Sijes
Salta, Puna, east of Salar de Pastos Grandes, Argentina
OtherB
- Type
- Neogene lacustrine borates (hydroboracite, colemanite, inyoite)
Puna Plateau (central Andes), internally drained basins filled since about 15 Ma; borates deposited since about 8 Ma by volcanism-related thermal springs. Largest known hydroboracite reserves; Pozuelos and Sijes formations (nearly 2000 m of volcaniclastic and evaporitic sequences), boron-bearing Monte Amarillo and Monte Verde members, chain of small permanent lakes; folded and faulted, borate beds largely intact. Kasemann et al. (2004): two assemblages, borax-ulexite-inyoite (fluid near -13 ‰, basement boron) and hydroboracite-colemanite (fluid near 0 ‰, heavier volcanic boron). Coordinates not published (map only).
δ11B in ‰ (per mil) Values of the same system
Standard : NIST SRM 951
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −17.2 ‰ | 1 | colemanite Single analysis (premier bloc). Hydroboracite-colemanite assemblage, calculated fluid near 0 ‰. Table 1 gives "Monte Verde Member" for both Sijes blocks; Appendix A places the second in the Monte Amarillo member. | Kasemann et al. (2004), Boron isotope composition of geothermal fluids and borate mineral… | |
| −15.6 ± 0.8 ‰ | −16.1 / −15 ‰ | 2 | hydroboracite Mean and standard deviation recalculated from 2 analyses, -16.1 to -15.0 (premier bloc -16.1; second bloc -15.0). Hydroboracite-colemanite assemblage, calculated fluid near 0 ‰. Table 1 gives "Monte Verde Member" for both Sijes blocks; Appendix A places the second in the Monte Amarillo member. | Kasemann et al. (2004), Boron isotope composition of geothermal fluids and borate mineral… |
| −22.4 ‰ | 1 | ulexite Single analysis (premier bloc). Borax-ulexite-inyoite assemblage, calculated fluid near -13 ‰. | Kasemann et al. (2004), Boron isotope composition of geothermal fluids and borate mineral… | |
| −16.8 ‰ | 1 | borax Single analysis (second bloc). Borax-ulexite-inyoite assemblage, calculated fluid near -13 ‰. | Kasemann et al. (2004), Boron isotope composition of geothermal fluids and borate mineral… | |
| −29.1 ± 0.5 ‰ | −29.5 / −28.5 ‰ | 3 | inyoite Mean and standard deviation recalculated from 3 analyses, -29.5 to -28.5 (premier bloc -29.3; second bloc -29.5; second bloc -28.5). Lowest values of the study; inyoite and colemanite share the same B[3]/B[4] ratio but differ by 12 ‰: different fluids for the two assemblages according to the authors. | Kasemann et al. (2004), Boron isotope composition of geothermal fluids and borate mineral… |
Deposits of the same type
- Central African Copperbelt (whole province) DR Congo and Zambia
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- Stelvio Italy
- Oris Italy
- Kupferschiefer, Lubin-Sieroszowice district Poland
- Timna Israël
- Datangpo-type manganese (Gaolou, Minle, Zhenxing) China
- Eyller Bruch bog iron ore Germany
Cite this page
IsoFind Atlas (2026). Sijes, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/sijes/ (accessed 2026-10-19).
@misc{isofind2026sijesisotopesignatures,
title = {Sijes, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/sijes/},
note = {Accessed 2026-10-19}
}Updated : 2026-10-19