TERTIARY TO PRESENT/Paleocene 459 there have been many published models of where the various terranes lay through geological time There is now considerable agreement on the identity, positions, and progression, through the Palaeozoic, of terranes surrounding what is today the North Atlantic area, around which the majority of academic geologists work However, the many terranes that make up Central and South America, Africa, Asia, and Australasia are, in many cases, rather poorly defined and recognised, and their relative positioning through the Phanerozoic (let alone the Precambrian) is a matter for unresolved debate and geological argument Figure shows a possible terrane reconstruction for half the globe at about 400 Ma (the Early Devonian), at a time when Laurentia, Baltica, and Avalonia had fused to form Laurussia and when various terranes such as Armorica, Adria, the Pontides of Turkey, and the Hellenic Terrane (including Moesia) had all left the Gondwana superterrane following the opening of the Palaeotethys Ocean to their south The other half of the globe, not shown in Figure 2, was largely occupied by the vast Panthalassic Ocean See Also Gondwanaland and Gondwana Palaeomagnetism Pangaea Precambrian: Overview Volcanoes Further Reading Cocks LRM and Torsvik TH (2002) Earth geography from 500 to 400 million years ago: a faunal and palaeomag netic review Journal of the Geological Society, London 159: 631 644 Leitch EC and Scheibner G (eds.) (1987) Terrane Accretion and Orogenic Belts Geodynamics Series 19 Washington DC: American Geophysical Union Stampfli GM and Borel GD (2002) A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrons Earth and Planetary Science Letters 196: 17 33 Torsvik TH and Cocks LRM (2004) Earth geography from 400 to 250 million years ago: a palaeomagnetic, faunal and sedimentological review Journal of the Geological Society, London 161: 348 361 Windley BF (1995) The Evolving Continents, 3rd edn New York: John Wiley TERTIARY TO PRESENT Contents Paleocene Eocene Oligocene Miocene Pliocene Pleistocene and The Ice Age Paleocene J J Hooker, The Natural History Museum, London, UK Copyright 2005, Natural History Museum All Rights Reserved Introduction The Paleocene Epoch/Series is the first of the Cenozoic Era/Erathem It is the first of five epochs in the Tertiary Period and the first of three in the Paleogene, which is treated either as a period in its own right or as a subdivision of the Tertiary The Paleocene succeeds the Cretaceous Period/System and precedes the Eocene Epoch The Paleocene lasted nearly 10 million years, from 65.5 till 55.8 Ma, and is divided approximately equally into three ages/stages (in order of decreasing age): the Danian, the Selandian, and the Thanetian (Figure 1) The naming of the Paleocene follows the earlier procedure of adding a prefix denoting degree of antiquity or modernity, in this case ‘paleo’, from the Greek palaios, meaning ‘ancient’, and ‘cene’, from the Greek kainos, meaning ‘recent’ The Paleocene was the last of the Cenozoic epochs to be named, originally being proposed by Schimper in 1874 Schimper was a palaeobotanist and, in contrast to the definitions of the other Cenozoic epochs,