The Mertz Drift: A Paleoenvironmental Archive in East Antarctica

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The Mertz Drift: A Paleoenvironmental Archive in East Antarctica


By Susan C. Ludwick







Submitted in partial fulfillment of
the requirements for the degree of Bachelor of Arts Department of Geology Middlebury College Middlebury, Vermont




May 2002 Ludwick, Susan C., 2002, The Mertz Drift: a paleoenvironmental archive in East
Antarctica: Unpublished senior thesis, Middlebury College, Middlebury, Vermont, 90 p.
ABSTRACT The Mertz Drift, located in the Mertz-Ninnis Trough of East Antarctica, is an area of high sedimentation and contains a high-resolution sedimentary record of paleoclimatic
variability (Harris et al., 2001). This record was expanded during East Antarctic Cruise
NBP0101, February 2001, when two Jumbo Piston Cores (JPC-10, JPC-1121.24m and
23.98m respectively) were obtained from the drift. Physical property data was collected,
along with p-wave velocity and electrical resistivity data at 5cm intervals for each core.
P-wave velocity and bulk density were used to generate synthetic seismograms to draw
comparisons between the sediments and the acoustic sediment profiles. Grain size
analysis was conducted on 397 samples from JPC-10, containing an expanded sediment
record, and on 224 samples from JPC-11, containing a more condensed record with
1.06m of diamicton at the base.
These sites, verified by radiocarbon dating, contain a record of Holocene climate change. At approximately 5000 yrs BP (between 1500-1750cm core depth), there is a
change in sedimentation rate for both cores. This corresponds to a lithology change from
laminated and water saturated oozes to silty/muddy diatom oozes, according to electrical
resistivity classifications created by Burgdorff (2002). This change in deposition is
reflected in the physical properties of electrical resistivity, bulk density, porosity, and
void ratio.
JPC-11 (sampled in a condensed stratigraphic section) recovered diamicton. Diamicton is the transition facies from ice-covered to open-marine conditions. Open
marine conditions were sampled throughout JPC-10. Spectral analysis of grain size and
electrical resistivity show variability indicating productivity trends. Paleoclimatic cycles
on the scale of 200 and 75 years are documented. A climate model and forcing
mechanism is proposed to explain the variations in data. ii DEDICATION This thesis is dedicated to the three most important people in my life: To my Mom and Dad for allowing me to be headstrong and pursue my dreams while encouraging me to always give my best and to my fianc

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