Kirka
Western Anatolia, Eskişehir Province (Seyitgazi district), Turkey
OtherB
- Type
- Neogene lacustrine borates (borax, ulexite, colemanite)
Borax deposit of western Anatolia in a Neogene volcano-sedimentary sequence (limestones, smectite clays, zeolitized tuffs) unconformable on Paleozoic basement, Mesozoic ophiolites and Eocene limestones. Borax body rimmed by a thin layer of ulexite then colemanite, all within limestones; deposited in playa sub-basins fed by geothermal springs related to calc-alkaline volcanism. Approximate coordinates of the town of Kırka. Palmer and Helvacı (1995): δ11B from -14.9 ‰ (colemanite) to -1.6 ‰ (borax), 87Sr/86Sr from 0.70830 to 0.70943.
δ11B in ‰ (per mil) Values of the same system
Standard : NIST SRM 951
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −3.68 ± 1.54 ‰ | −5.4 / −1.65 ‰ | 7 | borax Mean and standard deviation recalculated from 7 analyses, -5.40 to -1.65 (CH-8 -1.65; CH-14 -5.35; CH-15 -5.40; CH-18 -4.70; CH-24 -2.00; MRP-4 -2.95; MRP-5 -3.70). Replicates averaged before calculation: CH-8 -1.6 and -1.7; CH-14 -5.7 and -5.0; CH-15 -4.9 and -5.9; CH-18 -5.1 and -4.3; CH-24 -1.6 and -2.4; MRP-4 -3.3 and -2.6; MRP-5 -3.3 and -4.1. Massive or bedded borax of the borax zone (CH-8, CH-14, CH-15, MRP-4), below the ulexite nodules of CH-18, and cross-cutting recrystallized or secondary veins (CH-24, MRP-5). | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
| −7.29 ± 1.41 ‰ | −10.35 / −5.6 ‰ | 9 | ulexite Mean and standard deviation recalculated from 9 analyses, -10.35 to -5.60 (CH-7 -6.50; CH-10 -7.75; CH-9 -10.35; CH-12 -7.75; CH-17 -7.55; CH-18 -7.75; MRP-11 1° -6.05; MRP-11 * -5.60; MRP-17 -6.35). Replicates averaged before calculation: CH-7 -6.2 and -6.8; CH-10 -8.0 and -7.5; CH-9 -10.1 and -10.6; CH-12 -7.8 and -7.7; CH-17 -7.6 and -7.5; CH-18 -7.9 and -7.6; MRP-11 1° -5.7 and -6.4; MRP-11 * -5.9 and -5.3; MRP-17 -6.7 and -6.0. Fibrous layers above and below the borax zone, powdery cavity ulexite possibly secondary (CH-10), nodules on colemanite (CH-17) or on borax (CH-18); MRP-11: discoidal nodule (1°) and fine-grained ulexite in septarian cracks (*). | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
| −12.86 ± 1.82 ‰ | −14.8 / −9.75 ‰ | 7 | colemanite Mean and standard deviation recalculated from 7 analyses, -14.80 to -9.75 (CH-16 -13.10; CH-17 -9.75; MRP-12 1° -12.60; MRP-12 * -11.35; MRP-12 2° -14.80; MRP-14 c -14.70; MRP-14 e -13.70). Replicates averaged before calculation: CH-16 -12.9 and -13.3; CH-17 -9.6 and -9.9; MRP-12 1° -12.8 and -12.4; MRP-12 * -11.4 and -11.3; MRP-12 2° -14.9 and -14.7; MRP-14 c -14.7 and -14.7; MRP-14 e -13.7 and -13.7. Radiating nodules from the top of the deposit (CH-16) and above the borax zone (MRP-12, MRP-14), colemanite below the ulexite of CH-17; MRP-12: radiating colemanite (1°), recrystallized in veins (2°) and fine-grained in septarian cracks (*); MRP-14: centre (c) and exterior (e) of the nodule. Borax, ulexite, colemanite order consistent with the share of trigonal boron; with the Oi et al. (1989) factors, deposition at mean pH 8.2 for colemanite, 8.6 for ulexite and 8.83 for borax according to the authors. | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
| −13.35 ± 0.07 ‰ | −13.4 / −13.3 ‰ | 2 | colemanite from the small Göcenoluk deposit, northwest of Kirka Mean and standard deviation recalculated from 2 analyses, -13.40 to -13.30 (CH-22 -13.30; CH-22 -13.40). Two measurements of the same sample. 3 cm nodule, correlated by the authors with the colemanite level below the Kirka borax zone; name poorly legible in the scanned PDF. | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
87Sr/86Sr isotope ratio, no unit Values of the same system
Standard : E&A SrCO3
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 0.70892 ± 0.0003 | 0.70865 / 0.70943 | 5 | borax Mean and standard deviation recalculated from 5 analyses, 0.70865 to 0.70943 (CH-8 0.70891; CH-14 0.70865; CH-15 0.70874; CH-18 0.70943; CH-24 0.70889). Values for a subset of the samples measured for δ11B. | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
| 0.70874 ± 0.00038 | 0.7083 / 0.70941 | 6 | ulexite Mean and standard deviation recalculated from 6 analyses, 0.70830 to 0.70941 (CH-7 0.70862; CH-10 0.70855; CH-9 0.70890; CH-12 0.70830; CH-17 0.70864; CH-18 0.70941). Values for a subset of the samples measured for δ11B. | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
| 0.70889 ± 0.00039 | 0.70861 / 0.70916 | 2 | colemanite Mean and standard deviation recalculated from 2 analyses, 0.70861 to 0.70916 (CH-16 0.70916; CH-17 0.70861). Values for a subset of the samples measured for δ11B. | Palmer & Helvacı (1995), The boron isotope geochemistry of the Kirka borate deposit, west… |
Deposits of the same type
- Sagalassos hematite Turkey
- Dereköy magnetite sands (Sagalassos territory) Turkey
- Bigadiç Turkey
- Timna Israël
- Bahariya Oasis iron ores (El Gedida mine) Égypte
- Angouran Iran
- Kupferschiefer, Lubin-Sieroszowice district Poland
- Atlantis II Deep (Red Sea) Arabie saoudite et Soudan (zone commune)
Cite this page
IsoFind Atlas (2026). Kirka, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/kirka/ (accessed 2026-10-20).
@misc{isofind2026kirkaisotopesignatures,
title = {Kirka, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/kirka/},
note = {Accessed 2026-10-20}
}Updated : 2026-10-20