31 New Perspectives on Mineral Resources of the Northeast (Posters)

Monday, 18 March 2019
8:00 AM - 12:00 PM
Casco Bay Hall

THE GENESIS OF THE TIGRININE-TAABEST MVT PB-ZN ORE DEPOSIT IN CENTAL HIGH ATLAS: CONSTRAINTS FROM FLUID INCLUSION AND C-O-S-PB ISOTOPES STUDIES

Paper number: 31-2
Program: Theme Sessions
Time: 8:00 AM – 12:00 PM

Authors

  • Larbi Rddad Presenting Author
    Kingsborough Community College, Brooklyn, NY

Abstract

The Mississippi valley type Pb-Zn ore deposit of the Tigrinine-Taabest Pb-Zn ore district, located in the Moroccan Central High Atlas, is hosted in hydrothermally dolomitized Liassic carbonates. The mineralogical paragenetic sequence is simple: Quartz-dolomite-pyrite-copper-galena-sphalerite. Fluid inclusions carried out on sphalerite reveal that ore is precipitated from a NaCl-KCl-CaCl2-MgCl2 basin-derived warm (123 oC) and saline (34 wt% eq. NaCl) brine.

The δ34S values range from 6.6 to 9.4‰ and from 12.7 to 13.0‰ for galena and sphalerite respectively with an average δ34Sfluid of 13‰. Sulfur derived most likely from Triassic sulfates through thermochemical-sulfate reduction. Galena samples have a homogeneous Pb composition with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios ranging from 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios ranging from 18.229 to 18.236, 15.643 to 15.655, and 38.448 to 38.527 respectively. This Pb composition plots in the upper crust and the orogene and suggest well-mixed source rocks of metals.

During the African-European continental collision (Alpine orogeny), the metal-bearing fluids were remobilized and migrated through major E-W to NE-SW- trending faults. Mixing of the hot, ore-bearing fluids with a cooler fluid are likely the main cause of ore precipitation as indicated by C-O isotopes and fluid inclusions data.

Geological Society of America Abstracts with Programs. Vol. 51, No. 1

doi: 10.1130/abs/2019NE-328023

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