کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4466097 1622174 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Early diagenesis of elephant tusk in marine environment
ترجمه فارسی عنوان
تشنج زودهنگام بلندی فیل در محیط دریایی
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی


• Marine early diagenesis of elephant tusks
• Microscale study using a combined approach of ESEM, PIXE/RBS and SAXS
• Internal changes of the chemical composition of the mineral and organic parts
• Nanosized apatite, mineralized collagen fibers organizations and orientations
• Macroscopic surface state of the tusks does not reflect ivory preservation state

Three elephant tusks recovered from a 18th century Dutch shipwreck in Brittany seawaters were analyzed to study early diagenetic changes of ivory in a marine environment. Micro-small angle X-ray scattering (μSAXS) analysis revealed sub-microscopic structural modifications of ivory (hydroxyapatite particle thickness, mineralized collagen fibers organization and orientation). Chemical compositional changes of the organic fraction (nitrogen and carbon loss) and of the mineral part (magnesium loss, carbonate, calcium, chlorine and strontium uptake) were investigated by non-invasive micro-Particle Induced X-ray Emission/Gamma-ray Emission/Rutherford and Elastic Backscattering Spectrometry analysis (μPIXE/PIGE/RBS/EBS). These chemical and structural markers can serve as proxies for the early diagenesis of elephant tusk in marine settings. The results show that the macroscopic preservation state of the tusk surface does not reflect its microscopic preservation state. A diagenetic sequence is proposed, depending on the local environment of each tusk. First, collagen hydrolysis and ion adsorptions from the marine environment are proposed to occur. Second, a tusk buried in the sand was protected from Ca enrichment of the surface and the formation of a flaky white concretion whereas tusks out of the sand were subjected to these latter phenomena as well as sea-urchin attacks. Third, ion leaching and uptake, increased crystallinity of the hydroxyapatite crystals, and the modifications of the mineralized collagen fiber network are assumed to happen for all three tusks with different level of completion.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology - Volume 416, 15 December 2014, Pages 120–132
نویسندگان
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