The ‘Anthropocene’ and the Present is the Key to the Past.

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 ZALASIEWICZ ET AL.

Geological Society, London, Special Publications, 2014

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, ...

2021

The possibility of formalizing the Anthropocene as a chronostratigraphic unit by the International Commission on Stratigraphy (ICS) has been intensely debated. The aim of this paper is to explore and assess some of the stakes of this process from a philosophical point of view. In order to do this, I distinguish and explicate two senses of formalization, namely the descriptive and the evaluative senses. With this distinction at hand, I conclude the following. First, I submit that there are formalizations of the Anthropocene, in both descriptive and evaluative senses, beyond the confines of the ICS, which reveals a disunity of the sciences. Second, I suggest that some calls for rejecting the formalization of the Anthropocene in the context of the ICS are concerned with a lack of descriptive formality of the proposals in the form of incoherencies. I argue that these incoherencies are not a decisive reason for rejection. Third, I claim that the ICS could take a stance in terms of the ev...

The Anthropocene Review, 2015

Across a large proportion of Earth’s ice-free land surfaces, a solid-phase stratigraphic boundary marks the division between humanly modified ground and natural geological deposits. At its clearest, the division takes the form of an abrupt surface at the base of deposits variously called ‘artificial ground’, ‘anthropogenic ground’ or ‘archaeological stratigraphy’ – which together comprise a distinctive part of the geosphere called the ‘archaeosphere’. In other cases the bounding surface is more diffuse, gradational or mixed, due to action of non-human agencies and anthropedogenic forcings. It is alternately conformable and unconformable. Layers above typically contain artificial features, structures, artifacts and other material traces of human activity, in contrast to their relative absence in layers below. A fundamental characteristic of the boundary is that it is diachronous, still being formed and renewed today. In examining the boundary, this paper asks – does it reflect the di...

We propose a realignment of the terms geochronology and chronostratigraphy that brings them broadly into line with current use, while simultaneously resolving the debate over whether the Geological Time Scale should have a "single" or "dual" hierarchy of units: Both parallel sets of units are retained, although there remains the option to adopt either a single (i.e., geochronological) or a dual hierarchy in particular studies, as considered appropriate. Thus, geochronology expresses the timing or age of events (depositional, diagenetic, biotic, climatic, tectonic, magmatic) in Earth's history (e.g., Hirnantian glaciation, Famennian-Frasnian mass extinction). Geochronology can also qualify rock bodies, stratified or unstratified, with respect to the time interval(s) in which they formed (e.g., Early Ordovician Ibex Group). In addition, geochronology refers to all methods of numerical dating. Chronostratigraphy would include all methods (e.g., biostratigraphy, magnetostratigraphy, chemostratigraphy, cyclostratigraphy, sequence stratigraphy) for (1) establishing the relative time relationships of stratigraphic successions regionally and worldwide; and (2) formally naming bodies of stratified rock that were deposited contemporaneously with units formally defined at their base, ideally by a GSSP (Global Boundary Stratotype Section and Point = "golden spike") that represents a specific point in time.

Quaternary Science Advances , 2023

This paper outlines the stratigraphic basis of a proposed Anthropocene Event. It considers a diachronous event framework to be more appropriate for understanding the Anthropocene than treating it as a new geological series/epoch. Four general categories of material evidence are identified as of particular relevance: 'artificial' strata with natural constituents; humanly modified ground; legacy sediments; and 'natural' geo-deposits containing artefactual material. All these arise from the interaction and mixing of human, natural, and hybrid human-natural forces. Taken together, such stratigraphic evidence supports the case for recognising the Anthropocene as an unfolding event.

STRATI 2013, 2014

The Anthropocene was proposed as a term (Crutzen and Stoermer 2000) before consideration was given to the nature of the key signatures, contrasting with standard procedures for defining such units. The term is being widely used in both popular and scientific publications before a decision is made as to whether it warrants formalisation and definition of a Global Stratigraphic Section and Point (GSSP). The deliberate human modification of the landscape and its subsurface, and the creation of human-generated novel sedimentary deposits, minerals, and landforms, are characteristic features of the development of Earth's surface and near surface, which has accelerated in the past two centuries. The large-scale intentional excavation, transportation, and deposition of mixtures of rock and soil to form anthropogenic deposits and landforms represent a new geological process that could be used as a diagnostic signature of the Anthropocene.

GSA Today, 2013

By "formed" we mean when the main fabric of the rock was constructed; in sedimentary rocks, this is taken as when the sedimentary particles were deposited; in igneous rocks, this typically means intrusion or crystallization (although these processes may not be precisely synchronous). The "timing of formation" of any individual metamorphic rock is often more problematic, because such a rock commonly includes components that crystallized at different times along a pressure-temperaturetime path.