Multistage ore-forming processes in the genesis of the fluorite-baryte Merguechoum ore deposit (Moroccan eastern Meseta) in relation to Pangea rifting

IF 3.4 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Journal of Geochemical Exploration Pub Date : 2025-03-26 DOI:10.1016/j.gexplo.2025.107766

Larbi Rddad , Mohammed Cherai , Benjamin F. Walter , Fouad Talbi

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引用次数: 0

Abstract

This study investigates the origin of the hydrothermal fluorite-baryte veins at Merguechoum, hosted in Late Hercynian granite beneath the Paleozoic-Triassic unconformity in the Moroccan eastern Meseta. The ore comprises two stages: fluorite 1and baryte 1 precipitated from a hot (156 C°–180 °C), moderate- to- high salinity fluid (13.5 to 39.4 wt% NaCl+CaCl₂), followed by the deposition of fluorite 2 and baryte 2 from a cooler (100 °C–135 °C), lower salinity fluid (22.2–25.4 wt% NaCl). Crush-leach data and rare earth element signatures indicates that the ore-forming fluids were initially evaporated seawater, which infiltrated the Paleozoic basement via NNE-NE trending faults and fractures during the Permian-Triassic rifting and evolved into F- and Ba-rich brines through fluid-rock interactions.

During the Triassic-Jurassic extension, a high geothermal gradient triggered localized convection, circulating basement-derived metalliferous fluids toward shallower zones along reactivated faults and fractures. The mixing of these basement-derived fluids with less saline, calcium- and sulfate-rich fluids stored in open spaces causing the deposition of fluorite and baryte. This study highlights the role of rift-related convection and fault-controlled fluid pathways in ore genesis, offering insights for exploring similar unconformity-related ore deposits in extensional settings.

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来源期刊

Journal of Geochemical Exploration 地学-地球化学与地球物理

CiteScore

7.40

自引率

7.70%

发文量

148

审稿时长

8.1 months

期刊介绍： Journal of Geochemical Exploration is mostly dedicated to publication of original studies in exploration and environmental geochemistry and related topics. Contributions considered of prevalent interest for the journal include researches based on the application of innovative methods to: define the genesis and the evolution of mineral deposits including transfer of elements in large-scale mineralized areas. analyze complex systems at the boundaries between bio-geochemistry, metal transport and mineral accumulation. evaluate effects of historical mining activities on the surface environment. trace pollutant sources and define their fate and transport models in the near-surface and surface environments involving solid, fluid and aerial matrices. assess and quantify natural and technogenic radioactivity in the environment. determine geochemical anomalies and set baseline reference values using compositional data analysis, multivariate statistics and geo-spatial analysis. assess the impacts of anthropogenic contamination on ecosystems and human health at local and regional scale to prioritize and classify risks through deterministic and stochastic approaches. Papers dedicated to the presentation of newly developed methods in analytical geochemistry to be applied in the field or in laboratory are also within the topics of interest for the journal.