TY - JOUR
T1 - New paleomagnetic pole and magnetostratigraphy of Faroe Islands flood volcanics, North Atlantic igneous province
AU - Riisager, Peter
AU - Riisager, Janna
AU - Abrahamsen, Niels
AU - Waagstein, Regin
N1 - Funding Information:
The Danish National Research Foundation (P.R.) and the Carlsberg Foundation (J.R.) funded this work. The Inge Lehmann Foundation supported fieldwork in 1997 in the Faroe Islands. In our analysis we used software of Mireille Perrin, Phillip McFadden, Lisa Tauxe, Trond Torsvik and Mark Smethurst. We wish to thank the rock- and paleomagnetic laboratories in Lund (Sweden) and Montpellier (France) for offering laboratory facilities. We are grateful to Rory Cottrell and an anonymous referee for their constructive comments on the original manuscript. [RV]
PY - 2002/7/30
Y1 - 2002/7/30
N2 - A paleomagnetic sampling was carried out along four sections (altogether 86 lava flows, 548 samples) in the North Atlantic Igneous Province outcropping in Faroe Islands, Denmark. The four polarity zones in the 700-m-thick exposed part of the Faroes lower formation can be correlated with the geomagnetic polarity time scale as C26n-C25r-C25n-C24r. The seven lava flows erupted during C25n indicate a very low eruption rate in the upper part of the Faroes lower formation of ~ 1/70 kyr. The Faroes middle and upper formations (composite thickness ~ 2300 m) are all reversely magnetized corresponding to C24r. The eruption rate at the onset of middle formation volcanism was very high as evidenced by several thick lava sequences recording essentially spot readings of the paleomagnetic field. The shift in eruption rate between the Faroes lower and middle formations and evidence that onset of the Faroes middle formation volcanism took place in C24r are of particular importance, placing onset of middle formation volcanism in close temporal relation to North Atlantic continental break-up and the late Paleocene thermal maximum. After grouping flows recording the same field directions, we obtained 43 independent readings of the paleomagnetic field, yielding a paleomagnetic pole with coordinates 71.4°N, 154.7°E (A
95 = 6.0°, K = 14, N = 43); age 55-58 Ma. The pole is supported by a positive reversal test. Paleosecular variation, estimated as the angular standard deviation of the virtual geomagnetic pole distribution 21.7°+3.9°/-2.8°, is close to expected for the given age and paleolatitude. Our new Faroes paleomagnetic pole is statistically different from the majority of previously published poles from the British and Faroes igneous provinces, and we suggest that these older data should be used with care.
AB - A paleomagnetic sampling was carried out along four sections (altogether 86 lava flows, 548 samples) in the North Atlantic Igneous Province outcropping in Faroe Islands, Denmark. The four polarity zones in the 700-m-thick exposed part of the Faroes lower formation can be correlated with the geomagnetic polarity time scale as C26n-C25r-C25n-C24r. The seven lava flows erupted during C25n indicate a very low eruption rate in the upper part of the Faroes lower formation of ~ 1/70 kyr. The Faroes middle and upper formations (composite thickness ~ 2300 m) are all reversely magnetized corresponding to C24r. The eruption rate at the onset of middle formation volcanism was very high as evidenced by several thick lava sequences recording essentially spot readings of the paleomagnetic field. The shift in eruption rate between the Faroes lower and middle formations and evidence that onset of the Faroes middle formation volcanism took place in C24r are of particular importance, placing onset of middle formation volcanism in close temporal relation to North Atlantic continental break-up and the late Paleocene thermal maximum. After grouping flows recording the same field directions, we obtained 43 independent readings of the paleomagnetic field, yielding a paleomagnetic pole with coordinates 71.4°N, 154.7°E (A
95 = 6.0°, K = 14, N = 43); age 55-58 Ma. The pole is supported by a positive reversal test. Paleosecular variation, estimated as the angular standard deviation of the virtual geomagnetic pole distribution 21.7°+3.9°/-2.8°, is close to expected for the given age and paleolatitude. Our new Faroes paleomagnetic pole is statistically different from the majority of previously published poles from the British and Faroes igneous provinces, and we suggest that these older data should be used with care.
KW - Faeroe islands
KW - Magnetostratigraphy
KW - North atlantic
KW - Paleogene
KW - Paleomagnetism
UR - http://www.scopus.com/inward/record.url?scp=0036057890&partnerID=8YFLogxK
U2 - 10.1016/S0012-821X(02)00720-3
DO - 10.1016/S0012-821X(02)00720-3
M3 - Article
SN - 0012-821X
VL - 201
SP - 261
EP - 276
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 2
ER -