Petrology of basaltic glasses from the TAG Segment: Implications for a deep hydrothermal heat source

The trace element composition of basaltic glasses from the TAG segment of the MAR indicate that magmas erupted on the surface are derived from multiple primary magmas with Ce/Sm ratios varying from 2.2 to 3.9. In the pseudoquaternary system olivine-plagioclase-clinopyroxene-quartz, TAG glasses cluster between the 4 and 6 kb phase boundaries. This suggests that TAG primary magmas evolve by crystallization at moderate to high pressure, then ascend rapidly to the surface with very short residence times and limited degrees of crystallization in shallow chambers. Such a plumbing system implies a deep-seated heat source for hydrothermal circulation.

[1]  M. Hannington,et al.  Deducing patterns of fluid flow and mixing within the TAG active hydrothermal mound using mineralogical and geochemical data , 1995 .

[2]  T. Grove,et al.  Corrections and further discussion of the primary magmas of mid‐ocean ridge basalts, 1 and 2 , 1993 .

[3]  C. V. Raman,et al.  Active and relict sea-floor hydrothermal mineralization at the TAG hydrothermal field, Mid-Atlantic Ridge , 1993 .

[4]  Deborah K. Smith,et al.  Building the crust at the Mid-Atlantic Ridge , 1993, Nature.

[5]  A. Sobolev,et al.  Ultra-depleted primary melt included in an olivine from the Mid-Atlantic Ridge , 1993, Nature.

[6]  J. Sempere,et al.  Bathymetry of the mid-atlantic ridge, 24°-31°N: A map series , 1990 .

[7]  H. Dick,et al.  Melting in the oceanic upper mantle: An ion microprobe study of diopsides in abyssal peridotites , 1990 .

[8]  L. Zonenshain,et al.  Tectonics of the Mid-Atlantic rift valley between the TAG and MARK areas (26 24°N): Evidence for vertical tectonism , 1989 .

[9]  W. Bryan,et al.  Experimental petrology of normal MORB near the Kane Fracture Zone: 22°–25° N, mid-Atlantic ridge , 1987 .

[10]  C. Langmuir,et al.  Petrogenesis of basalt glasses from the Tamayo region , 1984 .

[11]  G. Thompson,et al.  Compositional variation in normal MORB from 22°–25°N: Mid‐Atlantic Ridge and Kane Fracture Zone , 1981 .

[12]  R. B. Scott,et al.  Crystal fractionation in a CUmulate Gabbro, Mid‐Atlantic Ridge, 26°N , 1980 .

[13]  J. A. Norberg,et al.  Reference Samples for Electron Microprobe Analysis , 1980 .

[14]  D. G. Temple,et al.  Geology of a submarine hydrothermal field, Mid-Atlantic Ridge, 26°n latitude , 1979 .

[15]  W. Bryan.  Regional Variation and Petrogenesis of Basalt Glasses from the FAMOUS Area, Mid-Atlantic Ridge , 1979 .

[16]  A. Albee,et al.  Correction factors for electron probe microanalysis of silicates, oxides, carbonates, phosphates, and sulfates , 1970 .

[17]  M. Ewing,et al.  Diversity and origin of abyssal tholeiite from the Mid-Atlantic Ridge near 24° and 30° North latitude , 1969 .

[18]  A. Albee,et al.  Empirical Correction Factors for the Electron Microanalysis of Silicates and Oxides , 1968, The Journal of Geology.

[19]  C. E. Tilley,et al.  Basalts from the Northern Part of the Mid-Atlantic Ridge , 1966 .

[20]  C. Langmuir,et al.  Petrological systematics of mid-ocean ridge basalts: Constraints on melt generation beneath ocean ridges , 1992 .

[21]  N. Grevesse,et al.  Abundances of the elements: Meteoritic and solar , 1989 .

[22]  S. Hart,et al.  Applications of the Ion Microprobe to Geochemistry and Cosmochemistry , 1982 .