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Since 2009, the Working Group on the ‘Anthropocene’ (or, commonly, AWG for Anthropocene Working Group), has been critically analysing the case for formalization of this proposed but still informal geological time unit. The study to date has mainly involved establishing the overall nature of the Anthropocene as a potential chronostratigraphic/geochronologic unit, and exploring the stratigraphic proxies, including several that are novel in geology, that might be applied to its characterization and definition. A preliminary summary of evidence and interim recommendations was presented by the Working Group at the 35th International Geological Congress in Cape Town, South Africa, in August 2016, together with results of voting by members of the AWG indicating the current balance of opinion on major questions surrounding the Anthropocene. The majority opinion within the AWG holds the Anthropocene to be stratigraphically real, and recommends formalization at epoch/series rank based on a mid-20th century boundary. Work is proceeding towards a formal proposal based upon selection of an appropriate Global boundary Stratotype Section and Point (GSSP), as well as auxiliary stratotypes. Among the array of proxies that might be used as a primary marker, anthropogenic radionuclides associated with nuclear arms testing are the most promising; potential secondary markers include plastic, carbon isotope patterns and industrial fly ash. All these proxies have excellent global or near-global correlation potential in a wide variety of sedimentary bodies, both marine and non-marine.

The early Silurian (Llandovery) Gondwanan South Polar ice sheet experienced episodes of ice retreat and re-advance. Marine base level curves constructed for the interval are widely assumed to provide a record of the associated glacioeustasy. In revealing a series of progradational sequences (progrades) bounded by flooding surfaces, recent work on the Type Llandovery succession in mid Wales (UK) has provided an opportunity to test this hypothesis. The grouping of these progrades into three composite sequences underpins the construction of both low order (small amplitude, high frequency) and high order (large amplitude, low frequency) base level movement curves. Revised biostratigraphical datasets for the type succession permit the accurate dating of base level events. The composite sequences record progradational acmes in the acinaces, lower convolutus and upper sedgwickii-halli graptolite biozones. A series of transgressions that postdate the Hirnantian glacial maximum culminated in an upper persculptus Biozone high-stand. Maximum flooding events also occurred during the revolutus and lower sedgwickii biozones, and the base of the early Telychian guerichi Biozone also marked the onset of a pronounced deepening. A review of 62 published datasets, including global and other regional base level curves, records of glacial activity, isotope data, patterns of facies and faunal flux and putative climate models, permits an evaluation of the origins of these local base level events. The concept of a Eustasy Index is introduced and shows that the impacts of global sea level movements can only be demonstrated within narrow ‘eustatic windows’ coincident with times of ice sheet collapse. At other times, the geometry of Llandovery area progrades reflects their accumulation across a faulted basin margin where, during periods of slow ice sheet advance, epeirogenic processes outstripped sea level movements as the dominant forcing factors. Increased levels of Telychian subsidence at first enhanced and then overwhelmed the influence of glacioeustasy as part of the region's response to the north European Scandian deformation.

The rise of plastics since the mid-20th century, both as a material element of modern life and as a growing environmental pollutant, has been widely described. Their distribution in both the terrestrial and marine realms suggests that they are a key geological indicator of the Anthropocene, as a distinctive stratal component. Most immediately evident in terrestrial deposits, they are clearly becoming widespread in marine sedimentary deposits in both shallow- and deep-water settings. They are abundant and widespread as macroscopic fragments and virtually ubiquitous as microplastic particles; these are dispersed by both physical and biological processes, not least via the food chain and the ‘faecal express’ route from surface to sea floor. Plastics are already widely dispersed in sedimentary deposits, and their amount seems likely to grow several-fold over the next few decades. They will continue to be input into the sedimentary cycle over coming millennia as temporary stores – landfill sites – are eroded. Plastics already enable fine time resolution within Anthropocene deposits via the development of their different types and via the artefacts (‘technofossils’) they are moulded into, and many of these may have long-term preservation potential when buried in strata.

The ice flow path and dynamic behaviour of the British-Irish Ice Sheet has been subject to renewed interest and controversy in recent years. Early studies in eastern England argued for interaction with Fennoscandian ice onshore in Britain, instigating re-examination of the sedimentology and provenance of many Pleistocene till successions. These studies instead supported an exclusively British provenance, and are used to predict southward advance of a broadly coast-parallel North Sea Lobe. Quantitative lithological and palynological analysis of the Pleistocene till succession in Holderness, East Yorkshire, however, remains to be carried out. We examined the lithologically diverse Skipsea Till in order to reconstruct ice flow pathways to the Holderness coast during the Pleistocene, thereby constraining which areas of substrate were subglacially eroded and entrained prior to deposition. The till yields a diverse range of soft, low-durability and uniquely British allochthonous material, including Permian Magnesian Limestone, Carboniferous limestone and coal, and Carboniferous pollen and spore assemblages that would be unlikely to survive polyphase reworking. Ice extended southwards through southern Scotland, incorporating material in north-east England, north-east Yorkshire and the western margin of the North Sea Basin (NSB), supporting a recurrent ice flow pathway for the eastern margin of the British-Irish Ice Sheet during the Mid to Late Pleistocene.

Many worlds harbour oceans – but that alone won't make them as life-friendly as Earth, say planetary scientists Jan Zalasiewicz and Mark Williams

We examine three fundamental changes in river systems induced by innovations of the biosphere, these being: (1) the evolution of oxygenic photosynthesis; (2) the development of vascular plants with root systems; and (3) the evolution of humans. The first two innovations provide context for the degree of human-induced river change. Early river systems of the Precambrian Archean Eon developed in an atmosphere with no free oxygen, and fluvial sediments accumulated ‘reduced detrital’ minerals. By 2.4 Ga the evolution of oxygenic photosynthesis produced an oxygenated atmosphere and ‘reduced detrital’ minerals mostly disappeared from rivers, affording a distinct mineralogical difference from subsequent fluvial deposits. Rivers of the Precambrian and early Phanerozoic were dominantly braided, but from 0.416 Ga, the evolution of vascular plants with roots bound floodplain sediments and fostered fine-grained meandering rivers. Early meandering river deposits show extensive animal activity including fish and arthropod tracks and burrows. Homo sapiens, appearing about 150 ka BP, has, in recent millennia, profoundly modified river systems, altering their mineralogical, morphological and sedimentary state. Changes in sediment fluxes caused by human ‘reverse engineering’ of the terrestrial biosphere include deforestation, irrigation and agriculture. Sediment retention has been encouraged by the construction of dams. Modern river systems are associated with extensive human trace fossils that show a developing complexity from ancient civilizations through to megacities. Changes induced by humans rank in scale with those caused by earlier biosphere innovations at 2.4 and 0.416 Ga, but would geologically soon revert to a “pre-human” state were humans to become extinct.

The ‘Tertiary’, omitted from IUGS-approved timescales since 1989, is still in common use. With the recent re-instatement of the Quaternary as a formal unit, the question arises as to whether the Tertiary too should be reinstated as a formal period, with the ‘Paleogene’ and ‘Neogene’ being downgraded to sub-periods. This paper presents arguments for and against this proposal, stemming from discussions by members of the Geological Society Stratigraphy Commission. It is intended to stimulate discussion of the topic in the wider community.

Here we show the use of graptolite periderm for chemostratigraphic study. Using material from the Aeronian (Silurian) interval from Wales and Scotland as examples, we show that the carbon isotope composition of the periderm (δ13Cgrap.) provides a signal that is locally different but not consistently so from surrounding whole-rock samples (δ13Cwhole-rock). Graptolite periderm δ13C seems not influenced by astogenetic stage of development or gross rhabdosome type and differences between δ13Cgrap. from different metamorphic grades are minimal. Taken as a whole, the Aeronian interval examined shows little overall change, but large variations are seen on the small scale, possibly reflecting very local carbon cycling. For carbon isotope stratigraphy in such rocks, therefore, large-scale bulk sampling will likely reduce inhomogeneities and give more reproducible results. Furthermore, in situations (for instance associated with sea level fluctuations) where terrestrial organic matter has been incorporated into the sediment, then graptolite carbon may more faithfully reflect bulk marine organic matter.

International audience; The Early-Mid Ordovician has long been considered a super-greenhouse world, based largely on high relative global sea levels and light stable oxygen isotope data from bulk carbonates. An alternative and largely untested hypothesis has suggested that, at least in equatorial palaeolatitudes, there was a steady cooling trend through the Early Ordovician reaching the range of modern equatorial sea surface temperatures by the Mid Ordovician. This hypothesis, though controversial, is supported by palaeobiogeographical studies of the early Late Ordovician (Sandbian) zooplankton (graptolite) biotopes. These are comparable to the modern planktonic foraminifera ¡®provinces¡¯ and suggest a latitudinal temperature gradient that is similar to the modern one. Chitinozoans are also an important group of Palaeozoic marine microfossils, but with a poorly known biological affinity. Here we present an analysis of chitinozoan species palaeobiogeography for the early Late Ordovician (Sandbian c. 460 Ma), which confirms that these microfossils, and likely their parent organisms, were epipelagic. Unlike the graptolites, chitinozoans had their highest diversity and abundance south of ~35°S during this time, which strongly suggests adaptation to temperate to cold waters. The distribution of chitinozoan biotopes during the gracilis time-slice allows us to identify the austral Subtropical, Subpolar and Polar belts; key oceanographic boundaries are identified as the Subtropical-Subpolar Transition at ~35°S and tentatively, the Polar Front at ~55°-70°S. Again, these are in a similar position to those in the modern Southern Ocean. Chitinozoan biotopes also map a steep latitudinal faunal gradient that is comparable to that of the graptolites and that of modern plankton. This likely indicates a steep latitudinal temperature gradient for early Late Ordovician seas and questions the notion that this interval of Earth history had a greenhouse climate.

The roddons of the English Fenlands are fossilised silt and sand-filled tidal creek systems of mid- to late-Holocene age, incised into contemporaneous clay deposits. However, anthropogenic change (drainage and agriculture) has caused the former channels to become positive topographical features. Three stratigraphically discrete generations of roddon have been discriminated. They all show well-developed dendritic meander patterns, but there is little or no evidence of sand/silt infill during meandering; thus, unlike modern tidal creeks and rivers they typically lack laterally stacked point bar deposits, suggesting rapid infill. Major “trunk” roddons are rich in fine sands and there is little change in grain size from roddon mouth to the upper reaches, suggesting highly effective sand transport mechanisms and uniform conditions of deposition. Tributaries are silt-rich, while minor tributaries also have a significant clay component. During infill, active drainage networks appear to have been choked by sediment, converting mudflat/salt-marsh environments into widespread peat-forming freshwater reed swamps.

The early, pre-orogenic stages of evolution in the Variscan belt, i.e. rifting processes, opening of sedimentary basins and associated igneous activities, are often obscure because many successions have yielded little or no biostratigraphic data, have a strong metamorphic overprint and are tectonically deformed and dislocated. The increasing application of SHRIMP zircon dating has provided useful constraints on magmatic and metamorphic processes, helped locate probable source areas for detritus within sedimentary successions and facilitated large-scale palaeogeographic correlations. This methodology has recently thrown considerable light on the age and relationships of the previously poorly constrained rock units of the Kaczawa Complex in the Polish West Sudetes. Thus, recent SHRIMP studies in the Kaczawa Mountains have yielded Early Ordovician ages of the initial rift type bimodal volcanic suites at the bottom part of the Kaczawa Succession: c. 503 Ma for metarhyodacites of crustal derivation, and c. 485 Ma for alkaline metatrachytes of mantle signature. These dates provide a firm temporal constraint on the initial rift magmatism interpreted as related to the continental break-up of the northern peripheries of Gondwana. New SHRIMP data from metavolcaniclastic and metasedimentary rocks of the Kaczawa Complex have yielded results that have provided significantly changed interpretations on their age and relationships. For instance, a siliciclastic sequence interpreted as belonging to the lower part of the Kaczawa Complex (the Gackowa Sandstones) and seemingly sourced (using an array of geochemical and mineralogical evidence) from nearby early Ordovician volcanic rocks has, surprisingly, yielded zircon ages not younger than Precambrian and thus this unit has tentatively been reinterpreted as a possible correlative of the Neoproterozoic Lusatian Graywackes. Felsic metavolcaniclastic rocks embedded in the carbonate succession of the Wojcieszow Limestone have yielded SHRIMP zircon ages of c. 497 Ma, thus supporting a late Cambrian/early Ordovician age for this shallow-water limestone sequence (which had been proposed to be late Ordovician/Silurian or younger in age, based on controversial foraminifera evidence, and more recently assigned to the Mid Cambrian, based on newly found archaeocyathid fragments). And, age spectra of zircon populations in the metamudstone sequence of the Radzimowice Slates of thus far enigmatic stratigraphic position indicate that these deposits may have accumulated during early Palaeozoic rifting, with source areas similar to those known from parts of Gondwana (e.g. NW Africa). Overall, the new SHRIMP zircon studies, both in metavolcanic and metasedimentary sequences, have considerably illuminated their affinities, and should provide encouragement for further application of this technique in this region. In general the results provide support and detail for interpretation of this rock complex as reflecting the early stages of development of the volcanic and sedimentary processes operating along North Gondwana during latest Precambrian and early Palaeozoic times.

Syn-kinematic pure muscovite strain-fringes grew around pyritized graptolites in response to the early Devonian (Acadian) closure and uplift of the Peri-Gondwanan Welsh Basin. They record Ar-isotope information on the timing of low-temperature deformation and the mudrock to slate transition. Here we have applied three different 40Ar/39Ar laserprobe dating methods to strain-fringes from the central Welsh Basin to test for variations in age and to explore the technical limitations of the method. Infrared laserprobe step-heating analyses yielded only occasional plateau ages (varying between ca. 403 Ma and 422 Ma) and strong evidence for discordance in the Ar-system. Likewise, ages from infrared laserprobe total fusion analysis are scattered, and range from ca. 390 Ma to 651 Ma. By contrast, ultraviolet laserprobe intra-fringe age profiles revealed a complex pattern of ages across individual strain-fringes. This is the highest spatial resolution technique available, and the resulting age profiles consistently showed an oscillatory pattern comprising troughs, or ‘baseline’ ages that are all within error of ca. 397 Ma, and peaks, or ‘apparent’ ages, ranging up to ca. 550 Ma. These ‘apparent’ ages we interpret as the results of repeated, periodic assimilation of excess 40Ar (40ArE) during deformation and the mudrock to slate transition. Here, basinal fluids carrying 40ArE are driven through bulk mudrock during contractional phases of the Acadian orogen, and 40ArE is taken up by muscovite strain-fringes. The concentration of 40ArE varies with metamorphic grade, and is inversely proportional to the temperature of metamorphism, and we suggest is controlled by the solubility of Ar in water, which has potentially quite severe implications for 40Ar/39Ar dating of K-bearing minerals in any mudrock. These results provide a first record of Ar-isotope information in strain-fringes, and a first record of orogenically-driven fluid-flow through bulk deforming mudrock. They also demonstrate how the high spatial resolution ultraviolet laserprobe 40Ar/39Ar method can access Ar-isotope information that is obscured by lower spatial resolution laser analysis, or bulk sampling methods.

The use of graptolites (specifically, of the planktonic graptoloids) in sedimentary facies analysis is discussed and illustrated, with particular reference to the margins of the former Iapetus Ocean in the UK. By far the most important use stems from the high time resolution afforded by graptolite biostratigraphy, particularly in the Silurian, where biozones/subzones average under half a million years in duration. Increased resolution may be obtained where biostratigraphy is combined with the event stratigraphy provided by repeated oscillations between anoxic and oxygenated sea floors, which yielded laminated (‘graptolite shale’) and burrowed (‘barren beds’) hemipelagites respectively. The resolution thus afforded has allowed the elucidation of detailed sedimentary architecture; examples are drawn from the Llandovery turbidites of the Welsh Basin and the late Ordovician to early Silurian accretionary prism of the Southern Uplands of Scotland. Use of this biozonation as a temporal framework has also allowed an interpretation of the plate tectonic setting of individual basins via subsidence analysis and the sequence stratigraphic interpretation of the basin-fills. The use of graptolites as indicators of broader palaeogeographic and palaeoceanographic settings shows promise but, in practice, is still hindered by incomplete understanding of the various factors that controlled the distribution of graptoloids within the early Palaeozoic seas. Finally, current-transported graptolites, may be used, cautiously, as palaeocurrent indicators.

Rare outsize clasts are present in hemipelagic rocks of the Rhuddanian (Llandovery: Silurian) Cwmere Formation in central Wales. They were very likely derived as dropstones from the holdfasts of large algae (kelp or fucoids) which colonized the margins of the Welsh Basin during the Silurian, and hint at a relatively high organic productivity.

Authigenic monazite nodules from Silurian turbiditic rocks in the central Welsh Basin are zoned with respect to Nd isotope composition. The cores are relatively radiogenic, and the rim-to-core trend projects toward the composition of associated, very early authigenic, apatite concretions. These authigenic phases therefore equilibrated with changing fluid composition as they formed. The apatites and the monazite nodule cores may have included significant Nd from organic matter or seawater, whereas the REEs in the outer parts of the monazite nodules were derived from clastic detritus. The apparent Sm Nd ‘age’ obtained from these phosphates is a mixing line, which gives an Ordovician age for these Silurian rocks. The U Pb isotope system does not show similar trends, and shows promise as an alternative method for dating such phosphates: a date of 417 ± 11 Ma 2σ (MSWD = 107) agrees well with recent estimates of the time of the diagenetic, smectite-illite transition in the rocks of this study. A Pb Pb isochron gave an age of 422 ± 24 Ma 2σ (MSWD = 0.9) this shows that the Pb is in isotopic equilibrium and is undisturbed, and that the elevated MSWD of the U Pb regression is caused by slight subsequent mobility in the U Pb system. The event dated by the monazite is probably compactional dewatering during accelerated mid-Silurian sediment loading in the central Welsh Basin.

The Westleton Beds of northeast Suffolk, England, represent a Pleistocene gravelly shoreline within which three facies are distinguished. A large-scale, cross-stratified, gravel-dominated facies (A) dips predominantly offshore and is interpreted as a beach-face deposit. This facies passes seawards into a ‘transitional’ zone characterized by a horizontally stratified sand facies (B). This is incised into, and replaced seawards, by a third facies (C) deposited in channel-forms. Nearshore these channels are gravel-filled; further offshore they are regularly spaced, up to 2 m deep, their bases commonly being rimmed by gravel which fines upwards into sand. Several such fining-upward pulses are present in the infill of some of the larger channel-forms. It is suggested that these channels were cut and infilled by sporadic high-energy seaward-directed rip-currents.

Is this the moment to declare that we have entered a new geological epoch created by humans, wonders Jan Zalasiewicz

A series of 7 boreholes (3 rotary and 4 shell and auger) were drilled by the British Geological Survey through the main outcrop of the Pliocene Coralline Crag Formation between Gedgrave and Aldeburgh in Suffolk between 1982 and 1985. The boreholes proved three members distinguished on the basis of grain size, sorting, carbonate content and fauna. The oldest, the Ramsholt Member, rests unconformably on the Palaeocene-Eocene London Clay Formation. It comprises a basal phosphorite-rich gravel with shelly mud-rich sands above. The Sudbourne Member unconformably overlies the Ramsholt Member and consists of cross-stratified, well-sorted carbonate sands, laid down as a tidal sand ridge. A third member, the Aldeburgh Member is found only in the northern part of the outcrop where it overlies the Ramsholt Member. It consists of mud-poor, moderately sorted carbonate sand, and is probably the offshore (deeper water) equivalent of the Sudbourne Member.

Deposits relating to the former Anglian ice-margin have been studied at two sites in southeast Suffolk: Rookery Farm, near Eyke; and at Shottisham. Their 3D geometry was established by a combination of ground conductivity mapping and augering/drilling. The deposits are predominantly clay-rich and commonly preserved in channels comparable with the ice-marginal channels described from adjacent parts of Suffolk. The early phase of sedimentation is characterized by till (boulder clay) and/or sand and gravel; subsequently lacustrine clay was deposited. These lacustrine clays are variably organic and were distinguished by their very high conductivity, enabling the thickest sequences to be pinpointed and drilled. Palynological investigation has shown that at both sites clays of mid-Hoxnian age are present. This indicates that the channelized Anglian ice-marginal drainage topography persisted until well into the succeeding warm Hoxnian Stage, with deposition of lacustrine clays commencing during a regional rise in water table in the mid-Hoxnian.

On April 8, 1988 a discussion meeting took place at Norwich with the aim of establishing correlations of the Early and Middle Pleistocene stages across the southern North Sea. On the basis of faunal, floral, and palaeoclimatic data the following correlations were considered highly probable. The Pastonian Stage of East Anglia is correlated with the Late Tiglian (TC5) Stage of the Netherlands, and the Bramertonian with the Middle Tiglian (TC1-4b). The possibility that the British Antian and Bramertonian Stages may represent parts of a single climatic event is mentioned. The Ludhamian is probably of Early Tiglian age and the Pre-Ludhamian may equate in part with the Praetiglian Stage. Possible correlation of the Waltonian with part of the Pliocene Reuverian Stage is also suggested. In the later Middle Pleistocene, the Anglian Stage correlates with the continental Elsterian. The precise correlation of the British type Cromerian Stage with part of the ‘Cromerian Complex’ Stage in the Netherlands remains uncertain.

A petrologically distinct suite of clays, silts, sands, gravels and diamictons has been recognised in the area north-west of Diss, Norfolk. These deposits rest on Chalk and are overlain by the Anglian Lowestoft Formation. We propose the term Banham Beds for these deposits and interpret them as glacigenic in origin. Their pebble content, grain-size distribution, heavy mineral assemblage and clay mineralogy are all used to distinguish them from the adjacent Anglian North Sea Drift and Lowestoft formations. The genesis and significance of the Banham Beds are discussed and it is concluded that the deposits were lain down in a mainly fluviatile and lacustrine system near the margin of the North Sea Drift ice-sheet. The Banham Beds are thought to be derived partly from locally extensive pre-Anglian Kesgrave Sands and Gravels and Ingham Sand and Gravel together with abundant silt- clay grade outwash material derived from the North Sea Drift ice-sheet. We provisionally designate the Banham Beds as a member of the North Sea Drift Formation.

A western extension of the Plio-Pleistocene Red/Norwich Crag deposits is described from south-west Suffolk and north-west Essex. The facies geometry of these sediments is described, and related to that of the well-exposed Crag sequence of the Suffolk coast. The same pattern of sedimentation occurs throughout. The Red Crag Formation comprises a basal pebble bed overlain by shelly coarse sands, now largely decalcified. The overlying Chillesford Sand Member of the Norwich Crag Formation is dominated by well sorted fine sands which, except near the coast, are generally devoid of body or trace fossils. However, evidence of opposing current directions indicates that deposition took place in a marine tidal environment. There is no evidence in the western parts to indicate age relationships with the Pre-Ludhamian Red Crag and Bramertonian Chillesford Sand of the coastal area. The Red Crag and Norwich Crag formations ascend westwards from the coast as parallel sheets, each up to 15 m thick, through a range in elevation of at least 100m. This range is interpreted as being due largely to post-depositional tilting rather than to former high sea levels. It is unlikely that sedimentation was influenced by Quaternary faulting.