<P> The first geologic time scale that included absolute dates was published in 1913 by the British geologist Arthur Holmes . He greatly furthered the newly created discipline of geochronology and published the world - renowned book The Age of the Earth in which he estimated Earth's age to be at least 1.6 billion years . </P> <P> In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy) began to define global references known as GSSP (Global Boundary Stratotype Sections and Points) for geologic periods and faunal stages . The commission's most recent work is described in the 2004 geologic time scale of Gradstein et al . A UML model for how the timescale is structured, relating it to the GSSP, is also available . </P> <P> The term "Anthropocene" is used informally by popular culture and a growing number of scientists to describe the current epoch in which we are living . The term was coined by Paul Crutzen and Eugene Stoermer in 2000 to describe the current time, in which humans have had an enormous impact on the environment . It has evolved to describe an "epoch" starting some time in the past and on the whole defined by anthropogenic carbon emissions and production and consumption of plastic goods that are left in the ground . </P> <P> Critics of this term say that the term should not be used because it is difficult, if not nearly impossible, to define a specific time when humans started influencing the rock strata--defining the start of an epoch . Others say that humans have not even started to leave their biggest impact on Earth, and therefore the Anthropocene has not even started yet . </P>

Which of the following is not a division on the geologic time scale