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Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry (Istria, Croatia)

Blanka Cvetko Tešović ; Odsjek za geologiju, Prirodoslovno matematički fakultet
Aleksandar Mezga ; Odsjek za geologiju, Prirodoslovno matematički fakultet
Bosiljka Glumac ; Department of Geology, Smith College

Sažetak

The Kirmenjak locality of western Istria, Croatia, represents the oldest evidence of a dinosaur presence on the Adriatic-
Dinaridic Carbonate Platform (ADCP). In a quarry at this locality, almost a thousand sauropod footprints are
recognized in one distinctive trackbearing horizon within the Upper Tithonian limestones. The stable isotopes of
oxygen and carbon, in conjunction with microfacies analysis of carbonate rocks exposed in this quarry, unravel details
about the marginal marine or coastal environments in which sauropods left their footprints. Rocks from the
trackbearing horizon, and laterally adjacent area, represent intertidal fenestral mudstones that form the top of a shallowing-
upward succession, capped with a thin peloidal packstone/grainstone layer and overlain by subtidal mudstone.
The formation and preservation of footprints was favoured by short-duration exposure of muddy sediment and
its rapid burial beneath more mud. The isotopic composition of the sample from the trackbearing horizon is not substantially
different from those of an adjacent area without footprints and from the overlying mudstone. Stable isotope
analysis supports petrographic observations that the conditions on the carbonate tidal fl at during formation of rocks
with dinosaur footprints were not unique. Documented variations in stable isotope compositions refl ect minor differences
in the depositional and diagenetic history of the Kirmenjak quarry succession.

Ključne riječi

Stable isotopes; Palaeoenvironments; Sauropods; Upper Tithonian Limestones; Istria; Croatia

Hrčak ID:

24877

URI

https://hrcak.srce.hr/24877

Datum izdavanja:

2.7.2008.

Posjeta: 1.722 *