Kelley, Deborah S; Vanko, David A; Gu, Chifeng (1995): Chemistry and fluid inclusions of the sheeted dike comples of ODP Holes 137-504B and 140-504B [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.806607, Supplement to: Kelley, DS et al. (1995): Fluid evolution in oceanic crustal layer 2: fluid inclusion evidence from the sheeted dike complex, Hole 504B, Costa Rica Rift. In: Erzinger, J; Becker, K; Dick, HJB; Stokking, LB (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 137, 191-198, https://doi.org/10.2973/odp.proc.sr.137140.015.1995
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Abstract:
Fluid inclusions in variably altered diabase recovered from Ocean Drilling Program Legs 137 and 140 at Hole 504B, Costa Rica Rift, exhibit fluid salinities up to 3.7 times that of seawater values (11.7 wt% NaCl equivalent) and exhibit uncorrected homogenization temperatures of 125°C to 202°C. The liquid-dominated inclusions commonly are entrapped in zones of secondary plagioclase and may be primary in origin. Fluid salinities are similar to compositions of fluids venting on the seafloor (0.4-7.0 wt% NaCl) and overlap with those measured in metabasalt samples recovered from near the Kane Fracture Zone on the Mid-Atlantic Ridge and from the Troodos ophiolite, Cyprus. The salinity variations may reflect hydration reactions involving formation of secondary mineral assemblages under rock-dominated conditions, which modify the ionic strength of hydrothermal fluids by consuming or liberating water and chloride ion. Rare CO2-CH4-bearing inclusions, subjacent to zones where talc after olivine becomes an important secondary mineral phase (1700 mbsf), may have formed due to local interaction of seawater and olivine at low water to rock ratios. Corrected average fluid inclusion homogenization temperatures exhibit a gradient from 159°C at a depth of 1370 mbsf to 183°C at a depth of 1992 mbsf and are in apparent equilibrium with the present conductive downhole temperatures. These data indicate that fluid inclusions may be used to estimate downhole temperatures if logging data are unavailable. The compositional and thermal evolution of the diabase-hosted fluids may reflect late-stage, off-axis circulation and conductive heating of compositionally modified seawater in the sheeted dike complex at Hole 504B.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Latitude: 1.226900 * Longitude: -83.730300
Date/Time Start: 1991-04-07T13:10:00 * Date/Time End: 1991-11-12T04:10:00
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
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Datasets listed in this publication series
- Kelley, DS; Vanko, DA; Gu, C (1995): (Table 2) Fluid inclusion analyses of ODP Holes 137-504B and 140-504B. https://doi.org/10.1594/PANGAEA.806606
- Kelley, DS; Vanko, DA; Gu, C (1995): (Table 1) Plagioclase analyses from ODP Hole 140-504B. https://doi.org/10.1594/PANGAEA.806595