Auxiliary Material for Paper 2010GC003402

Crustal thickness anomalies in the North Atlantic Ocean basin from gravity analysis

Tingting Wang 
Institute of Theoretical and Applied Geophysics, School of Earth and Space Sciences, Peking University, Beijing, China 

Jian Lin and Brian Tucholke
Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

Yongshun John Chen
Institute of Theoretical and Applied Geophysics, School of Earth and Space Sciences, Peking University, Beijing, China


Wang, T., J. Lin, B. Tucholke, and Y. J. Chen (2011), Crustal thickness anomalies in the North Atlantic Ocean basin from
gravity analysis, Geochem. Geophys. Geosyst., 12, Q0AE02, doi:10.1029/2010GC003402.

Introduction

The auxiliary material contains the comparison of the gravity effects of lithosphere cooling and MBA, the comparison of the gravity-derived 
crustal thickness with seismic refractory profiles.

1. 2010gc003402-fs01.pdf
Figure S1. Locations of 18 MBA gravity profiles (white lines) illustrated in Figure S2, plotted on a map of calculated gravity effects of lithospheric cooling.
  
2. 2010gc003402-fs02.pdf
Figure S2. Comparison of the calculated gravity effects of lithospheric cooling (red line) and MBA (black line) along the 18 profiles shown in Figure S1.

3. 2010gc003402-fs03.pdf
Figure S3. Comparison of seismic refraction profiles with our gravity-derived crustal thickness. Depths of the seafloor, basement, and Moho as determined 
in the seismic profiles are shown as purple, light blue, and black solid lines, respectively; Moho is assumed to be at 7.9-8.0 km s-1 unless otherwise indicated.  
Seafloor and basement depths from the dataset used in this study are shown as purple and light blue dashed lines, respectively.  Moho depths from our best fitting 
gravity-derived crustal thickness model (with crustal density of 2700 kg m-3) are shown as red solid lines.  Moho depths from our models that used other assumed
crustal densities are also shown along several profiles.  References for profiles: (1) Whitmarsh and Calvert [1986]; (2), (3), and (4) Hooft et al. [2000]; 
(5) Canales et al. [2000]; (6) Purdy and Detrick [1986]; (7) Detrick and Purdy [1980]; (8) Korenaga et al. [2000]; (9) Hopper et al. [2003]; (10) Holbrook et al. [2001]; 
(11) Funck et al. [2007]; (12) Funck et al. [2003]; (13) Van Avendonk et al. [2006]; (14) Lau et al. [2006]; (15) Funck et al. [2004]; (16) Wu et al. [2006]; 
(17) Lizarralde et al. [2004]; (18) Morris et al. [1993]; (19) Minshull et al. [1991];(20) Bunce et al. [1969]; (21) Bohnhoff and Makris [2004]; (22) White and Smith [2009]; 
(23) Barton and White [1997]; (24) Bullock and Minshull [2005]; (25) Ginzburg et al. [1985];(26) Whitmarsh et al. [1982]; (27) and (28) Whitmarsh et al. [1996]; (29) Dean et al. [2000]; 
(30) Whitmarsh et al. [1990]; (31) Afilhado et al. [2008]; (32) and (33) Klingelhoefer et al. [2009].

References not in the main text are as follows:

Afilhado, A., L. Matias, H. Shiobara, A. Hirn, L. Mendes-Victor, and H. Shimamura (2008), From unthinned continent to ocean: The deep structure of the West Iberia passive continental margin at 38 deg. N, Tectonophys., 458, 9-50, doi:10.1016/j.tecto.2008.03.002.

Barton, A. J., and R. S. White (1997), Crustal structure of Edoras Bank continental margin and mantle thermal anomalies beneath the North Atlantic, J. Geophys. Res., 102, 3109-3129, doi:10.1029/96JB03387. 

Bohnhoff, M., and J. Makris (2004), Crustal structure of the southeastern Iceland-Faeroe Ridge (IFR) from wide aperture seismic data, J. Geodyn., 37, 233-252, doi:10.1016/j.jog.2004.02.004.

Bullock, A. D., and T. A. Minshull (2005), From continental extension to seafloor spreading: Crustal structure of the Goban Spur rifted margin, southwest of the UK, Geophys. J. Int., 163, 527-546, doi:10.1111/j.1365-246X.2005.02726.x.

Bunce, E. T., D. A. Fahlquist, and J. W. Clough (1969), Seismic refraction and reflection measurements-Puerto Rico Outer Ridge, J. Geophys. Res., 74, 3082-3094, doi:10.1029/JB074i012p03082.

Canales, J. P., J. A. Collins, J. Escartin, and R. S. Detrick (2000), Seismic structure across the rift valley of the Mid-Atlantic Ridge at 23 deg. 20' (MARK area): Implications for crustal
accretion processes at slow spreading ridges, J. Geophys. Res., 105, 28,411-28,425, doi:10.1029/2000JB900301.

Dean, S. M., T. A. Minshull, R. B. Whitmarsh, and K. E. Louden (2000), Deep structure of the ocean-continent transition in the southern Iberia Abyssal Plain from seismic refraction profiles: The IAM-9 transect at 40 deg. 20'N, J. Geophys. Res., 105, 5859-5885, doi:10.1029/1999JB900301.

Detrick, R. S., and G. M. Purdy (1980), The crustal structure of the Kane Fracture Zone from seismic refraction studies, J. Geophys. Res., 85, 3759-3777, doi:10.1029/JB085iB07p03759.

Funck, T., J. R. Hopper, H. C. Larsen, K. E. Louden, B. E. Tucholke, and W. S. Holbrook (2003), Crustal structure of the ocean-continent transition at Flemish Cap: Seismic refraction results,
J. Geophys. Res., 108, 2531, doi:10.1029/2003JB002434. 

Funck, T., H. R. Jackson, K. E. Louden, S. A. Dehler, and Y. Wu (2004), Crustal structure of the northern Nova Scotia rifted continental margin (eastern Canada), J. Geophys. Res., 109, B09102, doi:10.1029/2004JB003008. 

Funck, T., H. R. Jackson, K. E. Louden, and F. Klingelhofer (2007), Seismic study of the transform-rifted margin in Davis Strait between Baffin Island (Canada) and Greenland: What
happens when a plume meets a transform, J. Geophys. Res., 112, B04402, doi:10.1029/2006JB004308. 

Ginzburg, A., R. B. Whitmarsh, D. G. Roberts, L. Montadert, A. Camus, and F. Avedik (1985), The deep seismic structure of the northern continental margin of the Bay of Biscay, Ann. Geophys., 3, 499-510.

Holbrook, W. S., et al. (2001), Mantle thermal structure and active upwelling during continental breakup in the North Atlantic, Earth Planet. Sci. Lett., 190, 251-266, doi:10.1016/S0012-821X(01)00392-2.

Hopper, J. R., T. Dahl-Jensen, W. S. Holbrook, H. C. Larsen, D. Lizarralde, J. Korenaga, G. M. Kent, and P. B. Kelemen (2003), Structure of the SE Greenland margin from seismic reflection
and refraction data: Implications for nascent spreading center subsidence and asymmetric crustal accretion during North Atlantic opening, J. Geophys. Res., 108, 2269, doi:10.1029/2002JB001996.

Klingelhoefer, F., C. Labails, E. Cosquer, S. Rouzo, L. Geli, D. Aslanian, J. L. Olivet, M. Sahabi, H. Nouze, and P. Unternehr (2009), Crustal structure of the SW-Moroccan margin from wide-angle and reflection seismic data (the DAKHLA experiment) Part A: Wide-angle seismic models,
Tectonophys., 468, 63-82, doi:10.1016/j.tecto.2008.07.022.

Korenaga, J., W. S. Holbrook, G. M. Kent, P. B. Kelemen, R. S. Detrick, H. C. Larsen, J. R. Hopper, and T. Dahl-Jensen (2000), Crustal structure of the southeast Greenland margin from
joint refraction and reflection seismic tomography, J. Geophys. Res., 105, 21,591-21,614, doi:10.1029/2000JB900188.

Lau, K. W. H., K. E. Louden, S. Deemer, J. Hall, J. R. Hopper, B. E. Tucholke, W. S. Holbrook, and H. C. Larsen (2006), Crustal structure across the Grand Banks-Newfoundland Basin continental margin-I. Results
from a seismic reflection profile, Geophys. J. Int., 167, 157-170, doi:10.1111/j.1365-246X.2006.02989.x.

Lizarralde, D., J. B. Gaherty, J. A. Collins, G. Hirth, and S. D. Kim (2004), Spreading-rate dependence of melt extraction at mid-ocean ridges from mantle seismic refraction data, Nature, 432, 744-747, doi:10.1038/nature03140.

Morris, E., R. S. Detrick, T. A. Minshull, J. C. Mutter, R. S. White, W. S. Su, and P. Buhl (1993), Seismic structure of oceanic crust in the western North Atlantic, J. Geophys. Res., 98, 13,879-13,903, doi:10.1029/93JB00557.

Purdy, G. M., and R. S. Detrick (1986), Crustal structure of the mid-Atlantic Ridge at 23 deg. N from seismic refraction studies, J. Geophys. Res., 91, 3739-3762, doi:10.1029/JB091iB03p03739

Van Avendonk, H. J. A., W. S. Holbrook, G. T. Nunes, D. J. Shillington, B. E. Tucholke, K. E. Louden, H. C. Larsen, and J. R. Hopper (2006), Seismic velocity structure of the rifted margin
of the eastern Grand Banks of Newfoundland, Canada, J. Geophys. Res., 111, B11404, doi:10.1029/2005JB004156. 

White, R. S., and L. K. Smith (2009), Crustal structure of the Hatton and the conjugate east Greenland rifted volcanic continental margins, NE Atlantic, J. Geophys. Res., 114, B02305, doi:10.1029/2008JB005856.

Whitmarsh, R. B., and A. J. Calvert (1986), Crustal structure of Atlantic fracture zones-I. The Charlie-Gibbs Fracture Zone, Geophys. J. R. Astron. Soc., 85, 107-138.

Whitmarsh, R. B., P. R. Miles, and A. Mauffret (1990), The ocean-continent boundary off the western continental margin of Iberia-I. Crustal structure at 40 deg. 30'N,
Geophys. J. Int., 103, 509-531, doi:10.1111/j.1365-246X.1990.tb01788.x.

Whitmarsh, R. B., R. S. White, S. J. Horsefield, J. C. Sibuet, M. Recq, and V. Louvel (1996), The ocean-continent boundary off the western continental margin of
Iberia: Crustal structure west of Galicia Bank, J. Geophys. Res., 101, 28,291-28,314, doi:10.1029/96JB02579.

Wu, Y., K. E. Louden, T. Funck, H. R. Jackson, and S. A. Dehler (2006), Crustal structure of the central Nova Scotia margin off Eastern Canada, Geophys. J. Int., 166, 878-906, doi:10.1111/j.1365-246X.2006.02991.x.