|
|||||
|
|
Thellier palaeointensity experiments on Faroes flood basalts: technical aspects and geomagnetic implications |
|
| Authors: | Peter Riisager Janna Riisager Niels AbrahamsenRegin Waagstein |
| Institution: | a Danish Lithosphere Centre, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark b Earth Sciences Department, University of California at Santa Cruz, Santa Cruz, CA 95064, USA c Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark d Geophysical Laboratory, Aarhus University, Finlandsgade 8, DK-8200 Aarhus N, Denmark e Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen NV, Denmark |
| Abstract: | Based on palaeomagnetic and rock magnetic results, 108 samples from 27 flows from Palaeogene flood basalts of Faroe Islands were chosen for whole-rock Thellier palaeointensity experiments. Altogether 90 samples were rejected due to either chemical alterations or typical multidomain (MD) behaviour evidenced by pTRM-tails. AF pre-treatment was used to reduce the effect of MD grains on Thellier experiments. Only five flows (18 samples) yielded acceptable palaeointensity estimates, with flow mean VDMs ranging from 3.5 to 7.4×1022 A m2. Modest selection criteria imposed on all published 5-160 Ma palaeointensity data left only 15 palaeomagnetic dipole moments: eight from whole-rock samples, six from submarine basaltic glass and one from single plagioclase crystals. More data are needed before the intriguing differences between results from different materials can be put into a geomagnetic context. |
| Keywords: | Palaeointensity Thellier method Faroe Islands Palaeogene |
| 本文献已被 ScienceDirect 等数据库收录！ | |