Zweikirchen (bentonite)

Bavaria, Landshut area, Germany

Otherbentonite

Type: Bentonite (Ca, Mg)

Smectite bentonite deposit. Mainly terrestrial deposition: distal fresh to brackish fluvial-lacustrine setting, parent material rhyolitic ash; soil, wetland and groundwater, 15 to 40 °C alteration; Middle Miocene (14.77 ± 0.03 Ma). Köster et al. (2019): δ11B of purified smectites and fluid δ11B calculated for trigonal or tetrahedral boron at 25 and 90 °C.

δ11B in ‰ (per mil) Values of the same system

Standard : NIST SRM 951

Value	Range	n	Mineral or matrix	Source
−12.8 ± 8.4 ‰	−22.8 / −3.9 ‰		smectite (< 0.2 µm) treated with mannitol Mean and standard deviation recalculated from the means of 2 samples: ZW50-M -6.8 (2SD 1.4, -8.8 to -3.9, 16.4 µg/g B); ZW48-M -18.7 (2SD 1.4, -22.8 to -13.6, 12.4 µg/g B).	Köster et al. (2019), The boron isotope geochemistry of smectites from sodium, magnesium …
−17.5 ± 1.05 ‰	−18.6 / −14.2 ‰		smectite (< 0.2 µm) treated with mannitol and ammonium-exchanged, structural boron Single sample, published mean and 2SD (uncertainty halved to 1σ): ZW48-A -17.5 (2SD 2.1, -18.6 to -14.2, 12.7 µg/g B).	Köster et al. (2019), The boron isotope geochemistry of smectites from sodium, magnesium …

Deposits of the same type

Central African Copperbelt (whole province) DR Congo and Zambia
Witwatersrand basin South Africa
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). Zweikirchen (bentonite), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/zweikirchen-bentonite/ (accessed 2026-10-20).

@misc{isofind2026zweikirchenbentoniteisotopesi,
  title = {Zweikirchen (bentonite), isotope signatures},
  author = {{IsoFind Atlas}},
  year = {2026},
  url = {https://www.isofind.tech/isotopes/en/deposits/zweikirchen-bentonite/},
  note = {Accessed 2026-10-20}
}

Updated : 2026-10-20