Publication Date:
2021-01-25
Description:
New paleomagnetic results from the late Eocene-Middle Miocene samples from Deep Sea
Drilling Project Site 274, cored during Leg 28 on the continental rise off Victoria Land, Ross
Sea, provide a chronostratigraphic framework for an existing paleoclimate archive during a
key period of Antarctic climate and ice sheet evolution. Based on this new age model, the
cored late Eocene-Middle Miocene sequence covers an interval of almost 20 Myr (from
∼35 to ∼15 Ma). Biostratigraphic constraints allow a number of possible correlations with
the Geomagnetic Polarity Time Scale. Regardless of correlation, average interval sediment
accumulation rates above 260 mbsf are ∼6 cm/kyr with the record punctuated by a
number of unconformities. Below 260 mbsf (across the Eocene/Oligocene boundary)
interval, sedimentation accumulation rates are closer to ∼1 cm/kyr. A major unconformity
identified at ∼180 mbsf represents at least 9 Myr accounting for the late Oligocene and
Early Miocene and represent non-deposition and/or erosion due to intensification of
Antarctic Circumpolar Current activity. Significant fluctuations in grain size and
magnetic properties observed above the unconformity at 180 mbsf, in the Early
Miocene portion of this sedimentary record, reflect cyclical behavior in glacial advance
and retreat from the continent. Similar glacial cyclicity has already been identified in other
Miocene sequences recovered in drill cores from the Antarctic margin.
Description:
Published
Description:
563453
Description:
5A. Ricerche polari e paleoclima
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink