Amino acids in a surface sediment core of the Atlantic abyssal plain

The amino acids in a 56 cm sphincter core (K-19-4-9, Woods Hole Oceanographie Institution) from 30°N latitude, 60°W longitude—approximately 300 miles southeast of Bermuda—at a water depth of 5454m were analyzed by gas and liquid chromatography. Amino acids decreased rapidly with depth with β-alanine and γ-aminobutyric acid predominating in deeper sections. Most of the amino acids are tightly bound in the sediment and are released only upon hydrolysis with 6N HC1. Amino acids accounted for only 0.40% of total nitrogen in the non-carbonate minerals in the top 0–8 cm and 7.9 × 10^?4 percent in the bottom 48–56 cm. The remaining nitrogen is removed from the sediment by amino acid extraction.     

Ground water geochemistry of 228Ra, 226Ra and 222Rn

²²⁸Ra, ²²⁶Ra, and ²²²Rn activities were determined on over 150 ground water samples collected from drilled, public water supply wells throughout South Carolina. A wide range of aquifer lithologies were sampled including the crystalline rocks of the Piedmont and sedimentary deposits of the Coastal Plain. A significant linear relationship between log ²²⁸Ra and log ²²⁶Ra (n = 182, r = 0.83) was indistinguishable between Piedmont and Coastal Plain ground water. Median ${}^{228}\text{Ra}{}^{226}\text{Ra}$ activity ratios for the Piedmont, 1.2, and Coastal Plain, 1.3, ground water are close to estimated average crustal ${}^{232}\text{Th}{}^{238}\text{U}$ activity ratios of 1.2 to 1.5 corresponding to Th/U weight ratios of 3.5 to 4.5. A linear correlation was also found between log ²²²Rn and log ²²⁶Ra for Piedmont (n = 68, r = 0.62) and Coastal Plain (n = 89, r = 0.64) ground water. However, the median ${}^{222}\text{Rn}{}^{226}\text{Ra}$ activity ratio for Piedmont ground water, 6100, was much higher than for Coastal Plain ground water, 230. Higher excess ²²²Rn activities may be due to greater retention of ²²⁶Ra by the chemically active Piedmont aquifers compared to the more inert sand aquifers sampled in the Coastal Plain. The relationship between log ²²⁸Ra and log ²²⁶Ra was used to predict total Ra (${}^{228}\text{Ra +}{}^{226}\text{Ra}$) distributions in Appalachian and Atlantic and Gulf Coastal Plain ground water. Predictions estimate that 2.4% of Appalachian and 5.3% of Atlantic and Gulf Coastal Plain ground water supplies contain total Ra activities in excess of the 5 pCi/l limit established by the U.S. Environmental Protection Agency. These predictions also indicate that 40–50% of these ground water wells may be overlooked using the presently suggested screening activity of 3.0 pCi/l of ²²⁶Ra for ²²⁸Ra analysis.     

A comparison of different magnetic methods for determining the relative grain size of magnetite in natural materials: Some results from lake sediments

A new rapid method for identifying relative grain size variations in magnetic involves the parameter anhysteretic susceptibility (χ_ARM, i.e. specific ARM obtained in a 1 Oe steady field), which is particularly sensitive to the single domain (SD) and small pseudo-single domain (PSD) grains of the finer magnetite fraction. A second parameter, low-field susceptibility (χ), is relatively more sensitive to the coarser magnetite fraction (larger PSD and smaller multidomain (MD) grains). We can then obtain a measure of the ratio of coarse- to fine-grain magnetite for large numbers of samples by plotting χ_ARversusχ. A simple idealized model based on sized magnetite samples is proposed to explain the use of the χ_ARMversusχ plot for detecting relative grain-size changes in the magnetic content of natural materials. The sediments of three lakes that contain magnetite or a similar magnetic carrier and have a wide range of values of χ_ARM and χ are used to test the model.The model is used to interpret the magnetic variations observed, and the interpretations are supported by high-field hysteresis measurements of the same sediments. The combination of the high-field hysteresis method of Day et al. [1] and the χ_ARM vs. χ method is a powerful technique allowing the rapid identification of both the relative grain size and domain state for large numbers of samples containing magnetite. The χ_ARMvs.χ method should be used as an intial means of identifying distinct groups of samples.The high-field hysteresis method should then be applied to a few representative samples from each group to confirm the initial interpretation.     

Geodetic accuracy of the Macrometer model V-1000

The Macrometer Model V-1000 is a geodetic positioning instrument that uses the radio signals broadcast by the GPS satellites. The Macrometer is the only GPS user equipment commercially available that does not require any of the GPS codes. The Model V-1000 receives only the 19-cm wavelength signals from GPS although similar instruments, built for the U.S. Air Force Geophysics Laboratory, receive both the 19-and the 24-cm wavelengths. In this paper we summarize the results of two years of field testing of the V-1000. This instrument, observing four or five satellites fof a few hours, yields a point position accurate within several meters in each coordinate: latitude, longitude and ellipsoidal height. All three components of the relative position vector between a pair of points can be determined within 2 parts per million of the distance, given a similar schedule of observations. This accuracy has been obtained for intersite distances from one kilometer to several thousand kilometers. Macrometer is a trademark of Aero Service Division, Western Geophysical Company of American, 8100 Westpark Drive, Houston, Texas, 77063, U.S.A.     

COMPUTING DRAWDOWN DISTRIBUTIONS USING MICROCOMPUTERS

Abstract. Using known or estimated values of trans-missivity and storativity, the distribution of drawdowns at any time within a discretized flow field can be generated by applying simple trigonometry and numerical approximations of the exponential integral to the Theis equation. Single- and multiple-well systems, as well as image boundaries, are readily simulated with this method. A program employing this technique is presented in BASIC for use with microcomputers. The availability, low cost, and computational power of many small computers makes them ideal for this type of application. Their user-oriented features allow many possible combinations of wells, boundaries, and hydraulic properties to be analyzed in a short time.     

SO2 from episode 48A eruption,Hawaii: Sulfur dioxide emissions from the episode 48A East Rift Zone eruption of Kilauea volcano,Hawaii

An SO₂ flux of 1170±400 (1) tonnes per day was measured with a correlation spectrometer (COSPEC) in October and November 1986 from the continuous, nonfountaining, basaltic East Rift Zone eruption (episode 48A) of Kilauea volcano. This flux is 5–27 times less than those of highfountaining episodes, 3–5 times greater than those of contemporaneous summit emissions or interphase Pu'u O'o emissions, and 1.3–2 times the emissions from Pu'u O'o alone during 48A. Calculations based on the SO₂ emission rate resulted in a magma supply rate of 0.44 million m³ per day and a 0.042 wt% sulfur loss from the magma upon eruption. Both of these calculated parameters agree with determinations made previously by other methods.     

Volume predictability of historical eruptions at Kilauea and Mauna Loa volcanoes

Cumulative volumes of eruptions at the Kilauea and Mauna Loa volcanoes in Hawaii appear to fit a volume-predictable model (i.e., the volume of an eruption episode is approximately proportional to the time since the previous episode) for many larger episodes during long periods of time (decades). This observation suggests that the magmatic pressure of each volcano tends to drop to a common level at the end of these episodes during each such period.     

Laboratory Kinetic Studies of the Reactions of Cl Atoms with Species of Biogenic Origin: δ3-Carene, Isoprene, Methacrolein and Methyl Vinyl Ketone

The rate coefficients for the reaction between atomic chlorine and a number of naturally occurring species have been measured at ambient temperature and atmospheric pressure using the relative rate technique. The values obtained were (4.0 ± 0.8) × 10^-10, (2.1 ± 0.5) × 10^-10, (3.2 ± 0.5) × 10^-10, and (4.9 ± 0.5) × 10^-10 cm³ molecule^-1 s^-1, for reactions with isoprene, methyl vinyl ketone, methacrolein and ³-carene, respectively. The value obtained for isoprene compares favourably with previously reported values. No values have been reported to date for the rate constants of the other reactions.