Science, the growth of reliable knowledge, became a major triumph of the European Enlightenment in the seventeenth century, under the guise of ‘natural philosophy’: investigating what the earth and universe are made of and how things work. It took another century for the parallel subject ‘natural history’ to glimpse how the earth, its geography and its richly diverse life came

Multiple stable isotope investigations from upper Eocene to lower Oligocene deep-water marine sequences record the transition from global greenhouse to the icehouse conditions (Oi-1 glacial). While Southern Ocean high latitude deep sea records of this transition are well known, their shallow marine equivalents are rare and have the potential to record the eustatic and oceanic consequences of Paleogene glacial variability. The well-known high paleolatitude (similar to 55 degrees S) neritic carbonate sequence at Browns Creek and Castle Cove in the Otway Basin in southeast Australia spans the Eocene-Oligocene boundary. During this time the area lay on the northeastern margin of the Australo-Antarctic Gulf facing the evolving Southern Ocean. The importance of this record has been hampered by a lack of a consistent stratigraphy and contradictory microfossil interpretations. To reconcile these issues we combine new bio-, chemo- and lithostratigraphic analyses of the outcrops and a new core (Colac-2) with pre-existing data to revise the stratigraphy. This confirms the middle/upper Eocene boundary is near the base of the section. The overlying upper Eocene siliciclastic strata are truncated by an unconformity (of similar to 0.8 Ma in duration) and overlain by glauconitic sand (the Notrostrea greensand) deposited after similar to 35.9 Ma. Subsequently deepening to middle to outer neritic depths deposited cyclic carbonates. Shallowing after similar to 35 Ma deposited laterally variable calcareous siliciclastic facies. These strata were tilted and eroded prior to 34 Ma leading to shallow water facies that may have been subaerially exposed during uplift. Brachiopod strontium isotope dates and an 0.5 parts per thousand carbon isotope excursion above this unconformity suggests the top of the Browns Creek and the base of the Castle Cove section correlate to Eocene-Oligocene transition (EOT-1) at similar to 34 Ma. The subsequent persistence of positive C/O isotope values above this level records the transition to the Oi-1 glaciation at similar to 33.7 Ma. Strong cyclicity in the inner shelf Castle Cove limestone is interpreted to record the commencement of obliquity dominated glacio-eustacy during the Oi-1 glacial phase. The shallowing from outer to inner shelf palaeodepths from the late Eocene to the early Oligocene is likely related to the onset of cryosphere expansion, however, palaeodepth estimates are complicated by the onset of regional compressional tectonism at the Eocene/Oligocene boundary that caused localized tilting and an unconformity with possible antisiphoning effects in this near-field site.

Detailed, stratigraphically well-constrained environmental reconstructions are available for Paleocene and Eocene strata at a range of sites in the southwest Pacific Ocean (New Zealand and East Tasman Plateau; ETP) and Integrated Ocean Discovery Program (IODP) Site U1356 in the south of the Australo-Antarctic Gulf (AAG). These reconstructions have revealed a large discrepancy between temperature proxy data and climate models in this region, suggesting a crucial error in model, proxy data or both. To resolve the origin of this discrepancy, detailed reconstructions are needed from both sides of the Tasmanian Gateway. Paleocene-Eocene sedimentary archives from the west of the Tasmanian Gateway have unfortunately remained scarce (only IODP Site U1356), and no well-dated successions are available for the northern sector of the AAG. Here we present new stratigraphic data for upper Paleocene and lower Eocene strata from the Otway Basin, southeast Australia, on the (north) west side of the Tasmanian Gateway. We analyzed sediments recovered from exploration drilling (Latrobe-1 drill core) and outcrop sampling (Point Margaret) and performed high-resolution carbon isotope geochemistry of bulk organic matter and dinoflagellate cyst (dinocyst) and pollen biostratigraphy on sediments from the regional lithostratigraphic units, including the Pebble Point Formation, Pember Mudstone and Dilwyn Formation. Pollen and dinocyst assemblages are assigned to previously established Australian pollen and dinocyst zonations and tied to available zonations for the SW Pacific. Based on our dinocyst stratigraphy and previously published planktic foraminifer biostratigraphy, the Pebble Point Formation at Point Margaret is dated to the latest Paleocene. The globally synchronous negative carbon isotope excursion that marks the Paleocene-Eocene boundary is identified within the top part of the Pember Mudstone in the Latrobe-1 borehole and at Point Margaret. However, the high abundances of the dinocyst Apectodinium prior to this negative carbon isotope excursion prohibit a direct correlation of this regional bio-event with the quasi-global Apectodinium acme at the Paleocene-Eocene Thermal Maximum (PETM; 56 Ma). Therefore, the first occurrence of the pollen species Spinizonocolpites prominatus and the dinocyst species Florentinia reichartii are here designated as regional markers for the PETM. In the Latrobe-1 drill core, dinocyst biostratigraphy further indicates that the early Eocene (similar to 56-51 Ma) sediments are truncated by a similar to 10 Myr long hiatus overlain by middle Eocene (similar to 40 Ma) strata. These sedimentary archives from southeast Australia may prove key in resolving the model-data discrepancy in this region, and the new stratigraphic data presented here allow for detailed comparisons between paleoclimate records on both sides of the Tasmanian Gateway.

Early Paleogene southern Australia, which comprises the north shore of the Australo-Antarctic Gulf, was covered in the equivalent of extant wet-tropical lowland vegetation at 60-65 degrees S, most richly during the Early Eocene Climatic Optimum. Cooling at similar to 50Ma triggered the spread of Nothofagus warm-temperate rainforests. Cooling reversed at the Khirthar transgression at similar to 42Ma with extensive neritic carbonate seas, diverse rainforest biomes and massive coals on the continental margins. Coals and limestones are strongly associated in time, from the late Paleogene at similar to 42-40Ma (the Middle Eocene Climatic Optimum) to the early Neogene at similar to 16-14Ma (the Miocene Climatic Optimum). Photosymbiotic foraminifera from north of Australia ingressed into the neritic biomes on the Leeuwin Current, signalling warm pulses. Terrestrial floras were still wet-temperate at the continental margins, but during the Oligocene various plants, already coping with low nutrients from extensive deep weathering in the Paleogene, had to cope with cooling, sudden drops in global CO2 levels and a drying-out in the continental interior. The rapid expansion of the Antarctic ice sheet in the early Oligocene had biotic impacts and responses, but not the dramatic impact of the subsequent expansion at similar to 14Ma. Late Neogene and modern Australia became a subdued, undernourished, arid continent with damp fringes. Neritic seas and their carbonate factories shrank; rainforests reduced in aerial extent and coal formation ceased. The last major warming, which temporarily interrupted the overall cooling into the late Neogene (Pleistocene) icehouse was in the early Pliocene, although the biogeographic pulses on the Leeuwin Current have continued to the present. The modern, fire-adapted Eucalyptus forests have deep Neogene roots but underwent significant expansion only recently.

The heart and soul of geology are to be found in rock relationships and earth history. The fossil record was central and critical to geology emerging as geohistory, the first historical science, from the speculative geotheories of the 18th Century. The key figure was Cuvier. In the process of shaping geohistory, Cuvier and palaeontology produced the second historical science, namely biohistory, including faunal and floral succession in deep time; and biohistory and geohistory have been intertwined for two centuries.Lamarck kept alive the venerable theory of organic change, but evolution as heuristic scientific theory was stumbling. Even so, the fossil-based geological time scale was constructed in the six decades between Cuvier nailing bioextinction and Darwin nailing biospeciation. by about 1830, French molluscan palaeontology was building Tertiary stratigraphic succession, correlation and age determination in the palaeontological synthesis, i.e., biostratigraphy. Palaeontology revealed ancient and exotic life in a deep-time panorama of succession punctuated by extinctions and demanding explanation, but it contributed little to theory of evolutionary processes.Darwin's world was lyell's gradualist world and his appreciation of environmental change as an evolutionary forcing factor lessened as competition came to dominate his thinking. Darwin's Darwinism comprised five theories. Two were historical theories (the world and its biospecies change in deep time; and common descent in branching evolution produces the tree of life) and both were widely accepted by the generation after Darwin. The other three were causal or nomothetic theories (respectively speciation; gradual change not saltational; and variational change by natural and sexual selection) and they were accepted only in the 20th Century. For its importance to our culture, Darwin's historicist worldview, in the face of entrenched, ahistorical opinion as to what science really is, outweighs disputes about the importance of selection.As stratigraphy and palaeontology went global and highly successful on most criteria, their evolutionary direction went 'anti-Darwinian' in the later 19th Century, towards such theories as orthogenesis, saltationism and a resurgent 'Neo-lamarckism', mostly in Hyatt, Cope and Osborn in North America. This cluster of trends culminated a second time in the 1930s-1940s, in the macromutational typostrophism of the German synthesis, dominated by Schindewolf.Meanwhile there was a thin red line of Darwinian palaeontology down those decades from the 1860s to the 1920s. When population genetics emerged from decades of its own anti-Darwinism the Modern Synthesis was forged between natural history, genetics and palaeontology, the latter especially embodied by Simpson's macroevolution. Darwin's three causal theories came into their own in the 1930s-1950s in completing the Darwinian Revolution-or, as I prefer, installing the Darwinian Restoration. However, the Restoration was dominated by variational evolution, whilst practitioners of embryology and morphology, in the transformational mode of evolution, felt excluded.The roots of modern palaeobiology are firmly in the Darwinian Restoration and Simpsonian palaeontology and macroevolution. Modern palaeobiology (i) is thoroughly Darwinian in its historicism and variational evolution but (ii) is beyond Darwin in becoming pervasively hierarchical whilst (iii) reconciling with elements of the German Synthesis through collaboration with developmental genetics in evo-devo. Also (iv) we have gone beyond Darwin (and Simpson) primarily in the rise of micropalaeontology with its untold millions of specimens and in enormous progress in chronologically resolving and reconstructing bioevents and environmental shifts in the geological past. And ( v) the tree of life is underlain by an anastomosing web of life. Deep-time palaeobiology becomes more autonomous as major soluble problems arise from the fossil record, utterly beyond the reach of shallow-time neontology.Securely embedded in thriving research programmes recovering the recorded history of life on earth, Darwinism lives!

Martin Glaessner (1906-1989) began publishing on fossil decapod crustaceans as a teenager, took doctorates in palaeontology and jurisprudence in Vienna, and developed his interest in forarninifera. Alpine tectonics was a central and lifelong theme. A second theme was economic geology. A third was organic evolution, and here it is important to note that, although the main evolutionary influence was Othenio Abel's palaeobiology, Glaessner avoided the Germanic extremes such as typostrophism arising from transformational evolution, becoming instead a variational evolutionist, that is, a Darwinian. Foraminifera took him to Moscow to organize research pertaining to hydrocarbon exploration and development. An outstanding clutch of publications in the mid-1930s were both evolutionary-taxonomic and biostratigraphical, the latter including the most compelling of all pre-war publications on the planktonic foraminifera. In Port Moresby and Melbourne in the 1940s, amongst applied micropalaeontology, reviewing and synthesis, he produced Principles of Micropalaeontology. In the 1950s and 1960s in Adelaide he supervised research extending from Cenozoic to Cambrian and Neoproterozoic, foraminifera and crabs to trilobites and stromatolites, meanwhile making the transition himself from foraminifera to the Ediacarans. Combining meticulous attention to evidence and detail with wide-ranging enquiry, he was a forerunner of the modern disciplines and mindsets such as palaeoceanography and integreted biogeohistory.

Abstract Appointing R.C. Sprigg in 1949 as Head of the new Regional Mapping Section of the Geological Survey of South Australia was decisive to its rapid success and high national reputation. Sprigg had vast enthusiasm for all things in natural history and especially earth history, appreciation of the economic drive, the ability to frame deep and meaningful questions in feedback with geological mapping, strong grasp of the interplay between geo-structure and geo-history, and exemplary followthrough to completion (not invariably) as richly illustrated papers and regional and thematic maps. By age 35 he had changed the culture of South Australian geology and departed the GSSA. In 1954 Sprigg moved on to geological and biological exploration in a spirit of private enterprise in economic development. Others expanded the research programs although from time to time he revisited his early interests in the light of developments in the earth sciences, such as the revolution in continental drift and plate tectonics and advances in late neogene chronology and correlation. The earth-science of hydrocarbon exploration unified most of Sprigg’s preoccupations in private enterprise with reviews and syntheses. His histories and popular works gave insights into the rapidly changing scientific, industrial and environmental-awareness scenes and into his view of his own contributions. Adelaide Geosyncline. At the outset of his career Sprigg achieved the most comprehensive advance in the geology of the complex and difficult Adelaide region in more than 150 years. The Mawson-Sprigg Adelaide System with its Torrensian, Sturtian and Marinoan Series was vintage Sprigg. He recognised the Adelaide miogeosyncline as a fossil continental terrace, much older than any that had been recognised hitherto. When his notions of flysch facies and the relationship of the Kanmantoo Group to the Adelaide System were clarified (with Bruno campana) Sprigg realized that the Kanmantoo eugeosynclinal trough marked the initiation of the great Tasman Geosyncline of eastern Australia. Ediacaran biota. In a clear case of the prepared mind and the deliberate search, Sprigg had been alert for a decade to the necessary existence of animals without mineralised skeletons before he discovered the fossils which became the basis for the Ediacaran assemblage of animals of latest Precambrian age. He described and named 17 species of pelagic coelenterates (“jellyfish”) of which about one-third survived as recognized taxa and some as higher animals. He saw himself as much biologist as geologist, and his handling of the comparative morphology, taphonomy and reconstruction, taxonomy and biological inferences was confident and secure. Late Neogene in southern Australia. In employing the term “Kosciuskan epoch” in his earliest work, Sprigg perceived the late uplift as being coeval with and part of the uplift of the highlands of southeastern Australia, and he sustained this view of neotectonic activity when it was unfashionable, as in petroleum exploration in Mesozoic-Cenozoic sedimentary basins. Finding strong indications of a cyclical pattern in the remarkably regular lateral succession of fossil beaches in the South-east of South Australia, he took the intuitive leap of explaining this regional pattern with the Milankovitch theory of ice ages, which were still be integrated with the geohistorical record. In due course geomagnetic and oxygen-isotopic stratigraphy would confirm his 1940s theory that the aeolianites record a punctuated succession of high sea levels (i.e., interglacials). (Subsequently Sprigg added the calcareous aeolianites to the counterclockwise whorl of siliciclastic dunes in a grand vision of windy, glacial Australia, but his initial theory is the survivor.) Predicting that the Pleistocene river Murray might produce a canyon at the shelf edge, he convinced the navy to make the necessary traverse and the canyons were found (the first on the Australian margin). With S.A. Shepherd, and again expanding his research far beyond Australian knowledge at the time, he systematically sampled the benthic faunas of Gulf St Vincent and investigator Strait, the ensuing map becoming a benchmark for monitoring subsequent degrading of the local marine environment and insights into generating bryozoan carbonates. Petroleum geology. Campaigning for hydrocarbon exploration, Sprigg kept the earth sciences in focus while shifting emphasis from the highly original and collaborative research of his early years to reviewing and supervising and, by the 1980s, to the history of petroleum geology and exploration. His tectonic style of structural lineaments and morphological trends at continental scale reversed (coevally with Sherbon Hills) the long-time neglect of young deformation on this continent (now neotectonics). Overview. The historicist and structural strands are clear in Sprigg’s science. His historicism, the sense of always-present historical change, of development, of succession in the world and its biosphere, inculcated most conveniently in education through palaeontology and stratigraphy, he got from Howchin. He lifted South Australian historical geology to a new level in three steps. One was comprehensive immersion in the geology of the Adelaide district. The second was responding strongly to M.F. Glaessner’s rigour in stratigraphic thinking. Third was general reinvigoration of his thinking as he concentrated more on petroleum geology. The second strand was structural, the deep-seated discontinuities acting as geosynclinal and basinal controls, coming down to him from Lockhart Jack, already apparent in his mapping in the 1940s and illuminated further by the Geosurveys geologists’ field mapping. Sprigg reiterated down the decades the absence of structural thinking and structural mapping, of three-dimensional visualizing, from the earlier collective consciousness of Australian geology and from the academic climate in Adelaide. His preoccupation with lineaments survived his embracing continental drift and plate tectonics; he appears to have been first in print to attempt to integrate the latter into Australian hydrocarbon exploration; but others were expanding our horizons in the stratotectonics of sedimentary basins. In balancing the structural with the historicist, Sprigg was well armed to resist the explorational simplicities of the times in minerals and hydrocarbon exploration. And he was uniquely versatile and inspiring in the natural sciences of this continent and their context of exploitation and conservation.

In the 1940s the Cenozoic molluscan record was ceding to the foraminiferal as main biostratigraphic driver. The central scientific problems for the stratigraphy of the Cenozoic Erathem in southern Australia were a patchy biostratigraphic succession, very few links with the tropical IndoPacific region and the classical sections of Europe, and a fragile sense of stratigraphic relationships within and between the various sedimentary basins in southern Australia. In more specific terms the stratigraphic problems were (or were about to emerge as) the Miocene/Pliocene hiatus, the evolution of the Orbulina bioseries and the age of the Orbulina surface, the recognition and correlation of Oligocene strata, and discovering and dating fossil assemblages below the Upper Eocene. M. F. Glaessner at the University of Adelaide's Geology Department and N.H. Ludbrook at the Geological Survey of South Australia made and led substantial progress in these matters, and Glaessner also stimulated research in foraminiferal morphology and evolutionary taxonomy.The progress occurred in feedback with shifts in scientific style and emphasis. Glaessner brought a new rigour to the recognition of microfossil assemblages and events and the relationship of bio-zones to chrono-stages. Exploiting the superb collection by W.J. Parr, A.N. Carter laid the groundwork with a biozoning of the Upper Eocene to Middle Miocene composite succession, employing a mix of benthic and planktonic events. M. Wade developed strong insights into the internal morphology of foraminiferal shells and its taxonomic significance, the relationships between morphospecies as biological species and morphospecies as pragmatic biostratigraphic tools, and correlating across the tropical-temperate transitions through the Cenozoic. J.M. Lindsay developed subsurface stratigraphic micropalaeontology in hydrogeology and engineering geology into a fine art, sharpened the delineation of the Miocene-Pliocene unconformity, did most to solve the Oligocene problem and (with Ludbrook) strengthened the Eocene-Miocene biozonation.By similar to 1970 there was a perceptual shift from species' ranges, in which implicitly imperfect records are linked, to species' occurrences including datums. The shift clarified insights into such geohistorical phenomena as climatic shifts and transgressions and regressions. It was encouraged by the first persuasive, numerically calibrated geological time scale. Micropalaeontology continued and stratigraphic horizons expanded in both institutions but the first two decades comprise a natural phase in Adelaide.

The carbon-isotope and palynological record through 580 m thick almost continuous brown coal in southeast Australia's Gippsland Basin is a relatively comprehensive southern hemisphere Middle Eocene to Middle Miocene record for terrestrial change. The carbon isotope delta C-13(coal) values of these coals range from -27.7 parts per thousand to -23.2. This isotopic variability follows gymnosperm/angiosperm fluctuations, where higher ratios coincide with heavier delta C-13 values. There is also long-term variability in carbon isotopes through time. From the Eocene greenhouse world of high gymnosperm-heavier delta C-13(coal) values, there is a progressive shift to lighter delta C-13(coal) values that follows the earliest (Oil?) glacial events around 33 Ma (Early Oligocene). The overlying Oligocene-Early Miocene brown coals have lower gymnosperm abundance, associated with increased % Nothofagus (angiosperm). and lightening of isotopes during Oligocene cooler conditions.The Miocene palynological and carbon-isotope record supports a continuation to the Oligocene trends until around the late Early Miocene (circa 19 Ma) when a warming commenced, followed by an even stronger isotope shift around 16 Ma that peaked in the Middle Miocene when higher gymnosperm abundance and heavier isotopes prevailed. The cycle between the two major warm peaks of Middle Eocene and Middle Miocene was circa 30 Ma long. This change corresponds to a fall in inferred pCO(2) levels for the same period. The Gippsland data suggest a link between gymnosperm abundance, long-term plant delta C-13 composition, climatic change, and atmospheric pCO(2). Climatic deterioration in the Late Miocene terminated peat accumulation in the Gippsland Basin and no further significant coals formed in southeast Australia. The poor correspondence between this terrestrial isotope data and the marine isotope record is explained by the dominant control on delta C-13 by the gymnosperm/angiosperm abundance, although in turn this poor correspondence may reflect palaeoclimate control. From the brown coal seam dating, the coal appears to have accumulated during a considerable part of the allocated 30 Ma Cenozoic time period. These brown coal carbon isotope and palynological data appear to record a more gradual atmospheric carbon isotope change compared to the marine record. (C) 2008 Elsevier B.V. All rights reserved.

The formal recognition of Quaternary as a Period/System was approved by JUGS in June 2009, in accordance with a proposal originated by INQUA. There are reasons to believe that this will have destabilizing consequences for the geological time scale. Until now, the primary divisions of the stratigraphic record, at the Period level and above, have been based on the progressive change of Earth's biota. The Quaternary, on the other hand, is a paleoclimatic concept based on glacial-interglacial variability, expressed in lithological change. The JUGS vote holds that this paradigm now supersedes the biochronological identity of the Neogene Period/System. Furthermore, to accomodate the most recent INQUA opinion about "when the Ice Ages began", the ICS agreed to relocate the base of the Pleistocene to 2.59 Ma from 1.81 Ma, enlarging the epoch by 43% and again without regard for its original paleontological definition, or for the vast literature in other fields of Pleistocene research. If history is a guide, the resulting disruption in late Cenozoic marine and vertebrate paleontology, human evolution, paleoceanography and paleoclimatology will be widely resisted, with potential impact on the authority of JUGS. The consequence of abandoning basic principles in order to satisfy the interest of a special group deserves a wider consideration than it has so far received.

Three time lines through the neritic stratigraphic record distributed around the northern margin of the Australo-Antarctic Gulf (AAG) mark three fundamental shifts in global environments collectively comprising the Auversian facies shift. The three lines are: (1) the beginning: the Khirthar transgression and the onset of neritic carbonate accumulation in the Bartonian Age (preceding onset of the Middle Eocene climatic optimum [MECO]); (2) the midlife change (Bartonian-Priabonian transition): the shift from carbonate-rich to carbonate-poor, higher-nutrient environments under estuarine circulation, causing widespread dysaerobia culminating in opaline silicas; and (3) the Eocene-Oligocene = Priabonian-Rupelian boundary and glaciation during oxygen isotope event Oi-1, with return of improved ventilation in neritic environments and resumption of carbonate accumulation. Meanwhile, it was warm and very wet at degrees 60 degrees S. In developing a scenario for the death of the AAG, the birth of the Southern Ocean, and the transition from Paleogene greenhouse Earth to Neogene icehouse Earth, the neritic record of the northern margin is more in accord with the "Dinocyst biogeographic hypothesis" than with the "Tasman gateway hypothesis."

Removing the Tertiary and Quaternary Periods whilst conserving the Paleogene and Neogene Periods in The Geological Timescale 2004 caused a storm of protest. One response was to advocate restoring an enlarged Quaternary and consigning the Neogene to a minor role within the Tertiary. Amongst an array of practical, traditional, sentimental and anthropocentric reasons for this response, the one hard-core justification was that the rigidly nested hierarchy of the geological timescale must be preserved.The central objective of this paper is conserving the historically legitimate, Miocene-present, Neogene Period and System. There are two options for conserving the Quaternary concurrently with the Neogene: (i) an inclusive compromise in a flexible hierarchy, and (ii) an upgrading of Pliocene and Pleistocene divisions to the level of epoch. In the inclusive compromise there coexist alternative pathways through the hierarchical ranks. Thus geohistorians and biohistorians have two options for traversing the hierarchy from era to age, as in this example using the hierarchical positioning of the Calabrian Age and Stage:either Cenozoic [era] <-> Neogene [period] <-> Pleistocene [epoch] <-> Calabrian [age],or Cenozoic [era] <-> Quaternary [subera] <-> Pleistocene [epoch] <-> Calabrian [age].We reaffirm that the inclusive compromise is entirely viable. In so doing we (i) challenge the necessity of the rigidly nested hierarchy, which should be capable of a little flexibility; (ii) reject all analogies of the arbitrary and conventional chronostratigraphic hierarchy with three natural biological hierarchies; (iii) reaffirm the integrity of the Neogene extending to the present; and (iv) see no reason to doubt the harmonious coexistence of the two options preserving the Quaternary and Neogene traditions in an orderly working and stable time scale.In the alternative schema conserving the Neogene, divisions of the Pliocene and Pleistocene are upgraded, so that the Late Pleistocene, Early Pleistocene and Late Pliocene Epochs comprise the Quaternary Subperiod, itself equivalent to Late Neogene. The inflexibly nested hierarchy is preserved but the Tertiary is lost. (C) 2009 Elsevier B.V. All rights reserved.

The International Commission on Stratigraphy (ICS) together with its subcommissions on Neogene Stratigraphy (SNS) and Quaternary Stratigraphy (SQS) are facing a persistent conundrum regarding the status of the Quaternary, and the implications for the Neogene System/Period and the Pleistocene Series/Epoch. The SQS, in seeking a formal role for the Quaternary in the standard time scale, has put forward reasons not only to truncate and redefine the Neogene in order to accommodate this unit as a third System/Period in the Cenozoic, but furthermore to shift the base of the Pleistocene to c. 2.6 Ma to conform to a new appreciation of when “Quaternary climates" began. The present authors, as members of SNS, support the well-established concept of a Neogene extending to the Recent, as well as the integrity of the Pleistocene according to its classical meaning, and have published arguments for workable options that avoid this conflict. In this paper, we return to the basic principles involved in the conversion of the essentially marine biostratigraphic/ biochronologic units of Lyell and other 19th-century stratigraphers into the modern hierarchical arrangement of chronostratigraphic units, embodied in the Global Standard Stratotype-section and Point (GSSP) formulation for boundary definitions. Seen in this light, an immediate problem arises from the fact that the Quaternary, either in its original sense as a state of consolidation or in the more common sense as a paleoclimatic entity, is conceptually different from a Lyellian unit, and that a Neogene/Quaternary boundary may therefore be a non sequitur. Secondly, as to retaining the base of the Pleistocene at 1.8 Ma, the basic hierarchical principles dictate that changing the boundary of any non-fundamental or “higher" chronostratigraphic unit is not possible without moving the boundary of its constituent fundamental unit. Therefore, to move the base of the Pleistocene, which is presently defined by the Calabrian GSSP at 1.8 Ma, to be identified with the Gelasian GSSP at 2.6 Ma, requires action to formally redefine the Gelasian as part of the Pleistocene. Finally, it is important to keep in mind that the subject under discussion is chronostratigraphy, not biostratigraphy. Both systems are based on the fossil record, but biostratigraphic units are created to subdivide and correlate stratigraphic sequences. The higher-level units of chronostratigraphy, however, were initially selected to reflect the history of life through geological time. The persistence of a characteristic biota in the face of environmental pressures during the last 23 my argues strongly for the concept of an undivided Neogene that extends to the present. Several ways to accommodate the Quaternary in the standard time scale can be envisaged that preserve the original concepts of the Neogene and Pleistocene. The option presently recommended by SNS, and most compatible with the SQS position, is to denominate the Quaternary as a subperiod/subsystem of the Neogene, decoupled from the Pleistocene so that its base can be identified with the Gelasian GSSP at c. 2.6 Ma. A second option is to retain strict hierarchy by restricting a Quaternary subperiod to the limits of the Pleistocene at 1.8 Ma. As a third option, the Quaternary could be a subera/suberathem or a supersystem/ superperiod, decoupled from the Neogene and thus with its base free to coincide with a convenient marker such as the base of the Pleistocene at 1.8 Ma, or to the Gelasian at 2.6 Ma, as opinions about paleoclimatology dictate. If no compromise can be reached within hierarchical chronostratigraphy, however, an alternative might be to consider Quaternary and Neogene as mutually exclusive categories (climatostratigraphic vs. chronostratigraphic) in historical geology. In this case, we would recommend the application of the principle of NOMA, or Non-Overlapping Magisteria, in the sense of the elegant essay by the late Stephen J. Gould (1999) on the mutually exclusive categories of Religion and Science. In this case the Quaternary would have its own independent status as a climatostratigraphic unit with its own subdivisions based on climatic criteria.

In 2004, the Quaternary was deliberately eliminated as a formal chronostratigraphic unit from the standard Geological Time Scale (GTS) while the Neogene extended to the Recent. This extended Neogene was not a spontaneous undertaking by the Neogene community. It is rooted in a strong and long-standing tradition in the study of especially the marine stratigraphic record.The original definition of the Neogene by Hornes in 1853 included stratigraphic units that are now considered middle Pleistocene in age, but is ambiguous with regard to its upper limit. Nevertheless the concept of an extended Neogene was incorporated in a number of time scales but was not widely employed until it was firmly adopted by marine stratigraphers when they started to explore the deep marine record of the Cenozoic in the middle of the 20(th) century.As such the extended Neogene is found in the original codification and subsequent modifications of all standard microfossil zonal schemes with N(eogene) zones continuing up to the Recent. Moreover the extended Neogene was generally accepted by the DSDP and ODP community and incorporated in widely used integrated - magnetobiochronostratigraphic - time scales and in prominent textbooks dealing with Earth history. It has been likewise accepted by vertebrate paleontologists. The concept of an extended Neogene also stood at the base of the recommendations for defining the Pliocene/Pleistocene (= Tertiary/Quatemary) boundary that originated from the 1948 International Geological Congress (IGC) in London.The continuous deep marine archive is most suitable for the formal definition of global chronostratigraphic units to be incorporated in the standard GTS. Clearly this marine standard is pre-eminently exemplified by the Neogene but is at odds with the dominantly continental-based Quaternary. In fact, the detailed study of the marine Neogene has revolutionized chronostratigraphic thinking during the last several decades. It has led to a stable astronomical-tuned Neogene time scale with a fully integrated magnetobiochronostratigraphic framework via first-order correlations. This innovative approach further resulted in re-emphasizing the usefulness of the unit stratotype concept, in the potential introduction of orbital controlled cycles as formal chronostratigraphic units of minor rank (chronozones) and in the inter-calibration of astronomical and radio-isotopic time. For all these reasons, the term Neogene should remain attached to the extended concept of 23-0 Ma. Furthermore, if nomenclature reflects geological thinking, understanding and practice of Earth history, the truncation of the Neogene at 2.6 Ma would introduce an artificial division, especially when looking from the marine perspective. This would prevent scientific communities who deal with Earth history beyond the last 2.6 myr from correctly expressing the continuity of the evolutionary, oceanographic, climatic, and tectonic dynamics over the last 23 my.

Concerned with the ordination, correlation and age determination of the rock record and the events entombed therein, stratigraphy is the central discipline in geohistory and biohistory. We consider (from our Cenozoic perch) changes in stratigraphy since the gestation of the International Stratigraphic Guide—changes in response to the “revolutions" of plate tectonics, bolide theory, sequence stratigraphy and cyclostratigraphy, and a cultural shift away from Lyellian gradualism. We discuss certain strictly stratigraphic matters in terms of the “Hedberg triad" of lithostratigraphy, biostratigraphy and chronostratigraphy, which triad has had its day as the core structure of the Guide. Sequence stratigraphy challenges both the lithostratigraphic formation and the notion of pervasive diachrony. Biostratigraphy flourishes in both its oppelzone and phylozone modes and is integrated increasingly with geomagnetic (the Cenozoic spine) and radiometric evidence in a sequence-and cyclostratigraphic context. Chronostratigraphic classification is hierarchical but rigid nesting is questioned.