This study investigates the first stable S-, O- and C-isotopes data on the Beleleita scheelite skarn deposit to assess the origin of the mineralising fluids involved in the formation of the skarn and
related W-As-Bi-(Au) mineralisation. Two skarn bodies are embedded within the Neoproterozoic gneisses, south of the Edough metamorphic complex, NE Algeria. They show subparallel,
discontinuous slabs (F1 and F2) approximately 700 m long and 10 m wide, striking NE–SW. The slabs were cross-cut by bore-hole drilling at a depth of 130 m during ORGM (Office de Recherche
Géologique et Minière) mining exploration in the 1980s. Textural observations reveal two main cycles. Cycle I displays early classical zoned skarn assemblage, including clinopyroxene, garnet,
plagioclase, pyrite, pyrrhotite, and chalcopyrite. Cycle II shows late lithiniferous and fluorinated skarn assemblage that corresponds to greisenised secant skarns, with fluorite, scheelite, lollingite,
allanite, zinnwaldite series, sphene, wolframite, arsenopyrite, native bismuth, and quartz. Stable O-isotope analyses were carried out on both whole-rock samples and clinopyroxene, quartz, and
garnet mineral separates, whereas C- and O-isotope analyses were conducted on gangue calcite. S-isotopes were carried out on sulphides (pyrite, chalcopyrite, lollingite and pyrrhotite). All the
results display relatively narrow ranges (δ18OSMOW varying from +8.4 to +9.9‰; δ13CPDB ranging between -6.9 to -4.2‰ and δ34SCDT between -0.3 to +5.3‰), indicating a homogeneous source of fluids with significant magmatic signatures that contribute to skarn formation and ore deposition. Accordingly, the involved mineralising fluids most likely originated from the I-type magmatic event that prevailed during Burdigalian times in the Edough massif, similar to many other ore deposits in the area. Moreover, previous fluid inclusion studies carried out on fluorite, scheelite, and quartz of Cycle II show that the ores were deposited from hot (Th = 500°-520°C), highly saline magmatic fluids under low pressure (0.5–0.6 kb), and this complies well with the present stable isotope data.
Abdelmalek LEKOUI and co-authors are grateful for the anonymous reviewers, including editors, whose comments contributed to the improvement of the manuscript.
Birincil Dil | İngilizce |
---|---|
Konular | Genel Jeoloji |
Bölüm | Makaleler |
Yazarlar | |
Yayımlanma Tarihi | 5 Aralık 2024 |
Gönderilme Tarihi | 21 Kasım 2023 |
Kabul Tarihi | 4 Eylül 2024 |
Yayımlandığı Sayı | Yıl 2024 Cilt: 175 Sayı: 175 |
Copyright and Licence
The Bulletin of Mineral Research and Exploration keeps the Law on Intellectual and Artistic Works No: 5846. The Bulletin of Mineral Research and Exploration publishes the articles under the terms of “Creatice Common Attribution-NonCommercial-NoDerivs (CC-BY-NC-ND 4.0)” licence which allows to others to download your works and share them with others as long as they credit you, but they can’t change them in any way or use them commercially.
For further details;
https://creativecommons.org/licenses/?lang=en