rinds for 8 Loihi rocks. Sample spectra, fits and model compounds are shown in Figure S5. All

Transcription

1 SUPPLEMENTARY INFORMATION Supplementary Table 1 Sample Location %Mats (M34, M39) 2L-FH (III)- smectite Vivianite Basalt glass red chi 2 J2-369-R2 Marker 17a 30% 21% - 11% 38% 0.06 J2-369-R5 Marker 17a 71% 11% % 0.03 J2-373-R1 Marker 18 54% 21% - 7% 18% 0.02 J2-308-R1 Marker 18 47% 21% - 11% 21% 0.06 J2-373-R3 PP to M18 42% 20% - 14% 24% 0.1 J2-365-R2 Pisces Peak 51% 21% 5% - 23% 0.03 J2-241-R7 Pisces Peak 63% 21% 7% - 9% 0.13 J2-368-R3 NE Rift 68% 12% 10% - 10% 0.04 Table S1 Least-squares fitting results for bulk -edge EXAFS spectra collected for surface rinds for 8 Loihi rocks. Sample spectra, fits and model compounds are shown in Figure S5. All samples were fit with the same subset of model compound spectra (M34 and M39 mats, (III)- smectite, 2L-ferrihydrite, vivianite, and basalt glass) after conducting target transforms of the entire model compound library against the sum of the principle components required to describe this sample set. The amorphous (III)-rich microbial mats, which are a dominant component in every linear-combination fit, also had the lowest spoil value (1.3) in the target transforms. The minimum detection limit is ~5%, and therefore the presence or absence of (III)-smectite (which is structurally identical to the EXAFS spectrum for nontronite) is questionable in almost all samples. The predicted accuracy of the values reported for each fit component is +/- 5%. nature geoscience 1

2 Supplementary Figure 1 EPS a b c Fig. S1 SEM and optical images of natural basalt surfaces to show that of varying morphologies and sizes are associated with the secondary mineral matrix. SEM images (a) 03PV549-X2 (b) 03PV547-X3 and (c-d) 03PV546-X1 were obtained for glutaraldehyde samples that were fixed, dehydrated and criticalpoint dried. d 2 nature geoscience

3 Supplementary Figure 2 Marker 17 (PV547-X3) Marker 17 (J2-369-R2) Pisces Peak (PV549-X2) Pisces Peak (J2-247-R7) Marker 18 to Pisces Peak (J2-373-R3) NE Rift (J2-368-R3) Fig. S2 30 micron thick petrographic sections of several basalts from the outer flanks of Loihi Seamount. Scale bar is 100 microns. The bright orange rims and crack-filling are -oxide rich, whereas the black pockets and clusters are -oxide rich. Only sample J2-373-R3 shows some interior ligher orange bands that might represent partial palagonitization of the basaltic glass. nature geoscience 3

4 Supplementary Figure 3 Optical Ca Ti High Redox 100% (III) a b c Low 12% (II) Fig. S3 Optical and x-ray fluorescence microprobe maps of, Ca, Ti, and distributions of microcrystalline basalts and associated surface rinds: (a) 03PV549-X2 from Pisces Peak, (b) 03PV546-X1 from Marker 18. Maps for a microfracture in the glassy basalt 03PV547-X3 are also shown in (c). The maps also include a redox map to show the transition from (II)-dominated (green) to (III)-dominated (red) regions, with (blue) overlaid for each 2x2 micron pixel. Scale bar is 20 microns for each panel. 4 nature geoscience

5 Supplementary Figure 4 J2-373-R3 J2-241-R7 03PV547-X1 High basalt crust basalt crust basalt crust Low Fig. S4 Additional X-ray fluorescence microprobe maps for the 3 samples shown in Figure 1, with small differences in the size of the map area. These maps were generated at 11 ev and provide data on distribution. and are shown again to indicate the location of the basalt vs. ferromanganse crust, and to demonstrate that there are no significant enrichments in the crusts. nature geoscience 5

6 Supplementary Figure 5 A J2-369-R5 (M17a) J2-369-R2 (M17a) J2-373-R1 (M18) k 3 χ(k) k 3 χ(k) B k (A -1 ) k (A -1 ) J2-308-R1 (M18) J2-373-R3 (PP -> M18) J2-365-R2 (Pisces Peak) J2-247-R2 (Pisces Peak) J2-368-R3 (NE Rift) Vivianite (III)-smectite 2L-rrihydrite M39 Mat M34 Mat Tholeitic glass k (A -1 ) Fig. S5 -edge extended x-ray absorption fine structure (EXAFS) spectra for (a) surface rinds from Loihi basalts and (b) the minimum number of model compounds required to fit all of the unknown spectra. The sample spectrum (solid) and least-squared fit (red dashed) are shown in (a). Fits required linearcombinations of the unique EXAFS spectra for basalt (tholeiitic glass), microbial mats (M34, M39), 2-L ferrihydrite, (III)-smectite/nontronite and vivianite. The proportions of microbial mats vs. the other models required to fit the surface rinds is shown in Supplementary table 1. 6 nature geoscience

7 Supplementary Figure Atomic% Glass Surface layer P Al Distance from glass surface (nm) Fig. S6 Quantitative TEM-EDS profile of (filled circles), P (empty circles) and Al (empty triangles) concentrations from sample SIO-52. The profile is derived from EDS spectra collected at a series of 30 nm spots below and above the top of the fresh basalt glass shown in Figure 3 (glass surface = 0 nm). nature geoscience 7