Coupled micromorphological and stable isotope analysis of Quaternary calcrete development

Kathryn Adamson, Ian Candy, Elizabeth Whitfield

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Pedogenic calcretes are widespread in arid and semi-arid regions. Using calcrete profiles from four river terraces of the Rio Alias in southeast Spain, this study explores the potential of using detailed micromorphological and stable isotopic analysis tomore fully understand the impacts of Quaternary environmental change on calcrete development. The four profiles increase in carbonate complexity with progressive age, reflecting calcretisation over multiple glacial–interglacial cycles sinceMIS 9 (c. 300 ka). Calcrete profiles contain amixture of Alpha (non-biogenic) and Beta (biogenic) microfabrics. Alpha fabrics have higher δ13C and δ18O values. The profiles contain a
range of crystal textures, but there is little difference between the δ13C and δ18O values of spar, microspar, and micrite cements. Strong positive covariance between δ13C and δ18O suggests that both isotopes are responding to the same environmental parameter,which is inferred to be relative aridity. The study reveals that the detailed co-analysis of calcretemicromorphology and stable isotope signatures can allowpatterns of calcrete formation to be placed into a wider palaeoclimatic context. This demonstrates the potential of this technique tomore reliably constrain the palaeoenvironmental significance of secondary carbonates in dryland settings where other proxy
records may be poorly preserved.
Original languageEnglish
Pages (from-to)272-286
Number of pages17
JournalQuaternary Research
Issue number2
Early online date15 Jun 2015
Publication statusPublished - 1 Sept 2015


  • Pedogenic calcrete Micromorphology Stable isotopes Paleoenvironments Mediterranean

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