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Tytuł:
Late Messinian palynoflora from Central Anatolian Plateau (Çankırı Basin)
Autorzy:
Atalar, M.
Kovacova, M.
Ozer, M.S.K.
Utescher, T.
Powiązania:
https://bibliotekanauki.pl/articles/184454.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
ALErl project
climatic boundary
tectonic boundary
Opis:
Within the framework of the Marie Curie FP7-PEOPLE-2013-ITN program, the ALErT project targets on tectonic and climatic boundary conditions in the regions along the densely populated and the associated with natural hazards part of the Central Anatolian Plateau. The wide Central Anatolian Plateau (CAP) extends between the Aegean extensional and Bitlis /Zagros compressional zones. The Çankırı Basin was opened in central Anatolia during Late Cretaceous between the Kırşehir block in the south and Sakarya continents in the north. During the Neo-Tethys closure, the basin became a large intermontane basin covered with continental sedimentary environments (Kazancı et al. 1999). During the Late Miocene, there were different types of lacustrine environments between the northern and southern parts of this basin. Age evidence of the Çankırı Basin deposits has been obtained from the European mammalian faunal zones, because the Sr analysis results have not be significant to interpreted age (Mazzini 2015). To figure out the paleoenvironmental and palaeoclimate changes in Çankırı Basin biotic (palynology) and abiotic proxy data (geochemical, δ18O – δ13C isotopes analyses and CaCO3) were analysed. Fifteen samples from Hancili Formation, Tuglu Suleymanli crossing border, Bozkır Formation and Değim Formation were collected from claystone, dark silty clay, gypsum and breccia with silty gypsum layers in the Çankırı Basin. The samples were treated by standard palynological procedures described by Cour (1974). All pollen samples, residues, and slides are stored in Comenius University in Bratislava, Slovakia. Each sample collected in the Çankırı Basin contains 150 pollen grains excluding Pinus . Pollen identification was performed under a Zeiss light microscope, and under a Quanta FEG250 Scanning electron microscope (SEM) used for high resolution imaging of pollen grains in Institute of Electrical Engineering Slovak Academy of Sciences. The pollen diagram was prepared with Tilia*-Graph (2.0) (http://www.chrono.qub.ac.uk/datah/tilia.html). According to Mosbrugger & Utescher (1997), coexistence approach derived quantative paleoclimate parameters. To explain the ecological characteristic, we used version of the Past 3.x – the Past of the Future free software scientific statistical data analysis program (http://folk.uio.no/ohammer/past/). Head map was prepared using program for four formations. The uplift during the Late Messinian in Çankırı Basin has been confirmed by palynological data and head map evaluation. We applied Xact 8 for the graphic presentation to show vegetation composition. We developed Steppe-Forest Index using a ratio of appropriate species of pollen (Traverse 1978), that serve as a climatic indicator (warm to cold), while interpreting aridity we follow Cour & Duzer (1978). As a consequence, the Poaceae/total Asteraceae ratio in a pollen diagram can be used as a climate index to find out dry to wet zones ines (Popescu 2006). It was calculated based on palynological results (using cluster analysis) to show that sections have four climate cycles with three dry periods. Based on those calculations, we confirmed long term cooling trend during the Late Messinian to the Plio-Pleistocene in Çankırı Basin. Most pollen spectra are mainly presented by Asteraceae, Chenopodiaceae, and Poaceae and by trees of Pinus, Cathaya, and Fagus. The group of herbs is important in the pollen spectra and mainly consists of Poaceae, Chenopodiaceae and Asteraceae, which document open grassland type of vegetation with warm – temperate climate.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 1; 57-58
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards a consistent Oxfordian/Kimmeridgian global boundary: current state of knowledge
Autorzy:
Wierzbowski, A.
Atrops, F.
Grabowski, J.
Hounslow, M.
Matyja, B. A.
Olóriz, F.
Page, K.
Parent, H.
Rogov, M. A.
Schweigert, G.
Villaseñor, A. B.
Wierzbowski, H.
Wright, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/2060996.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Upper Jurassic
stratigraphical correlation
ammonites
palaeomagnetism
biogeographical provinces
climatic changes
environmental changes
Oxfordian/Kimmeridgian boundary
jura dolna
korelacja stratygraficzna
amonity
paleomagnetyzm
prowincje biogeograficzne
zmiany klimatyczne
zmiany środowiskowe
Opis:
New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/ Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0.20 m interval – 1.28 m to 1.48 m below bed 36 – the latter corresponding to marine magnetic anomaly M26r). The boundary is clearly recognizable also in other sections of the Subboreal and Boreal areas discussed in the study, including southern England, Pomerania and the Peri-Baltic Syneclise, Russian Platform, Northern Central Siberia, Franz-Josef Land, Barents Sea and Norwegian Sea. It can be recognized also in the Submediterranean-Mediterranean areas of Europe and Asia where it correlates with the boundary between the Hypselum and the Bimmamatum ammonite zones. The changes in ammonite faunas at the boundary of these ammonite zones – mostly of ammonites of the families Aspidoceratidae and Oppeliidae – also enables the recognition of the boundary in the Tethyan and Indo-Pacific areas – such as the central part of the Americas (Cuba, Mexico), southern America, and southern parts of Asia. The climatic and environmental changes near to the Oxfordian/Kimmeridgian boundary discussed in the study relate mostly to the European areas. They show that very unstable environments at the end of the Oxfordian were subsequently replaced by more stable conditions representing a generally warming trend during the earliest Kimmeridgian. The definition of the boundary between the Oxfordian and Kimmeridgian as given in this study results in its wide correlation potential and means that it can be recognized in the different marine successions of the World.
Źródło:
Volumina Jurassica; 2016, 14, 1; 15--49
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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