scholarly journals Coupled micromorphological and stable isotope analysis of Quaternary calcrete development

2015 ◽  
Vol 84 (2) ◽  
pp. 272-286 ◽  
Author(s):  
Kathryn Adamson ◽  
Ian Candy ◽  
Liz Whitfield
Keyword(s):  
Stable Isotope ◽  
Arid Regions ◽  
Isotope Analysis ◽  
Isotopic Analysis ◽  
Proxy Records ◽  
River Terraces ◽  
Stable Isotopic Analysis ◽  
Stable Isotopic ◽  
Stable Isotope Signatures ◽  
Positive Covariance

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 to more 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 since MIS 9 (c. 300 ka). Calcrete profiles contain a mixture 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 calcrete micromorphology and stable isotope signatures can allow patterns of calcrete formation to be placed into a wider palaeoclimatic context. This demonstrates the potential of this technique to more reliably constrain the palaeoenvironmental significance of secondary carbonates in dryland settings where other proxy records may be poorly preserved.

Detecting predation of a burrow-nesting seabird by two introduced predators, using stable isotopes, dietary analysis and experimental removals

2007 ◽  
Vol 34 (6) ◽  
pp. 443 ◽  
Author(s):  
Grant A. Harper
Keyword(s):  
Rattus Rattus ◽  
Isotopic Analysis ◽  
Diet Analysis ◽  
Passerine Birds ◽  
Dietary Analysis ◽  
Stable Isotopic Analysis ◽  
Introduced Predators ◽  
Ship Rat ◽  
Stable Isotopic ◽  
Burrowing Seabirds

Burrowing seabirds are vulnerable to extirpation by introduced predators such as rats, but much evidence of predation is circumstantial. On Taukihepa, an island off southern New Zealand, two possible predators exist with sooty shearwaters (Puffinus griseus): the weka (Gallirallus australis), a large rail, and the ship rat (Rattus rattus), both introduced to the island. It was expected that chick predation would be principally by weka, the much larger of the two predators. To measure losses of sooty shearwater chicks to weka or rats, nests were monitored with burrow-scopes at six sites in the summers of 2003–04 and 2004–05. In three of the sites rats were removed on 4-ha grids by trapping. In the other three sites rats were not trapped. In addition, weka were removed from all six sites in 2005. Concurrent diet analysis of weka and rat stomachs was undertaken as well as stable isotopic analysis (δ13C, δ15N) of samples from rats and weka. These were compared with possible prey items including sooty shearwaters. Additional stable isotope samples were taken from Pacific rats (Rattus exulans), a small rat species present with weka and sooty shearwaters on nearby Moginui Island. Weka diet comprised ~40% of bird remains by volume and calculations using Isosource, an isotopic source portioning model, estimated sooty shearwaters contributed 59% (range: 15–71%) of weka diet during the sooty shearwater chick-raising period. Ship rats, in contrast, had very depleted δ13C isotope signatures compared with sooty shearwaters and bird remains contributed <9% of diet by volume, with Isosource calculations suggesting that ship rats consumed more passerine birds (mean: 30%; range 5–51%) than sooty shearwaters (mean 24%; range: 0–44%). In both summers, more chicks were lost on sites from which rats had been removed than on control sites. When weka were removed in 2005, fewer chicks were lost than in 2004 and significantly fewer weka-killed chicks were found on weka-removal sites than on non-removal sites. Weka were the principal predator of sooty shearwater chicks, depredating an estimated 9.9% of nests. Combining several techniques quantified the loss and identified the principal predator of a seabird in decline.

scholarly journals PALAEOCLIMATIC EVOLUTION IN LOUTRA ARIDEAS CAVE (ALMOPIA SPELEOPARK, MACEDONIA, N. GREECE) BY STABLE ISOTOPIC ANALYSIS OF FOSSIL BEAR BONES AND TEETH

2017 ◽  
Vol 43 (2) ◽  
pp. 958
Author(s):  
N. Zisi ◽  
E. Dotsika ◽  
E. Tsoukala ◽  
A. Giannakopoulos ◽  
D. Psomiadis
Keyword(s):  
Late Pleistocene ◽  
Isotopic Analysis ◽  
Climatic Variations ◽  
Stable Isotopic Analysis ◽  
Diagenetic Processes ◽  
Stable Isotopic ◽  
Oxygen Stable Isotope ◽  
Carbonate Matrix ◽  
Age Range ◽  
Palaeoclimatic Reconstruction

Carbon and oxygen stable isotope values (δ13C, δ18O) were obtained from structural carbonate in the bioapatite of bear bones (Ursus ingressus) from Loutra Arideas cave, Almopia Speleopark, Macedonia, N. Greece. Samples of Late Pleistocene bear bones were studied for palaeoclimatic reconstruction of the area. The age range of the fossil layers is from 32ka BP to a maximum of 38ka BP. Generally, the palaeoclimatic proxy is correlated with literature data for climatic variations in the area during Late Pleistocene, whereas dietary behavior was investigated taking into account possible diagenetic processes that may have affected the carbonate matrix of the bones.

Bone lesions in Hadrosaurs: computed tomographic imaging as a guide for paleohistologic and stable-isotopic analysis

2009 ◽  
Vol 29 (2) ◽  
pp. 315-325 ◽  
Author(s):  
William H. Straight ◽  
Gustave L. Davis ◽  
H. Catherine W. Skinner ◽  
Andrew Haims ◽  
Bruce L. McClennan ◽  
...  
Keyword(s):  
Isotopic Analysis ◽  
Tomographic Imaging ◽  
Bone Lesions ◽  
Computed Tomographic ◽  
Stable Isotopic Analysis ◽  
Stable Isotopic ◽  
Computed Tomographic Imaging
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