Jan Zalasiewicz

Profound changes to the species configuration of ecosystems globally during the 19th to 21st centuries, resulting from the introduction of neobiota, have produced a distinctive palaeontological signature in sedimentary deposits, here exemplified by those of the River Thames. Coring near Teddington Lock (ca. 4.3 m above sea level, ca. 89 km upstream from the mouth of the Thames estuary) yielded dense assemblages of shells of the invasive Asian clam Corbicula fluminea (recently invaded in 2004) and the zebra mussel Dreissena polymorpha (invaded 1824), which together accounted for 96% of individuals sampled. Population densities of C. fluminea of over 6000 individuals per m² were maintained for a depth of 1 m indicating that the Asian clam is an important biostratigraphical marker in the Thames for sedimentary deposits accumulating since 2004. The first modern European occurrence of C. fluminea was in Portugal in 1980. In 1987, the first occurrence of C. fluminea on the northern coast of South America was observed in the Caripe River, Venezuela. The non‐native range of D. polymorpha was restricted to continental Europe for over 200 years until it appeared in the Great Lakes, USA, in 1986 having been transported in ballast water. Within three years, it reached populations of over 750,000 individuals per m² and it is presently recorded in 35 states. Therefore, the pan‐Atlantic range expansion of D. polymorpha, coupled with the recent invasion history of C. fluminea in Venezuela and Portugal, identifies a biostratigraphical interval in sedimentary deposits forming from the early 1980s that can be correlated between Europe and the Americas.

Gothograptid retiolitines were distinctive in being one of the very few graptolite groups to thrive through the late Wenlock extinction event that killed off most graptoloid species, and their distinctive construction may have been a factor in this success amid environmental adversity. New and rich material from two localities in Poland and five localities in Lithuania contains Gothograptus nassa, Gothograptus obtectus and four new species. The detailed morphology and reconstruction of the tubarium shows its specific features, different from other lundgreni Biozone retiolitines. The tubarium is narrow, elongated, finite, massive and compact. The thecal orifices are hidden by simple hoods or by extraordinary reticulated veils, which may cover the ventral walls. The colonies of Gothograptus species from the lundgreni Biozone are short, usually having eight pairs of thecae, whereas species from the post-lundgreni interval may reach more than 20 pairs of thecae. A common feature of Gothograptus species is the presence of singular genicular structures tightly covering thecal orifices. Reticulated hoods and veils are characteristic of species from the lundgreni Biozone. The most common such structures are nassa hoods, located on the proximal thecae in some species from the lundgreni Biozone, and on every theca of post-lundgreni species. Only Gothograptus domeyki n. sp. has no genicular processes on most thecae. Within a total of four species from the lundgreni Biozone and three species from the nassa and praedeubeli Biozones, we describe here the new species Gothograptus domeyki and Gothograptus velo from the lundgreni Biozone, Gothograptus diminutus from the parvus/nassa Biozone, and Gothograptus auriculatus from the dubius/nassa and praedeubeli biozones; G. auriculatus n. sp. is the youngest form of the genus Gothograptus. Variation within the genus Gothograptus during the post-lundgreni interval period is shown for the first time.

The Anthropocene concept arose within the Earth System science (ESS) community, albeit explicitly as a geological (stratigraphical) time term. Its current analysis by the stratigraphical community, as a potential formal addition to the Geological Time Scale, necessitates comparison of the methodologies and patterns of enquiry of these two communities. One means of comparison is to consider some of the most widely used results of the ESS, the ‘planetary boundaries’ concept of Rockström and colleagues, and the ‘Great Acceleration’ graphs of Steffen and colleagues, in terms of their stratigraphical expression. This expression varies from virtually non-existent (stratospheric ozone depletion) to pronounced and many-faceted (primary energy use), while in some cases stratigraphical proxies may help constrain anthropogenic process (atmospheric aerosol loading). The Anthropocene concepts of the ESS and stratigraphy emerge as complementary, and effective stratigraphic definition should facilitate wider transdisciplinary communication.

We assess the scale and extent of the physical technosphere, defined here as the summed material output of the contemporary human enterprise. It includes active urban, agricultural and marine components, used to sustain energy and material flow for current human life, and a growing residue layer, currently only in small part recycled back into the active component. Preliminary estimates suggest a technosphere mass of approximately 30 trillion tonnes (Tt), which helps support a human biomass that, despite recent growth, is ~5 orders of magnitude smaller. The physical technosphere includes a large, rapidly growing diversity of complex objects that are potential trace fossils or ‘technofossils’. If assessed on palaeontological criteria, technofossil diversity already exceeds known estimates of biological diversity as measured by richness, far exceeds recognized fossil diversity, and may exceed total biological diversity through Earth’s history. The rapid transformation of much of Earth’s surface mass into the technosphere and its myriad components underscores the novelty of the current planetary transformation.

It is useful to have Todd Braje's perspective on the Anthropocene. As he states, it is a concept that has spread widely and that has had various interpretations (within not just the sciences, but the arts and humanities too) in the 15 years since Paul Crutzen and Eugene Stoermer proposed the term (Crutzen & Stoermer 2000). Various suggestions are made in Braje's paper: perhaps foremost is that the Anthropocene should be retained as a loosely defined term to focus on the nature and effect of human activities, to be a ‘rallying cry’ for better planetary stewardship. He suggests, indeed, that precise characterisation and formalisation as a stratigraphic unit may hinder such use, causing (for instance) all humans—rather than specific socio-economic groups—to be held equally responsible for the degradation of planetary systems.

As humans have colonised and modified the Earth’s surface, they have developed progressively more sophisticated tools and technologies. These underpin a new kind of stratigraphy, that we term technostratigraphy, marked by the geologically accelerated evolution and diversification of technofossils – the preservable material remains of the technosphere (Haff, 2013), driven by human purpose and transmitted cultural memory, and with the dynamics of an emergent system. The technosphere, present in some form for most of the Quaternary, shows several thresholds. Its expansion and transcontinental synchronisation in the mid 20th century has produced a global technostratigraphy that combines very high time-resolution, great geometrical complexity and wide (including transplanetary) extent. Technostratigraphy can help characterise the deposits of a potential Anthropocene Epoch and its emergence marks a step change in planetary mode.