Interstitial water studies on small core samples, Leg 15

Initial reports of the Deep Sea Drilling Project

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Analyses of pore fluids from reducing environments demonstrate that reduction of SO4 is accompanied by large increases in alkalinity and strong depletion of Ca and Mg. The data are compatible with a model of replacement of Fe3+ in clay lattices by Mg from the interstitial solutions and the precipitation of pyrite. Depletions of Na in the interstitial solutions are related to Mg losses by a ratio of approximately 1:3. Pore fluids from oxidizing pelagic sediments exhibit little SO4 depletion. Losses of Mg are accompanied by the addition of Ca to the pore solutions on a nearly 1:1 basis. Strong Sr enrichment is also found in these solutions. The magnitude of the Sr increase suggests that considerable carbonate recrystallization has occurred.

As part of an extensive interlaboratory and analytical calibration, the effect of squeezing sediment at different temperatures has been studied in depth. Samples of a variety of lithologies have been included. Enrichment of K by as much as 24 percent and depletion of Mg and Ca by up to 7 percent occurs during warming. However, no significant effect upon Cl and SO4 could be detected. The strongest effects are seen in the minor constituents studied. On warming, Sr, Si, and B are enriched as much as 19, 40, and 60 percent, respectively. The size of the observed concentration changes varies with the mineralogy of the sediment, but is significant in all types studied, particularly with regards to Mg and K.

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Journal Article
Interstitial water studies on small core samples, Leg 15
Series title:
Initial reports of the Deep Sea Drilling Project
Year Published:
Integrated Ocean Drilling Program Management International
Publisher location:
College Station, TX
Contributing office(s):
Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center
22 p.
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Larger Work Subtype:
Journal Article
Larger Work Title:
Initial reports of the Deep Sea Drilling Project
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Other Geospatial:
Caribbean Sea