Carbonate Platform Megafacies of the Jurassic and Cretaceous Deposits of the Karst Dinarides

Platform carbonate deposits of the Karst Dinarides area have a stratigraphic range from the Middle Triassic (or even Carboniferous in some places) to the Middle Eocene, forming a belt nearly 700 km long and, (after reduction by younger tectonics) 80–210 km wide. Besides their significant thickness (4500 to 8000 m) they are characterised by frequent lateral and vertical alternations of different facies, mostly associated with shallow marine environments. Environments ranging from peritidal through low-energy shallow subtidal–lagoons, restricted inner platform shallows, high-energy tidal bars, beach and shoreface to reefal–perireefal predominate, but there are also carbonate slope deposits and those representing temporarily drowned platform facies and intraplatform troughs. The Jurassic to Cretaceous part of this carbonate succession has been subdivided into 19 megafacies units (9 for the Jurassic and 10 for the Cretaceous), the majority of which represent an inner part of the ancient Adriatic Carbonate Platform. Marginal parts of the platform are mostly buried, either by the recent Adriatic Sea along the SW margin, or younger deposits along the NE margin; at some localities such Jurassic and Cretaceous deposits are represented by debrites and/or carbonate turbidites. An additional short review of the overlying Uppermost Cretaceous and Palaeogene deposits (4 megafacies units) enabled a better insight into the post-platform evolution. The very complex vertical and lateral alternation of different megafacies units, including emerged areas which were observed throughout the studied sequence in different parts of the Karst Dinarides, indicate the significant palaeogeographic dynamics of the region. This variability resulted from interaction of the global eustatic signal and local factors, including extensive organic production on the carbonate platform and synsedimentary tectonics controlled by the specific palaeogeographic position of the platform during its geological history

The Karst Dinarides are Composed of Relics of a Single Mesozoic Platform: Facts and Consequences

Croatian geological literature during the mid nineteen-eighties and nineties was marked by the appearance of a new geotectonic concept of the Dinarides proposing that the recent, very complex structural setting is a direct consequence of a specific palaeogeographic relationship during the Mesozoic, i.e. the proposed existence of two carbonate platforms separated by a long-lasting deep marine area (interplatform trough). Although the idea was very interesting and provoked discussion, resulting in the questioning of formerly established concepts, detailed analysis of available data indicate that the Karst Dinarides (External Dinarides) were formed by the destruction of a single, although morphologically considerably variable shallow water carbonate platform. This platform was in some periods very dynamic because of its palaeogeographic position during the Mesozoic, resulting in many periods of large-scale facies differentiation, especially during the Late Cretaceous. The final disintegration of the platform area culminated in the formation of flysch trough(s) in the latest Cretaceous and Palaeogene and the subsequent uplift of the Dinarides. Recently there have been some misunderstandings resulting from the imprecise use of newly established terms, which are, by circular logic, used to connect recent geotectonic relationships with Mesozoic palaeogeography without adequate material proof. Therefore, the terms Dinaricum and Adriaticum should be redefined and used only for description of the recent tectonic pattern, without implying a palaeogeographic component, since during the Mesozoic they represented a single entity. Additional confusion is added by different names used for the same shallow water carbonate platform. Probably the best, although not the ideal name is the most frequently used one: the Adriatic Carbonate Platform. Its duration may be estimated from the Late Lias to the Late Cretaceous, representing the most important part of a thick carbonate succession in the Karst Dinarides (ranging from Carboniferous to Eocene)

Stanja spinskih dubleta u spektru 9Be u modelu grozdova

The structure of the 9Be low-lying spectrum is studied within the cluster model α + α + n. In the model, the total orbital momentum is fixed for each energy level. Thus each level is determined as a member of the spin-flip doublet corresponding to the total orbital momentum (L π = 0+, 2 +, 4 +, 1 −, 2 −, 3 −, 4 −) of the system. The Ali-Bodmer potential (model E) is applied for the αα interaction. We employ a local αn potential which was constructed to reproduce the α − n scattering data. The Pauli blocking is simulated by the repulsive core of the s-wave components of these potentials. Configuration-space Faddeev equations are used to calculate the energy of the bound state (Ecalc = −1.493 MeV vs. Eexp = −1.5735 MeV) and resonances. A variant of the method of analytical continuation in the coupling constant is applied to calculate energies of the low-lying levels. Available 9Be spectral data are satisfactorily reproduced by the proposed model.Proučavaju se niskoležeća stanja 9Be polazeći od modela grozda α+α+n. Za svako stanje se uzima određen ukupni moment impulsa. Tako je svako stanje određeno kao član spinskih dubletnih stanja s danim ukupnim momentom impulsa sustava (L π = 0+, 2 +, 4 +, 1 −, 2 −, 3 −, 4 −). Primjenjuje se Ali-Bodmerov potencijal (model E) za međudjelovanje αα. Za međudjelovanje αn primjenjuje se lokalni αn potencijal, koji se podešava kako bi se postigao sklad s podacima za α − n raspršenje. Paulijeva zabrana se postiže s odbojnom jezgrom za s valove tih potencijala. Za računanje energije vezanog stanja (Ecalc = −1.493 MeV vs. Eexp = −1.5735 MeV) i rezonancija rabe se Faddeevljeve jednadžbe u običnom prostoru. Za računanje energija niskoležećih stanja primjenjuje se inačica metode za analitičko nastavljanje konstante međudjelovanja. Ovim modelom postižemo dobar sklad s poznatim spektralnim podacima za 9Be