| Stratigraphy of the Lower Cretaceous Sediments from the Carpathian Bend Area, Romania |
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| 作者姓名： | Mihaela-Carmen MELINTE-DOBRINESCU Dan C. JIPA |
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| 作者单位： | National Institute of Marine Geology and Geo-ecology (GeoEcoMar), 23-25 Dimitrie Onciul Street, RO-024053 Bucharest, Romania;National Institute of Marine Geology and Geo-ecology (GeoEcoMar), 23-25 Dimitrie Onciul Street, RO-024053 Bucharest, Romania |
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| 基金项目： | This work is in part supported by the National Key Basic Research Program, the Ministry of Science and Technology of China (MOST 973 Program, 2006CB701400),? and is a contribution to IGCP 463/555. |
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| 摘 要： | The Lower Cretaceous sediments of the Ceahl?u Nappe (from the bend region of the Romanian Carpathians) were investigated from lithological and micropaleontological (calcareous nannoplankton) points of view. Our investigations revealed that the studied deposits were sedimented within the latest Tithonian-Albian interval. The calcareous nannofossil assemblages of the turbidite calcareous successions (the Sinaia Formation) were assigned to the NJK-?NC5 calcareous nannofossil zones, which cover the Late Tithonian-Early Barremian interval. The sandy-shaly turbidites, which followed the calcareous turbidites of the Sinaia Formation, are Early Barremian-Early Albian in age (interval covered by the ?NC5-NC8 calcareous nannofossil zones). Because the studied deposited are mainly turbidites, many reworked nannofossils from older deposits are present in the calcareous nannofloras. Thus, some biozones (i.e., NC5), defined based on the last occurrences of nannofossils, could not be identified. The calcareous nannofossil assemblages are composed of Tethyan taxa (which dominate the nannofloras) and cosmopolitan taxa. During two intervals (the Late Valanginian and across the Barremian/Aptian boundary), Tethyan and cosmopolitan nannofossils, together with Boreal ones, were observed. This type of mixed calcareous nannoplankton assemblage is indicative for sea-level high-stand, which allows the nannofloral exchange between the Tethyan and Boreal realms, within the two-above mentioned intervals.
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| 关 键 词： | Early Cretaceous litho- and biostratigraphy calcareous nannofossils Romanian Carpathians |
| 收稿时间： | 2007/9/25 0:00:00 |
| 修稿时间： | 2007/10/25 0:00:00 |
Stratigraphy of the Lower Cretaceous Sediments from the Carpathian Bend Area, Romania |
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| Authors: | Mihaela-Carmen MELINTE-DOBRINESCU Dan C JIPA |
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| Abstract: | Abstract: The Lower Cretaceous sediments of the Ceahla?au Nappe (from the bend region of the Romanian Carpathians) were investigated from lithological and micropaleontological (calcareous nannoplankton) points of view. Our investigations revealed that the studied deposits were sedimented within the latest Tithonian‐Albian interval. The calcareous nannofossil assemblages of the turbidite calcareous successions (the Sinaia Formation) were assigned to the NJK‐?NC5 calcareous nannofossil zones, which cover the Late Tithonian‐Early Barremian interval. The sandy‐shaly turbidites, which followed the calcareous turbidites of the Sinaia Formation, are Early Barremian‐Early Albian in age (interval covered by the ?NC5‐NC8 calcareous nannofossil zones). Because the studied deposited are mainly turbidites, many reworked nannofossils from older deposits are present in the calcareous nannofloras. Thus, some biozones (i.e., NC5), defined based on the last occurrences of nannofossils, could not be identified. The calcareous nannofossil assemblages are composed of Tethyan taxa (which dominate the nannofloras) and cosmopolitan taxa. During two intervals (the Late Valanginian and across the Barremian/Aptian boundary), Tethyan and cosmopolitan nannofossils, together with Boreal ones, were observed. This type of mixed calcareous nannoplankton assemblage is indicative for sea‐level high‐stand, which allows the nannofloral exchange between the Tethyan and Boreal reaa?ms, within the two‐above mentioned intervals. |
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| Keywords: | Early Cretaceous litho-and biostratigraphy calcareous nannofossils Romanian Carpathians |
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