Auxiliary material for Paper 2009GL040984


Origin of the smooth zone in early Cretaceous North Atlantic magnetic anomalies

Masako Tominaga 
Department of Oceanography, Texas A&M University, College Station, Texas, USA

Now at Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

William W. Sager
Department of Oceanography, Texas A&M University, College Station, Texas, USA


Tominaga, M., and W. W. Sager (2009), Origin of the smooth zone in early Cretaceous North Atlantic magnetic anomalies, Geophys. Res. Lett., 36, L01304, doi:10.1029/2009GL040984.
	

Introduction

Auxiliary material for this article contains data used to build polarity sequences, flow chart of calculation method used in this study, and example of 
transition widths in polarity reversal modeling.
	

2009gl040984-fs01.jpg 
Figure S1. Data used in this study and calculation procedure.
All the calculations were carried out by using Matlab scripts by M. Tominaga 
based on the inversion and forward modeling procedures described in Parker and 
Huestis (1974). To match transition zones between observed and calculated 
anomalies, we used the Gaussian filtering technique. More details are in 
Figure S2.

Method here is used in:
Tominaga, M., and W. W. Sager, Revised Pacific M-anomaly Geomagnetic Polarity 
Time Scale, in revision, submitted to Geophys. Journ. Int.  

2009gl040984-ts01.txt
Table S1. Normalized polarity sequences.
These sequences are the results of the compilation of many profiles. For 
Keathley, NGDC lines used in this study are 0910001, 03030005TAG71, and 
03030015TAG70. For Canary, NGDC lines used in this study are 03030005TAG71, and 
03030015TAG70.

For Pacific composite model, NGDC lines used in Tominaga and Sager (in revision, 
submitted to Geophys. Journ. Int.) are 1030095, 3040053, 3040057, 15040233, 
1030193, 1030243, 8010069, 1010094, 1030055, 1030073, 3040053, 15050030, 
9030026, 1010074, 1010167, 1030193, 1030195, 1030211, 15010075, 15060015, 
15050089, 15050018, 15060015, J2010012, J2010018, J2010019, J2010022, J2010023, 
J2010024, 1010060, 1030195, 15080020, 1030215, 1030139, 15040185, 15040031, and 
1010079.

2009gl040984-fs02.jpg
Figure S2. Examples of changes in transition widths of modeled 
magnetic anomalies. Here, we changed the sigma value in the Gaussian smoothing 
filter to express transition widths in modeled magnetic anomalies. This 
presentation shows two important aspects in our magnetic anomaly analysis: (1) 
in inversion and forward modeling, to match the modeled anomalies (solid) with 
observed anomalies (dotted lines), it is clear that careful selection of the 
"best" smoothing filter is necessary, and (2) longer transition width (higher 
number in stdv =) is given, the smoother modeled anomalies become, suggesting 
a possible explanation of the smooth anomalies within the AMSZ.