Upper Darriwilian (Middle Ordovician) graptolite biostratigraphy and correlation of the Krapperup drill core, Scania, Sweden

GFF ◽  
2021 ◽  
pp. 1-24
Author(s):  
Jörg Maletz ◽  
Per Ahlberg
Keyword(s):  
Drill Core ◽  
Middle Ordovician

Morphology, evolution and stratigraphic distribution in the Middle Ordovician conodont genus Microzarkodina

2008 ◽  
Vol 99 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Anita Löfgren ◽  
Tatiana Tolmacheva
Keyword(s):  
Southern China ◽  
Morphology Evolution ◽  
Drill Core ◽  
Species Ranges ◽  
Middle Ordovician ◽  
Core Site

ABSTRACTMicrozarkodina is a genus of mainly Middle Ordovician conodonts that has its centre of distribution in Baltoscandia, and much less commonly occurs in southern China, Australia, Argentina and Laurentia. In Baltica a series of species, Microzarkodina russica n. sp., M. flabellum, M. parva, M. bella, M. hagetiana and M. ozarkodella, established themselves successfully. The succession of species ranges from just below the base of the Middle Ordovician (M. russica) to the upper part of the Middle Ordovician (M. ozarkodella). The species are frequently used for biostratigraphical purposes. The largely contemporaneous species Microzarkodina bella and M. hagetiana probably both evolved from M. parva and mostly occurred in separate areas. Microzarkodina ozarkodella probably evolved from M. hagetiana. This present investigation is based on a total of 94,208 elements, collected from 20 sections and one drill-core site in Sweden, one drill-core site and one outcrop in Estonia and two sections in the St Petersburg area in Russia. The Microzarkodina apparatus probably consisted of 15 or 17 elements: four P, two or four M and nine S elements. The S elements include different Sa, Sb1, Sb2, and Sc element types.

scholarly journals Structure and Composition of Basement and Sedimentary Cover in the Southwestern Part of the Siljan Ring, Central Sweden: New Data from the C-C-1 Drill Core

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 281
Author(s):  
Olga Sivalneva ◽  
Alexandr Postnikov ◽  
Vladimir Kutcherov ◽  
Marianna Tuchkova ◽  
Alexandr Buzilov ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Black Shales ◽  
Drill Core ◽  
Southwestern Part ◽  
Middle Ordovician ◽  
Additional Information ◽  
Metasedimentary Rocks ◽  
Basement Rocks ◽  
Geophysical Investigations ◽  
Type Of Fracture

The results from the geological and geophysical investigations of the Siljan Ring impact structure (central Sweden) have shown that the Paleozoic sedimentary succession and the Precambrian basement were strongly affected by complex deformational processes. Studies of a new drill core from the C-C-1 well provide valuable additional information necessary for the reconstruction of the geological setting in the southwestern part of the Siljan Ring. It was found that the contact between the basement and the sedimentary cover is tectonic, not normal sedimentary, in origin. The basement interval comprises Precambrian metavolcanic and metasedimentary rocks with a single mafic intrusion (gabbro-dolerite) in the upper part. The rocks have only been partially metamorphosed. The intercalation of calcareous mudstones, skeletal wackstones, and black shales in the sedimentary cover interval is not consistent with the regional lithostratigraphy scheme. Thus, more likely that the sedimentary sequence is not complete as a result of tectonic displacements, and a significant part of the Lower and Middle Ordovician succession is missing. The Post-Proterozoic tectonic reactivation and impact event also caused the formation of four types of fracture. The third type of fracture is accompanied by cataclastic zones and probably have an impact-related nature. In the highly fractured basement rocks, a dissolution along the second type of fracture has resulted in the development of open vugs. Open vugs and microporosity in cataclastic zones have been considered to be an effective storage space for hydrocarbons.

scholarly journals Darriwilian (Middle Ordovician) chemostratigraphy linked to graptolite, conodont and trilobite biostratigraphy in the Fågelsång-3 drill core, Scania, Sweden

GFF ◽  
2018 ◽  
Vol 140 (3) ◽  
pp. 229-240 ◽  
Author(s):  
Stig M. Bergström ◽  
Per Ahlberg ◽  
Jörg Maletz ◽  
Frans Lundberg ◽  
Michael M. Joachimski
Keyword(s):  
Drill Core ◽  
Middle Ordovician

The earliest ostracods from the Ordovician of the Prague Basin, Czech Republic

2014 ◽  
Vol 64 (4) ◽  
pp. 367-392 ◽  
Author(s):  
Karolína Lajblová ◽  
Petr Kraft
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Massif Central ◽  
Central European ◽  
Middle Ordovician ◽  
Prague Basin ◽  
Barrandian Area ◽  
Fossil Assemblages ◽  
European Variscides

Abstract The earliest ostracods from the Bohemian Massif (Central European Variscides) have been recorded from the Middle Ordovician of the Prague Basin (Barrandian area), in the upper Klabava Formation, and became an abundant component of fossil assemblages in the overlying Šarka Formation. Both early ostracod associations consist of eight species in total, representing mainly eridostracans, palaeocopids, and binodicopids. The revision, description, or redescription of all species and their distribution in the basin is provided. Their diversification patterns and palaeogeographical relationships to ostracod assemblages from other regions are discussed.

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