In chapter 2 the isotopic fractionation of water in some simple condensation-evaporation processes are considered quantitatively on the basis of the fractionation factors given in section 1.2. The condensation temperature is an important parameter, which has got some glaciological applications. The temperature effect (the δ's decreasing with temperature) together with varying evaporation and exchange appear in the “amount effect” as high δ's in sparse rain. The relative deuterium-oxygen-18 fractionation is not quite simple. If the relative deviations from the standard water (S.M.O.W.) are called δ D and δ 18 , the best linear approximation is δ D = 8 δ 18 . Chapter 3 gives some qualitative considerations on non-equilibrium (fast) processes. Kinetic effects have heavy bearings upon the effective fractionation factors. Such effects have only been demonstrated clearly in evaporation processes, but may also influence condensation processes. The quantity d = δ D −8 δ 18 is used as an index for non-equilibrium conditions. The stable isotope data from the world wide I.A.E.A.-W.M.O. precipitation survey are discussed in chapter 4. The unweighted mean annual composition of rain at tropical island stations fits the line δ D = 4.6 δ 18 indicating a first stage equilibrium condensation from vapour evaporated in a non-equilibrium process. Regional characteristics appear in the weighted means. The Northern hemisphere continental stations, except African and Near East, fit the line δ D = 8.0 δ 18 + 10 as far as the weighted means are concerned (δ D = 8.1 δ 18 + 11 for the unweighted) corresponding to an equilibrium Rayleigh condensation from vapour, evaporated in a non-equilibrium process from S.M.O.W. The departure from equilibrium vapour seems even higher in the rest of the investigated part of the world. At most stations the δ D and varies linearily with δ 18 with a slope close to 8, only at two stations higher than 8, at several lower than 8 (mainly connected with relatively dry climates). Considerable variations in the isotopic composition of monthly precipitation occur at most stations. At low latitudes the amount effect accounts for the variations, whereas seasonal variation at high latitudes is ascribed to the temperature effect. Tokyo is an example of a mid latitude station influenced by both effects. Some possible hydrological applications are outlined in chapter 5. DOI: 10.1111/j.2153-3490.1964.tb00181.x

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.2153-3490.1964.tb00181.x

Stable isotopes in precipitation

The relationship between deuterium and oxygen-18 concentrations in natural meteoric waters from many parts of the world has been determined with a mass spectrometer. The isotopic enrichments, relative to ocean water, display a linear correlation over the entire range for waters which have not undergone excessive evaporation.

https://science.sciencemag.org/content/sci/133/3465/1702.full.pdf

Isotopic Variations in Meteoric Waters

The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

Study and Interpretation of the Chemical Characteristics of Natural Water

Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide

Cosmochemistry of the rare earth elements: meteorite studies.

Oxygen isotopic compositions of the high-temperature phases in carbonaceous chondrites define a mixing line with an 0-16-rich component and show little superimposed chemical isotope fractionation. Within a single inclusion in Allende, variations of delta 0-18 and delta 0-17 of 39 thousands are found. The ordinary chondrites are slightly displaced from the terrestrial fractionation trend, implying that at least 0.2 percent of the oxygen in terrestrial rocks was derived from the 0-16-rich component.

https://ntrs.nasa.gov/api/citations/19780005034/downloads/19780005034.pdf

Heterogeneities in the solar nebula.

Oxygen isotopes in carbonaceous chondrites

Oxygen isotopic analysis of some molluscan shells from fossil littoral deposits of Pleistocene age

We have studied five meteorites [Wray (a), Cerro 10s Calvos, Willaroy, Moorabie and Suwahib (Buwah)] which differ from other chondritic meteorites and appear to form a new group. They are closely related to ordinary chondrites, but have lower FeO in the mafic silicates than H chondrites. Furthermore, their oxygen isotopic compositions are intermediate between E and H chondrites; they have highly variable metal contents, low Co concentrations in kamacite, and high troilite contents. The differences between low-FeO and H, L and LL chondrites appear to have been established in the solar nebula, not through parent body processes. Low-FeO chondrites did not originate on the H chondrite or IIE iron parent bodies, but probably represent a new ordinary chondrite parent body. PROPERTIES The low-FeO contents of Cerro 10s Calvos, Willaroy, Moorabie and Suwahib (Buwah) have been noted by several authors [e.g.,1,2] and these meteorites have been examined in detail [2]. We recently recognized the low-FeO nature of Wray (a) [3] and here report on our comparative studies. Classification Low-FeO chondrites are weakly metamorphosed and exhibit wide ranges of shock and weathering. Classification of petrologic types, shock stages [4] and weathering [5] are as follows: Wray (a): 4, S4, W1; Cerro 10s Calvos: 4, S2, W3; Willaroy: 3.8, S2, W4; Moorabie: 3.9, S4, Wl ; and Suwahib (Buwah): 3.8, S5, W1. MaJic Silicate Compositions Fa concentrations in low-FeO chondrites (Fa12.8-15.3) are below those of H chondrites (Fa16.9-20.4). Low-Ca pyroxene compositions are intermediate between H and E chondrites. Metal and Troilite Abundances Fe,Ni metal abundances in low-FeO chondrites are highly variable (1 1.2-19.4 wt.%, weathering corrected) and overlap with H and L chondrites. Troilite contents in the mildly weathered Moorabie (9.1 wt.%) and Suwahib (Buwah) (8.6 wt.%) are higher than found in any ordinary chondrite [6], although analyses of these meteorites by [7] suggest normal OC abundances of troilite. Sampling heterogeneity may be responsible. Cobalt in Kamacite The Co concentrations in kamacite of low-FeO chondrites (0.30-0.45 wt.% [2, this work]) are near or lower than those in H chondrites (0.44-0.51 wt.% [8]). Chondrule Sizes Low-FeO chondrites have mean chondrule diameters around 400 pm w r a y (a), Cerro 10s Calvos, Willaroy] and 600 pm [Moorabie, Suwahib (Buwah)]. These values are close to H (-300 pm) and L (-600-800 pm) chondrites [9]. The poorly constrained ranges of chondrule sizes in H, L and LL chondrites and large standard deviations for chondrule sizes in low-FeO chondrites suggest that this parameter is unreliable for establishing group membership. Oxygen Isotopes The A 1 7 0 values for low-FeO chondrites (0.32-0.87%0 [10,11]) are less than or equal to H chondrites (0.73B.09%0,[10]). Moorabie and Suwahib (Buwah), which have slightly larger chondrules, also have higher A17O. Figure 1 plots the compositions of lowFeO chondrites, along with the fields for H, L, LL and E chondrites. WASSON et al. [2] suggested that Willaroy & Cerro 10s Calvos and Suwahib (Buwah) & Moorabie are H and L chondrites, respectively, that were incorporated into, and partially equilibrated with, aubritic material, primarily because their study of Cumberland Falls chondritic inclusions indicated formation by this mechanism. Low-FeO chondrites also lack the high siderophile abundances of Netschaevo, which [12] called "HH" chondritic material based on extrapolation of H-L-LL trends. Because of the lack of definitive evidence for reduction (e.g., Fs>Fa) or a reducing host, high troilite contents, and short diffusion distances for oxygen in type 5 ordinary chondrites [lo], we suggest nebular processes produced the low-FeO concentrations. O Lunar and Planetary Institute Provided by the NASA Astrophysics Data System 866 LPSCXYV LOW-FeO CHONDRITES

/pdf/low-feo-ordinary-chondrites-a-nebular-origin-and-new-30rb7rijix.pdf

Low-FeO Ordinary Chondrites: A Nebular Origin and New Chondrite Parent Body

Nine specimens of the Kendleton L chondrite, chosen (from the total of 52 that were inspected) for the presence of a wide variety of clasts, were studied microscopically as well as by EMPA with the purpose of investigating the origin of regolith and fragmental meteorite breccias. The results indicate that Kendleton does not contain detectable amounts of solar-wind gases. The Kendleton clasts were found to include a wide variety of L3, L5, shock-blackened, and melt rock clasts, which are considered to have originated from normal L chondrite material, and a unique tridymite-rich inclusion. The results suggest that meteoritic regolith breccias may have different origin from that of lunar breccias.

Toshiko K. Mayeda

Papers

Heterogeneities in the solar nebula.

Oxygen isotopes in carbonaceous chondrites

Oxygen isotopic analysis of some molluscan shells from fossil littoral deposits of Pleistocene age

Low-FeO Ordinary Chondrites: A Nebular Origin and New Chondrite Parent Body

Origin of fragmental and regolith meteorite breccias - Evidence from the Kendleton L chondrite breccia