Non-uniform occurrence of short-term polarity fluctuations in the geomagnetic field? New results from Middle to Late Miocene sediments of the North Atlantic (DSDP Site 608) ...
New magnetostratigraphic results from DSDP Site 608 in the North Atlantic reveal the presence of nine short-term polarity fluctuations that do not correspond to subchrons in the most recent GPTS. Comparison with published results from ODP Sites 845 and 1092, and from the continental Orera Composite...
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| Format: | Text |
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Columbia University
2004
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| Online Access: | https://dx.doi.org/10.7916/d8ft8k63 https://academiccommons.columbia.edu/doi/10.7916/D8FT8K63 |
| Summary: | New magnetostratigraphic results from DSDP Site 608 in the North Atlantic reveal the presence of nine short-term polarity fluctuations that do not correspond to subchrons in the most recent GPTS. Comparison with published results from ODP Sites 845 and 1092, and from the continental Orera Composite Section, shows that all these polarity fluctuations are observed in more than one record. At DSDP Site 608, five of the intervals are ascertained by more than two samples and have an estimated duration that is larger than 10 kyr. We regard these as polarity subchrons, which define five new short polarity intervals in the Miocene: C4r.2r-ln, C4Ar.1r-1n, C5r.2r-1n, C5r.2r-2n, and C5r.3r-1n. Three polarity fluctuations within C5n and one in C5An.2n are each only determined by one sample and are hence not unambiguous. They have an estimated duration < 10 kyr and an inconsistent expression. Consequently, we believe they qualify better as directional excursions and that they are most likely associated with decreases ... |
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