Controls on the distribution and fractionation of yttrium and rare earth elements in core sediments from the Mandovi estuary, western India

摘要: Mineralogy, major elements (Fe, Mn and Al), rare earths yttrium (REY) of bulk sediments were analyzed in four gravity cores recovered along the main channel Mandovi estuary, western India, to determine sources controls on REY distribution. The accelerator mass spectrometer (AMS) ages total organic carbon indicated modern age for upper estuary and, maximum mean 1588 years AD 539 bottom lower bay, respectively. upper/middle showed abundant hematite, magnetite goethite high Fe, Mn, total-REE (ΣREE) Y, while those estuary/bay silicate minerals relatively low ΣREE Y. significant correlation with clay silt fractions Al (OC) content sediments. light heavy REE ratios (LREE/HREE) than Post-Archean Australian Shale (PAAS). PAAS-normalized (REY; Y inserted between Dy Ho) patterns middle (MREE)- HREE-enrichment positive Eu anomaly (Eu/Eu⁎) variable Ce (Ce/Ce⁎). is primarily controlled by its texture source sediment, which ore material-dominated estuary/bay. Low LREE/HREE suggest that very fine-grained carried away from because high-energy conditions. Fractionations (Y/Ho, Sm/Nd, Ce/Ce⁎ Eu/Eu⁎) are different mechanisms. High Y/Ho clayey silts due redistribution Ho adsorption onto organic-rich, clays. Variations Sm/Nd similar Eu/Eu⁎ mineral constituents Positive anomalies inherited material, material rocks, Negative related rock influenced lanthanum enrichment at certain sediment intervals.