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However, recognition of this would be eased, not hindered, by formal recognition of an Anthropocene epoch justified by our present assessment that the Earth System state has decisively exceeded Holocene norms but not yet those of the Quaternary (Waters et al., [21]). As Zalasiewicz et al. ([28]) pointed out, defining a base for the Anthropocene will provide completeness for our understanding of the highly stable Holocene, with both top and base defined, in contrast with the uncertain planetary boundary conditions that characterise the Anthropocene. Swindles et al. ([15]) correctly point out that there are many conceptions of the "Anthropocene" in use, and they argue that this flexibility in terminology is desirable. [Extracted from the article]

The extensive array of mid‐20th century stratigraphic event signals associated with the 'Great Acceleration' enables precise and unambiguous recognition of the Anthropocene as an epoch/series within the Geological Time Scale. A mid‐20th century inception is consistent with Earth System science analysis in which the Anthropocene term and concept arose, and would reflect the reality that our planet has sharply exited the range of natural variability characterizing the Holocene Epoch/Series, which the Anthropocene would therefore terminate. An alternative, recently proposed 'geological event' approach to the Anthropocene is primarily an interdisciplinary concept, encompassing historical and socio‐cultural processes and their global environmental impacts over a diachronous timeframe that extends back at least many millennia. Resembling more closely a geological episode than an event, it would decouple the Anthropocene from its chronostratigraphic delineation and association with an abrupt planetary perturbation; but separately defined and differently named it might be usefully complementary. We recommend a clear separation of epochs, events and episodes. An epoch is a formal subdivision of the Geological Time Scale, and its correlation may be assisted by one or more events; an event is usually, and particularly in the Quaternary, a brief incident or perturbation with a sedimentary expression; and an episode is a longer, internally complex time interval that may include several events and even extend across several epochs. [ABSTRACT FROM AUTHOR]

We examine three distinctive biostratigraphic signatures of humans associated with hunting and gathering, landscape domestication and globalization. All three signatures have significant fossil records of regional importance that can be correlated inter‐regionally and help describe the developing pattern of human expansion and appropriation of resources. While none have individual first or last appearances that provide a globally isochronous marker, all three signatures overlap stratigraphically, in that they are part of a continuum of change, with complex regional patterns. Here we show that during the later stages of globalization, late nineteenth to twentieth century records of species translocations can be used to build an interconnected web of palaeontological correlation with decadal or sub‐decadal precision that dovetails with other stratigraphic markers for the Anthropocene. This palaeontological web is also a proxy for accelerating species extinction and of a state shift in the biosphere in the twentieth century. [ABSTRACT FROM AUTHOR]

The term Anthropocene initially emerged from the Earth System science community in the early 2000s, denoting a concept that the Holocene Epoch has terminated as a consequence of human activities. First associated with the onset of the Industrial Revolution, it was then more closely linked with the Great Acceleration in industrialization and globalization from the 1950s that fundamentally modified physical, chemical, and biological signals in geological archives. Since 2009, the Anthropocene has been evaluated by the Anthropocene Working Group, tasked with examining it for potential inclusion in the Geological Time Scale. Such inclusion requires a precisely defined chronostratigraphic and geochronological unit with a globally synchronous base and inception, with the mid‐twentieth century being geologically optimal. This reflects an Earth System state in which human activities have become predominant drivers of modifications to the stratigraphic record, making it clearly distinct from the Holocene. However, more recently, the term Anthropocene has also become used for different conceptual interpretations in diverse scholarly fields, including the environmental and social sciences and humanities. These are often flexibly interpreted, commonly without reference to the geological record, and diachronous in time; they often extend much further back in time than the mid‐twentieth century. These broader conceptualizations encompass wide ranges and levels of human impacts and interactions with the environment. Here, we clarify what the Anthropocene is in geological terms and compare the proposed geological (chronostratigraphic) definition with some of these broader interpretations and applications of the term "Anthropocene," showing both their overlaps and differences. Plain Language Summary: The Anthropocene concept, that modern human impacts on Earth have been sufficient to bring in a new geological epoch, is only two decades old. In that short time, its use has grown explosively, not only in the Earth sciences but also far more widely to spread through the sciences generally, to spill over into the social sciences, arts, and humanities. This has led to welcome discussions between diverse scholarly communities, though also to some very different interpretations of the Anthropocene, when interpreted through different disciplinary lenses. Notably, the geological interpretation used as basis for a potential unit of the Geological Time Scale, of a time unit starting planet‐wide and synchronously in the mid‐twentieth century with the massive changes triggered by industrialization and globalization, jars with interpretations of an Anthropocene that ranges back many millennia to encompass early human environmental impacts. We analyze and compare these diverse standpoints and their effect upon evolving disciplinary practices, and discuss approaches that could make communication clearer and enhance cross‐disciplinary exchanges. Key Points: The Anthropocene concept developed in the Earth System science community is closely consistent with its proposed chronostratigraphic (geological) definitionA wide range of other meanings of the Anthropocene subsequently emerged that represent inherently valid, but partly different, conceptsCross‐disciplinary discussion is encouraged to help resolve issues of meaning and communication in this important area [ABSTRACT FROM AUTHOR]

As part of an international effort to evaluate potential replacement sections for the current Aeronian GSSP, the stratigraphy of the Rheidol Gorge section (central Wales, UK) is being restudied. A total of 28 samples from the Rhuddanian–Aeronian boundary interval at Rheidol Gorge were studied for chitinozoans. This famous Welsh Basin section, its stratigraphy rooted in the work of O.T. Jones and M. Sudbury, comprises a series of laminated black shales with abundant graptolites, alternating with grey mudstone intervals, deposited in anoxic to dysoxic/oxic seafloor conditions, respectively. The exposed section of c. 20 m spans the middle part of the upper Rhuddanian Pernerograptus revolutus Biozone through the lower Aeronian Neodiplograptus magnus Biozone of the lower to mid‐Llandovery Series (Cwmere and Derwenlas formations). Our chitinozoan analysis yielded an assemblage of over 2300 specimens distributed approximately uniformly throughout the entire succession. A total of 16 different taxa are identified, of which 12 remain in open nomenclature, reflecting the poor to moderately intact preservation of the specimens. Based on the presence of key species such as Spinachitina maennili and Conochitina iklaensis, the Rheidol Gorge section is referred to the Spinachitina maennili Biozone. This observation is in perfect alignment with the typical signature of other Rhuddanian–Aeronian boundary successions in the Welsh Basin and in other parts of the world. [ABSTRACT FROM AUTHOR]

By burning fossil fuels, humans have changed the carbon cycle, loading the atmosphere with extra carbon dioxide (CO2). Before the current Ice Age, high atmospheric CO2 levels generated warm climates. The Ice Age developed as the volcanic supply of CO2 lessened, and rock weathering increased. The CO2 lost from the atmosphere by chemical weathering was transferred to the ocean and trapped in carbonate sediments. Humans now replicate what volcanic activity did in the distant past, our CO2 emissions driving global warming. Earth's present climate should be cool, based on the present configuration of the Earth's orbit and the tilt of its axis, and on the decline in sunspot activity since 1990. Warming will grow further with rising emissions, further raising sea level. If business continues as usual we will end with an Eocene‐like ‘greenhouse climate’ and drowned coastal cities. [ABSTRACT FROM AUTHOR]

Most species on planet Earth have specific ecological ranges. In the near surface of the oceans, planktonic foraminifera define water masses that are warm in the tropics, and cold in polar regions. Tropical rainforests have trees and animals that are distinct from those in warm temperate or cold temperate zones. The fauna and flora of Australia are distinct from those of the Americas. These natural patterns, defined by factors such as latitudinal changes in surface temperature and rainfall, or geographical isolation, have evolved over millions, sometimes tens of millions of years. Now this natural pattern is being overprinted by the actions of a single species, Homo sapiens, which has made the whole Earth its ecological range, and some parts of nearby space too. The human ancestral pattern of gradually increasing impact on the Earth can be traced in the stratigraphic record for nearly 3 million years, and in its later and more pervasive phases may serve to help define a biostratigraphical signal for the Anthropocene Epoch. [ABSTRACT FROM AUTHOR]

What is the reach of geology, today? The word evokes strata, minerals and fossils. But how about metro systems, farmyard animals, factory smoke, ballpoint pens, tree‐rings and the fluff that comes off our clothes? These kinds of objects are just part of the evidence that is now being assembled to build a picture of the Anthropocene—the idea that human activities are now sufficiently powerful and pervasive to build the geology of the present—and to influence the course of the geology of our planet's future, too. [ABSTRACT FROM AUTHOR]

The Anthropocene Epoch, as currently being formulated, is a little under 70 years old. Geologists who are used to defining geological time intervals in rocks that are many millions of years old now need to make use of very high‐resolution time signals, such as annual growth layers and geochemical or artefact markers, to characterize this proposed new Epoch. [ABSTRACT FROM AUTHOR]

The Upper Carboniferous-Lower Permian (Upper Pennsylvanian-Asselian) Tobra Formation is exposed in the Salt and Trans Indus ranges of Pakistan. The formation exhibits an alluvial plain (alluvial fan-piedmont alluvial plain) fades association in the Salt Range and Khisor Range. In addition, a stream flow facies association is restricted to the eastern Salt Range. The alluvial plain facies association is comprised of clast-supported massive conglomerate (Gmc), diamictite (Dm) facies, and massive sandstone (Sm) lithofacies whereas the stream flow-dominated alluvial plain facies association includes fine-grained sandstone and siltstone (Fss), fining upwards pebbly sandstone (Sf), and massive mudstone (Fm) lithofacies. The lack of glacial signatures (particularly glacial grooves and striations) in the deposits in the Tobra Formation, which are, in contrast, present in their time-equivalent and palaeogeographically nearby strata of the Arabian peninsula, e.g. the Al Khlata Formation of Oman and Unayzah B member of the Saudi Arabia, suggests a pro- to periglacial, i.e. glaciofluvial depositional setting for the Tobra Formation. The sedimentology of the Tobra Formation attests that the Salt Range, Pakistan, occupied a palaeogeographic position just beyond the maximum glacial extent during Upper Pennsylvanian-Asselian time. [ABSTRACT FROM AUTHOR]

Stratigraphy provides insights into the evolution and dynamics of the Earth System over its long history. With recent developments in Earth System science, changes in Earth System dynamics can now be observed directly and projected into the near future. An integration of the two approaches provides powerful insights into the nature and significance of contemporary changes to Earth. From both perspectives, the Earth has been pushed out of the Holocene Epoch by human activities, with the mid-20th century a strong candidate for the start date of the Anthropocene, the proposed new epoch in Earth history. Here we explore two contrasting scenarios for the future of the Anthropocene, recognizing that the Earth System has already undergone a substantial transition away from the Holocene state. A rapid shift of societies toward the UN Sustainable Development Goals could stabilize the Earth System in a state with more intense interglacial conditions than in the late Quaternary climate regime and with little further biospheric change. In contrast, a continuation of the present Anthropocene trajectory of growing human pressures will likely lead to biotic impoverishment and a much warmer climate with a significant loss of polar ice. [ABSTRACT FROM AUTHOR]

Biospheric relationships between production and consumption of biomass have been resilient to changes in the Earth system over billions of years. This relationship has increased in its complexity, from localized ecosystems predicated on anaerobic microbial production and consumption to a global biosphere founded on primary production from oxygenic photoautotrophs, through the evolution of Eukarya, metazoans, and the complexly networked ecosystems of microbes, animals, fungi, and plants that characterize the Phanerozoic Eon (the last ∼541 million years of Earth history). At present, one species, Homo sapiens, is refashioning this relationship between consumption and production in the biosphere with unknown consequences. This has left a distinctive stratigraphy of the production and consumption of biomass, of natural resources, and of produced goods. This can be traced through stone tool technologies and geochemical signals, later unfolding into a diachronous signal of technofossils and human bioturbation across the planet, leading to stratigraphically almost isochronous signals developing by the mid-20th century. These latter signals may provide an invaluable resource for informing and constraining a formal Anthropocene chronostratigraphy, but are perhaps yet more important as tracers of a biosphere state that is characterized by a geologically unprecedented pattern of global energy flow that is now pervasively influenced and mediated by humans, and which is necessary for maintaining the complexity of modern human societies. [ABSTRACT FROM AUTHOR]

The status of the Quaternary, long regarded as a geological period effectively coincident with the main climatic deterioration of the current Ice Age, has recently been questioned as a formal stratigraphic unit. We argue here that it should be retained as a formal period of geological time. Furthermore, we consider that its beginning should be placed at the Gauss­Matuyama magnetic chron boundary at about 2.6 Ma, rather than at its current position at about 1.8 Ma. The Quaternary would be formally subdivided into the Pleistocene and Holocene epochs. The global chronostratigraphical correlation table proposed is enclosed at the back of this issue. [ABSTRACT FROM AUTHOR]

The Wenlock sequence of the Builth Wells district, central Wales is dominated by long-ranging Monograptus, Pristiograptus and Monoclimacis species. Cyrtograptus species, which underpin the graptolite biozonation, represent only about 10 per cent of recovered individuals. Ten Cyrtograptus species are present, most being zonal index species for the Builth district or other Wenlock sequences. Redescription of these Cyrtograptus species and comparison with all pertinent type material indicates that: the early Wenlock Cyrtograptus insectus, C. centrifugus and C. murchisoni are best distinguished by means of first whorl diameter, sicula length and differences of cladial development; mid Wenlock Cyrtograptus rigidus may bear a secondary cladium, but at Builth there are no stratigraphically discrete subspecies; Cyrtograptus linnarssoni is known only from its type locality; the long, gracile proximal part of the rhabdosome of C. ellesae facilitates its distinction from C. perneri, with which it has been confused, and indicates similarities to C. ramosus and C. lundgreni. Differences in the ranges of key Cyrtograptus species present problems for correlation between the lundgreni Biozone of the Builth district and the perneri-ramosus and lundgreni biozones of central Europe. The low diversity and abundance of the cyrtograptid fauna of the Builth district, compared to those of Arctic Canada and the Czech Republic, suggests relatively inhospitable conditions for graptolites. [ABSTRACT FROM AUTHOR]