Nanbaxian (Mahai Basin borates)
Qinghai, Mahai Basin (northern Qaidam), China
OtherB
- Type
- Salt-pit borates (ulexite, borax)
The only part of the Mahai Basin where solid borates were deposited: salt pits 4 to 5 m across, isolated or connected, with ulexite and natural borax accompanied by glauberite, in the southwest of the basin, west of Da Qaidam Lake. Xiang et al. (2024): boron derived from weathering and fluid-rock interaction in the ultra-high pressure metamorphic belt, borates deposited at pH above 8 and more than 400 mg/L B.
δ11B in ‰ (per mil) Values of the same system
Standard : NIST SRM 951
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −18 ± 8.58 ‰ | −24.07 / −11.93 ‰ | 2 | salt-pit brine Mean and standard deviation recalculated from 2 analyses, -24.07 to -11.93 (NBX-01 -24.07; NBX-02 -11.93). NBX-01 turbid (pH 8.1; 659.5 mg/L B), NBX-02 brownish-red and warmer (pH 9.4; 2143 mg/L B). | Xiang et al. (2024), Source and Formation of Boron Deposits in Mahai Basin on the Norther… |
| −21.87 ± 11.38 ‰ | −34.71 / −6.14 ‰ | 10 | water-soluble phase of boron-bearing sediments (2 g in 200 mL, 24 h at 25 °C) Mean and standard deviation recalculated from 10 analyses, -34.71 to -6.14 (BXS -6.14; NBXS-01 -11.89; NBXS-02 -15.38; NBXS-03 -22.12; NBXS-04 -34.71; NBXS-05 -32.39; NBXS-06 -32.66; NBXS-07 -34.32; NBXS-08 -22.35; NBXS-09 -6.70). 0.28 to 41.4 mg/L B in the leachate; values close to Da Qaidam Lake borates (-23.67 to -3.0 ‰), redissolution of borates according to the authors. | Xiang et al. (2024), Source and Formation of Boron Deposits in Mahai Basin on the Norther… |
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- Kupferschiefer, Lubin-Sieroszowice district Poland
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Cite this page
IsoFind Atlas (2026). Nanbaxian (Mahai Basin borates), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/nanbaxian-borates-du-bassin-de-mahai/ (accessed 2026-10-20).
@misc{isofind2026nanbaxianmahaibasinboratesiso,
title = {Nanbaxian (Mahai Basin borates), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/nanbaxian-borates-du-bassin-de-mahai/},
note = {Accessed 2026-10-20}
}Updated : 2026-10-20