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The Great Acceleration and the Disappearing
Surficial Geologic Record

Jason A. Rech, Department of Geology and Environmental Earth Science, Miami University, Oxford, Ohio 45056, USA; Kathleen B.
Springer and Jeffrey S. Pigati, U.S. Geological Survey, Denver Federal Center, Box 25046, MS-980, Denver, Colorado 80225, USA

The surficial geologic record is the rela-
tively thin veneer of young (<~1 Ma) and
mostly unconsolidated sediments that
cover portions of Earth’s terrestrial surface
(Fig. 1). Once largely ignored as “overbur-
den” by geologists, surficial deposits are
now studied to address a wide range of
issues related to the sustainability of
human societies. Geologists use surficial
deposits to determine the frequency and
severity of past climatic changes, quantify
natural and anthropogenic erosion rates,
identify hazards, and calculate recurrence
intervals associated with earthquakes,
landslides, tsunamis, and volcanic erup-
tions. Increasingly, however, humans are
eradicating the surficial geologic record in
many key areas through progressive modi-
fication of Earth’s surface.

IMPORTANCE OF THE SURFICIAL Figure 1. Surficial geologic deposits (late Pleistocene wetland deposits) in Wadi Hasa, Jordan, being
GEOLOGIC RECORD described and sampled. These deposits are being lost rapidly to agriculture and disturbance from
animal husbandry and human dwellings.
Do we as a society really need to study
high-resolution climate and environmental contain evidence of past geohazards, such as The original Great Acceleration graphs,
records that are preserved in the surficial earthquakes and volcanic eruptions, which developed by the International Geosphere-
geologic record? The short answer is a allow scientists to quantify the magnitude Biosphere Programme (IGBP), displayed
resounding “yes!” Most highly resolved and locations of the most recent events for a changes in socio-economic data (popula-
records of past environmental change given area. This information is a critical tion, gross domestic product [GDP], tele-
come from marine sediments and ice component of geologic hazard assessments, communications) relative to changes in
cores, or from specific localities on land, and the quality of such assessments is a Earth systems (atmospheric gas concentra-
such as lake sediments, loess (dust deposits), direct reflection of the quality of the surfi- tions, surface temperature, tropical forest
speleothems (cave deposits), and recently, cial record available for study. loss, domesticated land, etc.) from 1750
desert wetlands (springs in arid environ- until 2000 A.D. (Steffen et al., 2004). The
ments). These archives have provided THE GREAT ACCELERATION increase ca. 1950 in most of the parameters
detailed accounts of how Earth’s systems has been attributed to the growing impact
responded to past changes in climate and The term Great Acceleration is used to of human societies on Earth’s systems, and
help us understand how they may change describe a group of data that documents the has been used to demark the initiation of
in the future. increasing pressure that human society has the Anthropocene (Zalasiewicz et al.,
had on Earth systems (Steffen et al., 2015).
Planning for long-term sustainability
also requires an understanding of potential
geologic hazards. Surficial geologic records

GSA Today, v. 28, doi: 10.1130/GSATG341GW.1. Copyright 2017, The Geological Society of America.

8 GSA Today | November 2017