western Dolomites has been studied for more than 25 years by
the Geological Institute of the University of Ferrara. The culmination of this
effort is a two volume work by Pierro Leonardi in 1967, Le Dolomiti: Geologia dei
monti tra Isarco e Piave and the following paragraphs review part of it. See also
BoseIIini and Rossi (1974) for a review in English.
The great development of major carbonate banks was in Middle Triassic time
but a repetition of the shallow water restricted marine bank facies occurred also
in the Late Triassic. Stratigraphically the South Alpine Triassic is identical to
beds of this age in the complexly overthrust Northern Limestone Alps of Ba-
varia and Austria. These areas are separated from each other by the central and
metamorphosed axis of the Alps (Hohe Tauern Window) which crosses Austria in
an east-west direction (Fig. VIII-13). The precise area of derivation of the North-
ern Calcareous Alps is still one of the mysteries of the Alpine geology. Their root
zone may be either north or south of the crystalline axis.