Progress in mid palaeozoic palaeoceanographical studies from Ostracoda — from local to global importance (a review)

Latest Permian deep-water ostracods from southwestern Guangxi, South China

“…This fauna is restricted to deep-water environments, from 500 m to 5000 m deep, in connection with a global ocean supplied with cold water by ice caps. Becker (2000) suggested that the palaeopsychrospheric ecotype is more indicative of low-energy conditions than of water depth. The authors agree with the opinion of low-energy conditions; however, the bathymetric evaluations based on palaeopsychrospheric ostracods have been supported by the associated facies and fauna (see radiolarian results below).…”

Ostracods (Crustacea) as shelf to basin indicators: evidence from Late Devonian Yangdi and Nandong sections in Guangxi, South China

“…conodonts) suggest a slope environment in the Yangdi section (Ji, 1989;Ma and Bai, 2002;Chen et al, 2013;Huang and Gong, 2016). However, none of the spinose podocopids (indicative of deep-and cold-water environments; Blumenstengel, 1965Blumenstengel, , 1979Kozur, 1972;Bandel and Becker, 1975;Lethiers and Crasquin, 1987;Wang, 1988;Casier, 2004; some authors also considered spinose-podocopid ostracod assemblages as indicative for low-energy environments, which might not be particularly deep or cold; Becker, 2000;Groos-Uffenorde et al, 2000) were found together with the smooth-podocopid association in the Yangdi section. This means a deposition in a shallower environment than that of the slope.…”

The palaeopsychrosphere in the Devonian

“…Becker, however, always considered the comparison with the Tertiary–Recent psychrospheric fauna to be unsuccessful or inappropriate and maintained that the Thuringian Ecotype was characteristic simply of low‐energy conditions, not necessarily deep, cold or poorly oxygenated, and could be found in shallow‐water as well as deep‐water settings (Becker & Bless ; Becker et al . ; Becker ).…”

“…The existence of a palaeopsychrosphere during the Palaeozoic (Kozur 1972(Kozur , 1991 has been postulated on the evidence of a distinctive ostracod fauna known as the Thuringian Ecotype (Zagora 1968;Bandel & Becker 1975), members of which show morphological similarities (such as thin-shelled and spiny carapaces) with those of the modern psychrospheric fauna. This interpretation has been much debated, however (Lethiers & Crasquin 1987;Becker 2000b), as have the nature of deep ocean circulation through the Phanerozoic (Horne 1999) and its role in marine biological crises such as the Late Devonian Kellwasser and Hangenberg extinction events (Chen et al 2013;Carmichael et al 2014Carmichael et al , 2016. Here, we review the concept of a palaeopsychrospheric ostracod fauna in the context of global ocean circulation and marine extinction events in the Devonian period, and propose a new model for the origin, preservation and survival of the Thuringian Ecotype assemblage.…”

“…Bandel & Becker (1975) also recognized a third, hemipelagic facies ('Entomozoan Ecotype') characterized by 'fingerprint' ostracods of the Entomozooidea (Myodocopida) that are considered to have been planktonic. Becker, however, always considered the comparison with the Tertiary-Recent psychrospheric fauna to be unsuccessful or inappropriate and maintained that the Thuringian Ecotype was characteristic simply of low-energy conditions, not necessarily deep, cold or poorly oxygenated, and could be found in shallow-water as well as deepwater settings (Becker & Bless 1990;Becker et al 1993;Becker 2000b). Casier (2008) illustrated the depth distribution of the different Late Palaeozoic 'ecotypes' which he renamed as 'mega-assemblages' (Fig.…”