Geology topics

Lee S. Waterman

Publications and source records attributed to Lee S. Waterman.

4 recordsLinked to original sources

USGS1974

Interstitial water studies on small core samples, Leg 22

Interstitial waters from Leg 22 in the Indian Ocean revealed two unique results: Site 214, on the Ninetyeast Ridge, penetrated through a 30-meter sequence of fine-grained basalt and reentered hard, silty clay containing carbonate skeletal debris. Such a basalt layer may well have been impervious and extensive enough to seal off underlying (fossil) seawater of Paleocene age. However, except for a marked increase in calcium and a slight increase in chloride, no appreciable changes in pore fluid chemistry could be confirmed. Site 217, at the northernmost end of the Ninetyeast Ridge, demonstrated record concentrations of interstitial calcium in clayey nannofossil oozes and a relatively small but significant increment in chloride with depth. Presumably, these increments signal the existence of evaporitic sediments or evaporite-influenced brines at considerably greater depth than penetrated.

Initial reports of the Deep Sea Drilling Project↗

USGS1974

Diffusimetry (diffusion constant estimation) on sediment cores by resistivity probe

Measurement of formation factor (ratio of rock resistivity to interstitial water resistivity) from sediment cores provides an indirect measurment of the tortuosity of the fluid channels in the sediments. From these measurements one can estimate the diffusion coefficient of the sediment with depth. The F (formation factor) values for Indian Ocean sediments varied from 1.6 for a clayey diatom ooze having 87% porosity (70% water content) to 13.6 for a cemented limestone having 25% porosity (11% water content). These formation factors would yield diffusion coefficients for chloride ions in the corresponding sediments of 6.4 x 10 -6 to 1.5 x 10 -6 cm 2 /sec. In general, surficial sediments showed diffusion coefficients about one-half to one-third of those for free solution, values decreasing with depth and porosity.

Initial reports of the Deep Sea Drilling Project↗

USGS1973

Interstitial water studies on small core samples, Deep Sea Drilling Project: Leg 10

Leg 10 interstitial water analyses provide new indications of the distribution of rock salt beneath the floor of the Gulf of Mexico, both confirming areas previously indicated to be underlain by salt bodies and extending evidence of salt distribution to seismically featureless areas in the Sigsbee Knolls trend and Isthmian Embayment. The criterion for presence of salt at depth is a consistent increase in interstitial salinity and chlorinity with depth. Site 86, on the northern margin of the Yucatan Platform, provided no evidence of salt at depth. Thus, our data tend to rule out the suggestion of Antoine and Bryant (1969) that the Sigsbee Knolls salt was squeezed out from beneath the Yucatan Scarp. Cores from Sites 90 and 91, in the central Sigsbee Deep, were not obtained from a great enough depth to yield definite evidence for the presence of buried salt. Site 86, on the northern margin of the Yucatan Platform, provided no evidence of salt at depth. Thus, our data tend to rule out the suggestion of Antoine and Bryant (1969) that the Sigsbee Knolls salt was squeezed out from beneath the Yucatan Scarp. Cores from Sites 90 and 91, in the central Sigsbee Deep, were not obtained from a great enough depth to yield definite evidence for the presence of buried salt.

Initial reports of the Deep Sea Drilling Project↗

USGS1973

Interstitial water studies on small core samples, Leg 15

Analyses of pore fluids from reducing environments demonstrate that reduction of SO 4 is accompanied by large increases in alkalinity and strong depletion of Ca and Mg. The data are compatible with a model of replacement of Fe 3+ 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 SO 4 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 SO 4 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.

Initial reports of the Deep Sea Drilling Project↗