کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4406890 1307329 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Stable isotopic signatures of the modern land snail Eremina desertorum from a low-latitude (hot) dry desert—A study from the Petrified Forest, New Cairo, Egypt
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Stable isotopic signatures of the modern land snail Eremina desertorum from a low-latitude (hot) dry desert—A study from the Petrified Forest, New Cairo, Egypt
چکیده انگلیسی

This study was conducted on recent desert samples—including (1) soils, (2) plants, (3) the shell, and (4) organic matter from modern specimens of the land snail Eremina desertorum—which were collected at several altitudes (316–360 m above sea level) from a site in the New Cairo Petrified Forest. The soils and shellE. desertorum were analyzed for carbonate composition and isotopic composition (δ18O, δ13C). The plants and organic matterE. desertorum were analyzed for organic carbon content and δ13C. The soil carbonate, consisting of calcite plus minor dolomite, has δ18O values from −3.19 to −1.78‰ and δ13C values −1.79 to −0.27‰; covariance between the two values accords with arid climatic conditions. The local plants include C3 and C4 types, with the latter being dominant. Each type has distinctive bulk organic carbon δ13C values: −26.51 to −25.36‰ for C3-type, and −13.74 to −12.43‰ for C4-type plants.The carbonate of the shellE. desertorum is composed of aragonite plus minor calcite, with relatively homogenous isotopic compositions (δ18Omean = −0.28 ± 0.22‰; δ13Cmean = −4.46 ± 0.58‰). Most of the δ18O values (based on a model for oxygen isotope fractionation in an aragonite-water system) are consistent with evaporated water signatures. The organic matterE. desertorum varies only slightly in bulk organic carbon δ13C values (−21.78 ± 1.20‰) and these values suggest that the snail consumed more of C3-type than C4-type plants. The overall offset in δ13C values (−17.32‰) observed between shellE. desertorum carbonate and organic matterE. desertorum exceeds the value expected for vegetation input, and implies that 30% of carbon in the shellE. desertorum carbonate comes from the consumption of limestone material.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemie der Erde - Geochemistry - Volume 75, Issue 1, March 2015, Pages 65–72
نویسندگان
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