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Inoceramid and foraminiferal record and biozonation of the Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan

Walaszczyk I., Kopaevich L. F., Beniamovski V. N.

Acta Geologica Polonica

2013

Vol. 63, no. 4

469--487

The Turonian and Coniacian (Upper Cretaceous) of the Mangyshlak Mts., western Kazakhstan, yielded a rich and relatively complete inoceramid bivalve record. The faunas and their succession correspond to those known from central and eastern Europe, allowing the zonation established in the latter areas to be applied in a virtually identical form. The gaps in the record of the group in Mangyshlak stem from the regional hiatuses in the geological record in the area and do not reflect any biogeographical differences between eastern and central-western Europe. Planktonic foraminifera are rare. Four successive interval range zones can be distinguished: in ascending stratigraphic order, the Helvetoglobotrunaca helvetica, Marginotruncaca pseudolinneiana, Marginotruncana coronata, and Concavotruncana concavata zones. Their correlation with the inoceramid zonation and, consequently, with the chronostratigraphic scheme, is demonstrated. The zonation and chronostratigraphic subdivision as applied in Mangyshlak may easily be applied to other areas of the peri-Caspian region (Caucasus, Tuarkyr, Kopet-Dagh, SE margin of the East-European Craton).

Late Cretaceous (Turonian - Coniacian) irregular echinoids of western Kazakhstan (Mangyshlak) and southern Poland (Opole)

Olszewska-Nejbert D.

Acta Geologica Polonica

2007

Vol. 57, no. 1

1-87

During the Late Cretaceous, both Mangyshlak and the Opole area were part of the North European Province, and irregular echinoid faunas during the Turonian and Coniacian in both areas were dominated by holasteroids and spatangoids, in particular by Plesiocorys, Echinocorys and Micraster. Almost 1,000 specimens from both areas have been studied. Taxonomically more varied are the faunas species in 3 genera. One species, Micraster (Micraster) praerogalae, a transitional form between Micraster (Micraster) cortestudinarium(GOLDFUSS) and Micraster (Micraster) rogalae NOWAK, is described as new. Micraster (Micraster) rogalae is markedly diachronous within the North European Province, first appearing in the late Coniacian in Mangyshlak and reaching central and western Europe during the late Early Santonian. A similar pattern is revealed by a large morphotype of Echinocorys ex gr. scutata LESKE. Palaeoecological and actualistic data show the taxa studied to have been shallow infaunal (Catopygus), shallow epifaunal [Conulus (Conulus) subrotundus], deeper infaunal [Micraster (Micraster)], deeper semi-infaunal [Micraster (Gibbaster), Plesiocorys (Sternotaxis) plana], deeper epifaunal [Echinocorys, Plesiocorys (Plesiocorys) placenta], and deeper infaunal (Hemiaster). Echinoid bioevents described originally from the Salzgitter-Salder section (Lower Saxony, Germany) can also be recognised in the Opole area, but not further afield in Mangyshlak.