Sökning: "calcareous nannofossils"

Hittade 4 avhandlingar innehållade orden calcareous nannofossils.

1. 1. Late Eocene through Oligocene calcareous nannofossils from the paleo-equatorial Pacific Ocean – taxonomy, preservation history, biochronology and evolution

   Författare :Teodora Blaj; Jan Backman; Jorijntje Henderiks; Isabella Raffi; Paul Bown; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marine sediments; calcareous nannofossils; late Eocene; Oligocene; biochronology; evolution; morphometry; taxonomy; ODP Leg 199 Site 1218; paleo-equatorial Pacific Ocean; Historical geology and palaeontology; Historisk geologi och paleontologi; Marine Geoscience; marin geovetenskap;

   Sammanfattning : This study aims to unravel the ecological and evolutionary dynamics within the calcareous nannofossil communities at the Eocene/Oligocene (E/O) transition and during the Oligocene time when Cenozoic 'icehouse' conditions were established. The main question this study aims to answer is whether the changes in the nannofossil assemblages were controlled by intrinsic evolutionary trends or if the changes were controlled by environmental factors such as changes in temperature and nutrient availability in the surface water. LÄS MER

3. 2. The emergence of pelagic calcification and its influence on seawater chemistry in the Upper Triassic

   Författare :Isaline Demangel; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Calcareous nannofossils; Triassic; Neo-Tethys Ocean; Pelagic calcification;

   Sammanfattning : After the early biomineralisation event in the early Paleozoic (Cambrian –Ordovician; 541 – 443.8 Ma), the Late Triassic (237 – 201.3 Ma) represents another key period of biomineralisation with the onset of the Mesozoic plankton radiation. LÄS MER

4. 3. Eastern equatorial Pacific bulk sediment properties and paleoceanography since the late Neogene

   Författare :Daniele Reghellin; Helen K. Coxall; Jan Backman; Gerald R. Dickens; Steve Hovan; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleoceanography; late Neogene; eastern equatorial Pacific; deep sea sediments; bulk sediment; stable isotopes; surface mixed layer; sediment physical properties; Marine Geology; maringeologi;

   Sammanfattning : Reconstructing eastern equatorial Pacific (EEP) oceanography since the late Neogene (about 8 million years ago, Ma) is a central topic in current paleoceanographic investigations. The reason for this is two-fold. LÄS MER

5. 4. Origin and the evolution of diatoms through the integration of paleontology and phylogenetics

   Författare :Karolina Brylka; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diatoms; evolution; fossil record; Cretaceous; molecular evolution; Mesozoic; silicon transporter proteins; gene duplication;

   Sammanfattning : Diatoms, the prominent photosynthetic eucaryotes, have inhabited the world’s oceans for at least the past 120 Ma since their first appearance in the Lower Cretaceous. There are also records of older diatoms, from the Jurassic dating to ca. 172 Ma and ca. 165 Ma, however these are poorly documented. LÄS MER