Interstitial water studies on small core samples, leg 23 (Red Sea)
No abstract available.
Initial reports of the Deep Sea Drilling Project↗
Geology topics
L.S. Waterman
Publications and source records attributed to L.S. Waterman.
Interstitial water studies on small core samples from the Mediterranean Sea
Of ten Leg 13 sites studied by us, eight give definite evidence of the existence of halite-containing sediments beneath the seabed. This conclusion is based on the existence on continuous sodium and chloride enrichments in interstitial waters with depth. This is the only direct evidence of the existence of salt at these sites, for only evaporitic dolomite, gypsum, and/or anydrite were recovered in cores. Among other ionic relationships, influence of evaporites is seen in calcium, magnesium and sulfate concentrations. Record high barium (216 ppm) and strontium (345 ppm) concentrations were observed in sulfate depleted pore fluids of Site 128 in the Hellenic Trench.
Initial reports of the Deep Sea Drilling Project↗
Interstitial water studies on small core samples, legs 16, 17, and 18
Legs 16, 17, and 18 encountered three groups of sediment types: rapidly deposited biogenic deposits, showing marked changes in interstitial calcium, magnesium, and strontium; slowly deposited biogenic deposits, showing little variability in pore fluids other than elevated silica concentrations; and terrigenous deposits. The latter showed the usual loss of sulfate and combination of diagenetic reactions culminating in loss of Na + , K + , Mg ++ , with variable changes in Ca ++ . Very high barium concentrations (to 59 mg/kg) occurred at Site 178 (Leg 18).
Initial reports of the Deep Sea Drilling Project↗
Interstitial water studies on small core samples, leg 19
The sediments cored on Leg 19 consist primarily of diatomaceous oozes with variable proportions of volcanic material and terrigenous clays and silts. With a few exceptions, deposition rates are high at these sites, usually exceeding 5cm/10 3 y. The interstitial solutions sampled exhibit compositional changes which previously have been found to characterize rapidly deposited terrigenous sediments. Some of the largest changes in Na + , K + , Mg 2+ , Cl - , and HCO 3 yet found in DSDP samples occur in the pore waters studied from this leg (see Table 1).
Initial reports of the Deep Sea Drilling Project↗
Interstitial water studies on small core samples, leg XI
The sediments cored at Sites 98, 99 and 100 are predominantly biogenic; those cored at Sites 101 through 106 are composed mainly of terrigenous material. As reported previously, most constituents in pore waters from the biogenic oozes exhibit minor changes in chemistry relative to sea water. In the terrigenous-hemipelagic sediments interstitial solutions initially of sea water composition have undergone considerable reaction. These reactions have produced large changes in the concentrations of calcium (Ca), magnesium (Mg), sulfate (SO 4 ) and HCO 3 relative to sea water. In addition, this set of samples documents significant diagenetic alteration of sodium (Na) and chloride (Cl). Potassium exhibits little change in most samples, but in a few instances is depleted at depth. The analytical techniques employed are identical to those described in earlier volumes of the Initial Reports of the Deep Sea Drilling Project. In an effort to identify alteration of sample composition during storage, salinity determinations 2 are made on the pore solution immediately upon their recovery from the sediments. The same measurement is made in the laboratory when the sample containers are opened for analysis. Occasionally evidence of evaporation is found as in Sample 104-2-5; the shipboard salinity was 32%o, while the laboratory measurement yielded 38%o. Changes of 3 to 4 per cent were also noted in several other samples as noted in the tables. Adjustment of the analytically determined concentrations has been made and the corrected values presented in Tables 1 and 2. A large part of the work involved in the analyses of these samples has been done by Irene Uhlitzsch; we are indebted to her for the invaluable assistance she has rendered.
Initial reports of the Deep Sea Drilling Project↗
Interstitial Water studies on small core samples, deep sea drilling project, leg XII
With the exception of Site 114, all interstitial waters in Leg 12 showed marked increases in calcium, which can be attributed to diagenetic dissolution and recrystallization of calcium carbonate, especially coccolith and foraminiferal tests. Magnesium loss may be due to either or both replacement of iron in clays or the dolomitization of calcium carbonate. The lowest sample from Site 113, on the mid-Labrador Sea Ridge, yielded only 250 mg/kg magnesium but 2.56 g/kg calcium in interstitial water from a clayey, siliceous quartz silt. Strontium values close to and exceeding 100 mg/kg were noted, especially in sites showing extensive carbonate recrystallization. Few significant deviations in chloride concentration from sea water levels were noted.
Initial reports of the Deep Sea Drilling Project↗
Interstitial water studies on small core samples, leg 14
The interstitial waters from the sediments cored on Leg 14 exhibit characteristic compositional trends with three important exceptions. At most of the sites, the changes in Na and Cl are very small while enrichment of Ca and Sr and depletion of Mg and SO 4 is typical of patterns observed in similar types of sediment recovered on previous legs. At Sites 139 and 140, off the African coast, and Site 144, off the coast of South America, systematic increases in concentration with depth are found for Na and Cl. At these sites, the concentration changes, in Ca, Mg, SO 4 and Sr generally follow diagenic patterns observed previously, but there is some indication of other factors affecting Mg concentrations. All analyses reported here, with the exception of bulk water content and pH, were carried out on water samples which were squeezed from the sediments on board ship and preserved by heat-sealing in lengths of polyethylene tubing. Analytical methods were identical to those outlined in earlier volumes of this series. We wish to thank Wen Chang, James O'Neill and Irene Uhlitzsch for their assistance in conducting the laboratory determinations and data reduction
Initial reports of the Deep Sea Drilling Project↗
Interstitial water studies on small core samples, Leg 9
The chemistry of the pore fluids obtained on Leg 9 is remarkable primarily in its constancy. Excepting silicon and strontium, only at one site do the concentrations of the major and minor constituents deviate notably from sea water concentrations (see Tables 1 and 2). The trends, or lack of them, seen in these samples have been discussed previously and only references will be given here. The constancy of composition and similarity to sea water is particularly noteworthy, as the sediments at all of the 9 sites are thought to be intruded by the basal basalt. The pore fluid chemistry exhibits no evidence of intrusion except possibly at Site 84.
Initial reports of the Deep Sea Drilling Project↗