Long-term interaction between mid-ocean ridges and mantle plumes

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1 SUPPLEMENTARY INFORMATION DOI: /NGEO2437 Long-term interaction between mid-ocean ridges and mantle plumes Whittaker, J. M., Afonso, J. C., Masterton, S., Müller, R. D., Wessel, P., Williams S. E. and Seton, M. NATURE GEOSCIENCE 1

2 Long-term interaction between mid-ocean ridges and mantle plumes Whittaker, J.M., Afonso, J.C., Masterton, S., Müller, R.D., Wessel, P., Williams, S.E., and Seton, M. Supplementary Information 0-22 Ma Ma Ma Ma Ma Ma Ma Ma Ma Ma Supplementary Figure 1: Present- day distribution of LIPs (Coffin and Eldholm, 1994). Colour- coded by age of formation (Supp. Table 1). Supplementary Figure 2: LIPs (Coffin and Eldholm, 1994) reconstructed to location at time of formation. Colour- coded by age of formation. Note the clusters of LIPs exhibit significant ranges in age (Supp. Table 2).

3 Supplementary Figure 3: Histogram of the number of LIPs (Coffin and Eldholm, 1994) associated with each deeply sourced plume (Courtillot et al., 2003; Montelli et al., 2004) only. LIPs were assigned to the closest deeply sourced plume based on their reconstructed position at formation. A) B)

4 C) D)

5 E) F)

6 G) H)

Verde, c) Galapagos, d) Iceland, e) Kerguelen, f) Marion,

7 I) Supplementary Figure 4: Reconstructed LIPs (Coffin and Eldholm, 1994) clustered around a) Bouvet/Shona, b) Cape Verde, c) Galapagos, d) Iceland, e) Kerguelen, f) Marion, g) Marqueses, h) Reunion, and i) Tristan de Cunha plume.

8 Supplementary Figure 5. Workflow for the construction of predicted volume of extracted mantle (VEM).

Supplementary Figure 6: Distribution of mean palaeo- ridge positions within each grid cell following division of Earth's surface into a regular global grid of resolution a) 1 x 1, b) 2 x 2, c) 3 x 3

9 Supplementary Figure 6: Distribution of mean palaeo- ridge positions within each grid cell following division of Earth's surface into a regular global grid of resolution a) 1 x 1, b) 2 x 2, c) 3 x 3 and d) 5 x 5. Mean positions are colour- coded by the number of irregularly- spaced age points that have been averaged within each grid cell: n < 5 (red), 5 < n 15 (orange), 15 < n 25 (green), 25 < n 35 (blue), n > 35 (cyan). Areas with no data coverage have not experienced seafloor spreading in the past 140 Myr. Grid resolution 5 x 5 is used as majority of grid cells comprise n > 15.

Supplementary Figure 7: Age distributions of reconstructed palaeo- MOR points within a 5 x 5 grid: a) Total interquartile age ranges; b) colour- coded locations (stars) of grid cells selected for age

10 Supplementary Figure 7: Age distributions of reconstructed palaeo- MOR points within a 5 x 5 grid: a) Total interquartile age ranges; b) colour- coded locations (stars) of grid cells selected for age distribution examination; selected cells exhibit large differences between total and interquartile age ranges; c) Box- and- whisker plots of age distributions in selected grid cells (colour- coded to stars in b)). Coloured blocks show upper and lower age quartiles; median age is a black line within each block; Red circles: mean age; Black `whiskers': total age range; Red `whiskers': standard deviation about mean age.

11 Supplementary Figure 8: a) Mean full seafloor palaeo- spreading rate and b) interquartile age range of palaeo- spreading centres within 5 x 5 grid cells. Supplementary Figure 9: Schematic of the derivation of units for estimated relative mantle extraction within each cell within a 5 x 5 grid.

12 Supplementary Figure 10: Distribution of non- backarc MORB samples from Gale et al. (2013) relative to deeply- sourced plumes (Courtillot et al., 2003).

13 Supplementary Figure 11: Estimated global Volume of Extracted Mantle (VEM) compared with major element geochemistry (CaO/Al2O3, Na8.0, Fe8.0; Gale et al. (2013)) from present- day MOR segments that are >1,400 km from the nearest deeply- sourced plume(courtillot et al., 2003). 0 T [oc] Depth [km] a 200 Depth [km] 100 b distance [km] 200 Supplementary Figure 12: Mantle flow pattern (white arrows) from numerical simulations of MORs without (a) and with (b) ridge migration. The standard equations of mass, momentum and energy under the Boussinesq approximation are solved with staggered and regular 2D finite difference grid (Gerya, 2009) and Newtonian viscosity. The numerical box represents a domain of 14,000 (length) x 600 (depth) km. Background color represents temperature distribution. In (b) the rate of MOR migration is 1/3 that of the spreading rate. Lateral boundary conditions are external no slip (Gerya, 2009); top and bottom boundary conditions are no slip. Schematic Figs. 3b and 3c in the main text are based on these simulations. Supplementary Table 3. Statistical analysis of the distance from each LIP at the time of formation to the nearest plume using alternative absolute reference frames for either the Indo- Atlantic or Pacific LIPs. Bold type shows reference frames used. Note that in both regions alternative reference frames result in very similar results. Median (km) St.Dev (km) Median (km) St. Dev. (km) Doubrovine et al. (2012) 428 km km 3.22 O Neill et al. (2005) 268 km km 3.51 Müller et al. (1993) 338 km km 3.24 van der Meer et al. (2010) Indo- Atlantic 498 km km 3.14 Pacific Torsvik et al. (2008) 262 km km 3.43 Wessel and Kroenke (2008) 518 km km 3.44 Chandler et al. (2012) 519 km km 3.87 Andrews et al. (2006) 528 km km 3.32

14 References Andrews, D. L., Gordon, R. G., and Horner- Johnson, C., 2006, Uncertainties in plate reconstructions relative to the hotspots; Pacific- hotspot rotations and uncertainties for the past 68 million years: Geophysical Journal International, v. 166, no. 2, p Chandler, M. T., Wessel, P., Taylor, B., Seton, M., Kim, S. S., and Hyeong, K., 2012, Reconstructing Ontong Java Nui: Implications for Pacific absolute plate motion, hotspot drift and true polar wander: Earth Planet Sci Lett, v. 331, p Coffin, M. F., and Eldholm, O., 1994, Large Igneous Provinces: Crustal Structure, Dimensions, and External Consequences: Reviews of Geophysics, v. 32, no. 1, p Courtillot, V., Davaille, A., Besse, J., and Stock, J., 2003, Three distinct types of hotspots in the Earth s mantle: Earth Planet Sci Lett, v. 205, no. 3, p Doubrovine, P. V., Steinberger, B., and Torsvik, T. H., 2012, Absolute plate motions in a reference frame defined by moving hot spots in the Pacific, Atlantic, and Indian oceans: Journal of Geophysical Research: Solid Earth, v. 117, no. 9. Gale, A., Dalton, C. A., Langmuir, C. H., Su, Y., and Schilling, J.- G., 2013, The mean composition of ocean ridge basalts: Geochemistry Geophysics Geosystems, v. 14, no. 3, p. doi: /2012gc Gerya, T., 2009, Introduction to numerical geodynamic modelling, Cambridge University Press. Montelli, R., Nolet, G., Dahlen, F. A., Masters, G., Engdahl, E. R., and Hung, S.- H., 2004, Finite- Frequency Tomography Reveals a Variety of Plumes in the Mantle: Science, v. 303, no. 5656, p Müller, R. D., Royer, J.- Y., and Lawver, L. A., 1993, Revised plate motions relative to the hotspots from combined Atlantic and Indian Ocean hotspot tracks: Geology, v. 16, p O'Neill, C., Müller, R. D., and Steinberger, B., 2005, On the Uncertainties in Hotspot Reconstructions, and the Significance of Moving Hotspot Reference Frames: Geochemistry, Geophysics, Geosystems, v. 6, p. doi: /2004gc000784, Torsvik, T. H., Müller, R. D., Van Der Voo, R., Steinberger, B., and Gaina, C., 2008, Global plate motion frames: Toward a unified model: Reviews of Geophysics, v. 46, no. 3. van der Meer, D. G., Spakman, W., van Hinsbergen, D. J. J., Amaru, M. L., and Torsvik, T. H., 2010, Towards absolute plate motions constrained by lower- mantle slab remnants: Nature Geoscience, v. 3. Wessel, P., and Kroenke, L. W., 2008, Pacific absolute plate motion since 145 Ma: An assessment of the fixed hot spot hypothesis: Journal of Geophysical Research v. 113, no. B6.

SUPPLEMENTARY INFORMATION

SUPPLEMENTARY INFORMATION Patterns of intraplate volcanism controlled by asthenospheric shear Clinton P. Conrad 1,,*, Todd A. Bianco 1,, Eugene I. Smith 2, and Paul Wessel 1 1 Department of Geology & Geophysics,