کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1045837 944836 2011 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Pleistocene-Holocene environmental change in the Canary Archipelago as inferred from the stable isotope composition of land snail shells
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Pleistocene-Holocene environmental change in the Canary Archipelago as inferred from the stable isotope composition of land snail shells
چکیده انگلیسی
The isotopic composition of land snail shells was analyzed to investigate environmental changes in the eastern Canary Islands (28-29°N) over the last ~ 50 ka. Shell δ13C values range from −8.9‰ to 3.8‰. At various times during the glacial interval (~ 15 to ~ 50 ka), moving average shell δ13C values were 3‰ higher than today, suggesting a larger proportion of C4 plants at those periods. Shell δ18O values range from −1.9‰ to 4.5‰, with moving average δ18O values exhibiting a noisy but long-term increase from 0.1‰ at ~ 50 ka to 1.6-1.8‰ during the LGM (~ 15-22 ka). Subsequently, the moving average δ18O values range from 0.0‰ at ~ 12 ka to 0.9‰ at present. Calculations using a published snail flux balance model for δ18O, constrained by regional temperatures and ocean δ18O values, suggest that relative humidity at the times of snail activity fluctuated but exhibited a long-term decline over the last ~ 50 ka, eventually resulting in the current semiarid conditions of the eastern Canary Islands (consistent with the aridification process in the nearby Sahara). Thus, low-latitude oceanic island land snail shells may be isotopic archives of glacial to interglacial and tropical/subtropical environmental change.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Research - Volume 75, Issue 3, May 2011, Pages 658-669
نویسندگان
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