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F.L. Sayles

Publications and source records attributed to F.L. Sayles.

17 recordsLinked to original sources
USGS1975

Interstitial solutions and diagenesis in deeply buried marine sediments: Results from the Deep Sea Drilling Project

Through the Deep Sea Drilling Project samples of interstitial solutions of deeply buried marine sediments throughout the World Ocean have been obtained and analyzed. The studies have shown that in all but the most slowly deposited sediments pore fluids exhibit changes in composition upon burial. These changes can be grouped into a few consistent patterns that facilitate identification of the diagenetic reactions occurring in the sediments. Pelagic clays and slowly deposited (<1 cm/10 3 yr) biogenic sediments are the only types that exhibit little evidence of reaction in the pore waters. In most biogenic sediments sea water undergoes considerable alteration. In sediments deposited at rates up to a few cm/10 3 yr the changes chiefly involve gains of Ca 2+ and Sr 2+ and losses of Mg 2+ which balance the Ca 2+ enrichment. The Ca-Mg substitution may often reach 30 mM/kg while Sr 2+ may be enriched 15-fold over sea water. These changes reflect recrystallization of biogenic calcite and the substitution of Mg 2+ for Ca 2+ during this reaction. The Ca-Mg-carbonate formed is most likely a dolomitic phase. A related but more complex pattern is found in carbonate sediments deposited at somewhat greater rates. Ca 2+ and Sr 2+ enrichment is again characteristic, but Mg 2+ losses exceed Ca 2+ gains with the excess being balanced by SO 4 post staggered2- losses. The data indicate that the reactions are similar to those noted above, except that the Ca 2+ released is not kept in solution but is precipitated by the HCO 3 post staggered- produced in SO 4 post staggered2- reduction. In both these types of pore waters Na + is usually conservative, but K + depletions are frequent. In several partly consolidated sediment sections approaching igneous basement contact, very marked interstitial calcium enrichment has been found (to 5.5 g/kg). These phenomena are marked by pronounced depletion in Na + , Si and CO 2 , and slight enhancement in Cl - . The changes are attributed to exchange of Na + for Ca 2+ in silicate minerals forming from submarine weathering of igneous rocks such as basalts. Water is also consumed in these reactions, accounting for minor increases in total interstitial salinity. Terrigenous, organic-rich sediments deposited rapidly along continental margins also exhibit significant evidences of alteration. Microbial reactions involving organic matter lead to complete removal of SO 4 post staggered2- , strong HCO 3 post staggered- enrichment, formation of NH 4 post staggered+ , and methane synthesis from H 2 and CO 2 once SO 4 post staggered2- is eliminated. K + and often Na + (slightly) are depleted in the interstitial waters. Ca 2+ depletion may occur owing to precipitation of CaCO 3 . In most cases interstitial Cl - remains relatively constant, but increases are noted over evaporitic strata, and decreases in interstitial Cl - are observed in some sediments adjacent to continents.

Geochimica et Cosmochimica Acta↗
USGS1973

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↗
USGS1973

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↗
USGS1973

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↗
USGS1972

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↗
USGS1972

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↗
USGS1972

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↗
USGS1972

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↗
USGS1971

Interstitial water studies on small core samples, Deep Sea Drilling Project, Leg 6

Sediments from Leg 6 sites, west of the Hawaiian Islands, consisted primarily of various combinations of deep-sea biogenic oozes, volcanic ash, and its breakdown products. Pore fluids from most of the sites were similar in composition to present day ocean water, and in some sties almost identical. However, interstitial fluids from Site 53 (Philippine Sea) showed changes in ionic composition which were beyond those previously considered attributable to diagenetic influence. These samples show the beginnings of metamorphism by dramatic increases in calcium concentrations and corresponding decreases in alkali concentrations. Analytical methods were similar to those outlined in previous Leg Reports. However, obvious contamination of aliquots for sodium determination in the laboratory made it necessary to determine all sodium values by difference between anion and cation balances. These values are, if anything, more accurate than direct determinations which have been discussed in earlier legs. However, the authors will continue to analyze sodium directly, and in the future they may be able to improve the precision of the determinations to the point where small losses and gains of sodium in the pore fluids may be established accurately. Agreement between colorimetric and spectrometric determinations of silicon has improved, but there are still occasional marked differences for which the writers have no explanation. T. Takahashi has allowed the authors to compare total Carbon Dioxide (CO 2 ) measurements from his laboratory with their alkalinity determinations: both sets of data were obtained from fluids from the same squeezings of sediments and should give similar values at the indicated pH levels. Some disturbingly large discrepancies in the two sets of data are evident. The authors do not think that their back-titration alkalinity technique alone is responsible for the differences. However, they have not evaluated the possible influence of the heat-sealed polyethylene pipes on the alkalinity values; this should be considered a potential source of error. The pH data from water samples processed and measured on shipboard are reported here. In view of the major changes in pressure and temperature (laboratory temperatures were reported to be 26 to 28°C) and the sediments to new gaseous regimes prior to pH measurement, these values should be interpreted mainly as applying to the squeezed effluents, not to in situ values.

Initial reports of the Deep Sea Drilling Project↗
USGS1971

Interstitial water studies on small core samples, deep sea drilling Project, leg 7

The sediments cored on Leg 7 are predominantly deep sea biogenic oozes and chalks; only rarely were significant quantities of pelagic clays and volcanic detritus encountered. The biogenic sections include both siliceous and calcareous deposits. At three sites the drilling terminated in basalt, one of which (Site 62) is interpreted as being intrusive on the basis of intense alteration of the overlying sediment. With the exception of Ca++ and Sr , compositional changes in the pore waters are characteristically small relative to those reported previously for rapidly deposited, non-biogenic sediments. Ca++ and Sr + , however, exhibit concentrations of up to three times and ten times, respectively, those found in sea water. In several instances, constant concentration gradients as a function of depth have been found. The sampling, storage and analytical procedures employed have been briefly described in an earlier report (Sayles et al, 1970) and are detailed in a manuscript in preparation (Manheim and Chan). Sodium has been calculated as the difference between the summation of the anions and the summation of the major cations exclusive of sodium; to date, this method has proven more accurate than direct analytical methods. Agreement between the two types of silica determination used (emission spectrometric and colorimetric) is poor; the values obtained by emission spectrometry are characteristically higher. The colorimetric technique measures only "reactive" silica (monomeric and possibly dimeric) while the emission spectrometric technique will determine all of the silica in solution and in suspension. The silica content of most of the solutions is high (60 ppm) and polymerization is likely. We are currently investigating this discrepancy. The pH and water content data reported were obtained aboard the Glomar Challenger immediately after sampling

Initial reports of the Deep Sea Drilling Project↗
USGS1971

Interstitial water studies on small core samples, Deep Sea Drilling Project, Leg 8

Leg 8 sites are dominated by siliceous-calcareous biogenic oozes having depositional rates of 0.1 to 1.5 cm/1000 years. Conservative constituents of pore fluids showed, as have cores from other pelagic areas of the Pacific, insignificant or marginally significant changes with depth and location. However, in Sites 70 and 71, calcium, magnesium and strontium showed major shifts in concentration with depth. These changes appear to be related to recrystallization phenomena in skeletal debris of nannoplankton and to the relative accumulation rate of the sediments. The chemical anomalies increase relatively smoothly with depth, demonstrating the effectiveness of vertical diffusional communication, and apparent lack of bulk fluid movement, as noted in Leg 7 and other sites.

Initial reports of the Deep Sea Drilling Project↗
USGS1970

Brines and interstitial brackish water in drill cores from the deep Gulf of Mexico

Marked increases in interstitial salinity occur in two drill holes located in the Gulf of Mexico at a water depth of more than 3500 meters. The increases probably arose through diffusion of salt from buried evaporites. In one hole, however, brackish water was encountered on penetrating the oil-permeated cap rock of a salt dome. The phenomenon is attributed to production of fresh water during oxidation of petroleum hydrocarbons and decomposition of gypsum to form native sulfur.

Science↗
USGS1970

Interstitial water studies on small core samples, leg 4

Reorganization and recodification of shipboard procedures for collecting interstitial waters has resulted in improved and more regular collection and analysis of pore fluids. Comparative studies of waters squeezed and analyzed on shipboard and analyzed in the shore laboratory show generally good agreement, except for some aberrations whose sources are hard to track down. Influences of pressure and temperature during squeezing on composition of effluents were re-examined for clayey samples from Leg 4 cores. Pressure was not found to be significant, whereas the temperature effects are significant, but are less than variations attributable to diagenetic reactions in the sediments. Conservative constituents, such as, chloride, sodium and bromide, remain relatively constant (within about 1.5 per cent) with changing depth in the holes; but, large depletions with respect to normal sea water occur in calcium (to 0.06 g/kg), magnesium (to 0.7), potassium (to 0.20), and sulfate (to 0.11) in most of the cores. On the other hand, large enrichments of calcium (to 1.57 g/kg) and lithium (to 1.7 ppm) occurred in Holes 24 and 24A. The depletion of several constituents in pore waters of Hole 26 (Vema fracture zone) caused a drop in total salt content to as low as 31 o/oo. However, no real dilution effects are involved, since chloride and sodium values remain typical of those in ocean bottom waters.

Initial reports of the Deep Sea Drilling Project↗
USGS1970

Interstitial water studies on small core samples, Deep Sea Drilling Project, Leg 5

Leg 5 samples fall into two categories with respect to interstitial water composition: 1) rapidly deposited terrigenous or appreciably terrigenous deposits, such as in Hole 35 (western Escanaba trough, off Cape Mendocino, California); and, 2) slowly deposited pelagic clays and biogenic muds and oozes. Interstitial waters in the former show modest to slight variations in chloride and sodium, but drastic changes in non-conservative ions such as magnesium and sulfate. The pelagic deposits show only relatively minor changes in both conservative and non-conservative pore fluid constituents. As was pointed out in earlier Leg Reports, it is believed that much of the variation in chloride in pore fluids within individual holes is attributable to the manipulation of samples on board ship and in the laboratory. On the other hand, the scatter in sodium is due in part to analytical error (on the order of 2 to 3 per cent, in terms of a standard deviation), and it probably accounts for most of the discrepancies in total anion and cation balance. All constituents reported here, with the exception of bulk water content, were analyzed on water samples which were sealed in plastic tubes aboard ship and were subsequently opened and divided into weighed aliquots in the laboratory. Analytical methods follow the atomic absorption, wet chemical and emission spectrochemical techniques briefly summarized in previous reports, e.g. Manheim et al., 1969, and Chan and Manheim, 1970. The authors acknowledge assistance from W. Sunda, D. Kerr, C. Lawson and H. Richards, and thank D. Spencer, P. Brewer and E. Degens for allowing the use of equipment and laboratory facilities.

Initial reports of the Deep Sea Drilling Project↗
USGS1969

Interstitial water studies on small core samples, Deep Sea Drilling Project, Leg 1

The most dramatic variations in pore water composition occurred in Holes 2 and 3 in the Gulf of Mexico. Both holes showed a strong increase in salinity with depth, evidently owing to diffusion from underlying salt bodies. However, on Challenger Knoll (Hole 2) a sharp drop in salinity was observed in the cap rock of the salt dome in which chloride fell to only 4.8 percent. The drop is attributed to production of fresh water during the formation of native sulfur. Outside of the Gulf of Mexico, changes in total salinity with depth did not exceed a few percent, but differences in diagenetic modification of the ionic ratios of sea water were pronounced. In nondiapiric strata in the Gulf of Mexico (Hole 1) both magnesium and potassium were depleted in the pore waters, whereas in the open ocean holes (4, 5, 6, and 7), potassium appeared in excess. Water content (porosity) of the cores was irregular.

Initial reports of the Deep Sea Drilling Project↗