Първа находка на олигоценска флора от …...86 cene–Miocene with...
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85 БЪЛГАРСКО ГЕОЛОГИЧЕСКО ДРУЖЕСТВО, Национална конференция с международно участие „ГЕОНАУКИ 2017“ BULGARIAN GEOLOGICAL SOCIETY, National Conference with international participation “GEOSCIENCES 2017” First records of Oligocene flora in Erma River Gorge (Western Bulgaria) Първа находка на олигоценска флора от ждрелото на р. Ерма (Западна България) Vladimir Bozukov 1 , Nikolay Simov 2 , Milorad Vatsev 3 Владимир Бозуков 1 , Николай Симов 2 , Милорад Вацев 3 1 Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 24, 1113 Sofia; E-mail: [email protected] 2 National Museum of Natural History, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000 Sofia; E-mail: [email protected] 3 University of Mining and Geology “St. Ivan Rilski”, 1 Prof. B. Kamenov str., 1700 Sofia; E-mail: [email protected] Keywords: Bogoyna Village, Erma River Gorge, fossil flora, Oligocene sediments, West Bulgaria. Introduction Data on the fossil plants from Tran and Breznik re- gions (Western Bulgaria) are very scarce. Palamarev (1980) recorded 4 species of Characeae and based on these findings discussed the Еarly Oligocene age of bitominous sediments in Breznik region. Here we present the first data on Oligocene fossil plants from the Erma Gorge and Tran region. The fossil plant material examined for this study came from the Oligocene sediments exposed near the road to Bogoyna Village in the Bulgarian part of the Erma Gorge. They were embedded in bitominous argillites that have been strongly compressed during diagenesis. Therefore, they are preserved as compres- sion fossils with only minor relief. The bulk of the fos- sil material and the more of the specimens described here were collected in 2017 during a small palaeobot- anical expedition conducted by the authors. Oligocene sediments are poorly exposed in the area and they are represented by unevenly layered mudstones, fine grained sandstones and siltstones, but the dominant in the locality are sandy, bituminous and calcareous argillites with normal transition in muddy limestones. The thickness of the above mentioned sediments is about 150 m. They occur in the form of a narrow strip with NW-SE direction, situated in the northern pericline of the Tran anticline, close to the border area with the Tran-Kosharevo fault and situ- ated to the soth of the Lyubash monocline. Results and discussion Seven fossil taxa from 7 families were recorded. The material is stored in Division of Palaeobotany and Palynology, Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria. Other fossils found in the sediments of the same locality are several species of bony fishes (in- cluding Perciformes) (unpublished data). Laurus cf. pliocenica (Sap. et Mar.) Kolak. (Lauraceae) Material: leaf imprint No Er-1; Stratigraphical range of the species: Middle Miocene–Pliocene. Note: Six previous records of L. pliocenica in Bulgaria from Rhodopes and NW Bulgaria, Middle Miocene (Palamarev et al., 2005). Aldrovanda aff. vesiculosa L. (Droseraceae) Material: imprint of stems with leafs No Er-4b. Note: Seeds of closely related species A. praevesicu- losa Kirchh. were recorded in 4 localities in Rhodope Mts., Rila Mts. and Sofia Basin, Upper Miocene (Palamarev et al., 2005). Ulmus sp. (Ulmaceae) Material: imprint of round wind-dispersed samara No Er-15. Note: The shape of samara is very close to recent U. americana L. and U. laevis Pall. The above mentioned elm species are accepted by paleobotanical commu- nity as the nearest living relatives of fossil U. pyrami- dalis Goepp. and U. carpinoides Goepp. Leaf imprints of U. pyramidalis and U. carpinoides were recorded in many localities in Western Bulgaria from Early Oligocene to Miocene–Pliocene boundary (Palamarev et al., 2005). Myrica acuminata Ung. (Myricaceae) Material: leaf imprint No Er-3; Stratigraphical range of the species: Eocene–Oligocene. Note: Three previous records in SW Bulgaria (Upper Eocene–Lower Oligocene) (Palamarev et al., 2005). Zizyphus zizyphoides (Ung.) Weyland (Rhamnaceae) Material: leaf imprints No No Er-2, 5, 10; Strati- graphical range of the species is predominantly Oligo-
Transcript of Първа находка на олигоценска флора от …...86 cene–Miocene with...
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БЪЛГАРСКО ГЕОЛОГИЧЕСКО ДРУЖЕСТВО, Национална конференция с международно участие „ГЕОНАУКИ 2017“BULGARIAN GEOLOGICAL SOCIETY, National Conference with international participation “GEOSCIENCES 2017”
First records of Oligocene flora in Erma River Gorge (Western Bulgaria)Първа находка на олигоценска флора от ждрелото на р. Ерма (Западна България)Vladimir Bozukov1, Nikolay Simov2, Milorad Vatsev3
Владимир Бозуков1, Николай Симов2, Милорад Вацев3
1 Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 24, 1113 Sofia; E-mail: [email protected] National Museum of Natural History, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000 Sofia; E-mail: [email protected] 3 University of Mining and Geology “St. Ivan Rilski”, 1 Prof. B. Kamenov str., 1700 Sofia; E-mail: [email protected]
Keywords: Bogoyna Village, Erma River Gorge, fossil flora, Oligocene sediments, West Bulgaria.
Introduction
Data on the fossil plants from Tran and Breznik re-gions (Western Bulgaria) are very scarce. Palamarev (1980) recorded 4 species of Characeae and based on these findings discussed the Еarly Oligocene age of bitominous sediments in Breznik region. Here we present the first data on Oligocene fossil plants from the Erma Gorge and Tran region.
The fossil plant material examined for this study came from the Oligocene sediments exposed near the road to Bogoyna Village in the Bulgarian part of the Erma Gorge. They were embedded in bitominous argillites that have been strongly compressed during diagenesis. Therefore, they are preserved as compres-sion fossils with only minor relief. The bulk of the fos-sil material and the more of the specimens described here were collected in 2017 during a small palaeobot-anical expedition conducted by the authors.
Oligocene sediments are poorly exposed in the area and they are represented by unevenly layered mudstones, fine grained sandstones and siltstones, but the dominant in the locality are sandy, bituminous and calcareous argillites with normal transition in muddy limestones. The thickness of the above mentioned sediments is about 150 m. They occur in the form of a narrow strip with NW-SE direction, situated in the northern pericline of the Tran anticline, close to the border area with the Tran-Kosharevo fault and situ-ated to the soth of the Lyubash monocline.
Results and discussion
Seven fossil taxa from 7 families were recorded. The material is stored in Division of Palaeobotany and Palynology, Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia,
Bulgaria. Other fossils found in the sediments of the same locality are several species of bony fishes (in-cluding Perciformes) (unpublished data).
Laurus cf. pliocenica (Sap. et Mar.) Kolak. (Lauraceae)
Material: leaf imprint No Er-1; Stratigraphical range of the species: Middle Miocene–Pliocene.Note: Six previous records of L. pliocenica in Bulgaria from Rhodopes and NW Bulgaria, Middle Miocene (Palamarev et al., 2005).
Aldrovanda aff. vesiculosa L. (Droseraceae)Material: imprint of stems with leafs No Er-4b. Note: Seeds of closely related species A. praevesicu-losa Kirchh. were recorded in 4 localities in Rhodope Mts., Rila Mts. and Sofia Basin, Upper Miocene (Palamarev et al., 2005).
Ulmus sp. (Ulmaceae)Material: imprint of round wind-dispersed samara No Er-15.Note: The shape of samara is very close to recent U. americana L. and U. laevis Pall. The above mentioned elm species are accepted by paleobotanical commu-nity as the nearest living relatives of fossil U. pyrami-dalis Goepp. and U. carpinoides Goepp. Leaf imprints of U. pyramidalis and U. carpinoides were recorded in many localities in Western Bulgaria from Early Oligocene to Miocene–Pliocene boundary (Palamarev et al., 2005).
Myrica acuminata Ung. (Myricaceae)Material: leaf imprint No Er-3; Stratigraphical range of the species: Eocene–Oligocene.Note: Three previous records in SW Bulgaria (Upper Eocene–Lower Oligocene) (Palamarev et al., 2005).
Zizyphus zizyphoides (Ung.) Weyland (Rhamnaceae)
Material: leaf imprints No No Er-2, 5, 10; Strati-graphical range of the species is predominantly Oligo-
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cene–Miocene with scarce records in Eocene and Pliocene.Note: 13 previous records in Bulgaria from Rhodopes, Rila, and Vlahina Mts., and Struma River Valley (Lower Eocene–Upper Oligocene). The closest local-ity is Boboshevo, Upper Eocene–Lower Oligocene (Pa lamarev, Petkova, 1975).
Cyperus aff. fuscus L. (Cyperaceae)Material: spikelet imprint No Er-11, imprint of leaf part No Er-16.Note: This is the first confirmed fossil record of the genus Cyperus L. in Bulgaria. All previous Bulgarian records of Cyperus, have been transferred in Cyperites Heer (Palamarev et al., 2005).
Typha latissima A. Braun (Typhaceae)Material: leaf part imprints No No Er-4a, 14; Stra-tigraphical range of the species: Oligo cene–Plio cene.Note: 10 previous localities in Bulgaria from Rhodope Mts. and Western Bulgaria, Lower Oligocene–Upper Pliocene (Palamarev et al., 2005).
The studied Oligocene sediments in Erma Gorge near Bogoyna Village are well documented on the Geological map of Bulgaria at a scale 1:100 000 (Zagorchev et al., 1991) but are lacking on the Geological map of Bulgaria at a scale 1:50 000 (Marinova et al., 2010) where all sediments are treat-ed as Upper Cretaceous. Owing to the combination of taxa from the Eocene–Oligocene boundary with taxa distributed in the subsequent period we could speculate the Oligocene age of the studied flora and sediments. Early Oligocene age have bituminous sediments from nearest Breznik region (Palamarev, 1980). Oligocene sediments are widely and well ex-posed in the Babushnica Basin, on the neighboring territory of Serbia (Andjelković et al., 1991). The Babushnica Basin is filled with Late Eocene red and gray conglomerates, sandstones, carbonate argillites and marlstones, covered by Oligocene conglomerates, sandstones, clay sandstones and sandy argillites, tran-sitioning in bitominous argillite with fossil plants and
bony fishes, including Dapalis sp. (Perciformes). The south-easternmost part of this basin continues to the Bulgarian border area close to Bogoyna Village, but it became very narrow due to its reduction by superim-posed reverse and thrust faults in Serbia and Bulgaria. Our data on the Oligocene age of argillite sediments in the Erma River Gorge necessitate further geologi-cal investigations in this region, especially in the area of the south-east to the Stanyovtsi and Ruzhevets Villages and Breznik region. This would clarify better the geological history of the studied locality and its connection with neighboring sedimentary basins from Western Bulgaria and Eastern Serbia.
ReferencesAndjelković, M., M. Eremija, M. Pavlović, J. Andjelković, J.
Mitrović-Petrović. 1991. Paleogeography of Serbia, The Tertiary. University of Belgrade, Institute for regional ge-ology and paleontology, 238 p. (in Serbian with an English abstract).
Marinova, R., V. Grozdev, D. Ivanova, D. Sinnyovski, P. Milovanov, I. Petrov, A. Popov. 2010. Geological Map of the Republic of Bulgaria 1:50 000. Map Sheets Cervena Buka, Vlasotince, Tran-north, Tran-south. Ministry of Environment and Water, Bulgarian National Geological Survey, Sofia, Apis 50 Ltd.
Palamarev, E. 1980. Paläobotanische Beweise für das geologis-che Alter des Bresnik-Ölschieferkomplexes. – Paleontol. Stratigr. and Lithol., 13, 35–40 (in Bulgarian with a German abstract).
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Palamarev, E., A. Petkova. 1975. Neue Daten über die paläo-gene Flora Bulgariens. – In: Velchev, V., B. Kuzmanov, E. Palamarev (Eds.). Honour of Acad. D. Jordanov. Sofia, Bulg. Acad. Sci., 203–236 (in Bulgarian with a German abstract).
Zagorčev, I., V. Kostadinov, D. Tchounev, R. Dimitrova, I. Sapunov, P. Tchouumatchenco, S. Yanev. 1991. Geological Map of Bulgaria on scale 1:100 000. Map SheetVlasotince and Breznik. Sofia, Committee of Geology, Dept. of Geophysical Prospecting and Geological Mapping.
Fig. 1. Fossil photographs: a, Aldrovanda aff. vesiculosa; b–c, Cyperus aff. fuscus; d, Typha latissima; e, Ulmus sp.; f, Myrica acuminata; g, Ziziphus ziziphoides; h, Laurus cf. pliocenica (measuring bar – 1 cm).
