-
Faculty of Arts and HumanitiesDean's Office, Faculty of Arts and HumanitiesJakobi 2, r 116-121 51005 Tartu linn, Tartu linn, Tartumaa EST0Institute of History and ArchaeologyJakobi 2 51005 Tartu linn, Tartu linn, Tartumaa EST0Institute of Estonian and General LinguisticsJakobi 2, IV korrus 51005 Tartu linn, Tartu linn, Tartumaa EST0Institute of Philosophy and SemioticsJakobi 2, III korrus, ruumid 302-337 51005 Tartu linn, Tartu linn, Tartumaa EST0Institute of Cultural ResearchÜlikooli 16 51003 Tartu linn, Tartu linn, Tartumaa EST0Institute of Foreign Languages and CulturesLossi 3 51003 Tartu linn, Tartu linn, Tartumaa EST0School of Theology and Religious StudiesÜlikooli 18 50090 Tartu linn, Tartu linn, Tartumaa EST0Viljandi Culture AcademyPosti 1 71004 Viljandi linn, Viljandimaa EST0Professors emeriti, Faculty of Arts and Humanities0Associate Professors emeriti, Faculty of Arts and Humanities0Faculty of Social SciencesDean's Office, Faculty of Social SciencesLossi 36 51003 Tartu linn, Tartu linn, Tartumaa EST0Institute of EducationJakobi 5 51005 Tartu linn, Tartu linn, Tartumaa EST0Johan Skytte Institute of Political StudiesLossi 36, ruum 301 51003 Tartu linn, Tartu linn, Tartumaa EST0School of Economics and Business AdministrationNarva mnt 18 51009 Tartu linn, Tartu linn, Tartumaa EST0Institute of PsychologyNäituse 2 50409 Tartu linn, Tartu linn, Tartumaa EST0School of LawNäituse 20 - 324 50409 Tartu linn, Tartu linn, Tartumaa EST0Institute of Social StudiesLossi 36 51003 Tartu linn, Tartu linn, Tartumaa EST0Narva CollegeRaekoja plats 2 20307 Narva linn, Ida-Virumaa EST0Pärnu CollegeRingi 35 80012 Pärnu linn, Pärnu linn, Pärnumaa EST0Professors emeriti, Faculty of Social Sciences0Associate Professors emeriti, Faculty of Social Sciences0Faculty of MedicineDean's Office, Faculty of MedicineRavila 19 50411 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Biomedicine and Translational MedicineBiomeedikum, Ravila 19 50411 Tartu linn, Tartu linn, Tartumaa ESTInstitute of PharmacyNooruse 1 50411 Tartu linn, Tartu linn, Tartumaa ESTInstitute of DentistryL. Puusepa 1a 50406 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Clinical MedicineL. Puusepa 8 50406 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Family Medicine and Public HealthRavila 19 50411 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Sport Sciences and PhysiotherapyUjula 4 51008 Tartu linn, Tartu linn, Tartumaa ESTProfessors emeriti, Faculty of Medicine0Associate Professors emeriti, Faculty of Medicine0Faculty of Science and TechnologyDean's Office, Faculty of Science and TechnologyVanemuise 46 - 208 51003 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Computer ScienceNarva mnt 18 51009 Tartu linn, Tartu linn, Tartumaa ESTInstitute of GenomicsRiia 23b/2 51010 Tartu linn, Tartu linn, Tartumaa ESTEstonian Marine Institute0Institute of PhysicsInstitute of ChemistryRavila 14a 50411 Tartu linn, Tartu linn, Tartumaa EST0Institute of Mathematics and StatisticsNarva mnt 18 51009 Tartu linn, Tartu linn, Tartumaa EST0Institute of Molecular and Cell BiologyRiia 23, 23b - 134 51010 Tartu linn, Tartu linn, Tartumaa ESTTartu ObservatoryObservatooriumi 1 61602 Tõravere alevik, Nõo vald, Tartumaa EST0Institute of TechnologyNooruse 1 50411 Tartu linn, Tartu linn, Tartumaa ESTInstitute of Ecology and Earth SciencesJ. Liivi tn 2 50409 Tartu linn, Tartu linn, Tartumaa ESTProfessors emeriti, Faculty of Science and Technology0Associate Professors emeriti, Faculty of Science and Technology0Institute of BioengineeringArea of Academic SecretaryHuman Resources OfficeUppsala 6, Lossi 36 51003 Tartu linn, Tartu linn, Tartumaa EST0Area of Head of FinanceFinance Office0Area of Director of AdministrationInformation Technology Office0Administrative OfficeÜlikooli 17 (III korrus) 51005 Tartu linn, Tartu linn, Tartumaa EST0Estates Office0Marketing and Communication OfficeÜlikooli 18, ruumid 102, 104, 209, 210 50090 Tartu linn, Tartu linn, Tartumaa EST0Area of Vice Rector for DevelopmentCentre for Entrepreneurship and InnovationNarva mnt 18 51009 Tartu linn, Tartu linn, Tartumaa EST0University of Tartu Natural History Museum and Botanical GardenVanemuise 46 51003 Tartu linn, Tartu linn, Tartumaa EST0International Cooperation and Protocol Office0University of Tartu MuseumLossi 25 51003 Tartu linn, Tartu linn, Tartumaa EST0Area of RectorRector's Strategy OfficeInternal Audit OfficeArea of Vice Rector for Academic AffairsOffice of Academic AffairsUniversity of Tartu Youth AcademyUppsala 10 51003 Tartu linn, Tartu linn, Tartumaa EST0Student Union OfficeÜlikooli 18b 51005 Tartu linn, Tartu linn, Tartumaa EST0Centre for Learning and TeachingArea of Vice Rector for ResearchUniversity of Tartu LibraryW. Struve 1 50091 Tartu linn, Tartu linn, Tartumaa EST0Grant Office
Doctoral defence: Bilal Gul „Palaeotemperature reconstruction based on oxygen stable isotopic trends from the Ordovician-Silurian brachiopods of Baltoscandia“
On 29 November at 12.15 Bilal Gul will defend his doctoral thesis „Palaeotemperature reconstruction based on oxygen stable isotopic trends from the Ordovician-Silurian brachiopods of Baltoscandia“ for obtaining the degree of Doctor of Philosophy (in Geology).
Supervisors:
Professor Tõnu Meidla, University of Tartu
Professor Leho Ainsaar, University of Tartu
Opponent:
Professor Oliver Lehnert, Friedrich-Alexander-Universität Erlangen-Nürnberg (Germany)
Summary
Over the last two decades, extensive research has focused on climate fluctuations during the Ordovician-Silurian period. Baltoscandia is considered an ideal region for such studies due to well-preserved Palaeozoic sediments and minimal post-depositional alteration. The current study is focusing on the environmental and climatic changes reflected in the Ordovician-Silurian Baltoscandian Palaeobasin, using the stable oxygen isotopic data from the brachiopod shell calcite as a proxy for paleoclimate, providing a comprehensive record of palaeotemperature trends in this region. Despite certain limitations in absolute temperature precision, the results show that brachiopod isotope data can be used for interpretation of climatic trends. The study identifies that more significant global δ¹³C excursions in the Ordovician-Silurian periods, including the Mid-Darriwilian Carbon Isotope Excursion (MDICE), the Hirnantian Isotope Carbon Excursion (HICE) and Ireviken Event, are also reflected in the brachiopod shell composition. The oxygen isotope data from brachiopods shows an overall trend of cooling from the Early to Middle Ordovician, with a significant temperature decrease of about 8 °C. This cooling likely reflects global climate trends rather than local environmental disturbances. Following a relatively warm late Katian age, a significant global cooling occurred during the Hirnantian glaciation, with a subsequent rise of temperatures during the early Silurian. The study also highlights that, despite the plate tectonic drift of Baltica towards tropical latitudes, the regional palaeoenvironmental changes were primarily influenced by the global climatic shifts towards cooler climate. The δ¹⁸O values from brachiopods of the Baltoscandian region are consistent with those from other continents. Brachiopods are therefore considered a reliable proxy for understanding palaeoclimate during the Ordovician-Silurian periods.