1,721,078 research outputs found
The ammonoid succession in the Bagolino Section (Ne Italy)
No full textWe wish to present here some considerations on Comment
on: “Refined ammonoid biochronostratigraphy of
the Bagolino section (Lombardian Alps, Italy), GSSP candidate
for the base of the Ladinian Stage” by Mietto P,
Gianolla P., Manfrin S. & Preto N. recently presented by
Brack P. & Rieber H. We find necessary to reply to this
comment, because we cannot agree with most of the criticisms
exposed there. In our reply, we will try, once again
to follow the spirit of constructive criticism suggested by
the International Code of Stratigraphic Nomenclature
Middle Triassic evolution of the Rio Freddo volcanism, southern Alps, Italy
No full textPetrographic and petrochemical investigations permit: 1) to distinguish the Upper Anisian volcanism from the Lower Ladinian one; 2) to suggest an evolution within the Rio Freddo Volcanics (rhyolitic to rhyodacitic); 3) to point out different characters of the various kinds of pyroclastics. Particularly, K-contents show anomalous enrichments in the ignimbrites. A model of vapour-phase crystallization, related to a fumerolic activity and fluid circulation, is suggested. -from English summaryPetrographic and petrochemical investigations permit: 1) to distinguish the Upper Anisian volcanism from the Lower Ladinian one; 2) to suggest an evolution within the Rio Freddo Volcanics (rhyolitic to rhyodacitic); 3) to point out different characters of the various kinds of pyroclastics. Particularly, K-contents show anomalous enrichments in the ignimbrites. A model of vapour-phase crystallization, related to a fumerolic activity and fluid circulation, is suggested. -from English summar
The Geoheritage inventory of the UNESCO Dolomites property (northern Italy): project and advances.
No full text
New insights on the eastern margin of the Early Jurassic Trento Platform (Southern Alps)
Full text linkNew correlations of sequence stratigraphic patterns in the Southern Alps across Ladinian/Carnian boundary
No full textTriassic amber of the Southern Alps (Italy)
No full textThe Heiligkreuz-Santa Croce Formation (also known as Dürrenstein Formation, Upper Triassic) in the Dolomites contains one of the most ancient and substantial Triassic amber deposits in the world. The amber is found in sandstones and paleosols. It has an affinity to the conifer family Cheirolepidiaceae, and amber samples from the Julian and Carnic Alps (Southern Alps) also show an affinity to this family.
Physico-chemical investigations of the amber from the Dolomites by solid-state Fourier-transform infrared analysis (FTIR), nuclear magnetic resonance (NMR), pyrolysis-gas-chromatography/mass-spectrometry (pyr-GC/MS), thermogravimetry (TG), differential thermogravimetry (DTG), and automatized elemental analysis yielded a complete characterization of the amber, and allowed comparison with other ambers and younger resins (copals). FTIR revealed absorption bands typical of all fossil resins, and the spectrum region from 8–10 μm provided a fingerprint of the Triassic amber that differs from other known resins. The NMR spectrum also shows a typical pattern for fossil resins, but peculiar peak abundances permitted further characterization of the Triassic amber, both in the saturated (10–70 ppm) and unsaturated carbon region (100–160 ppm). The amber also lacks exomethylene resonances found in younger resins at 110 and 150 ppm. Pyrolysis-gas-chromatography/mass-spectrometry (pyr-GC/MS) experiments showed the amber was of class II, with some components of Class I. Thermogravimetric (TG) and differential thermogravimetric (DTG) analyses of combustion behavior of Triassic amber indicated a main exothermal event near 437°C, higher than that of other known resins. The elemental composition of Triassic amber is consistent with well-known constituents of natural resins, although the sulfur content was higher, likely due to high sulfur content in the embedding sediment. Triassic amber from the Dolomites appears to be a new kind of fossil resin with unique stratigraphical and physico-chemical characteristics
La successione terrigena ladino-carnica di Passo Duran (Dolomiti, Belluno): un'ipotesi di lavoro
No full textThe interplay of carbonate systems and volcanics: Cues from the 3D model of the Middle Triassic Sciliar/Schlern platform (Dolomites, Southern Alps)
No full textIn the Dolomites (Southern Alps), the original stratigraphic relationships and depositional geometries of Middle Triassic carbonate systems are exceptionally preserved and exposed, and well-constrained in a high-resolution sequence stratigraphic and bio-chronostratigraphic framework. During the late Ladinian, the region experienced a strong tectono-magmatic event, leading to local uplifts and sinks, partial collapses of carbonate edifices and large submarine landslides, as well as the emplacement of thick volcanic and volcanoclastic deposits. The relationships between carbonate and magmatic bodies can be observed in detail in the area between the Sciliar/ Schlern mountain group and the Alpe di Siusi/Seiser Alm. In order to better constrain the distribution, geometries and relationships between carbonate, volcanic and volcanoclastic facies, a 3D geological model of the Anisian-Ladinian platform-to-basin system of the Sciliar and Catinaccio carbonate platforms has been developed. The input data set is composed by a net of geological sections built on an updated geological map, field data and formation boundaries digitized on a high-resolution DTM.
The resulting pre-volcanic, platform-to-basin system shows a slightly arcuate shape of the margin part facing a starved basin. The volcanic stage is accompanied by strong tectonic subsidence in local sectors of the investigated area, with infilling by mass flow deposits, volcanic rocks, and volcanoclastic material. Major fault-scarps related to the collapse of pre-volcanic carbonate platforms have been modeled. The distribution and thickness of magmatic bodies in the area is however quite variable. The modeled post-volcanic platform-to-basin system shows the impact of the Late Ladinian irregular sea bottom on the distribution and thickness of the younger (mixed carbonate and volcanoclastic) basinal sediments. The model also show that the post-volcanic edifices extended beyond the collapsed portions and occupied an area slightly larger than their pre-volcanic predecessors.
The last interval documents the development of lowstand fringing reefs around the older carbonate platform and
possibly around demised volcanic areas
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