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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Belemniti jury severních Čech - stratigrafie, paleobiogeografie a možný izotopový záznam / The Jurassic belemnites of northern Bohemia - stratigraphy, palaeobiogeography and possible isotope record

Geist, Jan January 2020 (has links)
4 Abstract The work is based on a revision of collection from several scientific institutions from the Czech Republic and the Federal Republic of Saxony (National Museum in Prague, Chlupáč Museum of Earth History, Senckenberg Natural History Collections Dresden, etc.). The collection is based on samples published by Oskar Lenz and George Bruder from the second half of the 19th century. Both authors also processed the findings of other researchers (e.g. Cotta, Weisse). The belemnite rostra were systematically divided into four families, five genera and seven identifiable genera. One rostrum has not exactly been determined. The age of the samples was established to be the Middle and Upper Jurassic (Bajocian- Kimmeridgian). The length of the expected sedimentation in this area has been prolonged to the past (deeper to the Middle Jurassic), mainly due to the finding of the species Megateuthis gigantea Schlotheim, 1820. Earlier research (especially in the 20th century) assumed the extent of preserved carbonate rocks only in the Oxfordian and Kimmeridgian age, with a not much fossiliferous Callovian Brtníky Formation. The studied sedimentary rocks show a significant influence of Milankovich cycles with repeated alternation of carbonate and non- carbonate layers in the sequence. Preliminary results of isotope...
2

Belemniti spodní křídy lokality Štramberk: taxonomie, stratigrafie, paleoekologie, paleobiogeografie / Lower Cretaceous belemnites of the locality Štramberk: taxonomy, stratigraphy, palaeoecology, palaeobiogeography

Vaňková, Lucie January 2015 (has links)
The study (MS, diploma thesis) is based on more than 1200 belemnite rostra set from the Lower Cretaceous sediments of locality Štramberk (N Moravia). Investigated rostra come from the collection of Dr. V. Houša, who collected them during the seventies to eighties of the last century, during intensive excavation of the Lower Cretaceous tectonic block named Š-12 "pocket". Belemnite rostra were determined at species and generic levels including 7 species and 18 genera. The majority of belemnite assemblage comes from the Lower Valanginian strata, however, also the Tithonian, Berriasian and Hauterivian taxa are present, what clearly documents the redeposition. The presence of mesohibilitids, known from the Barremian and younger deposits, still remains enigmatic. For better understanding of the redeposition proces, the alveolar infill formed by several generations of sediments, are investigated. Study of these sediments outlines the sedimentary development of the Baška elevation inside the Outer Carpathian system. Preliminary stable isotope data δ18 O and δ13 C received from belemnite rostra show different belemnite life-style during the ontogeny - i.e. juvenile bottom life style and adults inhabiting shallow/warmer waters. Negative values of δ18 O should be correlated with the "Valanginian extinction...

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