/pdf/global-boundary-stratotype-section-and-point-gssp-for-the-v5vwn8ge08.pdf

Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene Series: Where and how to look for potential candidates

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. © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. The Anthropocene: Comparing Its Meaning in Geology (Chronostratigraphy) with Conceptual Approaches Arising in Other Disciplines Jan Zalasiewicz , Colin N. Waters , Erle C. Ellis , Martin J. Head , Davor Vidas , Will Steffen, Julia Adeney Thomas, Eva Horn, Colin P. Summerhayes , Reinhold Leinfelder , J. R. McNeill, Agnieszka Gałuszka , Mark Williams, Anthony D. Barnosky , Daniel de B. Richter, Philip L. Gibbard , Jaia Syvitski , Catherine Jeandel , Alejandro Cearreta , Andrew B. Cundy , Ian J. Fairchild , Neil L. Rose , Juliana A. Ivar do Sul , William Shotyk, Simon Turner , Michael Wagreich , and Jens Zinke Geography, Geology and the Environment, University of Leicester, Leicester, UK, Geography & Environmental Systems, University of Maryland, Baltimore, MD, USA, Earth Sciences, Brock University, St. Catharines, ON, Canada, The Fridtjof Nansen Institute, Lysaker, Norway, Fenner School of Environment and Society, The Australian National University, Canberra, Australia, History, University of Notre Dame, South Bend, IN, USA, German Studies, University of Vienna, Vienna, Austria, Scott Polar Research Institute, University of Cambridge, Cambridge, UK, Geological Sciences, Freie Universität, Berlin, Germany, Department of History, Georgetown University, Washington, DC, USA, Institute of Chemistry, Jan Kochanowski University, Kielce, Poland, Jasper Ridge Biological Preserve and Department of Biology, Stanford University, Stanford, CA, USA, Nicholas School of the Environment, Duke University, Durham, NC, USA, Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA, LEGOS, Université de Toulouse, CNES, CNRS, IRD, Toulouse, France, Geología, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Bilbao, Spain, Ocean and Earth Science, University of Southampton, National Oceanography Centre (Southampton), Southampton, UK, School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK, Geography, University College London, London, UK, Leibniz Institute for Baltic Sea Research Warnemüende (IOW), Rostock, Germany, Renewable Resources, University of Alberta, Edmonton, AB, Canada, Geology, University of Vienna, Vienna, Austria Key Points: • The Anthropocene concept developed in the Earth System science community is closely consistent with its proposed chronostratigraphic (geological) definition • A wide range of other meanings of the Anthropocene subsequently emerged that represent inherently valid, but partly different, concepts • Cross-disciplinary discussion is encouraged to help resolve issues of meaning and communication in this important area

The Anthropocene: comparing its meaning in geology (chronostratigraphy) with conceptual approaches arising in other disciplines

With growth of the Canadian oil sands industry, concerns have been raised about possible seepage of toxic oil sands process-affected water (OSPW) into the Athabasca River (AR). A sampling campaign in fall 2015 was undertaken to monitor for anthropogenic seepage while also considering natural sources. Naphthenic acids (NAs) and thousands of bitumen-derived organics were characterized in surface water, groundwater, and OSPW using a highly sensitive online solid phase extraction-HPLC-Orbitrap method. Elevated NA concentrations and bitumen-derived organics were detected in McLean Creek (30.1 μg/L) and Beaver Creek (190 μg/L), two tributaries that are physically impacted by tailings structures. This was suggestive of OSPW seepage, but conclusive differentiation of anthropogenic and natural sources remained difficult. High NA concentrations and bitumen-derived organics were also observed in natural water located far north of the industry, including exceedingly high concentrations in AR groundwater (A5w-GW, 2000...

Characterization of Naphthenic Acids and Other Dissolved Organics in Natural Water from the Athabasca Oil Sands Region, Canada.

The mining and processing of the Athabasca oil sands (Alberta, Canada) has been occurring for decades; however, a lack of consistent regional monitoring has obscured the long-term environmental impact. Here, we present sediment core results to reconstruct spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region. Early mining operations (during the 1970s and 1980s) led to elevated V and Pb inputs to lakes located <50 km from mining operations. Subsequent improvements to mining and upgrading technologies since the 1980s have reduced V and Pb loading to near background levels at many sites. In contrast, Hg deposition increased by a factor of ~3 to all 20 lakes over the 20th century, reflecting global-scale patterns in atmospheric Hg emissions. Base cation deposition (from fugitive dust emissions) has not measurably impacted regional lake sediments. Instead, results from a principal components analysis suggest that the presence of carbonate bedrock underlying lakes located close to development appears to exert a first-order control over lake sediment base cation concentrations and overall lake sediment geochemical composition. Trace element concentrations generally did not exceed Canadian sediment quality guidelines, and no spatial or temporal trends were observed in the frequency of guideline exceedence. Our results demonstrate that early mining efforts had an even greater impact on trace element cycling than has been appreciated previously, placing recent monitoring efforts in a critical long-term context.

https://iopscience.iop.org/article/10.1088/1748-9326/aa9505/pdf

Spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region (Alberta, Canada)

Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the Athabasca Bituminous Sands, the largest reservoir of bitumen in the world. Frozen cores were sectioned into 1 cm slices, and trace metals determined in the ultraclean SWAMP lab using ICP-QMS. The uppermost sections of the cores were age-dated with 210Pb using ultralow background gamma spectrometry, and selected plant macrofossils dated using 14C. At each site, trace metal concentrations as well as enrichment factors (calculated relative to the corresponding element/Th ratio of the Upper Continental Crust) reveal maximum values 10 to 40 cm below the surface which shows that the zenith of atmospheric contamination occurred in the past. The age-depth relationships show that atmospheric contamination by trace metals (Ag, Cd, Sb, Tl, but also V, Ni, and Mo which are enriched in bitumen) has been declining in northern Alberta for decades. In fact, the greatest contemporary enrichments of Ag, Cd, Sb, and Tl (in the to...

Peat bogs document decades of declining atmospheric contamination by trace metals in the Athabasca Bituminous Sands region

Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmospheric deposition of Pb, a valuable tracer of human activities. In each profile, the maximum Pb enrichment is found well below the surface. Radiometric age dating using three independent approaches (14C measurements of plant macrofossils combined with the atmospheric bomb pulse curve, plus 210Pb confirmed using the fallout radionuclides 137Cs and 241Am) showed that Pb contamination has been in decline for decades. Today, the surface layers of these bogs are comparable in composition to the “cleanest” peat samples ever found in the Northern Hemisphere, from a Swiss bog ~ 6000 to 9000 years old. The lack of contemporary Pb contamination in the Alberta bogs is testimony to successful international efforts of the past decades to reduce anthropogenic emissions of this potentially toxic metal to the atmosphere.

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Bob Shannon

Papers

Peat bogs document decades of declining atmospheric contamination by trace metals in the Athabasca Bituminous Sands region

Peat bogs in northern Alberta, Canada reveal decades of declining atmospheric Pb contamination

High-resolution age modelling of peat bogs from northern Alberta, Canada, using pre- and post-bomb 14C, 210Pb and historical cryptotephra