Petrogenesis of the Mayo-Darley tin formations, anorogenic complex of the Cameroon Line: implication for tin deposit

• 作者: OA Ndema Mbongué Jean Lavenir Ndongfong Edson Fuh Emmanuel Eseya Mengu Junior .Department of Geology Faculty of Sciences University of Buea .Department of Earth Sciences Faculty of Sciences University of Yaoundé I
• 来源期刊: 地球化学学报(英文）
• 学科: 地球科学
• 年，卷（期）: 2025,（4）
• 页码范围: 120-141
• 页数: 22页
• 语种: 中文

摘要

The Mayo-Darley massif is an anorogenic complex of the Cameroon Line that has a mantle origin.Tin-bearing rocks were analyzed by ICP-AES and INAA analytical methods. The purpose of this work was to provide new geochemical data for the Mayo-Darley tin formation and to understand its petrogenesis and the origin of tin mineralization. The Mayo-Darley tin deposit is made up of tin-granite, and tin-greisen, greisenification was developed on the borders of quartz dykes. These rocks belong to the alkaline series and were classified into acid（SiO2-= 61.6%–73.8%; 65.4%–98% respectively） and basic（42.9%–47% SiO2） rocks. They showed enrichment in HSFE, LILE, Ga/Al and chondrite normalized REE patterns indicating LREE enrichment relative to HREE with a negative Eu anomaly, only sample SB8 of tin-granite showed Eu/Eu* = 1.11. Rocks display metaluminous,peralkaline, peraluminous, ferroan, high-K calc-alkaline to shoshonitic, alkalic to calcic affinity, and crystallized at800 °C. The chemistry of this deposit reflects the primary composition of granite, quartz monzonite, gabbro, and foid gabbro. This complex experienced multi-stage sub-solidus hydrothermal fluid reactions and shows variable alteration of feldspars alkali mobility. The rocks are classified as A1-type granite, overlap with the OIB field, and were derived from a within-plate setting, similar to mantle non plumederived magmas. The origin of tin mineralization in MayoDarley has a complex evolution, tin mineralization was derived from hydrothermal and hydrogenous metal-rich deposits and shows Sn–Hf–Zr and Sn–Tl–Nb association.These new data confirm the complexity of the Mayo-Darley tin complex and elucidate the origin of tin mineralization.