Geological Time Units Research Articles

The Anthropocene as a civil time unit

Geologists are currently finalizing the specification of a new geological time unit, the Anthropocene Epoch, characterized by the Earth’s response to humans driving geological change. Once it is ratified we can use it also as a civil time unit. The standard for time reckoning used worldwide today is the Gregorian calendar, introduced in 1582. As a calendar of the Catholic church, it is structured around supernatural events and indeterminate religious dates. Astronomical year numbering has long fixed the arcane arithmetic and religious notations of the Gregorian calendar, but the origin of its time scale perpetuates the links to religious and supernatural dates. If we shift the origin of the astronomical time scale to the onset of the Anthropocene, we can update the calendar with a science based time scale that is anchored by real world data and events. Such a time scale would be better suited as a culturally inclusive standard in a multi-cultural world.

The Anthropocene, should it be a new geological time unit?

The Anthropocene, should it be a new geological time unit?

Antonio Stoppani's 'Anthropozoic' in the context of the Anthropocene.

The figure of Antonio Stoppani (1824-91), an Italian priest, geologist and patriot, has re-emerged in the last decade thanks to discussions gravitating around the 'Anthropocene' - a term used to designate a proposed geological time unit defined and characterized by the mark left by anthropogenic activities on geological records. Among these discussions, Stoppani is often considered a precursor for popularizing the term 'Anthropozoic', which he used to describe and characterize the latest 'era' of Earth's geological time. His writings, largely unknown to an international audience before the 'Anthropocene saga', have been particularly in the spotlight after Valeria Federighi translated excerpts of his main geological work, Corso di Geologia, originally published in three volumes between 1871 and 1873. In the first edition of Corso di Geologia, namely Note ad un Corso Annual di Geologia, or simply Note, published between 1865 and 1870, Stoppani characterized the Anthropozoic in stratigraphic terms. In particular, Chapter 15 of the second volume of Note (1867) represents the first stratigraphic characterization that the author provides of the Anthropozoic. Our contribution here brings, for the first time, a translation of Chapter 15 to a broader international audience, accompanied by a critical commentary elucidating the broader social, political, religious and scientific context wherein the notion of Anthropozoic emerged in Stoppani's writings. The text of the original document and its translation can be found in the supplementary material tab at https://doi.org/10.1017/S0007087422000590.

Amplifying Solidarity in The Anthropocene: Public Engagement for Hope in Dialogic Organizing

In this paper, through the analysis of ethnographic accounts of citizens engagement events, we will explore manners in which experiences with the momentous impacts of the Anthropocene has given way to calls for new ways of organizing our lives. These engagement events were organized in Vietnam and UK with the purpose of presenting the concept of the Anthropocene, its stakes and its effects; taking into account the participants impressions and everyday experiences; and contemplating and discussing alternative forms of business models less detrimental to/impactful on the environment and the Earth System. A common theme emerging in these workshops was that of doing something in a form of solidarity: a commitment to the idea that we owe it to ourselves and others to unite in new ways, to act and organize differently, forgoing what we already have and do, redressing, reinventing and reconfiguring, for the sake of an (ever) emerging “we” that cuts across the borders of time and space and species that we usually identify ourselves by. We investigate specifically the impetus for the questions most frequently posed by the participants of the ethnographic work: what can we do as engaged citizens, how to become active together, and in which ways is it possible to hope for a future in this new geological time unit of the Anthropocene. In the paper, we theorise two of the features to the Anthropocene Experience: the practical question of when and where and, especially, on which scale to begin reorganizing our ways of living when apprehending the Anthropocene ramifications — which we will show some features of in the narrative account concerning the citizens engagement events; and how the responses to the Anthropocene challenges are motivated when people begin to consider them together. Our paper contributes, in the first instance, to the body of work on the grassroots movements and forms of activism in different spaces of hope and to theorise the concept of solidarity

Holocene book review: The Anthropocene as a Geological Time Unit: A Guide to the Scientific Evidence and Current Debate

Holocene book review: The Anthropocene as a Geological Time Unit: A Guide to the Scientific Evidence and Current Debate

A formal Anthropocene is compatible with but distinct from its diachronous anthropogenic counterparts: a response to W.F. Ruddiman’s ‘three flaws in defining a formal Anthropocene’

We analyse the ‘three flaws’ to potentially defining a formal Anthropocene geological time unit as advanced by Ruddiman (2018). (1) We recognize a long record of pre-industrial human impacts, but note that these increased in relative magnitude slowly and were strongly time-transgressive by comparison with the extraordinarily rapid, novel and near-globally synchronous changes of post-industrial time. (2) The rules of stratigraphic nomenclature do not ‘reject’ pre-industrial anthropogenic signals – these have long been a key characteristic and distinguishing feature of the Holocene. (3) In contrast to the contention that classical chronostratigraphy is now widely ignored by scientists, it remains vital and widely used in unambiguously defining geological time units and is an indispensable part of the Earth sciences. A mounting body of evidence indicates that the Anthropocene, considered as a precisely defined geological time unit that begins in the mid-20th century, is sharply distinct from the Holocene.

The Working Group on the Anthropocene: Summary of evidence and interim recommendations

Abstract 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 "Anthropocene": neglects, misconceptions, and possible futures: The term "Anthropocene" is often erroneously used, as it is not formally defined yet.

The term “Anthropocene” to describe anthropogenic global changes and their socio‐political and philosophical repercussions has gained popularity during the past years. Although it originated as a scientific term to designate the geologic epoch in which we live, characterized by the global impact of human activities on Earth [1], “Anthropocene” has adopted a variety of meanings in many other areas such as philosophy, sociology, communication, politics, or law. In philosophy, the “Anthropocene” has become an expression of modernity, an attack on Earth and the biosphere, or a biological imperative that is inherent to human existence. In a political context, it has been contemplated a logical consequence of global capitalism or the decoupling between environmental health and human welfare [2]. > … the current definition of “Anthropocene” is a bet on the future and, as such, its meaning and eventual formalization depend on the future development of human affairs. Notwithstanding its frequent and widespread use, however, the appropriateness of the term and concept of the “Anthropocene” is under vibrant debate. This essay aims to clarify the issue and briefly discuss some points that are often ignored or go unnoticed. First, the concept of the “Anthropocene” is not a recent invention but was first proposed about one century and a half ago albeit under a different name. Second, its frequent and extended usage may create the misconception that the term is already a formal official unit of geologic time scale, but it is not. Third, the current definition of “Anthropocene” is a bet on the future and, as such, its meaning and eventual formalization depend on the future development of human affairs. ### The precursors of the “Anthropocene” In geology, “‐cene” is the suffix for an epoch, whereas “‐zoic” is the corresponding suffix for an era. Geological time units are rock layers, called strata, organized into …

Making the case for a formal Anthropocene Epoch: an analysis of ongoing critiques

A range of published arguments against formalizing the Anthropocene as a geological time unit have variously suggested that it is a misleading term of non-stratigraphic origin and usage, is based on insignificant temporal and material stratigraphic content unlike that used to define older geological time units, is focused on observation of human history or speculation about the future rather than geologically significant events, and is driven more by politics than science. In response, we contend that the Anthropocene is a functional term that has firm geological grounding in a well-characterized stratigraphic record. This record, although often lithologically thin, is laterally extensive, rich in detail and already reflects substantial elapsed (and in part irreversible) change to the Earth System that is comparable to or greater in magnitude than that of previous epoch-scale transitions. The Anthropocene differs from previously defined epochs in reflecting contemporary geological change, which in turn also leads to the term's use over a wide range of social and political discourse. Nevertheless, that use remains entirely distinct from its demonstrable stratigraphic underpinning. Here we respond to the arguments opposing the geological validity and utility of the Anthropocene, and submit that a strong case may be made for the Anthropocene to be treated as a formal chronostratigraphic unit and added to the Geological Time Scale.

Earth Systems, Human Agency, and the Anthropocene: Planet Earth in the Human Age

A proposal to designate a new geological epoch of our own making—the Anthropocene—is being considered by the International Commission on Stratigraphy (ICS), part of the International Union of Geological Sciences. Based on a set of formal criteria, there is growing consensus for a Holocene–Anthropocene boundary set at some point in the last 200 years. A number of scientists have questioned the utility of such a designation because it overlooks the millennia-long history of human impacts on the planet and fails to focus on the causes of human domination of the Earth in favor of the effects. I review these debates and synthesize a variety of proposals for an Anthropocene beginning 10,000 years ago to as little as 50. I then review a number of parallel debates focused less on the geosciences and more on the political, social, and institutional implications of the Anthropocene. I demonstrate how and why formal ICS criteria for the designation of geological time units may be inadequate for effectively meeting the underlying rationale for designating a human-induced geological epoch and the role it is currently and, potentially, will continue to play in the court of public opinion.

A transparent framework for defining the Anthropocene Epoch

Lewis and Maslin (2015) applied modern geological requirements to a systematic search for evidence of markers that could be used to define a new geological time unit, the Anthropocene Epoch. These must include (1) a near-permanent change to the Earth System that sets it on to a new trajectory and (2) global changes to the Earth System recorded in a number of stratigraphic deposits worldwide to provide a correlative boundary event or marker called a Global Stratotype Section & Point (GSSP) or ‘golden spike’. Using this framework Lewis and Maslin conclude that just two time periods likely adhere to the criteria. These are the irreversible cross-ocean exchange of species alongside the globally synchronous coolest part of the ‘Little Ice Age’ in the 17th century, marked by the 1610 minima of CO2 (Orbis Spike), or the accelerating atmospheric, oceanic and terrestrial changes in the second half of the 20th century, conveniently marked by the 1964 peak radionuclide fallout (Bomb Spike). Two recent responses by members of the Anthropocene Working Group (Zalasiewicz, 2015a, 2015b) to Lewis and Maslin (2015) do not dispute the GSSP framework, nor that these are the only two time periods that minimally fit the requirements for a new epoch. Instead they question our selection of two specific 1610 and 1964 GSSP primary markers. We respond to their misconceptions and misunderstandings about geological criteria and relevant evidence required to define a GSSP. Our primary goal, however, is to present a framework to assist the scientific community in objectively and transparently arriving at a robust selection of a GSSP and correlated markers to define the Anthropocene Epoch.

Can an Anthropocene Series be defined and recognized?

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.

Designing and implementing a geologic information system using a spatiotemporal ontology model for a geologic map of Korea

A geologic information system was utilized for geologic mapping in Korea using a spatiotemporal ontology model. Five steps were required to make the GIS representation of the geologic map information. The first step was to limit the geologic mapping to Korean area. The second step was to extract the rock units with spatial objects from the geologic map and the geologic time units with temporal objects. The third step was to standardize the geologic terms in Korean and English for both the spatial and temporal objects. The fourth step was to conceptualize the classified objects in the geologic map units and the formation of guidelines for the specification of a spatiotemporal ontology model. Finally, we constructed a spatiotemporal retrieval system and an ontology system related to the geologic map of Korea, which were applied to the spatiotemporal ontology model. The spatiotemporal ontology model was defined as a sophisticated model that provides for the evolution from a data base to a knowledge base. This ontology model can be conceptualized as a well-defined set of terms used for expressing spatial objects in rock units and temporal objects in geologic time units, as well as a system of contents and structures. In addition, it includes symbology units such as color and pattern symbols mapped one-to-one with the spatiotemporal concepts. The existing information retrieval services provide information that is limited to the user's knowledge, whereas our geologic ontology system provides a broad range of information in graphical form, including locations and interrelationships. In this way, the information can be upgraded to the level of knowledge. A geologic term tree was designed, based on the existing classification schemes, with the goal of creating an accessible internet source.

Global geological map of Venus

The surface area of Venus (∼460×106km2) is ∼90% of that of the Earth. Using Magellan radar image and altimetry data, supplemented by Venera-15/16 radar images, we compiled a global geologic map of Venus at a scale of 1:10M. We outline the history of geological mapping of the Earth and planets to illustrate the importance of utilizing the dual stratigraphic classification approach to geological mapping. Using this established approach, we identify 13 distinctive units on the surface of Venus and a series of structures and related features. We present the history and evolution of the definition and characterization of these units, explore and assess alternate methods and approaches that have been suggested, and trace the sequence of mapping from small areas to regional and global scales. We outline the specific defining nature and characteristics of these units, map their distribution, and assess their stratigraphic relationships. On the basis of these data, we then compare local and regional stratigraphic columns and compile a global stratigraphic column, defining rock-stratigraphic units, time-stratigraphic units, and geological time units. We use superposed craters, stratigraphic relationships and impact crater parabola degradation to assess the geologic time represented by the global stratigraphic column. Using the characteristics of these units, we interpret the geological processes that were responsible for their formation. On the basis of unit superposition and stratigraphic relationships, we interpret the sequence of events and processes recorded in the global stratigraphic column. The earliest part of the history of Venus (Pre-Fortunian) predates the observed surface geological features and units, although remnants may exist in the form of deformed rocks and minerals. We find that the observable geological history of Venus can be subdivided into three distinctive phases. The earlier phase (Fortunian Period, its lower stratigraphic boundary cannot be determined with the available data sets) involved intense deformation and building of regions of thicker crust (tessera). This was followed by the Guineverian Period. Distributed deformed plains, mountain belts, and regional interconnected groove belts characterize the first part and the vast majority of coronae began to form during this time. The second part of the Guineverian Period involved global emplacement of vast and mildly deformed plains of volcanic origin. A period of global wrinkle ridge formation largely followed the emplacement of these plains. The third phase (Atlian Period) involved the formation of prominent rift zones and fields of lava flows unmodified by wrinkle ridges that are often associated with large shield volcanoes and, in places, with earlier-formed coronae. Atlian volcanism may continue to the present. About 70% of the exposed surface of Venus was resurfaced during the Guineverian Period and only about 16% during the Atlian Period. Estimates of model absolute ages suggest that the Atlian Period was about twice as long as the Guineverian and, thus, characterized by significantly reduced rates of volcanism and tectonism. The three major phases of activity documented in the global stratigraphy and geological map, and their interpreted temporal relations, provide a basis for assessing the geodynamical processes operating earlier in Venus history that led to the preserved record.

THE GEOZOIC SUPEREON

Geological time units are the lingua franca of earth sciences: they are a terminological convenience, a vernacular of any geological conversation, and a prerequisite of geo-scientific writing found throughout in earth science dictionaries and textbooks. Time units include terms formalized by stratigraphic committees as well as informal constructs erected ad hoc to communicate more efficiently. With these time terms we partition Earth’s history into utilitarian and intuitively understandable time segments that vary in length over seven orders of magnitude: from the 225-year-long Anthropocene (Crutzen and Stoermer, 2000) to the ,4-billion-year-long Precambrian (e.g., Hicks, 1885; Ball, 1906; formalized by De Villiers, 1969).

Phanerozoic changes in the high-rank suprageneric diversity structure of brachiopods: Linear and non-linear effects

Phanerozoic evolution of brachiopods produced many linear (established by a comparison of successive geologic time units) and non-linear (established by a comparison of non-successive geologic time units) effects, which can be examined quantitatively by using the similarity coefficients (Czekanowski's Quantified Coefficient and Gower Index) and correlation tools. The high-rank suprageneric diversity structure accounts for a number of superfamilies in each of 26 orders for every epoch of geological time. The intensity of turnovers in this structure was generally low during the entire Phanerozoic. It was slightly stronger during the Early Paleozoic, but close to zero during the Cenozoic, when the high-rank suprageneric diversity structure of brachiopods stabilized finally. Significant turnovers took place at the Middle Cambrian–Early Ordovician, the Late Ordovician–Early Silurian, the Late Silurian–Early Devonian, the Middle Devonian–Mississippian, and the Permian–Triassic transitions. Influences of mass extinctions, both major like those End Ordovician or Permian/Triassic and minor like Early Jurassic or Jurassic/Cretaceous, on the high-rank suprageneric diversity structure of brachiopods is registered. The strongest was the consequences of the Permian/Triassic catastrophe, which perhaps even reset the brachiopod evolution. No evident direct relationships are established between intensity of turnovers and eustatic fluctuations. However, the changes in the diversity structure recorded with the Gower Index provide evidence that eustatic lowstands were more favorable for intensification in these changes.

Do GSSPs render dual time-rock/time classification and nomenclature redundant?

The Geological Society of London Proposal for "...ending the distinction between the dual stratigraphic terminology of time-rock units (of chronostratigraphy) and geologic time units (of geochronology). The long held, but widely misunderstood distinction between these two essentially parallel time scales has been rendered unnecessary by the adoption of the global stratotype sections and points (GSSP-golden spike) principle in defining intervals of geologic time within rock strata." Our review of stratigraphic principles, concepts, models and paradigms through history clearly shows that the GSL Proposal is flawed and if adopted will be of disservice to the stratigraphic community. We recommend the continued use of the dual stratigraphic terminology of chronostratigraphy and geochronology for the following reasons: (1) time-rock (chronostratigraphic) and geologic time (geochronologic) units are conceptually different; (2) the subtended time-rock's unit space between its "golden spiked-marked" lower and upper boundaries, actually corresponds to the duration of the time-rock unit's defining geologic s.l. events-set; therefore, in no way can physical time (instants or intervals) be directly defined by GSSPs, (3) combining in a single system of "chronostratigraphic units" the time-rock and geologic time units as currently understood, leads to the epistemological error of uniting evidence (rock successions) with inference (the interpreted duration of chosen defining events); (4) the redundancy of the terms eonothem, erathem, system, series, and stage with eon, era, period, epoch and age lacks support, given that they are conceptually different; in fact, referring to "eon," "era," etc. as terms uniting both time-rock and geochronologic connotations will produce needless nomenclatorial confusion, attaching different meanings to already well known and widely used geologic terms; and (5) the reversion of 'geochronology' to its main stream and original meaning of numerical dating has no foundation, just by considering that the use of geochronolgy precedes numerical dating, which became practical by the 1960's. We endorse the following: (1) the GSSP network needs to be improved through the use of reference sections at high latitude sites, and in sedimentary continental rock successions of achievable, dependable positioning in the global standard timetable; and (2) to attend to researchers using astronomically-forced sedimentary systems, the designation of unit stratotypes needs to be reinstated as a valid and as a, complementary means of defining chronostratigraphic units, particularly at the stage and lower chronostratigraphic rank.

6. British clay stratigraphy

There are three principal types of stratigraphy, each with its own terminology: geochronolog —units of geological time (e.g. period, epoch), with a parallel and exactly corresponding stratigraphy; chronostratigraphy —time-rock units or time-stratigraphic units represent stratified rock successions (e.g. system, series, etc.) assigned to geological time units; geochronometry —the measurement of absolute time in years as numerical ages (e.g. 345 Ma), principally by means of radiometric dating, but increasingly, in Phanerozoic rocks, by the numerical dating of Milankovitch cycles. This has led to some confusion. Current recommendations, led by the Geological Society (Zalasiewicz et al . 2004) are to adopt the geochronology scheme, which has been used in this chapter. Part of the geological timescale, covering the last 545 million years of earth's history (Phanerozoic—from the greek meaning ‘visible life’), is shown in Table 6.1 (Gradstein & Ogg 1996) with the youngest at the top. This shows the broadest sub-divisions of era and period (the Neogene and Palaeogene are often referred to as the Tertiary, though this name may fall into disuse). The names for the eras derive from the greek meaning ‘ancient’, ‘middle’, and ‘new’ life. Periods further sub-divide into early, middle, and late (or in some cases simply early and late), and thence into epochs and ages (refer to Appendix C). Time before the Phanerozoic is usually referred to as the Pre-Cambrian. Clays are found in three principal geological environments: as primary deposits in the sedimentary environment, as alteration products of other materials in the weathering and

Status of Divisions of the International Geologic Time Scale

Each chronostratigraphic unit of the International Geologic Time Scale will be defined at its base by a Global Stratotype Section and Point (GSSP) or Global Standard Stratigraphic Age (GSSA). Nearly 50 GSSPs and 10 GSSAs have now been ratified. Ideally, the GSSP coincides with events having a global correlation potential. The international stage divisions of some systems, such as the Jurassic or Neogene, are similar to traditional usage in European geology. However, in order to utilize global correlation horizons, the international stage divisions of other systems, such as the Ordovician or Permian, have required assembling new stage nomenclatures or hybrids of different regional stages. A reference table by the International Commission on Stratigraphy itemizes the current or potential GSSP and GSSA definitions of all international geologic time units.

Age and origin of the lowlands of Mars

One of the many significant findings of the Mars Global Surveyor mission is the presence of hundreds of quasi-circular depressions (QCDs) observed from high-resolution MOLA topography data. Their presence has recently been interpreted to reflect a northern lowlands that archive some of the earliest recorded rocks on Mars, mostly below a veneer of Hesperian and Amazonian materials. Here we analyze these data, coupled with a recent synthesis of geologic, geophysical, geomorphic, topographic, and magnetic information. Such analysis allows us to suggest a potential plate tectonic phase during the recorded Early into Middle Noachian martian history that transitioned into a monoplate world with episodic magmatic-driven activity persisting to present. This working hypothesis is based on: (1) the observation that the basement of the northern plains is younger than the basement of the southern highlands, but older than the material exposures of the cratered highlands, suggesting different formational ages for each one of the three geologic-time units; (2) the observation that parts of the very ancient highland's crust are highly magnetized, thus suggesting that most if not all of the formation of the lowlands basement postdates the shut off of the martian dynamo, some 4 Gyr ago, and so allowing hundreds of millions of years for the shaping of the buried lowlands. Consequently, the role of endogenic processes in the earliest geological evolution of Mars (Early perhaps into Middle Noachian) requires reconsideration, since MOLA topographic and MGS magnetic data afford a temporal window sufficient for very early, non-primordial shaping of the northern lowlands' basement.