Episodic Ice-Free Arctic Ocean in Pliocene and Pleistocene Time: Calcareous Nannofossil Evidence

Science  17 Oct 1980:
Vol. 210, Issue 4467, pp. 323-325
DOI: 10.1126/science.210.4467.323


Today's ice cover (2 to 4 meters thick) over the Arctic Ocean provides a shadow that prevents coccolithophorids (photosynthetic, planktonic algae) from living there. Sparse, low-diversity, but indigenous coccolith assemblages in late Pliocene to mid-Pleistocene (but not Holocene) sediments imply deep penetrating warm currents or an ice-free Arctic Ocean, or both, as those layers were being deposited.