Abstract Seismic mapping of key Paleozoic surfaces in the East Irish Sea–North Channel region has been incorporated into a review of hydrocarbon prospectivity. The major Carboniferous basinal and inversion elements are identified, allowing an assessment of the principal kitchens for hydrocarbon generation and possible migration paths. A Carboniferous tilt-block is identified beneath the central part of the (Permian–Mesozoic) East Irish Sea Basin (EISB), bounded by carbonate platforms to the south and north. The importance of the Bowland Shale Formation as the key source rock is reaffirmed, the Pennine Coal Measures having been extensively excised following Variscan inversion and pre-Permian erosion. Peak generation from the Bowland source coincided with maximum burial of the system in late Jurassic–early Cretaceous time. Multiphase Variscan inversion generated numerous structural traps whose potential remains underexplored. Leakage of hydrocarbons from these into the overlying Triassic Ormskirk Sandstone reservoirs is likely to have occurred on a number of occasions, but currently unknown is how much resource remains in place below the Base Permian Unconformity. Poor permeability in the Pennsylvanian strata beneath the Triassic fields is a significant risk; the same may not be true in the less deeply buried marginal areas of the EISB, where additional potential plays are present in Mississippian carbonate platforms and latest Pennsylvanian clastic sedimentary rocks. Outside the EISB, the North Channel, Solway and Peel basins also contain Devonian and/or Carboniferous rocks. There have, however, been no discoveries, largely a consequence of the absence of a high-quality source rock and a regional seal comparable to the Mercia Mudstone Group and Permian evaporites of the Cumbrian Coast Group in the EISB.

Abstract Recognition of intimate feedback mechanisms linking changes across the atmosphere, biosphere, geosphere and hydrosphere demonstrates the pervasive nature of humankind’s influence, perhaps to the point that we have fashioned a new geological epoch, the Anthropocene. To what extent will these changes be evident as long-lasting signatures in the geological record? To establish the Anthropocene as a formal chronostratigraphical unit it is necessary to consider a spectrum of indicators of anthropogenically induced environmental change, and to determine how these show as stratigraphic signals that can be used to characterize an Anthropocene unit and to recognize its base. It is important to consider these signals against a context of Holocene and earlier stratigraphic patterns. Here we review the parameters used by stratigraphers to identify chronostratigraphical units and how these could apply to the definition of the Anthropocene. The onset of the range of signatures is diachronous, although many show maximum signatures which post-date 1945, leading to the suggestion that this date may be a suitable age for the start of the Anthropocene.

Abstract The proposal that the ‘Anthropocene’ should be ratified as a unit of the International Chronostratigraphic Chart/Geological Time Scale deserves serious consideration by the International Commission on Stratigraphy (ICS). The ‘Anthropocene’ task group within the ICS Subcommission on Quaternary Stratigraphy is responsible for producing a recommendation to be evaluated and considered for approval at high levels in the ICS organization. It must consider the rank and extent of the unit as well as a GSSP or GSSA that defines its lower boundary or beginning. Furthermore, the task group must address several questions related to the proposed unit and the nature of the ICS chart/timescale that are unique to it. Is the ‘Anthropocene’ a concept in search of a distinct stratigraphic record? Should it be defined on a stratigraphic signal or on a date in human history? Is the ‘Anthropocene’ a unit of Earth history or human history or primarily a future projection? Is the ‘Anthropocene’ useful as a chronostratigraphic unit on geological maps? Has the perceived change to a human-dominated Earth system overwhelmed the natural Earth system? What is the conceptual basis of the International Chronostratigraphic Chart/Geologic Time Scale? Will the term ‘Anthropocene’ have value even if not ratified as a formal unit?

Abstract In recent years, ‘Anthropocene’ has been proposed as an informal stratigraphic term to denote the current interval of anthropogenic global environmental change. A case has also been made to formalize it as a series/epoch, based on the recognition of a suitable marker event, such as the start of the Industrial Revolution in northern Europe. For the Anthropocene to merit formal definition, a global signature distinct from that of the Holocene is required that is marked by novel biotic, sedimentary and geochemical change. Although there is clear evidence of anthropogenic effects in geological sequences, it is uncertain whether these trends are sufficiently distinct, consistent and dated for the proposal for a Holocene/Anthropocene boundary to be substantiated. The current view of the Earth-Science community is that it should remain informal. For formal definition a Global Stratigraphic Section and Point (GSSP) is required. Adoption of the term ‘Anthropocene’ will ultimately depend on recognition of a global event horizon. Without this, there is no justification for decoupling the Anthropocene from the Holocene. If the Anthropocene is deemed to have utility, it should be as an informal historical designation rather than a formally defined stratigraphic unit (of whatever status) within the geological timescale.

Abstract We consider the Anthropocene as a physical, chronostratigraphic unit across terrestrial and marine sedimentary facies, from both a present and a far future perspective, provisionally using an approximately 1950 CE base that approximates with the ‘Great Acceleration’, worldwide sedimentary incorporation of A-bomb-derived radionuclides and light nitrogen isotopes linked to the growth in fertilizer use, and other markers. More or less effective recognition of such a unit today (with annual/decadal resolution) is facies-dependent and variably compromised by the disturbance of stratigraphic superposition that commonly occurs at geologically brief temporal scales, and that particularly affects soils, deep marine deposits and the pre-1950 parts of current urban areas. The Anthropocene, thus, more than any other geological time unit, is locally affected by such blurring of its chronostratigraphic boundary with Holocene strata. Nevertheless, clearly separable representatives of an Anthropocene Series may be found in lakes, land ice, certain river/delta systems, in the widespread dredged parts of shallow-marine systems on continental shelves and slopes, and in those parts of deep-water systems where human-rafted debris is common. From a far future perspective, the boundary is likely to appear geologically instantaneous and stratigraphically significant.

Abstract The deliberate anthropogenic movement of reworked natural and novel manufactured materials represents a novel sedimentary environment associated with mining, waste disposal, construction and urbanization. Anthropogenic deposits display distinctive engineering and environmental properties, and can be of archaeological importance. This paper shows that temporal changes in the scale and lithological character of anthropogenic deposits may be indicative of the Anthropocene. However, the stratigraphy of such deposits is not readily described by existing classification schemes, which do not differentiate separate phases or lithologically distinct deposits beyond a local scale. Lithostratigraphy is a scalable, hierarchical classification used to distinguish successive and lithologically distinct natural deposits. Many natural and anthropogenic deposits exhibit common characteristics; they typically conform to the Law (or Principle) of Superposition and exhibit lithological distinction. The lithostratigraphical classification of surficial anthropogenic deposits may be effective, although defined units may be significantly thinner and far less continuous than those defined for natural deposits. Further challenges include the designation of stratotypes, accommodating the highly diachronous nature of anthropogenic deposits and the common presence of disconformities. International lithostratigraphical guidelines would require significant modification before being effective for the classification of anthropogenic deposits. A practical alternative may be to establish an ‘anthrostratigraphical’ approach, or ‘anthrostratigraphy’.

Abstract This paper investigates the relationship between archaeological stratigraphy (in archaeology) and artificial ground (in geology) and considers their wider application to the investigation and characterization of the Anthropocene. Evidence from two archaeological case studies is used to illuminate key points. The first case study examines stratigraphic sequences from beneath the city of Leicester, UK; the second looks at stratified deposits within the prehistoric settlement mound of Abu Hureyra, Syria. Earthworks, riverworks and cultivation soils are also considered. Archaeological and geological perspectives are combined to develop a unified view of anthropogenic deposits that cover large parts of the surface of the Earth.

Abstract The Earth has shown a systematic increase in mineral species through its history, with three ‘eras’ comprising ten ‘stages’ identified by Robert Hazen and his colleagues ( Hazen et al. 2008 ), the eras being associated with planetary accretion, crust and mantle reworking and the influence of life, successively. We suggest that a further level in this form of evolution has now taken place of at least ‘stage’ level, where humans have engineered a large and extensive suite of novel, albeit not formally recognized minerals, some of which will leave a geologically significant signal in strata forming today. These include the great majority of metals (that are not found natively), tungsten carbide, boron nitride, novel garnets and many others. A further stratigraphic signal is of minerals that are rare in pre-industrial geology, but are now common at the surface, including mullite (in fired bricks and ceramics), ettringite, hillebrandite and portlandite (in cement and concrete) and ‘mineraloids’ (novel in detail) such as anthropogenic glass. These have become much more common at the Earth’s surface since the mid-twentieth century. However, the scale and extent of this new phase of mineral evolution, which represents part of the widespread changes associated with the proposed Anthropocene Epoch, remains uncharted. The International Mineralogical Association (IMA) list of officially accepted minerals explicitly excludes synthetic minerals, and no general inventory of these exists. We propose that the growing geological and societal significance of this phenomenon is now great enough for human-made minerals to be formally listed and catalogued by the IMA, perhaps in conjunction with materials science societies. Such an inventory would enable this phenomenon to be placed more effectively within the context of the 4.6 billion year history of the Earth, and would help characterize the strata of the Anthropocene.

Abstract Geomagnetic and mineral magnetic data provide geological indices that are both independent of human impact (i.e. geomagnetic) and respond to human-induced environmental impact (i.e. mineral magnetic). We provide the first discussion of such magnetic events for help in defining the Anthropocene. Within the Holocene, a potential geomagnetic marker for the Anthropocene is the low dipole latitude at c. 2700 cal a BP, which is associated with distinct palaeosecular variation features in northerly mid- to high-latitude sites. Mineral magnetic records from lake and marine sediments identify major deforestation and soil delivery events from catchment systems in many parts of the world during the last 4000 years. In Europe, clusters of these events occur around both 2600 cal a BP and AD 1100, the former coinciding with a low in geomagnetic field dipole latitude and peak intensity. Mineral magnetic records in peats and lake sediments can reflect particulate pollution from fossil fuel burning. The expansion of major coal burning began c. AD 1800 in western Europe and eastern North America, but around AD 1900 this expanded due to more widely distributed coal use, and this event is the most clear mineral magnetic marker for the base of the Anthropocene.

Abstract The base of the Cambrian System is recognized by a characteristic (marine) trace fossil suite assigned to the Treptichnus pedum Biozone, which signals increasing complexity of animal behaviour and demarcates the Cambrian from the (older) Ediacaran System (Proterozoic Eonathem). Ichnotaxa of the T. pedum Biozone are not the earliest trace fossils, and are preceded in the latest Proterozoic by a progressive increase in the diversity of trace-producing organisms and the communities they comprised, the structural and behavioural complexity of the trace fossils, and even the depth of burrowing in sediments. Parallels can be drawn with the increasing complexity of subsurface structures associated with human cities, which also reflect evolution of an increasingly complex community. Before the nineteenth century, these structures were limited and simple, but beginning with the development of London in the mid-nineteenth century as the world’s first megacity, subsurface structures have become increasingly complex, reflecting the technology-driven behaviour of twentieth- and twenty-first-century humans.

Abstract Palaeontology formed the basis for defining most of the geological eras, periods, epochs and ages that are commonly recognized. By the same token, the Anthropocene can be defined by diverse palaeontological criteria, in accordance with commonly accepted biostratigraphic practice. The most useful Anthropocene biostratigraphic zones will be assemblage and abundance zones based on mixes of native and non-native species in both the marine and terrestrial realms, although lineage zones based on evolution of crop plants may also have utility. Also useful are human-produced trace fossils, which have resulted in prominent biohorizons that can mark the onset of the Anthropocene, especially the paved road system, widespread through terrestrial regions, and microplastics, ubiquitous in near-shore and deep-water marine sediments. Most of these palaeontological criteria support placing the Holocene–Anthropocene boundary near 1950. Continuation of current extinction rates would produce an extinction biohorizon on the scale of the Big Five mass extinctions within a few centuries, but enhanced conservation measures could prevent making mass extinction an Anthropocene signature. A grand challenge for palaeontologists now is to define Anthropocene biostratigraphic zones rigorously, not only as a necessary precursor to formalizing the epoch, but also to more fully understand how humans have restructured the biosphere.

Abstract Tropical coastal ecosystems such as coral reefs have provided food, income and resources to humans for millennia. The first interactions that people had with coral reef ecosystems left little signature or impact, most probably due to the restricted access, as well as the challenges and ephemeral technologies that people used to exploit these important ecosystems. As human populations expanded along tropical coastal areas, however, the influence of coastal people on coral reefs grew rapidly. Deforestation and coastal agriculture reduced coastal water quality, with many fringing coral reefs disappearing as impacts grew. Increasing numbers of fishers with increasingly advanced technologies exploited tropical coastal fisheries so that many marine species declined dramatically. These activities have removed some functional groups to the point where ecological transformations away from coral-dominated communities increasingly occurred. Shipping and marine pollution, as well as ocean warming and acidification from the burning of fossil fuels, have added further stress on tropical marine ecosystems. The latter represents a major threat with even small amounts of change potentially driving the ecological extinction of coral reefs and other marine ecosystems. Given inaction on the core drivers of these changes, the future does not look bright for coral reef ecosystems as we move into the critical phase of the Anthropocene Epoch.

Abstract The term ‘Anthropocene’ has been proposed to indicate a geological interval characterized by global anthropogenic environmental change. This paper attempts to recognize a method by which the Anthropocene can be defined micropalaeontologically. In order to do this, microfloras and microfaunas (diatoms, macrophytes, dinoflagellate cysts, foraminifera and ostracods) from nearshore waters through to paralic and freshwater aquatic milieux are considered, and biotic variability with an anthropogenic causation identified. Microbiotic change can be related to anthropogenically induced extinctions, pollution-related mutation, environmentally influenced assemblage variability, geochemistry of carapaces/tests, floral change related to lacustrine acidification, faunal and floral correlation to industrial and agricultural signatures and introduction of exotic species via shipping. The influence of humanity on a local scale can be recognized in assemblages as far back as 5000 years BP. However, widespread anthropogenic change took place in Europe and America, particularly in the nineteenth and twentieth centuries, although in Asia (e.g. Japan) it cannot be observed prior to the twentieth century. Profound and global biotic change began in the mid-twentieth century and, if the Anthropocene is to be defined in this way, then the period 1940–1945 might encompass the biotic base of the interval.

Abstract Anthropogenic chemical contamination is one of the most evident signals of human influence on the environment. The large amounts of industrially produced pollutants that have been introduced, over decades, into air, soil and water have caused modifications to natural elemental cycling. Anthropogenic contamination usually leads to enrichment in many elements, particularly in industrial areas. Thus, certain elements and their isotopes can be used as geochemical tracers of anthropogenic impact. Some human-induced changes in the environment may be regarded as a secondary effect of pollution, such as acidification, which causes increased geochemical mobility of several trace elements in surficial deposits. Methods used by geochemists to assess the scale of anthropogenic influence on the environment include calculations of anthropogenic influence on the environment via enrichment and contamination factors, geoaccumulation index and pollution load index. The use of geochemical background levels for delineating between natural and anthropogenic pollution is important. A historical perspective of anthropogenic contamination, allied with isotopic and geochemical signatures in dated sediment cores, may be applied to help define the Anthropocene.

Abstract Annually laminated stalagmites from natural caves and limestone mines capture a number of significant environmental and climatic signals during the anthropogenically disturbed era. The effects of forest clearance, or development of agricultural or industrial practices, can be marked by changes in soil or hydrological responses leading to shifts in both chemical (e.g. carbon and oxygen isotope ratios or trace elements) and physical (e.g. fabric, thickness of laminae) signals. However, these signals are diachronous because of the spatial heterogeneity of human societies. Twentieth-century changes in atmospheric composition are known from speleothems at several sites and demonstrate pollution disturbance of the sulphur cycle and the signal provided by the 1950s rise in radiocarbon caused by atmospheric nuclear tests. This latter is a global signal and hence a strong candidate to define the start of the Anthropocene, although other considerations, including comparison with instrumental archives, would favour an earlier timing. An attractive option is the climate amelioration marking the end of the Little Ice Age in the mid-nineteenth century, which is marked in Alpine and other Northern Hemisphere areas. Examples are illustrated from the Grotta di Ernesto cave to illustrate the appearance of a putative mid-nineteenth-century boundary.

Abstract Ice could play a role in identifying and defining the Anthropocene. The recurrence of northern hemisphere glaciation and the stability of the Greenland Ice Sheet are both potentially vulnerable to human impact on the environment. However, only a very long hiatus in either would be unusual in the context of the Quaternary Period, requiring the definition of a geological boundary. Human influence can clearly be discerned in several ice-core measurements. These include a sharp boundary in radioactivity due to atmospheric nuclear testing; increases, unprecedented at least in the Holocene, in Greenland concentrations of sulphate, nitrate and metals such as lead; the appearance in ice-core air bubbles of previously undetectable compounds such as SF 6 ; and the rise, unprecedented in the last 800 ka, in concentrations of carbon dioxide and methane. Some combination of these changes could be used by future generations to clearly identify the onset of a new epoch defined at a particular calendar date. However, it is not yet clear what the character of the fully developed Anthropocene will be, and it might be wise to let future generations decide, with hindsight, when the Anthropocene started, acknowledging only that we are in the transition towards it.

Abstract Atmospheric testing of nuclear weapons during the period 1945–1980 ushered in the ‘atomic age’ and released large quantities of anthropogenic radiogenic nuclides into the atmosphere. These radionuclides were subsequently deposited as fallout to the entire surface of the planet. While many have decayed to negligible levels, long-lived radionuclides persist and will do so for thousands of years. Isotopes of plutonium, 239 Pu (half-life 24 100 years) and 240 Pu (half-life 6563 years), provide the best chronological markers for the onset of this anthropogenic event both now and into the future due to their long half-lives, particle-reactivity, and the fact that they were present in negligible quantities prior to anthropogenic production and release. Chronostratigraphic markers established by distinct Pu concentration profiles and Pu isotope changes in sediment sequences and ice and coral cores can provide high-resolution dating over the last 60 years. However, even though fallout has ceased, it is found that the Pu inventory currently held in surface soil layers and the oceans will continue to supply Pu to sediment deposition zones for millennia and centuries, respectively. The delivery of this Pu will depend on soil erosion and bioturbation rates, and the rate of removal of dissolved Pu from the ocean.

Abstract Volcanic ash is dispersed over thousands of kilometres during large-scale eruptions, forming sedimentary layers. These ash (tephra) deposits are increasingly being used as unique marker layers in a variety of sedimentary archives including ice cores, and terrestrial and marine records. Tephra dispersed during large explosive eruptions that coincide with the defined beginning of the Anthropocene could therefore be used to help identify this event in various archives, and assess the relative spatial differences in marked anthropogenic change. The 1815 eruption of Tambora, Indonesia, was the largest in historical time and occurred in the middle of Europe’s Industrial Revolution. Volatile emissions injected into the atmosphere during this eruption caused widespread effects including the ‘year without a summer’ during which there were anomalously cooler temperatures recorded across much of North America and Europe. Sulphate aerosols associated with the eruption were dispersed by stratospheric and tropospheric winds across the entire globe. Deposits of these are clearly recorded in the Earth’s key palaeoclimatic records: polar ice cores. Significantly, the Tambora eruption occurred immediately prior to substantial increases in greenhouse gases, a defining feature of the Anthropocene.

Abstract The technosphere, the interlinked set of communication, transportation, bureaucratic and other systems that act to metabolize fossil fuels and other energy resources, is considered to be an emerging global paradigm, with similarities to the lithosphere, atmosphere, hydrosphere and biosphere. The technosphere is of global extent, exhibits large-scale appropriation of mass and energy resources, shows a tendency to co-opt for its own use information produced by the environment, and is autonomous. Unlike the older paradigms, the technosphere has not yet evolved the ability to recycle its own waste stream. Unless or until it does so, its status as a paradigm remains provisional. Humans are ‘parts’ of the technosphere – subcomponents essential for system function. Viewed from the inside by its human parts, the technosphere is perceived as a derived and controlled construct. Viewed from outside as a geological phenomenon, the technosphere appears as a quasi-autonomous system whose dynamics constrains the behaviour of its human parts. A geological perspective on technology suggests why strategies to limit environmental damage that consider only the needs of people are likely to fail without parallel consideration of the requirements of technology, especially its need for an abundant supply of energy.