Some encrusted hardgrounds from the Ordovician of Estonia (Baltica)

Carnets de Geologie: Notebooks of geology

关键词: hardground;    Cornulites;    Bryozoa;    echinoderms;    Ordovician;    Baltica;   

学科分类：地质学

来源: Carnets de Geologie

【 摘 要 】

The Ordovician hardground faunas of Estonia are not diverse. They include echinoderm holdfasts (i.e., eocrinoids and crinoids), edrioasteroids, bryozoans (both hemispherical trepostomes and stalked ptilodictyids) and cornulitids. The earliest hardground faunas appeared in the Dapingian (i.e., bryozoans and echinoderms). The Estonian hardground faunas are less diverse than the North American ones. North American hardgrounds seem to be more heavily encrusted than the Estonian ones. These differences may be due to the paleogeographic distances, different climates and different sedimentation environments of the paleocontinents.

【 授权许可】

CC BY