Geochemical characteristics of a ferromanganese nodule with a tooth nucleus from the northwestern Pacific: Implications for element migration between Fe-Mn (oxyhydr)oxide and biogenic apatite

作者：Fangyu Shen, Xuefa Shi, Dongjie Bi, Mu Huang, Miao Yu, Jia Li, Yan Zhang, Aimei Zhu, Fengdeng Shi, Jihua Liu · 发表于：Ore Geology Reviews · 年份：2024 · DOI：10.1016/j.oregeorev.2024.105925 · 被引用次数：12 · 研究领域：Geochemistry and Elemental Analysis、Geological and Geochemical Analysis、Paleontology and Stratigraphy of Fossils

Biogenic apatite (fish teeth/bones) is considered the primary host mineral of rare earth elements and Y (REY) in deep-sea REY-rich sediments. Meanwhile, Fe-Mn (oxyhydr)oxides in the form of ferromanganese nodules and micronodules are also enriched in REY. Although studies have suggested that micronodules might release REY to pore water, eventually migrating into biogenic apatites during early diagenesis, robust evidence and mechanism for such migration remain elusive. Here, we present findings from a ferromanganese nodule with a fossil tooth nucleus discovered in surface sediments from the northwestern Pacific. Detailed geochemical characteristics of different parts of the ferromanganese nodule are provided, along with new analysis of modern shark teeth from the study area. The Fe-Mn (oxyhydr)oxides from the outer crust of the nodule are typically hydrogenetic, with lower Mn/Fe ratios (mean = 1.35, n = 33), in contrast to those filled in the tooth nucleus (mean Mn/Fe = 3.83, n = 20). Combined with compiled data on (micro)nodules and biogenic apatites in deep-sea sediments, we have identified the initial stage (Mn/Fe = 2.5 – 5) of early diagenesis of Fe-Mn (oxyhydr)oxides characterized by preferential release of light and middle rare earth elements (except Ce) compared to Fe-Mn (oxyhydr)oxides (micronodules) with higher degree of diagenesis. We demonstrated that biogenic apatites can inherit distinct fractionation of REY released from Fe-Mn (oxyhydr)oxides during different sta...