Apatite ratios

Sorption of plutonium (l.fixlO-11 M) and americium (2xl0-9 M) in artificial groundwater (salt concentration 300 mg/liter total carbonate 120 mg/liter Ref. 59) on some geologic minerals, quartz, biotite, o apatite, o attapulgite, montmorillonite. Dashed lines indicate the range for major minerals in igneous rocks. Experimental conditions room temperature, particle size 0.04-0.06 mm, solid/liquid ratio 6-10 g/1, aerated system, contact time 6 days. 

The 8 C values of the Preclassic humans at Cuello (Table 2.1) average -12.9 0.9%o (n = 28) in collagen, -9.8 1.0 in bone apatite (n = 16), and -8.7 2.3%o in tooth enamel apatite (n = 33) the S N values in collagen average 8.9 1.0%o (n = 23). The discrepancy in the number of specimens is due to the fact that more teeth were available than post-cranial material, while some of the specimens contained insufficient collagen to measure the nitrogen isotope ratios. Additional bone apatite analyses are in progress. 

Lee-Thorp, J.A., Sealy, J.C. and van der Merwe, N.J. 1989 Stable carbon isotope ratio differences between bone collagen and bone apatite, and their relationship to diet. Journal of Archaeological Science 16 585-599. 

Schoeninger, M.J. and DeNiro, M.J. 1982 Carbon isotope ratios of apatite from bone cannot be used to reconstruct diets of animals. Nature 297 577-578. 

Carhon isotope ratios of hone apatite and animal diet reconstruction. Nature 301 ... 

In their study of the Laacher See eruption. Bourdon et al. (1994) obtained an isochron from their data on phonolitic pumice glasses (probably with U/Th ratios similar to those of the whole rocks) and glasses from cumulate nodules. The fractionation of U/Th ratios is attributed in that case to the crystallization of accessory U and Th-enriched phases such as sphene and apatite. The age of 14.3 6.5 ka is similar to the ages deduced from mineral isochrons (see section 3.5) and to the eruption age of 12.5 0.5 ka (Fig. 7b). Thus differentiation within the phonolitic magma occurred shortly before eruption. 

William Schopf studied supercrustal rock samples from Akilia Raman and ion microscopic photographs showed the presence of carbon-containing inclusions in grains of apatite. The carbon isotope ratio was determined by secondary ion mass spectroscopy (SIMS) the 813C value was -29% 4%, in agreement with earlier analyses. This in turn confirmed the values obtained by Mojzsis (1996), which had been questioned by Lepland et al. three years later. The final verdict on the oldest fossils in western Greenland may not be reached for several years yet (McKeegan et al., 2007 Eiler, 2007). 

Apatite formation on/in hydrogel matrixes using an alternate soaking process II. Effect of swelling ratios of poly(vinyl alcohol) hydrogel matrixes on apatite formation. Journal of Biomaterials Science-Polymer Edition, 10, 331-339. 

In conclusion, the solubility data indicate that upon precipitation from aqueous solutions which have a F/OH molar ratio less than a certain value, slightly fluoridated hydroxyapatites will be formed (x .0.15), and above that ratio nearly pure fluor-apatite will be formed. Usually the F/OH ratio varies so that intimate mixtures of hydroxyapatite and fluorapatite will result (64). The effect of fluoride on teeth and bones are discussed elsewhere (52, 57). 

Model 467), x-ray powder diffracton (Philips XRG-3000, x-ray diffractometer, CuK radiation Ni filter), and scanning electron microscopy, SEM (ISI scanning electron microscope, Model II). Infrared spectra and powder diffraction data were in agreement with the published values for apatite (19,20). Chemical analysis of the solid gave a molar ratio of Ca/P = 1.64 +0.01 the SSA was 21.5 m g"1. 

Of special geological interest is the isotopic analyses of coeval carbonate-phosphate pairs (Wenzel et al. 2000), which helps to distinguish primary marine signals from secondary alteration effects and sheds light on the causes for 5 0 variations of fossil ocean water. Wenzel et al. (2000) compared Silurian cal-citic brachiopods with phosphatic brachiopods and conodonts from identical stratigraphic horizons. They showed that primary marine oxygen isotope compositions are better preserved in conodonts than in brachiopod shell apatite and suggested that conodonts record paleotemperature and ratios of Silurian sea water. 

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