Abstract
The chronostratigraphical type profile of the Kimmeridgian of Dorset is subdivided biostratigraphically into five ostracod zones. Six other areas in Northern and Western Europe with Kimmeridgian ostracods are examined. The species are listed, counted, and examined in relation to the zones of the type Kimmeridgian.In the Lower Kimmeridgian the ostracod faunas bear the impression of a relatively uniform composition between the examined areas. In the Upper Kimmeridgian two different faunal regions are developed. In the North Sea Basin in the North Western Danish Embayment and in Dorset relatively uniform faunas occur, separated from other, again rather uniform faunas occuring in the Mid-European Region, from Northwestern Poland and Scania to the Paris Basin.Stratigraphically important are species of the genera Galliaecytheridea, Mandelstamia, and Macrodentina. 19 species are given diagnoses. Two new subgenera and seven new species are established.
Highlights
The aim of this paper is to attempt to utilize ostracod faunas for biostratigraphical correlations in the Kimmeridgian of Northern and Western Europe
During the last two decades a considerable amount of information has accumulated about the Kimmeridgian ostracods of this area, and the various areas are documented to varying degrees it seems possible at this stage to give an outline of the biostratigraphy
The two ostracod zones of the Lower Kimmeridgian of Dorset are clearly recognizable in the North German Basin and they seem to be the equivalents of the Mittlerer Malm 1-2
Summary
Biostrati~aphy based on marinebrackish ostracods, cannot equal the precision afforded by the use of quickly evolving as well as quickly migrating planktonic and nektonic organisms (Ammonoidea etc.) The great advantage of ostracods in biostratigraphy is the wealth of marine and marine-brackish species which are not effected by a certain deviation from the standard marine salinity This is important in the Upper Kimmeridgian where in the areas considered - with the exception of Dorset - ammonite faunas are scarce or totally absent. ARKELL (1933) divided the Kimmeridge Clay (and the Kimmeridgian Stage) into a Lower and Upper division, taking the "Yellow Ledge Stone Band" as the line of division In this sense he included the Gravesia Zone into the lower division.
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