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| Titel |
Paleomagnetic record and sediments flux since middle Miocene in the NE equatorial Pacific |
| VerfasserIn |
Wonnyon Kim, Kiseong Hyeong, Youngtak Ko, Sang-Bum Chi, Jai-Woon Moon |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094284
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| Publikation (Nr.) |
 EGU/EGU2014-9688.pdf |
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| Zusammenfassung |
| Deep-sea sediments in the Northeast equatorial Pacific have been gathered scientific interests
as a vast reservoir of manganese nodule and rare earth elements, however their
sedimentation environments through the geologic time are poorly understood. A
570 cm long sediment core was retrieved at 9°57’N and 131°42’W in 5,080 m
water depth. To identify sedimentation age and periodical difference in sediments
flux, paleomagnetic and rock-magnetic studies were carried out. Age constraints
made by a combination of 10Be and paleomagnetic measurements. Successive AF
demagnetization reveals eight times geomagnetic field reversals. In the reference
geologic time scale, the eight reversal events correspond to the age of about 4.5 Ma.
However, 10Be based age correction shows 13.4 Ma at 465 cm below seafloor (cmbsf).
In addition, calculated sedimentation rates are changed in the range of 0.1 – 2.44
mm/kyr. Since 110 cmbsf, showing sedimentation rate of about 0.1 mm/kyr, ancient
geomagnetic field reversal events of at least 1.8 Myr time span are not recorded.
Above 76 cmbsf horizon, an abrupt increase of sedimentation rate is identified to
2.44 mm/kyr. A dramatic change is also observed in the rock-magnetic properties.
Throughout a core concentration and grain-size of magnetic minerals are changed
continuously and show an upward decreasing trend, except in the sediments of 110 – 15
cmbsf. With a boundary at 76 and 75 cmbsf, lower and upper sediments contain
rock-magnetic properties of varying toward opposite. Such separation after the
lowest sediment flux (0.1 mm/kyr) is probably connected to the sedimentation hiatus. |
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