Stable carbon isotopic fractionation of individual n-alkanes accompanying primary migration: Evidence from hydrocarbon generation–expulsion simulations of selected terrestrial source rocks

The amount of isotopic fractionation (change in isotope ratios) between diet and animal tissues is generally poorly known and may be affected by trophic position. Diet-tissue fractionation of stable-carbon and -nitrogen isotopes was measured in several tissues of red foxes (Vulpes vulpes) raised on a commercial pellet feed. Stable carbon isotopic fractionation in red fox was positive for all tissues and was greatest in fur (2.6), intermediate in muscle (1.1), and least in liver and blood fractions (0.4-0.6). These carbon isotope fractionation values were greater than those previously measured for mammalian herbivores but were similar to values for marine mammals in most tissues. Little variation in stable nitrogen isotopic fractionation occurred among tissues, except in the blood fractions. Nitrogen isotopic fractionation was much higher in blood serum (4.2) than in liver, muscle, and fur (3.3-3.5). Cellular fractions of blood had the lowest fractionation values (2.6). There was a significant age effect in nitrogen- but not in carbon-isotopic fractionation. Subadult foxes (<1 year) were significantly enriched in 15N compared with adult foxes for fur, muscle, and liver (no blood was collected from adults). The cause of this enrichment is unclear, but it may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first to report isotopic fractionation values for a terrestrial mammalian carnivore. Such estimates are necessary to interpret stable-isotope patterns in wild carnivores.

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Compositional and stable carbon isotopic fractionation during non-autocatalytic thermochemical sulfate reduction by gaseous hydrocarbons

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2014.05.004 ◽

2014 ◽

Vol 139 ◽

pp. 472-486 ◽

Cited By ~ 20

Author(s):

Xinyu Xia ◽

Geoffrey S. Ellis ◽

Qisheng Ma ◽

Yongchun Tang

Keyword(s):

Sulfate Reduction ◽

Isotopic Fractionation ◽

Stable Carbon ◽

Carbon Isotopic ◽

Thermochemical Sulfate Reduction ◽

Gaseous Hydrocarbons ◽

Carbon Isotopic Fractionation

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Preliminary Study on Relations between Methane Carbon Isotopic Fractionation and Accumulation of Natural Gas of Lower Paleozoic in the Center of Ordos Basin, China

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.318.477 ◽

2013 ◽

Vol 318 ◽

pp. 477-481

Author(s):

Yun Feng Zhang

Keyword(s):

Thermal Evolution ◽

Ordos Basin ◽

Isotopic Fractionation ◽

Source Rocks ◽

Gas Migration ◽

Lower Paleozoic ◽

Carbon Isotopic ◽

Physical And Chemical ◽

Methane Carbon ◽

Carbon Isotopic Fractionation

Carbon isotopic fractionation frequently occurs during the process of source rocks generating hydrocarbon and its migration through the pore media. Conversely, the recorded isotopic information reflects some physical and chemical characteristics of the rocks, such as porosity, permeability and thermal evolution, etc. In this paper, based on the preliminary analysis of methane carbon isotopic fractionation of Lower Paleozoic in the center of Ordos Basin, China, some reservoir-forming factors like thermal evolution centers, gas pool margins, gas migration directions and the favorable accumulation zones were roughly identified. The results show the hydrocarbon-generating centers located in the Yanan-Jingbian area, the gas migrating direction from southeast to northwest, and the gas reservoir bounded by the lower permeable zone of Wuqi-Suligemiao-Yulin-Jiaxian. Finally, the isotopic results are supported by the otherss special research conclusions of source rock maturity and lithofacies palaeogeography. Therefore, the suggested viewpoints about carbon isotope in this paper have higher reliability.

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