Hydrogen and carbon isotopes of petroleum and related organic matter     

Hsueh-Wen Yeh  Samuel Epstein 《Geochimica et cosmochimica acta》1981,45(5):753-762

$\text{D}\text{H}$ and ${}^{13}\text{C}{}^{12}\text{C}$ ratios were measured for 114 petroleum samples and for several samples of related organic matter. δD of crude oil ranges from ?85 to ?181‰, except for one distillate (?250‰) from the Kenai gas field; δ¹³C of crude oil ranges from ?23.3 to ?32.5‰, Variation in δD and δ¹³C values of compound-grouped fractions of a crude oil is small, 3 and 1.1%., respectively, and the difference in δD and δ¹³C between oil and coeval wax is slight. Gas fractions are 53–70 and 22.6–23.2‰ depleted in D and ¹³C, respectively, relative to the coexisting oil fractions.The δD and δ¹³C values of the crude oils appear to be largely determined by the isotopic compositions of their organic precursors. The contribution of terrestrial organic debris to the organic precursors of most marine crude oils may be significant.  相似文献   

Etude systématique des isotopes de l'oxygène,du carbone et du strontium dans les carbonatites     

Françoise Pineau  Marc Javoy  Claude J Allegre 《Geochimica et cosmochimica acta》1973,37(11):2363-2377

${}^{18}\text{O}{}^{16}\text{O}$, ${}^{13}\text{C}{}^{12}\text{C}$ and ${}^{87}\text{Sr}{}^{86}\text{Sr}$ ratios have been measured on the same samples for carbonatite complexes. The results show that besides the ‘carbonatite box’ of Tayloret al. (1967) there exist higher δ¹⁸O and δ¹³C values than can be explained by late magmatic or deuteric processes. These processes correspond to high concentrations of CO₂ and lead to big enrichments in ¹⁸O and ¹³C as well as in some ‘volatile’ elements. Strontium results are consistent with a model of selective contamination of deep-seated material by highly radiogenic strontium. The whole study leads to the opinion that parent magmas of carbonatites differentiated in a crustal environment with or without significant contamination.  相似文献   

Hydrogen and carbon isotopic ratios of the cellulose nitrate and saponifiable lipid fractions prepared from annual growth rings of a California redwood     

Donald W. Northfelt  Michael J. DeNiro  Samuel Epstein 《Geochimica et cosmochimica acta》1981,45(10):1895-1898

The $\text{D}\text{H}$ and ${}^{13}\text{C}{}^{12}$C ratios of the cellulose nitrate and saponifiable lipid fractions prepared from eleven annual growth rings of a California redwood were determined. The $\text{D}\text{H}$ ratios of the two fractions are related to one another for the annual rings in the sapwood portion of the tree, but not for those in the heartwood or in the wood undergoing the transition from sapwood to heartwood. No relationship was observed between the ${}^{13}\text{C}{}^{12}$ ratios of the two fractions. These results suggest that analysis of the hydrogen isotopic composition of the saponifiable lipid fractions in plants will provide information useful for climatic reconstruction provided the initial isotopic record has not been changed by subsequent physiological or diagenetic processes.  相似文献   

The isotopic composition of carbon in the Alberta oil sand     

Kamal N. Jha  John Gray  Otto P. Strausz 《Geochimica et cosmochimica acta》1979,43(9):1571-1573

The carbon isotopic ratios obtained from Athabasca bitumen, asphaltene and maltene have the same value $\text{δ}{}^{13}\text{C}\text{= ?29.6}\text{per ml}$. The corresponding values in the Cold Lake deposits are ?30.6, ?30.0 and ?31.6 per ml. The ratios determined for methane collected from the oil sand and its fractions are about 15 per ml lower than the above values. It appears that the Athabasca and Cold Lake Reservoirs have similar histories.  相似文献   

Two notes on the isotopic constitution of carbon in minerals     

Frans E Wickman  H.v Ubisch 《Geochimica et cosmochimica acta》1951,1(2):119-122

Measurements of the $\text{C}{}^{12}\text{C}{}^{13}$ ratio on two generations of calcite and the matrix from a single specimen are given and discussed. This ratio has also been determined for four examples of graphite and limestone occurring together. The formation of the graphite is briefly discussed in relation to the $\text{C}{}^{12}\text{C}{}^{13}$ ratios.  相似文献   

Hydrogen,oxygen and carbon isotopic evidence for the origin of rodingites in serpentinized ultramafic rocks     

David B. Wenner 《Geochimica et cosmochimica acta》1979,43(4):603-614

$\text{D}\text{H}$, ${}^{18}\text{O}{}^{16}\text{O}$ and ${}^{13}\text{C}{}^{12}\text{C}$ analyses were made of 14 whole rock and 28 mineral samples of rodingites associated dominantly with lizardite-chrysotile serpentinites from the West Coast of the U.S.A., New Zealand, and the Northern Appalachian Mtns. The δD values of the rodingite minerals are in three groupings: 5 monomineralic veins of pectolite, ?281 to ?429; 8 monomineralic veins of xonotlite, ?112 to ?135; all other minerals, including hydrogarnet, idocrase, prehnite, actinolite, nephrite, and chlorite, ?34 to ?80. Most calcites in rodingites have δ¹⁸O (+9.3 to +14.4) and (δ¹³C (?6.7 to +0.9) values similar to calcites in other Franciscan rocks, but distinct from the very low temperature calcite veins in serpentinites. The $\text{D}\text{H}$ data, combined with δ¹⁸O values of xonotlite (+5.7 to +10.9) and pectolite (+8.9 to +12.4) suggest formation from meteoric-type waters at low temperatures; the $\text{D}\text{H}$ depletion of pectolite, however, is anomalous. Rodingite whole rock values range from δ¹⁸O = +4.1 to +11.5 and δD = ?50 to ?86; one sample containing minor amounts of lizardite-chrysotile serpentinite has δD = ?92, outside this range. However, most rodingites of basaltic or gabbroic parentage are more restricted in δ¹⁸O (+4.1 to +8.6). Such a wide range in δ¹⁸O is consistent with the idea that most rodingites form over a relatively broad range of hydrothermal temperatures. Hydrogen isotopic data for most rodingite minerals (except xonotlite and pectolite) and for whole rocks are suggestive of non-meteoric waters. These $\text{D}\text{H}$ data overlap those observed for veins of hydrous minerals found in Franciscan igneous rocks studied by Margaritz and Taylor (1976, Geochim. Cosmochim. Acta40, 215–234), possibly suggesting evolved D-enriched, connate type metamorphic waters generated during high P, low T Franciscan-type metamorphism at temperatures (250–500°C) comparable to estimates based on mineral stabilities. Such an interpretation is supported by the ${}^{18}\text{O}{}^{16}\text{O}$ and ${}^{13}\text{C}{}^{12}\text{C}$ data for calcite in rodingites.The isotope data appear to contradict some of the conclusions derived from geologic and petrologic studies that indicate concomitant metasomatism and serpentinization of their presently observed host rock. These data appear most consistent with the interpretation that most rodingite minerals, with the exception of late-stage veins of xonotlite and possibly pectolite, may involve metasomatism in association with antigorite serpentinization of ultramafic rock. Subsequent upward tectonic transport in many instances may result in incorporation of the rodingites into their presently observed lizarditechrysotile host rock during or subsequent to pervasive shallow level serpentinization by meteoric waters.  相似文献   

Annual periodicity of the 18O16O and 13C12C ratios in the coral Montastrea annularis     

Richard G. Fairbanks  Richard E. Dodge 《Geochimica et cosmochimica acta》1979,43(7):1009-1020

The isotopic ratios ${}^{18}\text{O}{}^{16}\text{O}$ and ${}^{13}\text{C}{}^{12}\text{C}$ show an annual periodicity in the coral Montastrea annularis from Bermuda, Jamaica and Barbados. The abundances of ¹⁸O and ¹³C are positively correlated in the Jamaica and Barbados samples, but inversely related in the Bermuda sample. Annual high density growth bands are formed during the season of warmest water temperature at all 3 sites and are enriched in ¹⁶O. M. Annularis has a constant displacement from oxygen isotopic equilibrium and accurately records seasonal temperature variations via the temperature-dependent aragonite-water fractionation factor. Light intensity, through the activity of the coral's endosymbiotic algae, regulates the depth-dependent and seasonal variations in the skeletal carbon isotopic composition.  相似文献   

Carbon and oxygen isotopes in epigenetic hydrothermal rocks from Hamam-el-Farun,Sinai     

Mordechai Magaritz  Arie Issar 《Chemical Geology》1973,12(2):137-146

Rock samples from an Eocene cliff above the thermal spring of Hamam-el-Farun (west coast of Sinai) show various degrees of dolomitization and calcitization ${}^{18}\text{O}{}^{16}\text{O}$ and ${}^{13}\text{C}{}^{12}\text{C}$ ratios indicate that dolomite and secondary calcite precipitated from hot brines.  相似文献   

Stable carbon isotopes of graphite from Bogala Mine,Sri Lanka     

Albert Dobner  Wolfgang Graf  Paula Hahn-Weinheimer  Alfred Hirner 《Lithos》1978,11(3):251-255

The ratios of the carbon isotopes ¹³C and ¹²C of twenty-four graphite samples from Bogala Mine, Sri Lanka have been determined. The graphites are isotopically very similar (mean value $\text{?7.76? °}{}^{13}\text{C}{}_{\mathrm{PDB}}$; range $\text{<2?}$). Three models for the biogenic or abiogenic origin of the graphite deposit are discussed.  相似文献   

Growth pattern and 13C12C isotope fractionation of Cyanidium caldarium and hot spring algal mats     

J. Seckbach  I.R. Kaplan 《Chemical Geology》1973,12(3):161-169

A study was undertaken with the thermophilic green alga Cyanidium caldarium which grows optimally at low pH and high concentrations of CO₂. Carbon-isotope fractionation was not found to be a simple linear function of temperature. Maximum enrichment of ¹²C in cellular material occurred under optimum growth conditions (at approximately pH 2 and at temperatures between 40–50°C in a CO₂ atmosphere). A maximum measured fractionation of ?24‰ may account for low values ($\text{δ}{}^{13}\text{C}\text{< ?30‰}{}_{\mathrm{<mtext>PDB</mtext>}}$) in Precambrian kerogen presumably derived from algal mats.  相似文献   

Coupling among the terrestrial sulfur,carbon and oxygen cycles: numerical modeling based on revised Phanerozoic carbon isotope record     

Manfred Schidlowski  Christian E Junge 《Geochimica et cosmochimica acta》1981,45(4):589-594

Numerical modeling of the terrestrial oxygen budget based on the revised δ¹³C_carb record by Veizeret al. (1980) has shown that total photosynthetic oxygen has varied between ±7% and ±10% of its average reservoir size (～3.2 × 10²² g) during the last 800 myr as a result of oscillations of the sedimentary reservoir of organic carbon. Calculated curves of oxygen evolution display a distinct minimum in the Early Paleozoic framed by two maxima in the Latest Proterozoic and the Mesozoic. The sympathetic relationship observed between the curves of total oxygen evolution and respective functions for the partial reservoir of sulfate-bound oxygen suggests that the O₂ required for an additional conversion of sulfide to sulfate was most probably provided by excess burial of organic carbon, the results of the modeling thus adding credence to current interpretations proposed for the negative correlation between the secular ${}^{13}\text{C}{}^{12}\text{C}$ and ${}^{34}\text{S}{}^{32}\text{S}$ trends.  相似文献   

Stable isotopic investigations of early development in extant and fossil chambered cephalopods I. Oxygen isotopic composition of eggwater and carbon isotopic composition of siphuncle organic matter in Nautilus     

Kimberley C. Crocker  Michael J. DeNiro  Peter D. Ward 《Geochimica et cosmochimica acta》1985,49(12):2527-2532

Eggwaters from the chambered cephalopod Nautilus are depleted in both ¹⁸O and deuterium relative to ambient seawater. Eggwaters from six other species, including the related chambered cephalopod Sepia, do not show such depletion. These observations indicate that the previously observed step towards more positive $\text{δ}{}^{18}\text{O}$ values in calcium carbonate laid down after Nautilus hatches, relative to carbonate precipitated prior to hatching, can be explained by equilibration of the carbonate with water in the egg before hatching and with seawater after hatching. The presence of an oxygen isotope difference between eggwater and seawater for Nautilus and its absence for Sepia suggest that hatching will be recorded in the $\text{δ}{}^{18}\text{O}$ values of shell carbonates for some but not all extinct and extant chambered cephalopods.The $\text{δ}{}^{13}\text{C}$ values of the organic fraction of the siphuncle in Nautilus do not show any consistent pattern with regard to the time of formation before or after hatching. This observation suggests that the minimum in $\text{δ}{}^{13}\text{C}$ values previously observed for calcium carbonate precipitated after Nautilus hatches is not caused by a change in food sources once the animal becomes free-swimming, as has been suggested.  相似文献   

Stable carbon isotope constraints on mixing and mass balance of CO2 in an urban atmosphere: Dallas metropolitan area,Texas, USA     

《Applied Geochemistry》2003,18(1):75-95

  相似文献   

The geochemical evolution of the Pleistocene Lake Lisan-Dead Sea system     

Amitai Katz  Yehoshua Kolodny  Arie Nissenbaum 《Geochimica et cosmochimica acta》1977,41(11):1609-1626

The geochemical history of Lake Lisan, the Pleistocene precursor of the Dead Sea, has been studied by geological, chemical and isotopic methods.Aragonite laminae from the Lisan Formation yielded (equivalent) Sr/Ca ratios in the range 0.5 × 10^?2?1 × 10^?2, Na/Ca ratios from 3.6 × 10^?3 to 9.2 × 10^?3, $\text{δ}{}^{18}\text{O}{}_{\mathrm{PDB}}$ values between 1.5 and 7%. and $\text{δ}{}^{13}\text{C}{}_{\mathrm{PDB}}$ from ?7.7 to 3.4%..The distribution coefficient of Na⁺ between aragonite and aqueous solutions, $\text{λ}{}^{\mathrm{A}}{}_{\mathrm{Na}}$, is experimentally shown to be very sensitive to salinity and nearly temperature independent. Thus, Na/Ca in aragonite serves as a paleosalinity indicator.Sr/Ca ratios and $\text{δ}{}^{18}\text{O}$ values in aragonite provide good long-term monitors of a lake's evolution. They show Lake Lisan to be well mixed, highly evaporated and saline. Except for a diluted surface layer, the salinity of the lake was half that of the present Dead Sea (15 vs 31%).Lake Lisan evolved from a small, yet deep, hypersaline Dead Sea-like, water body. This initial lake was rapidly filled-up to its highest stand by fresh waters and existed for about 40,000 yr before shrinking back to the present Dead Sea. The chemistry of Lake Lisan at its stable stand represented a material balance between a Jordan-like input, an original large mass of salts and a chemical removal of aragonite. The weighted average depth of Lake Lisan is calculated, on a geochemical basis, to have been at least 400, preferably 600 m.The oxygen isotopic composition of Lake Lisan water, which was higher by at least 3%. than that of the Dead Sea, was probably dictated by a higher rate of evaporation.Na/Ca ratios in aragonite, which correlate well with $\text{δ}{}^{13}\text{C}$ values, but change frequently in time, reflect the existence of a short lived upper water layer of varying salinity in Lake Lisan.  相似文献   

Stable sulfur and nitrogen isotopic compositions of crude oil fractions from Southern Germany     

A.V Hirner  W Graf  R Treibs  A.N Melzer  P Hahn-Weinheimer 《Geochimica et cosmochimica acta》1984,48(11):2179-2186

Eleven samples of crude oil from the Molasse Basin of Southern Germany were fractionated and their contents of sulfur and nitrogen as well as the stable isotope compositions of these elements (${}^{34}\text{S}{}^{32}\text{S}$ and ${}^{15}\text{N}{}^{14}\text{N}$, resp.) investigated.According to the δ³⁴S determinations, all crude oils from the Tertiary base of the Western and Eastern Molasse belong to one oil family and differ significantly from the Triassic and Liassic oils in the Western Molasse.An enrichment of ³⁴S was observed with increasing polarity of crude oil fractions. The isotope distributions of sulfur in the polar constituents of the biodegraded oils from the sandstones of Ampfing, however, approach a homogeneous distribution.The nitrogen isotope distribution is rather uniform in Southern German oils. A regional differentiation can be recognized, although the overall isotopic variation is small. The δ¹⁵N values of the crudes and asphaltenes do not correlate.  相似文献   

Interstellar organic matter in meteorites     

Jongmann Yang  Samuel Epstein 《Geochimica et cosmochimica acta》1983,47(12):2199-2216

Hydrogen which is highly enriched in deuterium is present in organic matter in a variety of meteorites including non-carbonaceous chondrites. The concentrations of this hydrogen are quite large. For example Renazzo contains 140 μmoles/g of the 10,000‰ δD hydrogen. The $\text{D}\text{H}$ ratios of hydrogen in the organic matter vary from 8 × 10^?5 to 170 × 10^?5 (δD ranges from ? 500‰ to 10,000‰) as compared to 16 × 10^?5 for terrestrial hydrogen and 2 × 10^?5 for cosmic hydrogen. The majority of the unequilibrated primitive meteorites contain hydrogen whose $\text{D}\text{H}$ ratios are greater than 30 × 10^?5. If the $\text{D}\text{H}$ ratios in these compounds were due to enrichment relative to cosmic hydrogen by isotope exchange reactions, it would require that these reactions take place below 150 K. In addition the organic compounds having $\text{D}\text{H}$ ratios above 50 × 10^?5 would require temperatures of formation of < 120 K. These types of deuterium enrichments must take place by ion-molecule reactions in interstellar clouds where both ionization and low temperatures exist. Astronomically observed $\text{D}\text{H}$ ratios in organic compounds in interstellar clouds are typically 180 × 10^?5 and range between about 40 × 10^?5 and 5000 × 10^?5. The $\text{D}\text{H}$ values we have determined are the lower limits for the organic compounds derived from interstellar molecules because all processes subsequent to their formation, including terrestrial contamination, decrease their $\text{D}\text{H}$ ratios.In contrast, the $\text{D}\text{H}$ ratios of hydrogen associated with hydrated silicates are relatively uniform for the meteorites we have analyzed with an average value of 14 × 10^?5; very similar to the terrestrial value. These phyllosilicates values suggest equilibration of H₂O with H₂ in the solar nebula at temperatures of about 200 K and higher.The ${}^{13}\text{C}{}^{12}\text{C}$ ratios of organic matter, irrespective its $\text{D}\text{H}$ ratio, lie well within those observed for the earth. If organic matter originated in the interstellar medium, our data would indicate that the ${}^{13}\text{C}{}^{12}\text{C}$ ratio of interstellar carbon five billion years ago was similar to the present terrestrial value.Our findings suggest that other interstellar material, representing various inputs from various stars, in addition to the organic matter is preserved and is present in the meteorites which contain the high $\text{D}\text{H}$ ratios. We feel that some elements existing in trace quantities which possess isotopic anomalies in the meteorites may very well be such materials.  相似文献   

Isotopic abundances of water of crystallization of gypsum from the Miocene evaporite formation,Carpathian Foredeep,Poland     

S. Hałas  H.R. Krouse 《Geochimica et cosmochimica acta》1982,46(2):293-296

For sulfates of Miocene evaporites in the Carpathian Foredeep, the waters of crystallization of gypsum (w.c.g.) have $\text{δD = ?38 to ?113\%.}$ and $\text{δ}{}^{18}\text{O = 0 to ?11\%.}$ (SMOW). The $\text{δ}{}^{34}\text{S}$ and $\text{δ}{}^{18}\text{O}$ values of the sulfates are uniform and consistent with a marine origin. It is proposed that the original w.c.g. was equilibrated with marine water. Subsequently, it re-equilibrated towards very isotopically light water (δD ～ ?100%., δ¹⁸O ～ ?14%) during a glacial or postglacial period and is now trending towards current waters circulating through the deposits (δD ～ ?50%., δ¹⁸ ～ ?7%). The extent of reequilibration increased with decreasing crystal size.  相似文献   

The formation of caliche in soils of the Mojave Desert,California     

William H. Schlesinger 《Geochimica et cosmochimica acta》1985,49(1):57-66

Radiocarbon and ²³⁰Th-²³⁴U dates of calcic horizons from calciorthid soil profiles in the Mojave Desert were used to calculate the rate of deposition of pedogenic CaCO₃. A major period of CaCO₃ deposition appears to have occurred about 20000 yBP forming calcic horizons below 100-cm depth during a climatic regime with greater effective rainfall than in the present. The overall rate of deposition has been 1.0 to 3.5 g CaCO₃/m²/yr during soil formation. This rate is consistent with present-day rates, assuming that the atmospheric deposition of Ca limits the process. Stable isotope ratios in calcic horizons indicate that CaCO₃ precipitated from a soil environment with CO₂ of ? 15.5%. ${}^{13}\text{C}{}^{12}\text{C}$ (vs. PDB) and H₂O of + 2.0%. ${}^{18}\text{O}{}^{16}\text{O}$ (vs. SMOW). These values suggest that CaCO₃ precipitates when seasonal drought simultaneously lowers soil pore pCO₂ and enriches soil water ¹⁸O by evaporation. The role of soil calcic horizons in the global geochemical cycle of carbon is discussed.  相似文献   

Aragonite from deep sea ultramafic rocks     

E. Bonatti  J.R. Lawrence  P.R. Hamlyn  D. Breger 《Geochimica et cosmochimica acta》1980,44(8):1207-1214

Aragonite mineralization was observed in serpentinized peridotites from the Romanche and Vema Fracture Zones in the Atlantic and the Owen Fracture Zone in the Indian Ocean, either in veins or as radial aggregates in cavities within the serpentinites. Evidence of incipient dissolution of the aragonite crystals was observed in one case. The aragonites tend to have lower Mg content (< 0.03%) and higher Sr content (> 0.95%) relative to other marine aragonites. Their ${}^{18}\text{O}{}^{16}\text{O}$, ${}^{13}\text{C}{}^{12}\text{C}$ and ${}^{87}\text{Sr}{}^{86}\text{Sr}$ isotopic ratios suggest the aragonite was deposited at ocean floor temperatures from solutions derived from sea water circulating in fissures and fractures within the ultramafic rocks. The ${}^{18}\text{O}{}^{16}\text{O}$ ratios of the serpentines indicate serpentinization occurred at higher temperatures, probably deeper in the crust. Low-T reactions between circulating seawater and Mg-silicates (primarily serpentine and pyroxenes) caused high pH and enrichment of Mg and Ca in the solution, conditions favoring carbonate precipitation. Aragonite was formed rather than calcite presumably because the high Mg²⁺ concentration in the solution inhibited calcite precipitation. The high Sr content of the aragonites is probably related, at least in part, to their low temperature of formation. Opaque mineral grains containing over 8% NiO and over 40% MnO were observed concentrated along the margins of some of the aragonite veins, suggesting that Ni is one of the elements mobilized during reactions between ultramafic rocks and circulating seawater.  相似文献   

Redistribution of uranium and thorium series isotopes during isovolumetric weathering of granite     

Jacqueline Michel 《Geochimica et cosmochimica acta》1984,48(6):1249-1255

Previous studies of the distribution of U and Th in parent versus weathered granites have shown both depletion and enrichment of these elements during weathering. In this study, the distribution of U and Th decay series isotopes was determined in a weathering profile of a granitic saprolite, which showed textural preservation indicating isovolumetric weathering. Two types of dissolution methods were used: a whole-rock dissolution and a sodium-citrate dithionite leach to preferentially attack noncrystalline phases of weathering products. Using volume-based activities, 45–70 percent of the total ²³²Th was gradually removed during weathering. Although the whole-rock ${}^{228}\text{Th}{}^{232}\text{Th}$ activity ratios were in equilibrium, there were large excesses of ²²⁸Th in the leachable fraction of both parent rock (${}^{228}\text{Th}{}^{232}\text{Th}\text{= 2.06}$) and partially weathered saprolite (${}^{228}\text{Th}{}^{232}\text{Th}\text{= 3–6.5}$), due to alpha recoil and release of daughter ²²⁸Th to the weathering rind of the mineral grain. For the most weathered sample, 81 percent of the thorium was in the teachable fraction and ${}^{228}\text{Th}{}^{232}\text{Th}\text{= 1}$, indicating that even the more resistant minerals were attacked.The total U activities showed as much variation in the six parent rock samples as in the weathered profile, and ${}^{234}\text{U}{}^{238}\text{U}$ were in equilibrium in both the whole-rock and leachable fractions. ²³⁰Th was deficient relative to ²³⁴U and ²²⁶Ra in both fractions, suggesting recent addition of U and Ra to the entire profile. The large variation in U was not from absorption onto the intermediate weathering products, because only 11–23 percent of the U was in the leachable fraction.  相似文献