摘要：The South China Block hosts extensive sedimentary phosphorites that offer valuable insights into both paleoenvironmental reconstruction and rare earth element (REE) resource potential. However, the mechanisms governing REE enrichment in these deposits remain poorly understood. This study investigates two distinct phosphorite layers from the Lower Cambrian Zhujiaqing (ZJQ) Formation in the Bailongtan (BLT) area of the Yangtze Platform using integrated analyses including petrology, XRD, major and trace elements, delta C-13 and delta O-18 isotopes, and LA-ICP-MS. The lower thin-bedded phosphorite, composed of finer phosphatic grains (＜300 mu m), exhibits significantly higher REE concentrations (883.6 +/- 160.9 ppm; n = 48) compared to the upper thick-bedded phosphorite (303.2 +/- 82.7 ppm; n = 64), which is dominated by larger, reworked grains (300-600 mu m). Intervening strata consist of laminated phosphate-bearing carbonates interbedded with quartz, dolomite, and pyrite. PAAS-normalized REE patterns display MREE-HREE enrichment, negative Ce anomalies (avg. 0.60 +/- 0.18; n = 18), and positive Y anomalies-indicative of oxic depositional conditions. The elevated REE content in the lower layer, coupled with the lowest delta C-13 values (-4.59 parts per thousand), suggests enrichment linked to organic matter degradation. A proposed two-stage depositional model links REE enrichment to proximity with REE-rich deep-shelf waters, underscoring the critical role of redox and depositional dynamics in phosphorite-hosted REE accumulation.

关键字：phosphorite; REE enrichment mechanism; Lower Cambrian; stable isotopes; sedimentary facies

ISSN号：2075-163X

卷、期、页：卷: 15期: 6

发表日期：2025-05-29

期刊分区（SCI为中科院分区）：四区

收录情况：SCI（科学引文索引印刷版）,SCIE（科学引文索引网络版）

发表期刊名称：MINERALS

参与作者：Mei, Wenhua,Ming, Xinyu,Wang, Zichen,Jiang, Lei

第一作者：蔡春芳

论文类型：期刊论文

论文概要：Mei, Wenhua,蔡春芳,Ming, Xinyu,Wang, Zichen,Jiang, Lei，Geochemistry and Enrichment of Rare Earth Elements in Phosphorite Successions in the Lower Cambrian, Eastern Yun＇nan, South China，MINERALS，2025，卷: 15期: 6

论文题目：Geochemistry and Enrichment of Rare Earth Elements in Phosphorite Successions in the Lower Cambrian, Eastern Yun＇nan, South China