![]() ![]() This is because change is usually diachronous, unfolding at different moments and at different rates in different places. Even less consistent is evidence for establishing – through radiometric dating – uniform time boundaries between the layers. ![]() The difficulty for geologists is that there is very little uniformity in fossil layers in the rock. What constitutes a stratigraphic boundary is primarily the ‘sudden’ appearance or disappearance of a particular type of fossil: the carboniferous period, for example, is characterised by the appearance of coal 360 million years ago. This last will have trouble making the grade: an anthropogenic effect tied to one locale is very different to an epoch-defining global marker. Originating in different scholarly papers, yet widely touted by the media, these are: 16 July 1945 (the first nuclear explosion, proposed by the AWG itself) a much earlier date of 1610 (marked by a dip in CO2 that can be detected in an ice core in Antarctica, and representing the time that forests overtook agricultural land after 50 million people in the Americas perished with the arrival of Europeans) and even ca.100,000 years ago, by which time a thick ‘carpet’ of stone tools had accumulated on an escarpment in Libya, evidence of massive scale lithic industry by early hominids that changed the landscape seemingly forever. This year so far three candidate start dates have been proposed for the Anthropocene. Never mind that the most acute symptoms of the Anthropocene kicked in only around 70 years ago – less than a blink in geological terms – the AWG is going all-out in its global search, from the desert of New Mexico to glacial lakes in Norway, to establish a stratigraphic basis for the human epoch. It styles humans as a geological force, as powerful as any ‘natural’ one (we move more material than all natural processes combined, including river and ocean sedimentation), and acknowledges that we have re-engineered all the Earth systems, notably the carbon dioxide and nitrogen cycles, leaving a poisonous crust for far-future civilisations to excavate and ponder.Īt the same moment that the Holocene’s golden spike was driven into Greenland’s ice-core in 2009, the Anthropocene Working Group (AWG) – consisting of a few dozen geologists and other interested parties – began searching for the next spike, to identify the point when humans became a global geological force. We simply can’t wait to declare a new epoch.Ĭonceived in its current form by the Dutch chemist and Nobel Prize-winner Paul Crutzen and the American biologist Eugene F Stoermer in 2000, and developed by Crutzen and colleagues in a landmark 2007 paper, the Anthropocene is a neologism that attempts to pin down a lot of free-floating anxiety about climate change and the myriad ways that Homo sapiens are making over the planet in our own image. As a proposition, the Anthropocene is so compelling (featuring on the covers of The Economist, The Guardian, Le Monde and Der Spiegel), and apparently so urgent (can a word save the world?) that it is forcing the geological hierarchy to speed up its glacial procedures. The next marker in rock-time, but one yet to earn its golden spike, is the Anthropocene – aka us. It can take decades to find a suitable spot on the planet in which to plant it, one where the change in the rock is irrefutable. Since the system was introduced in the 1970s, a golden spike has become the holy grail of stratigraphy. It is ceremoniously driven into a rock face (or ice core) between two types of strata and, by extrapolation, two different epochs. And that hardening is represented by the GSSP.Ī valedictory piece of metal, the ‘golden spike’ is awarded by the International Commission of Stratigraphy. ![]() The science, and the bureaucracy, of geology takes after its subject matter in the enormous stretches of time required (176 years for the Holocene) for ideas to bed down in the discipline’s conceptual sediment and then harden into universally accepted facts. But it would be another 84 years before the term was endorsed by the US Commission on Stratigraphic Nomenclature in 1969, and only in 2009 was the Holocene awarded its very own Geological Stratigraphic Section and Point (GSSP) – or ‘golden spike’ – located in an ice core 1,492 metres below the surface of Greenland. French paleontologist Paul Gervais dubbed it the Holocene in 1867, a name which was formalised at the Third International Geological Congress in Bologna in 1885. The geological epoch we currently inhabit – the ‘wholly recent’ period since the last ice age – was first mooted in 1833 by the English geologist Charles Lyell to encompass the time during which Earth had been ‘tenanted by man’. ![]()
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