ON THAMNASTERIA CONCINNA (GOLDFUSS) (SCLERACTINIA:THAMNASTERIIDAE) IN PLEISTOCENE ERRATICS OF BELARUS

Abstract

For the first time, erratic Upper Jurassic Scleractinian corals are reported herein from Pleistocene outcrops of Belarus. The studied material belongs to a widespread species, Thamnasteria concinna (Goldfuss). These findings are of interest primarily because Jurassic erratic fossils are extremely rare in this region. The main distribution areas of Thamnasteria concinna (Goldfuss) in bedrock as well as erratics are located to the west of the places of its discovery in Belarus. Less often this species was reported further south. Previously the presence of Thamnasteria concinna
(Goldfuss) was also mentioned in the Upper Jurassic biohermal deposits in the extreme southeast of Belarus. However, these deposits are overlain by younger sediments at a considerable depth and are therefore not regarded the most probable source of the material described here. If we consider the area of distribution of Thamnasteria concinna (Goldfuss) as erratics, then the localities closest to the Belarusian ones are confined to the north-west of Poland. As far as it can be judged from some previously published data, certain features of preservation of erratic specimens collected in Belarus resemble those from Poland, where, as it is assumed here, they may come from. Thus, their occurrence in Belarus is not readily explained by sublongitudinal glacial transport from the north and northwest, which is usually accepted for erratics. A probable explanation for this may be sublatitudinal transport by floating ice.

Fig. 3. Ref.: 10 titles.