462 TERTIARY TO PRESENT/Paleocene and West Greenland and between East Greenland and Europe A hotspot formed beneath Greenland, producing outpourings of lava that intensified at the end of the epoch as the East Greenland–Europe area drifted over the hotspot Between Europe and Asia, the epicontinental West Siberian Sea, although more restricted than in either earlier or later times, extended southwards from the Arctic Ocean, reaching the northeastern part of the Tethys Ocean (known as the Peritethys) separating Asia from Europe near the end of the epoch Africa moved and rotated north, pushing Apulia (comprising Italy, the former Yugoslavia, and western Greece) towards the main European craton, and producing the initial phases of the Alpine Orogeny Eastward extension of this structural belt through Asia Minor and southern Iran partially isolated the Peritethys India was an island continent still moving north towards Asia The massive outpourings of hotspot-related basaltic lava that occurred in the Deccan region of West India during the latest Cretaceous continued for a brief interval in the earliest Paleocene The Aluk Plate in the South Pacific continued to be subducted beneath the western edge of the Antarctic Peninsula Rifting occurred between Antarctica and Australasia, but the two continents did not separate In fact, during the Paleocene, the three major elements of Gondwana (South America, Antarctica, and Australasia) remained in contact At the opposite pole, the Arctic Ocean was, for most of the epoch, an enclosed water body, separated by land from the rest of the world’s oceans Biota After the End-Cretaceous extinctions (see Mesozoic: End Cretaceous Extinctions), the earliest Paleocene biota was notable for the absence of such major and formerly diverse groups as ammonites, belemnites, rudists, plesiosaurs, mosasaurs, and non-avian dinosaurs, as well as for the low abundance and diversity of brachiopods, bivalve and gastropod molluscs, and marine reptiles There is generally low abundance and diversity of marine life at the beginning of the Paleocene In fact, some groups (both in the sea and on land) show a low-diversity recovery phase followed by radiation However, the pattern is different for other groups of organisms Key biotic events are discussed below Marine Realm Calcareous nannoplankton Few members of the calcareous nannoplankton, a group of microscopic calcifying algae (coccolithophores and their possible relatives), survived the end of the Cretaceous Paleocene nannofloras comprise these relict survivors plus an array of rapidly radiating new taxa (24 genera in the course of the epoch) By the end of the Paleocene, another major turnover resulted in over half of the Cretaceous relict species, and nearly a third of the newly evolved genera, becoming extinct The rapidity of this evolutionary turnover and the widespread occurrence of these fossils in marine strata have resulted in the establishment of nine globally recognized Paleocene biozones (Figure 1) Dinoflagellates The dinoflagellates, a group of cystforming unicellular algae, exhibit a stepwise origination pattern in the Early Paleocene Nevertheless, rapid evolution and widespread occurrence make dinoflagellates important zone fossils In particular, the biostratigraphically important genus Apectodinium originates during this epoch A nearly worldwide acme of the genus occurs at the very beginning of the succeeding Eocene and this is one of the primary markers used for recognizing the boundary between the two epochs Foraminifera Rapid radiation of planktonic foraminifera typical of the Cenozoic continued in the earliest Paleocene from its beginnings in the last few hundred thousand years of the Cretaceous The result was almost complete replacement of latest Cretaceous species by Cenozoic ones in an interval of less than 1.5 million years It is thought that some planktonic foraminiferal species acquired photosynthetic algal symbionts during the Paleocene, which may have allowed them to spread into oligotrophic environments Benthic foraminifera fared better than did the planktonics, and low-oxygen-tolerant species increased to dominate early in the epoch Notable newcomers were the textulariids among the agglutinated-shelled forms and the nummulitids among the calcareous-shelled forms, these latter representing one of the best known groups of larger benthic foraminifera of the Cenozoic A major extinction, the benthic foraminiferal extinction (BFE), affected benthic foraminifera at the end of the Paleocene The evolutionary and cosmopolitan attributes of planktonic foraminifera, like those of the calcareous nannoplankton, have resulted in planktonic foraminifera being used to divide the Paleocene into eight global biozones (Figure 1) Coelenterata and bryozoans The millepore hydrozoans made their appearance during the Paleocene, as did two families of octocorals There were no innovations at family level within the scleractinian corals However, this group does show a marked low in terms of diversity Based on gross morphology, there is no