The stratigraphic and paleoecological significance of Bolivinitidae in the pliocene of south Adriatic basin
Abstract
En
The present study, which is considered as a continuation of the previous one, is based on the stratigraphic and paleoecological significance of the middle to the late Miocene Bolivinitidae of the same basin. However, in the previous study the existing Bolivinitidae dominant biofacies in many cases has been associated with distinct planktic / benthic ratio fluctuations from the latest Serravallian to Messinian in numerous sections of the Ionian area; but these fluctuations are not present in Pliocene. Only those based on the transgressive and regressive sequences can be present on two sedimentary sub-basins during Pliocene in the Ionian area of Albania. In spite of this, based on the characteristics of Brizalina, Bolivina and Ammonia associations here are suggested on sedimentary environments during the Pliocene. Brizalina dilatata could have been used in Pliocene only for paleoecological purposes in the studied area. Also individual species of Bolivinitidae are stratigrafically and paleoecologcally less significative than those of the late Miocene ones. The presence in Rogozhina Pliocene Formation of Ammonia inflata frequent biofacies followed by Ammonia beccarii dominant in Lushnja and Rrogozhina sections as in late Miocene indicate for (account for?) the replacement nearly the same paleoenvironments by the end of Pliocene particularly for the both above-mentioned sections. In the main part of Mediteranian basin the Miocene sediments, which in most of cases don’t have marine faunas, terminate with "lagomare" biofacies. The Pliocene or entire Neogene sediments, which are found nearly everywhere in the Ionian area, terminate with coarse clastic material of Astian facies (now Rrogozhina Formation), which in most of cases are devoid of fossils.
The present study, which is considered as a continuation of the previous one, is based on the stratigraphic and paleoecological significance of the middle to the late Miocene Bolivinitidae of the same basin. However, in the previous study the existing Bolivinitidae dominant biofacies in many cases has been associated with distinct planktic / benthic ratio fluctuations from the latest Serravallian to Messinian in numerous sections of the Ionian area; but these fluctuations are not present in Pliocene. Only those based on the transgressive and regressive sequences can be present on two sedimentary sub-basins during Pliocene in the Ionian area of Albania. In spite of this, based on the characteristics of Brizalina, Bolivina and Ammonia associations here are suggested on sedimentary environments during the Pliocene. Brizalina dilatata could have been used in Pliocene only for paleoecological purposes in the studied area. Also individual species of Bolivinitidae are stratigrafically and paleoecologcally less significative than those of the late Miocene ones. The presence in Rogozhina Pliocene Formation of Ammonia inflata frequent biofacies followed by Ammonia beccarii dominant in Lushnja and Rrogozhina sections as in late Miocene indicate for (account for?) the replacement nearly the same paleoenvironments by the end of Pliocene particularly for the both above-mentioned sections. In the main part of Mediteranian basin the Miocene sediments, which in most of cases don’t have marine faunas, terminate with "lagomare" biofacies. The Pliocene or entire Neogene sediments, which are found nearly everywhere in the Ionian area, terminate with coarse clastic material of Astian facies (now Rrogozhina Formation), which in most of cases are devoid of fossils.
DOI Code:
10.1285/i15910725v31p93
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