Publication Date:
2015-12-17
Description:
A detailed magnetic analysis has been conducted on the borehole CJ-1 (172.3 m in length) from the Changjiang (Yangtze) River delta. Results show that the dominant magnetic carriers are magnetite and hematite. Palaeomagnetic results reveal that high-frequency changes in palaeomagnetic inclinations are tied significantly to abnormal anisotropy of magnetic susceptibility (AMS) patterns due to effects of the high-energy depositional environment in this region. On the basis of AMS patterns, doubtful palaeomagnetic directional anomalies can be distinguished from authentic palaeomagnetic excursions. Magnetostratigraphic results indicate that the Matuyama–Brunhes boundary (MBB) was recorded at a depth of ~152.5 m. The presence of several short-lived inclination anomalies implied that the sedimentation could be continuous even at the millennial timescale at certain depth intervals bracketing these fast geomagnetic events. In summary, our study provides new insights into constructing reliable magnetostratigraphy in the delta region. Moreover, our new magnetostratigraphy of the Changjiang River delta deposits will facilitate studies on the relevant long-term palaeoenvironmental evolution of the delta.
Keywords:
Geomagnetism, Rock Magnetism and Palaeomagnetism
Print ISSN:
0956-540X
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
