Biostratigraphy of Upper Cretaceous Deposits in the Southern Eastern Carpathians near Brasov
1968; Micropaleontology Press; Volume: 14; Issue: 2 Linguagem: Inglês
10.2307/1484736
ISSN1937-2795
Autores Tópico(s)Marine and environmental studies
ResumoThe lithological and microfaunal facies of the Upper Cretaceous in the southern part of the Eastern Carpathians are discussed. The characteristics of the sedimentation basin, which included high turbidity and turbulence and rapid deposition, as well as rapid fluctuation of sea level, had a strong influence on the microfaunal association. Description and illustration of four new species (Haplophragmoides herbichi, Parafissurina lageniformis, Pleurostomella dacica, Pleurostomella pseudocurta) and two new subspecies (Fissurina orbignyana inornata, Fissurina orbignyana bicornis) are also presented, along with lists of the successive foraminiferal assemblages. Biostratigraphy of Upper Cretaceous deposits in the southern Eastern Carpathians near Brasov INTRODUCTION The geological structure of the Eastern Carpathians is rather intricate both from a lithologic and a tectonic viewpoint. Rumanian geologists distinguish several tectonic units (nappes) by the extremely varied lithologic constitution of these deposits as well as by their macrofaunal and microfaunal content. Detailed micropaleontological studies are rather few due to the varied lithology, the scarceness of foraminifera in some formations, and the very intricate tectonic structure. Owing to the fact that macrofossil remains are rather scarce, workers rely more and more on data obtained from microfossils in order to establish a more judicious and detailed stratigraphy of these deposits. With this situation in mind, as subject of the thesis for my doctor's degree I was allotted the study of the Upper Cretaceous deposits in the southern end of the Eastern Carpathians. My studies have resulted in a detailed zonation of the Upper Cretaceous deposits in this region. SOURCE OF MATERIAL The material studied was obtained from the Upper Cretaceous deposits located in an area to the east of the city of Brasov that is situated between the villages of Vama Buzaului, Intorsura Buzaului, Valea Mare, Valea Dobirlau and Teliu, covering an area of approximately 190 sq. km. (text-figure 1). More than 500 samples from various outcrops exposed in the valleys crossing this area were collected and analysed in the period 1957-1964. The material has been treated in the Paleontological Laboratory of the University of Bucharest and has been deposited in its collections. GENERAL CHARACTER OF FAUNA The general microfaunal character of the Upper Cretaceous in this region is indicated by the scarcity and often the complete lack of planktonic elements and by the great abundance of agglutinated tests. I tried to use as much as possible the evidence offered by planktonic species (when they did appear), but a more important basis of my work was formed by those species or groups of species whose frequency and constancy is appreciable in the various lithologic sequences encountered. In the sequence of Cenomanian deposits, the presence of species of the planktonic genera Rotalipora, Schackoina, Praeglobotruncana and Hedbergella provided extremely valuable information. The Turonian deposits, however, on account of their marked shalysandy character with interbedded sideritic marly limestones, red clays and volcanic cinerites, are almost completely lacking in planktonic micropaleontology, vol. 14, no. 2, pp. 225-241, pis. 1-2, april, 1968 225 This content downloaded from 40.77.167.121 on Thu, 27 Apr 2017 17:49:54 UTC All use subject to http://about.jstor.org/terms
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