English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/145620
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Now a bone, then calcite

AuthorsFernández-Jalvo, Yolanda ; Pesquero, María Dolores ; Tormo, Laura
KeywordsCalcite-aragonite
Phosphate-migration
Carbonate
Bioapatite
Issue Date15-Feb-2016
PublisherElsevier
CitationPalaeogeography, Palaeoclimatology, Palaeoecology 444: 60-70 (2016)
AbstractCritical transformation and degradation of skeletal tissues most frequently affect their organic componentswhile the mineral component of bones and fossils comprises one of the most stable mineral groups on Earth: the apatites. The case we present here relates to fossil bones from palaeolake-shores whose shapes are preserved within the sediment itself, but which disintegrate into a chalky, disaggregated substance at the slightest touch or breath. The rarity of bone apatite transformation into calcite is due to the extreme insolubility and stability of bone mineral, which is highly tolerant of ionic substitutions and inclusions without changing its basic mineral nature and composition. Observation of this chalky substance under high magnifications reveals a delicate structure of microcrystals. These crystals enclose microtunnels and grooves identical in shape and size to the characteristic bone bioerosion caused by aquatic microorganisms. This microtunnelling preservation allows us to confirm that disaggregate calcite crystals replaced areas where once there had been bone. Furthermore, the bone-chalky material transformation had to occur when microorganisms were still in the interior of these tunnels; otherwise, the delicate empty microtunnels observed today would have collapsed. Two calcareous palaeo-lakeshore sites show identical phenomenon. Detailed taphonomic, environmental and chemical studies indicate that the transformation process was initiated by microorganisms arising from a combination of their metabolism and the alkaline environment they inhabited that caused a local and sudden increase in local acidity. This chalky material is referred to as biogenic, in contrast to environmental calcite deposits (geodes and calcite infilling bone fissures) that formed in the lake conditions. The calcium carbonate phase of both biological and environmental origin in these two palaeolakes is aragonite,which forms under restricted situations of aridity andwarming, andmay provide a precise indication of environmental conditions when these sites formed. Similar situations may occur today in arid areas.
URIhttp://hdl.handle.net/10261/145620
DOI10.1016/j.palaeo.2015.12.002
Identifiersdoi: 10.1016/j.palaeo.2015.12.002
issn: 0031-0182
Appears in Collections:(MNCN) Artículos
Files in This Item:
File Description SizeFormat 
accesoRestringido.pdf15,38 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.