This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the ...This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the Slovenian Basin.The age of the section ranges from the Lacian 1 to the Alaunian 1.The Lacian part of the succession is predominantly characterized by the representatives of the genus Ancyrogondolella.Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition.This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament-dominated wackestone-packstone,and the formation of small neptunian dykes,which may reflect environmental perturbations and/or a change in basin geometry.The proliferation of the genera Epigondolella and Mockina is observed in the Alaunian part of the section,though the genus Ancyrogondolella is still present in this interval.Systematic description of the conodont taxa is provided,and seven new species and two new subspecies are established.The new advances will be of great value in further biostratigraphic studies,especially in areas without ammonoid faunas,and in the reconstruction of the paleogeography of the Slovenian Basin.展开更多
Middle Triassic volcaniclastic depositsin the External Dinarides of Croatia and Bosnia and Herzegovina are related to the rifting of the Tethyan Ocean. Three localities in the External Dinarides： Donje Pazariste, Bos...Middle Triassic volcaniclastic depositsin the External Dinarides of Croatia and Bosnia and Herzegovina are related to the rifting of the Tethyan Ocean. Three localities in the External Dinarides： Donje Pazariste, Bosansko Grahovo and Zelovo were biostratigraphically analysed in this study. The Middle Triassic carbonate deposits with volcaniclastic interlayers in Donje Pazariste were defined by means of conodonts. Rare ammonoid specimens were collected.Recovered conodont and ammonoid taxa suggest these sections are of Early Illyrian to Early Fassanian Age. The section studied in Bosansko Grahovo is dominantly composed of volcanic and volcaniclastic rocks. Limestone peperites were collected for conodont analysis. Two conodont zones were defined, suggesting volcanic activity in the same, from Lower Illyrian to Fassanian, time interval. The Zelovo Section was biostratigraphically investigated by several authors. The pietra verde deposits from Zelovo are referred as late Fassanian to Early Longobardian Age. Biostratigraphic correlation from mentioned three localities imply that the magmatic activity in the External Dinarides, and formation of different volcaniclastic facies lasted from Illyrian to Longobardian, similar as in the surrounding western Tethyan territories.展开更多
In the central part of the External Dinarides in Plavno, Croatia, near Knin, a remarkably thick （927.5 m） Early Triassic depositional sequence was investigated. The Plavno sequence starts in the EarlyGriesbachian an...In the central part of the External Dinarides in Plavno, Croatia, near Knin, a remarkably thick （927.5 m） Early Triassic depositional sequence was investigated. The Plavno sequence starts in the EarlyGriesbachian and ends with a continuous transition into the Anisian strata. A complete 13C isotope curve has been achieved and combined with conodonts, bivalves and ammonoids to establish and correlate stage and substage boundaries. The 613C curve is consistent with former studies. It displays a general increase from the Griesbachian to a prominent maximum beyond the ＋8%0 amplitude around the Dienerian-Smithian boundary （DSB）, followed by a steep and continuous decline to low, negative values in the Smithian. Around the Smithian-Spathian boundary （SSB） a steep rise to a second maximum occurred. It is followed by a saw-tooth shaped decline in the Spathian and a similar increase to a peak at the Spathian-Anisian boundary （SAB）. Sedimentologically, the Plavno sequence is interpreted as having been deposited on an extensive epeiric ramp under long-term transgressive conditions, sharing depositional characteristics of both the epeiric platform and the carbonate ramp. The entire Plavno sequence was deposited above the storm-wave base and was storm influenced. Three informal members are differentiated： 1） the dolostone member （Early Griesbachian）; 2） the silicielastic member （red-coloured shale, siltstone, sandstone with oolitic/bioclastie grainstone intercalations）, which can be further divided into lower, middle and upper intervals （Late Griesbachian, Dienerian and Smithian）; and 3） the mudstone member （grey lime mudstones, marls and calcisiltites with common ammonoids and gastropods- Spathian）. The Plavno sequence is compared with other western Tethyan sections. Observed differences stem from local controls on deposition in the overall shallow marine environment.展开更多
基金partially supported by the Slovenian Research Agency(No.P1-0011)partially by the NKFIH PD-131536 Project。
文摘This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the Slovenian Basin.The age of the section ranges from the Lacian 1 to the Alaunian 1.The Lacian part of the succession is predominantly characterized by the representatives of the genus Ancyrogondolella.Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition.This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament-dominated wackestone-packstone,and the formation of small neptunian dykes,which may reflect environmental perturbations and/or a change in basin geometry.The proliferation of the genera Epigondolella and Mockina is observed in the Alaunian part of the section,though the genus Ancyrogondolella is still present in this interval.Systematic description of the conodont taxa is provided,and seven new species and two new subspecies are established.The new advances will be of great value in further biostratigraphic studies,especially in areas without ammonoid faunas,and in the reconstruction of the paleogeography of the Slovenian Basin.
基金financed by the Croatian Ministry of Science and EducationUniversity of Zagreb financial support founds
文摘Middle Triassic volcaniclastic depositsin the External Dinarides of Croatia and Bosnia and Herzegovina are related to the rifting of the Tethyan Ocean. Three localities in the External Dinarides： Donje Pazariste, Bosansko Grahovo and Zelovo were biostratigraphically analysed in this study. The Middle Triassic carbonate deposits with volcaniclastic interlayers in Donje Pazariste were defined by means of conodonts. Rare ammonoid specimens were collected.Recovered conodont and ammonoid taxa suggest these sections are of Early Illyrian to Early Fassanian Age. The section studied in Bosansko Grahovo is dominantly composed of volcanic and volcaniclastic rocks. Limestone peperites were collected for conodont analysis. Two conodont zones were defined, suggesting volcanic activity in the same, from Lower Illyrian to Fassanian, time interval. The Zelovo Section was biostratigraphically investigated by several authors. The pietra verde deposits from Zelovo are referred as late Fassanian to Early Longobardian Age. Biostratigraphic correlation from mentioned three localities imply that the magmatic activity in the External Dinarides, and formation of different volcaniclastic facies lasted from Illyrian to Longobardian, similar as in the surrounding western Tethyan territories.
基金part of the Austrian-Croatian Bilateral Project (No. 2014-15) supported by OeADthe Austrian Agency for International Mobility and Cooperation in Education+1 种基金the Croatian Ministry of Science, Education and Sportpartly supported by the Slovenian Research Agency (No. P1-0011)
文摘In the central part of the External Dinarides in Plavno, Croatia, near Knin, a remarkably thick （927.5 m） Early Triassic depositional sequence was investigated. The Plavno sequence starts in the EarlyGriesbachian and ends with a continuous transition into the Anisian strata. A complete 13C isotope curve has been achieved and combined with conodonts, bivalves and ammonoids to establish and correlate stage and substage boundaries. The 613C curve is consistent with former studies. It displays a general increase from the Griesbachian to a prominent maximum beyond the ＋8%0 amplitude around the Dienerian-Smithian boundary （DSB）, followed by a steep and continuous decline to low, negative values in the Smithian. Around the Smithian-Spathian boundary （SSB） a steep rise to a second maximum occurred. It is followed by a saw-tooth shaped decline in the Spathian and a similar increase to a peak at the Spathian-Anisian boundary （SAB）. Sedimentologically, the Plavno sequence is interpreted as having been deposited on an extensive epeiric ramp under long-term transgressive conditions, sharing depositional characteristics of both the epeiric platform and the carbonate ramp. The entire Plavno sequence was deposited above the storm-wave base and was storm influenced. Three informal members are differentiated： 1） the dolostone member （Early Griesbachian）; 2） the silicielastic member （red-coloured shale, siltstone, sandstone with oolitic/bioclastie grainstone intercalations）, which can be further divided into lower, middle and upper intervals （Late Griesbachian, Dienerian and Smithian）; and 3） the mudstone member （grey lime mudstones, marls and calcisiltites with common ammonoids and gastropods- Spathian）. The Plavno sequence is compared with other western Tethyan sections. Observed differences stem from local controls on deposition in the overall shallow marine environment.
