摘要 : To help understand bioapatite microstructures and related chemical variations, their impact on O-isotope compositions measured and give insights on sample preparation, this study analysed conodonts and shark teeth prepared in diff... 展开 To help understand bioapatite microstructures and related chemical variations, their impact on O-isotope compositions measured and give insights on sample preparation, this study analysed conodonts and shark teeth prepared in different orientations through microanalytical and bulk sampling techniques: scanning electron microscopy (SEM); electron probe microanalysis (EPMA); continuous-flow and high-temperature reduction - isotope ratio mass spectrometry; and secondary ion mass spectrometry (SIMS). The SEM and EPMA measurements in conodonts allowed to distinguish the tissues commonly analysed by SIMS, which included albid and hyaline crowns but given their often small-scale intergrowth, mixtures of these are difficult to avoid. In situ SIMS O-isotope analyses provided different delta O-18 values: lower values with higher variance (16 +/- 1 parts per thousand n = 13, 15.7 +/- 1.9 parts per thousand n = 11) for mixed albid-hyaline tissues, and higher, homogeneous values (17.1 +/- 0.2 parts per thousand, n = 13) for mainly hyaline tissues. Recent shark teeth delta O-18(SIMS) value for dentine of the same tooth was 10 parts per thousand lower than the mean delta O-18(SIMS) value for enameloid whereas the delta O-18(PO4) values measured for enameloid and dentine using the HTR method were identical. The variation of delta O-18 seems sensitive to analytical artefacts related to sample textures, caused during the sample preparation over more porous biomineral surfaces. 收起