Auxiliary Material for Paper 2008GC001959


MORB generation beneath the ultraslow spreading Southwest Indian Ridge (9-25[deg]E): Major element chemistry and 
the importance of process versus source


Jared J. Standish
Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA (standish@fas.harvard.edu)

Henry J. B. Dick
Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

Peter J. Michael
Department of Geosciences, University of Tulsa, Tulsa, Oklahoma, USA

William G. Melson and Timothy O'Hearn
Department of Mineral Sciences, U.S. National Museum of Natural History, Washington, D. C., USA


Standish, J. J., H. J. B. Dick, P. J. Michael, W. G. Melson, and T. O'Hearn (2008), MORB generation beneath the 
ultraslow spreading Southwest Indian Ridge (9-25[deg]E): Major element chemistry and the importance of process versus 
source, Geochem. Geophys. Geosyst., 9, Q05004, doi:10.1029/2007GC001959.


Introduction:

This supplemental material includes three files: 1 suppl. text file and 2 suppl. tables. The first supplemental file 
"2008gc001959-txts01.txt" contains text describing the detailed dredge lithology statistics, analytical methods, 
caveats for the pressure of crystallization calculation in section 4.2 of main text, and fractionation correction 
methodology.  The distribution and statistics of dredge lithology as well as phenocryst/vesicle populations within 
the basaltic rocks are displayed in tabular format in table file "2008gc001959-ts01.txt". The full major element, 
H2O, and CO2 concentration dataset presented within this manuscript is contain in table "2008gc001959-ts02.txt".

1. 2008gc001959-txts01.txt, 2008gc001959-txts01.pdf Supplemental text in support of manuscript.
1.1 Lithologic Distribution.
1.2 Analytical Methods.
1.3 Pressure of Partial Crystallization - Caveats.
1.4 Correction for Hydrous Fractionation to 8 wt.% MgO

2. 2008gc001959-ts01.txt Velocity model used in earthquake locations, adapted from the seismic refraction studies of 
Menke [1995]. Linear interpolation should be used to calculate velocities between those specified in table.
2.1 Column "Dredge #3", dredge and sample identification number.
2.2 Column "Latitude ([deg]S)", latitude in degrees south.
2.3 Column "Longitude ([deg]E)", longitude in degrees east.
2.4 Column "Depth4 (mbsl)", depth in meters below sea level.
2.5 Column "Location", geologic location of dredge within the rift valley.
2.6 Column "SR5 (mm/yr)", absolute spreading rate in millimeter per year.
2.7 Column "ESR6 (mm/yr)", calculated effective spreading rate in millimeters per year.
2.8 Column "Weight (kg)", recovered total weight of dredged rocks.
2.9 Column "Pillow Basalt & Basalt", recovered weight of basaltic rocks.
2.10 Column "Peridotite & Dunite", recovered weight of mantle rocks.
2.11 Column "Gabbro", recovered weight of gabbro.
2.12 Column "Diabase", recovered weight of diabase.
2.13 Column "Hawaiite", recovered weight of hawaiite. 
2.14 Column "Hydroth. & Volc-clastic", recovered weight of hydrothermal & volcanoclastic rocks.
2.15 Column "Sed. Rocks & Erratics", recovered weight of sedimentary rocks and erratics.
2.16 Column "% Plag Phenos", percentage of plagioclase phenocrysts in basaltic samples.
2.17 Column "% Oliv Phenos", percentage of olivine phenocrysts in basaltic samples.
2.18 Column "% Cpx Phenos", percentage of clinopyroxene phenocrysts in basaltic samples.
2.19 Column "% Vesicles", percentage of vesicles in basaltic samples.

3. 2008gc001959-ts02.txt Supplemental data set which includes major element oxide, water, and carbon dioxide 
concentrations for all samples.

3.1 Column "Sample no. a", dredge and sample identification number.
3.2 Column "Latitude", latitude in degrees south.
3.3 Column "Longitude", longitude in degrees east.
3.4 Column "Depth", depth in meters below sea level.
3.5 Column "SiO2", weight percentage silica oxide.
3.6 Column "Al2O3", weight percentage alumina oxide.
3.7 Column "FeO*", weight percentage iron oxide.
3.8 Column "MgO", weight percentage magnesium oxide.
3.9 Column "CaO", weight percentage calcium oxide.
3.10 Column "Na2O", weight percentage sodium oxide.
3.11 Column "K2O", weight percentage potassium oxide.
3.12 Column "TiO2", weight percentage titanium oxide.
3.13 Column "P2O5", weight percentage phosphorous oxide.
3.14 Column "MnO", weight percentage manganese oxide.
3.15 Column "H2O", parts per million (ppm) water content.
3.16 Column "CO2 b", parts per million (ppm) carbon dioxide content.
3.17 Column "Mg# c", magnesium number, Mg# = 100*(Mg2+)/(Mg2+ + Fe2+); Fe2O3/FeO = 0.15.
3.18 Column "CaO/Al2O3", ratio of calcium oxide over aluminum oxide.
3.19 Column "K/Ti", molar ratio of potassium over titanium.