Physical Sciences and Mathematics Commons^™

New U/Pb And Pb/Pb Zircon Ages From The Biharia Terrane Rocks, Apuseni Mountains, Romania, Ioan Balintoni, Constantin Balica, Monica Clivet̡I, Li-Qiu Li, Horst Peter Hann, Fukun Chen, Volker Schuller

Studia UBB Geologia

The Biharia sequence from the Apuseni Mountains is a component of the Biharia Paleozoic terrane. The Biharia terrane probably evolved as an island arc between the Cadomian Someş and Baia de Arieş terranes. A gneissic metagranodiorite associated with metabasites from the Valea Ierţii creek, was sampled for U/Pb and Pb/Pb zircon age determination. The zircons extracted out of the sampled rock were subjected both to dilution and evaporation methods. Dilution method offered Concordia intercepts at 227±23 Ma, 312±13 Ma, 465.7+8.4/-8.0 Ma, 703±21 Ma and 1604±45 Ma. Evaporated zircon grains gave 450±20 Ma and 543±17 Ma. The 227±23 Ma age and …

Upper Cretaceous Rudist-Bearing Deposits From The Eastern Border Of The Gilau Mountains (Corni Section, Hasdate): Palaeoecological Remarks, Liana SăSăRan, Emanoil SăSăRan, Ioan I. Bucur

Studia UBB Geologia

Along the eastern border of the Gilău Mountains crop out carbonate deposits which were formed during the Late Cretaceous (Santonian-Campanian). These deposits are characterized by a significant presence of rudists and were formed on the border of a narrow marine shelf. The typical feature is represented by the dominance of the coral-rudist associations. The paleontological study of these deposits revealed the presence of four evolutionary stages when corals, rudists and red calcareous algae stabilised and colonised the sediment depending on the relative sea level evolution. All the evolutionary stages have been included into an idealised ecological sequence.

Facies Analysis Of The Late Cretaceous Deposits From Corni Quarry (North-Eastern Border Of Gilău Mountains), Emanoil SăSăRan, Liana SăSăRan

Studia UBB Geologia

The Late Cretaceous deposits outcropping along the northeastern border of Gilău Mountains form a NW-SE-oriented crest. The crest is delimited westwards by the crystalline formations of Baia de Arieş Nappe. Within these deposits, two distinctive sedimentary complexes could be separated: a) The Gosau-type facies formation, that can be correlated to the “Lower Gosau Subgroup” (Wagreich & Faupl, 1994), represented by alluvial/fluvial fans and shallow marine deposits; b) The flysch-type formation, that is similar with the “Upper Gosau Subgroup” (Wagreich & Faupl, 1994) and includes deep sea deposits (hemipelagites/turbidites).The syndepositional and postdepositional tectonics controlled the sedimentation and facies distribution; the shallow …

Microfacies And Microfossils In Upper Jurassic Limestones From Cheile Turenilor, Emanoil SăSăRan, Ioan I. Bucur, Ioana Prica

Studia UBB Geologia

In the Cheile Turenilor (Tureni Gorges) area, a carbonate succession about 150 m thick developed on top of island arc magmatites. It mainly consist of gravity - induced deposits (debris flows, mass flows and grain flows). Coral, sponges and stromatoporoid bioconstructions are associated. Microbolites play an important role, as binders of the intraclastic rudstones/ grainstones facies, as well as of the incorporated corals, sponges, stromatoporoids, bryozoans, molluscs.

Diffusion Coronas Around Quartz Xenocrysts In Basaltic Andesite From Capus (Cionca Hill, Gilau Mountains - Romania), Nicolae Har, Ana-Maria Rusu

Studia UBB Geologia

Diffusion coronas consisting of Al – poor pyroxene (augite), glass and silica polymorphs are developed around the quartz xenocrysts in the olivine basaltic andesite from Cionca Hill (Gilău Mountains). The quartz of xenolitic origin was magmatically corroded and sometimes reacted with the basaltic melt. According to the time of coexistence between quartz and the basaltic melt, two different spatial disposition of the pyroxene of reaction can be noticed. For a shorter reaction time the Al – poor pyroxene are commonly tangentially to the quartz rim while for the crystals which presumably had longer reaction time the pyroxene are radially from …

Sedimentary Succesion Of The Lower Cretaceous Deposits From The North-Western Part Of Pădurea Craiului (Apuseni Mountains, Romania), Daniel F. Lazar, Ioan I. Bucur, Ioan Cociuba, Emanoil Sasaran

Studia UBB Geologia

Within the general succession of the Lower Cretaceous deposits from the Vârciorog-Dobreşti area (Pădurea Craiului Mountains), carbonate and terrigenous deposits were identified. The limestones were assigned to two distinctive lithostratigraphic units: the Valea Măgurii and Vârciorog formations. Based on the orbitolinids Palorbitolina lenticularis and Mesorbitolina texana their ages are assigned to the early Aptian, and respectively late Aptian–Albian. The terrigenous facies mainly include fine grained deposits (clays, siltites, marls) and, to a lesser extent, coarser ones (glauconitic sandstones and conglomerates), and they are attributed to the Ecleja and Vârciorog formations. The marls of the Ecleja Formation have been observed in …

Calcareous Nannofossils And Sedimentary Facies In The Upper Cretaceous Bozeş Formation (Southern Apuseni Mountains, Romania), Ramona Balc, Lóránd Silye, Luminita Zaharia

Studia UBB Geologia

The lithology, sedimentology and biostratigraphy of the Bozes Formation, which crop out in the SE Metaliferi Mountains (Apuseni Mts.) have been investigated in order to establish the age of the deposits and the depositional environment.

The sedimentary structures and facies are interpreted as indicating a deep-water depositional environment, representing part of a submarine fan lobe. Three facies assemblages have been identified and described. Calcareous nannofossils were used to determine the age of the investigated deposits. The presence of Lucianorhabdus cayeuxii and Calculites obscurus indicates the CC17 biozone, while UC13 Zone is pointed out by the continuous occurrence of Arkhangelskiella cymbiformis …