IODP Expedition 377: Arctic Ocean Paleoceanography (ArcOP) - Toward a
Continuous Cenozoic Record from a Greenhouse to an Icehouse Earth
Abstract
Investigations of both short-term natural climate variability, and
long-term, large-scale changes in climate state are advanced by
scientific ocean drilling at globally-distributed locations. Despite its
global importance as both a contributor to climate change and a region
that is most affected by global warming, the Arctic Ocean is the last
major region on Earth where the long-term climate history remains poorly
known. While many major advances in understanding were achieved in 2004
with the successful completion of IODP Expedition 302: Arctic Coring
Expedition (ACEX), the record was hampered by generally poor recovery
and by a 26-myr hiatus (or condensed interval depending on the age
model) spanning the global transition from the Greenhouse to Icehouse
climate states. In August-September 2022, IODP Expedition 377: Arctic
Ocean Paleoceanography (ArcOP) will enable another step in
reconstructing the detailed history of climate change in the Arctic over
the last 50+ million years. The overall goal of the ArcOP drilling
campaign is the recovery of a complete stratigraphic sedimentary record
on the southern Lomonosov Ridge to meet the highest priority
paleoceanographic objective: the continuous long-term Cenozoic climate
history of the central Arctic Ocean. Key scientific themes to be
addressed by ArcOP are represented in Figure 1. The expedition goals can
be achieved through 1) careful site selection, 2) the use of appropriate
drilling technology and ice management supported by two ice breakers,
and 3) applying multi-proxy approaches to paleoceanographic,
paleoclimatic, and age-model reconstructions. The expedition will
complete one primary deep drill hole (LR-11B) to 900 meters below
seafloor (mbsf; twice as deep as the ACEX core depth). This will be
supplemented by a short drill site (LR-10B) to 50 mbsf, to recover an
undisturbed Quaternary sedimentary section to ensure complete recovery
for construction of a composite section spanning the full age range
through the Cenozoic. Expected sedimentation rates two to four times
higher than those of ACEX will permit higher-resolution studies of
Arctic climate change. More information on ArcOP can be found at the
expedition website: https://www.ecord.org/expedition377/.