Sökning: "Upper Ordovician"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden Upper Ordovician.

1. 1. Middle and Upper Ordovician graptolites, trilobites, and biostratigraphy of Scania and Jämtland, Sweden

   Författare :Christian Pålsson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; physical geography; Geology; Sweden; Jämtland; Scania Skåne ; Upper Ordovician; Middle Ordovician; palaeoecology; biostratigraphy; lithostratigraphy; Graptolites; trilobites; Geologi; fysisk geografi; Palaeontology; Paleontologi;

   Sammanfattning : Graptolites and some trilobites from Middle–Upper Ordovician siliciclastic and calcareous rocks in Scania (Skåne), southern Sweden, and Jämtland, central Sweden, are described and discussed. Their stratigraphic distribution is discussed on the basis of new and old collections from outcrops and drill cores. LÄS MER

3. 2. Trilobites from the Middle and Upper Ordovician Andersön Shale Formation in Jämtland and the equivalent Killeröd Formation in Skåne, Sweden

   Författare :Kristina Månsson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fysisk geografi; Geologi; physical geography; Geology; Sweden; Jämtland; Skåne; Upper Ordovician; Middle Ordovician; Killeröd Formation; Andersön Shale Formation; ontogeny; biostratigraphy; Trilobita; taxonomy; trilobite associations; Systematic zoology; zoogeography; Zoologisk systematik; djurgeografi; Development biology; growth animal ; embryology; Utvecklingsbiologi; ontogeni; embryologi;

   Sammanfattning : Trilobites from the Middle and Upper Ordovician Andersön Shale Formation in Jämtland, central Sweden, and the Middle Ordovician Killeröd Formation in Skåne (Scania), southern Sweden, are revised and discussed. These formations have several genera and a few species in common, e.g. LÄS MER

4. 3. Cambro-Ordovician microorganisms: acritarchs and endoliths

   Författare :Martin Stockfors; Malgorzata Vidal-Moczydlowska; John S. Peel; Kenneth John Dorning; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Cambrian; Ordovician; acritarch; endolith; Kolguev Island; North Greenland; Stratigraphy; Geovetenskap; Earth sciences; Geovetenskap;

   Sammanfattning : Organic-walled microfossils are abundant and taxonomically diverse in Cambrian-Ordovician strata; some are important for biostratigraphy and for the correlation of geological successions. New assemblages of Cambrian-Ordovician acritarchs from Kolguev Island, Arctic Russia and Middle Cambrian ichnofossils of endoliths from Peary Land, North Greenland are studied. LÄS MER

5. 4. Early Palaeozoic jawed polychaetes with focus on polychaetaspids and ramphoprionids from the Silurian of Gotland, Sweden

   Författare :Mats Eriksson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fysisk geografi; Geologi; physical geography; Geology; chemistry; palaeobiogeography; palaeoecology; taxonomy; apparatus reconstructions; Silurian; Recent; Ordovician; early Palaeozoic; scolecodonts; Annelida; polychaeta;

   Sammanfattning : Jawed polychaete annelid worms were abundant and diverse in the early Palaeozoic seas and their jaws (scolecodonts) are common microfossils in sedimentary rocks of that age. Despite their abundance, relatively little work has been focused on these fossils. LÄS MER

7. 5. The flux of extraterrestrial spinels to Earth associated with He-3 anomalies in Cenozoic and Ordovician sediments

   Författare :Samuele Boschi; Kärnfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Chromite; He-3 anomaly; Cenozoic; mid-Ordovician; asteroid breakup; ordinary chondrites; Popigai ejecta; iridium anomaly; Zircons; ice age;

   Sammanfattning : The main goal of this thesis is to reconstruct the flux of extraterrestrial matter to Earth in specific time intervals of our past in order to add an astronomical dimension to the understanding of Earth's history. To accomplish this, extraterrestrial chrome-spinel grains have been extracted and analysed. LÄS MER