Publication Date:
2016-10-10
Description:
The main purpose of cruise JR298 was to collect marine geological and geophysical
samples and data to support International Ocean Discovery Program (IODP) proposal 732-
Full2, “Sediment drifts off the Antarctic Peninsula and West Antarctica” (Channell, Larter,
Hillenbrand et al.). The ship time was allocated for this purpose on the basis of a Site Survey
Investigation grant from the NERC UK-IODP Programme (NE/J006548/1: Depositional
patterns and records in sediment drifts off the Antarctic Peninsula and West Antarctica) to
R.D. Larter, C.-D. Hillenbrand (both BAS), D.A. Hodell (University of Cambridge) and
A.G.C. Graham (University of Exeter). The data and samples collected will also be used in
two Collaborative Gearing Scheme projects, an Antarctic Science Bursary project, a
University of Cambridge PhD studentship, and within the National Capability remit of the
BAS Science Teams in “Geology and Geophysics” and “Palaeoenvironments and Climate
Change”.
These projects are:
• Tracing and reconstructing the neodymium and carbon isotopic composition of
circum-Antarctic waters (CGS-100, PI: A.M. Piotrowski, Department of Earth
Sciences, University of Cambridge; cruise participants: A.M. Piotrowski and T.J.
Williams).
• Structural characterisation of Late Quaternary sediments from West Antarctic
contourite drifts using three dimensional X-ray imaging (CT-scanning) (CGS-98, PI:
C. Ó Cofaigh, Department of Geography, Durham University; cruise participant: J.
Horrocks)
• Tracing the Quaternary evolution of the Antarctic Peninsula and West Antarctic Ice
Sheets using lead isotopes in ice-rafted feldspar mineral grains (Antarctic Science
Bursary awarded to C. Cook).
• Seismic imaging of oceanographic structures and processes in the Southern Ocean
south of the Polar Front (component of University of Cambridge/BP Institute PhD
studentship; primary supervisor: N.J. White, Department of Earth Sciences, University
of Cambridge; PhD student and cruise participant: K.L. Gunn).
• Modelling crustal structure across the Bellingshausen Gravity Anomaly and oceanic
fracture zones formed at the Antarctic-Phoenix Ridge through integration of marine
potential field and seismic data (Collaboration between two BAS Science Teams;
cruise participant: T.A.R.M. Jordan).
2
The cruise also provided support for physical oceanography projects by deploying six
Argo floats and rescuing a malfunctioning sea glider.
Towards the end of the cruise, RRS James Clark Ross was diverted to Rothera to uplift 16
personnel who had been flown across from Halley in two ALCI Basler aircraft because the
sea ice situation in the Weddell Sea was considered to pose a significant risk to the scheduled
last call of the season at Halley by RRS Ernest Shackleton. This uplift resulted in a two-day
delay to arrival at Punta Arenas at the end of the cruise, which was in addition to a two-day
extension already agreed as a result of departure from Punta Arenas having been delayed by
slow refuelling.
Adverse weather conditions, particularly during the first half of the cruise, resulted in
more downtime than the amount of contingency time that had been allowed in the proposal.
As a result, one less piston core and about 20% fewer line-km of seismic data were collected
than had been planned. Nevertheless, the key objectives were achieved and the cores and data
that were collected are of very good quality. The data and cores collected on cruise JR298,
combined with existing data and cores, should satisfy all of the requirements of the Site
Characterisation Panel and the Environmental Protection and Safety Panel of IODP. They will
also provide a good basis for addressing the science objectives set out in the UK-IODP Site
Survey Investigation proposal and those of the ancillary projects listed above.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Miscellaneous
,
notRev
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