Upper Miocene magnetic stratigraphy at ODP site 1092 (sub-Antarctic South Atlantic): recognition of 'cryptochrons' in C5n.2n

U-channel samples from ODP site 1092 in the sub-Antarctic South Atlantic Ocean provide an interpretable magnetic stratigraphy from 1.95 to ∼3.6 Ma and from ∼5.9 to 13.5 Ma. Although the interpretation is unclear within the Gilbert Chron (C3), the record represents one of the more complete Upper Mioc...

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Bibliographic Details
Published in:Geophysical Journal International
Main Authors: Evans, Helen F., Channell, James E. T.
Format: Text
Language:English
Published: Oxford University Press 2003
Subjects:
Online Access:http://gji.oxfordjournals.org/cgi/content/short/153/2/483
https://doi.org/10.1046/j.1365-246X.2003.01916.x
Description
Summary:U-channel samples from ODP site 1092 in the sub-Antarctic South Atlantic Ocean provide an interpretable magnetic stratigraphy from 1.95 to ∼3.6 Ma and from ∼5.9 to 13.5 Ma. Although the interpretation is unclear within the Gilbert Chron (C3), the record represents one of the more complete Upper Miocene polarity stratigraphies from the South Atlantic. Eight polarity subchrons that are not included in the standard polarity timescale are identified. Polarity subchron C4r.2r contains a normal-polarity interval that has also been identified in sediments from ODP leg 138. Three short subchrons are recorded within C4n.2n, C5r.3r and C5AAr. The record of C5n.2n contains four short reverse-polarity subchrons of durations estimated to be 3–6 kyr.