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working group in 2009 to consider these questions. Since then,
discussion of the Anthropocene has been extensive, with articles
in both scientific publications and the public media, as well as in
the greater academic sphere, including the social sciences and the
legal community.
Summaries of anthropogenic changes to the Earth system and
their occurrence in the stratigraphic record can be found in
Zalasiewicz et al. (2008, 2011) and Waters et al. (2014a, 2014b).
That stratigraphic record is negligible (Walker et al., 2015), espe-
cially with a boundary set at 1945, as recently proposed by the
Anthropocene working group (Zalasiewicz et al., 2015). Most of
the stratigraphic records mentioned are potential records that
might appear in the future; they are based on predictions. Human
structures, excavations, boreholes, bioturbation of soils (agricul-
ture) and the sea floor (drag net fishing) are not strata. Made
ground, refuse piles, mine dumps, and leach pads are made by
humans rather than by natural sedimentation. The strata with
records of anthropogenic change are speleothems, ice cores, and
non-lithified sediments of rivers, marshes, lakes, coasts, and the
ocean floor. In most of these depositional settings, it would be
difficult to distinguish the upper few centimeters of sediment
from the underlying Holocene, or sediment that has accumulated
versus that that is in transit. Published logs with geochemical
signatures of human impact are at most a few tens of centimeters
thick (Nozaki et al., 1978; Al-Rousan et al., 2004; Marshall et al.,
2007). Locating a boundary at 1945 would be difficult for anthro-
pogenic isotope shifts in greenhouse gases that have been rising
for 100 years or more (Wolff, 2014).
DEFINING THE ANTHROPOCENE BY ITS BASE (GSSP) OR
BEGINNING (GSSA)
The Anthropocene working group has focused on defining the
base or beginning of the Anthropocene, and several recent proposals
have been published (e.g., Lewis and Maslin, 2015). That of
Zalasiewicz et al. (2015), co-authored with 25 other members of the
Anthropocene working group, sets a GSSA (Global Standard
Stratigraphic Age) for the Anthropocene as 1945, the year of the first Permian in 1840 to recognize the beginning of both the Triassic
nuclear bomb explosion. Regrettably, focusing on the definition of
the beginning of the Anthropocene can result in the lack of consid-
eration of its stratigraphic content and its concept. It conveys the
opinion that units of the geologic time scale are defined solely by
their beginnings, rather than their content.
Zalasiewicz et al. (2004, p. 1) argued that the distinction
between chronostratigraphic and geochronologic units is no
longer necessary because of the widespread adoption of GSSPs “in
defining intervals of geologic time within rock strata.” Because
GSSPs are placed at stratigraphic horizons that also represent
specific points in time, two successive GSSPs define an interval of
time that is a geochronologic unit (period, epoch, age), and all
strata interpreted as deposited during that interval of time would
comprise the corresponding chronostratigraphic unit (system,
series, stage). The difference between this concept and that
espoused in the International Stratigraphic Guide (Salvador,
1994)—that chronostratigraphic units and their boundaries serve
to define corresponding geochronologic units—is subtle, yet
important. It is stratigraphic content that allows for the recogni-
tion and correlation of a chronostratigraphic unit. Most correla-
tions are made within units and not to their boundaries. The
GSSP serves to set a limit on the stratigraphic content of a unit; it GSA TODAY | www.geosociety.org/gsatoday
defines a boundary, not a unit. Formal systems, series, and stages
have been recognized since 1881, yet the first GSSP was not ratified
until 1972. Obviously, chronostratigraphic units and their corre-
sponding geochronologic units were used long before there were
GSSPs. The International Stratigraphic Guide (Salvador, 1994)
provides specific criteria for definition of chronostratigraphic units,
but it provides no guidelines whatsoever for defining geochronologic
units other than the intervals of time represented by the corre-
sponding chronostratigraphic units. Furthermore, the guide
discusses GSSPs only with regard to defining boundaries of chro-
nostratigraphic units and not to defining beginnings or ends of
geochronologic units. For these reasons, the concept and definition
of chronostratigraphic units of Zalasiewicz et al. (2004), which are
further presented in Zalasiewicz et al. (2008, 2011, 2015), are not
consistent with the history of these units nor with the International
Stratigraphic Guide.
The lower boundary of the Cretaceous System is not yet defined
by a GSSP, and neither are the Lower Cretaceous Series and its
constituent stages (Berriasian, Valanginian, Hauterivian,
Barremian, Aptian, and Albian). Nevertheless, these are tradi-
tional units of the ICS Chart and thus are units of the geologic
time scale. They have content. They can be correlated into strati-
graphic successions worldwide. They have long been used world-
wide. Their deficiency is that limits have not been formally set for
their stratigraphic content. At an ICS workshop in 2010, the
proposal of Zalasiewicz et al. (2004) was considered at length and
rejected unanimously by the ICS voting members, who considered
the distinction as unnecessary and obvious. It is of concern that
this rejected concept is being followed by the Anthropocene
working group and promoted in both scientific and public media.
The focus of proponents on the beginning of the Anthropocene
has led to a misrepresentation by the leaders of the working group
in the lead article (Waters et al., 2014b) of A Stratigraphical Basis
for the Anthropocene (Waters et al., 2014a). The second paragraph
states, “J. Phillips used the major mass extinction at the end of the
Period and of the Mesozoic Era.” This statement is false. The
Triassic was established in 1837, and Phillips (1840) focused on the
term Palaeozoic. The term Mesozoic was used only once in a list
contained within parentheses. In 1841, Phillips mentioned the
Mesozoic only in one sentence:
The lower of these …, the Magnesian Limestone formation,
contains corals, brachiopoda, and fishes, so extremely
similar in detail or analogous in their general history to the
corresponding forms of the mountain-limestone, that it is
impossible in any fair classification to sever this group of fossils
from the Palæozoic series; while, on the other hand,
the upper of the two formations, the Red-Sandstone
and Keuper series, presents almost no resemblance to the
older, but a decided analogy to the newer, or, as we wish
to call it, Mesozoic series of the Oolites. (Phillips, 1841, p. 355)
Later, in his book Life on Earth: Its Origin and Succession,
Phillips (1860, p. 64) described the prevalent fauna in each system
as rising to a maximum and dying away to a final minimum to be
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