The Paleomagnetism of Sediments and Sedimentary Rocks: Importance and Reliability - Paleomagnetism of Sedimentary Rocks: Process and Interpretation - page 8

Declinations

-40 0 40 -40 0 40 -40 0 40

0 0

d

e

2000 2000

f

4000 4000

g

6000 6000

h

8000 8000

i

10000 10000

12000 12000

cal BP

-40 0 40 -40 0 40 cal BP

Inclinations

40 60 80 40 60 80 40 60 80

0

0

α

β

γ

2000 2000

4000 4000

6000

6000

κ

8000 8000

λ

μ

10000 10000

12000

12000

cal BP 40 60 80 40 60 80 cal BP

SMM HZM Stack UK

MFM

Fig. 1.3 Paleosecular variation records from the sediments of three maar lakes in Germany. The declination and inclination
records of the three lakes (Schalkenmehrener Maar: SMM; Holzmaar: HZM; Meerfelder Maar: MFM) are shown with 95%
confi dence intervals drawn around them from multiple cores collected from each lake. The stack shows the data stacked from
all three lakes, compared to the master secular variation curve from the UK. H Stockhausen, Geomagnetic paleosecular
variation (0-13000 yr BP) as recorded in sediments from three maar lakes from the West Eifel (Germany), Geophysical Journal
International , 135, 898-910, 1998, John Wiley & Sons, Ltd.

(1998) stacks the PSV records from three maar lakes
in Europe and sees very good reproducibility in declina-
tion (± 2.5 ° ) and inclination ( ± 1.5 ° ) (Fig. 1.3 ). This
very low scatter and high reproducibility of the fi eld is
one reason for the detailed study of maar lake paleo-
magnetism. Maar lakes have a very quiet depositional
environment with no streams bringing in sediment
loads, thus allowing the most accurate records of the
geomagnetic fi eld (Merrill et al . 1996 ).
In their study of the secular variation recorded by
the DRM of wet sediments from Lake Pepin in the Mis-
sissippi River, Brachfeld & Banerjee (2000) compare
the Lake Pepin secular variation record to that of
nearby Lake St Croix. They report good agreement of

the inclinations with differences typically less than 5°,
but in some cases they indicate that the records
deviate by up to 10°. Brachfeld and Banerjee also
look at anhysteretic remanent magnetization (ARM)-
normalized relative paleointensity records from Lake
Pepin and compare them to both relative paleointensi-
ties from Lake St Croix and variations in absolute
paleointensity observed in the archeomagnetic data-
base for the past 3000 years. The variability between
these paleointensity records is reported as a standard
deviation of about 0.38 around a normalized mean of
unity (Brachfeld & Banerjee 2000). This is amazingly
similar to that reported by Guyodo & Valet (1996) for
S int 200. Since non-dipole effects are less likely to