New insights about the presence of celestite into fossil bones from Molí del Baró 1 site (Isona i Conca Dellá, Lleida, Spain)

Abstract

We have addressed an X-ray fluorescence (XRF) and X-ray diffraction (XRD) on a collection of thirteen fossil bone belonging to the Molí del Baró 1 paleontological site located near Sant Romà d'Abella (Isona i Conca Dellà Municipality, Lleida Province, Spain, dated to about 66.5 Ma, to investigate the fossilization occurred in this site in terms of physico-chemical properties. As a general behaviour, the XRD patterns showed the bioapatite mineral at a varying level of percentage, and accordingly, the correspondent XRF spectra turned out to be mainly dominated by the presence of Ca, obviously accompanied by phosphorus. Simultaneously, other elements such as Sr, Fe, Ba and Zn were found at non-negligible concentration levels and helped to assign the phase components in the XRD spectra. In three specimens, it was observed by XRD the rather unusual case where the original bioapatite bone mineral was completely substituted for by other mineralogical phases. In addition to this, celestite was also found as an important phase in ten specimens out of the thirteen examined. The occurrence of celestite in the bone structure appears a rather unusual observation within the literature of bones diagenesis. Its provenance is generally ascribed to marine vertebrate organisms, but the presence in the fossil bones of this site, where no evidence of marine environment exists, can be reconciled with occurrence of refluxing processes involving diagenetically altered fluids which were discharged into beds containing strontium sulphate-rich waters.

The Molí del Baró-1 site, a diverse fossil assemblage from the uppermost Maastrichtian of the southern Pyrenees (north-eastern Iberia)

“…The occurrence of well-preserved planktonic foraminifera in these debris, but also in the floodplain rocks of the Tremp Formation, suggests marine influence in the fluvial settings of the Tremp Formation, according to Díez-Canseco et al (2014). This is also supported by the presence of celestite into fossil bones from Molí del Bar o-1 (Piga et al, 2014). Altogether, the Molí del Bar o-1 locality can be envisaged as a result of plant and other organic material accumulation in small meandering rivers during the periods of relative low activity, or cessation of it.…”

Potential of Bioapatite Hydroxyls for Research on Archeological Burned Bone

“…Archaeological and fossilized remains usually contain several contaminants consequent of diagenetic processes such as calcite (CaCO 3 ), celestite (SrSO 4 ), gypsum (CaSO 4 ·2H 2 O), quartz (SiO 2 ), goethite (FeO­(OH)), kaolinite (Al 2 Si 2 O 5 (OH) 4 ), among others. ,− Their infrared bands will therefore add to the vibrational profile of bioapatite and may confuse the analysis and identification of the OH lib and ν­(OH) features. The presence of these mineral phases must be evaluated through X-ray diffraction.…”

“…For these reasons, the 603 cm -1 signal is more appropriate for the calculation of the indices. ), among others (13,(78)(79)(80). Their infrared bands will therefore add to the vibrational profile of bioapatite and may confuse the analysis and identification of the OH lib and ߥ(OH) features.…”

A structural approach in the study of bones: fossil and burnt bones at nanosize scale

“…Only in another case concerning a dinosaur bone we had found brushite as a complete substitute of biopapatite [6].…”

“…In fact minerals in fossil bones can have specific alteration in appropriate circumstances, which qualify it for determination of its chronology, paleo-environment and sometimes paleo-climate [6][7]. Considering multiple uses and importance of bone studies, a well-known bone structure is expected.…”