Digonnière peatland (Dig1Ter core)
Pilat massif, Loire (eastern Massif Central), France
Sediments
- Type
- Sediment
Ombrotrophic peatland of 2.4 ha at 1055 m elevation, on leucogranite, about 12 km south of Saint-Étienne, along the Semène river. Fed only by the atmosphere, it records lead deposited since about 5300 BCE, in a region rich in Hercynian argentiferous lead deposits. Lead ratios, grouped by period, serve as a reference to separate the regional natural background from mining and industrial inputs.
206Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 18.7346 ± 0.063 | 18.6141 / 18.8152 | 8 | Mean and standard deviation recalculated from 8 levels, peat levels, before 2200 BCE (Neolithic to Chalcolithic), Table S4. Natural background according to the authors, who see it dominating before 2200 BCE: lead more radiogenic than later, in the direction of uncontaminated peatlands (206Pb/204Pb about 18.90 on average). Pb from 0.78 to 21.31 ppm. No isotope ratios: Di171, Di199. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.649 ± 0.0522 | 18.5196 / 18.722 | 13 | Mean and standard deviation recalculated from 13 levels, peat levels, Bronze Age (2200 to 800 BCE), Table S4. First mining imprints, increasing towards the end of the period. Pb from 0.02 to 3.76 ppm. No isotope ratios: Di49, Di76, Di79. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.5882 ± 0.0181 | 18.5743 / 18.6142 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Iron Age (800 to 50 BCE), Table S4. Pb from 2.31 to 3.24 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.5191 ± 0.0365 | 18.4876 / 18.5719 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Roman period (50 BCE to 500 CE), Table S4. First major peak of the European mining signal in the Early Roman period. Pb from 1.72 to 12.04 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.4623 ± 0.0026 | 18.4607 / 18.4653 | 3 | Mean and standard deviation recalculated from 3 levels, peat levels, Middle Ages (500 to 1500), Table S4. One level per sub-period (Early, High and Late Middle Ages). Pb from 11.35 to 13.56 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.4324 ± 0.0372 | 18.3446 / 18.4587 | 10 | Mean and standard deviation recalculated from 10 levels, peat levels, Industrial period (1750 to 1950), Table S4. No Early Modern level (1500 to 1750) in the core. Pb from 16.49 to 48.93 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 18.0636 ± 0.1498 | 17.9113 / 18.2864 | 6 | Mean and standard deviation recalculated from 6 levels, peat levels, Contemporary period (after 1950), Table S4. Mixture of coal, smelters and leaded gasoline; minimum 206Pb/204Pb (17.91) around 1994. Pb from 42.47 to 100.85 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
207Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 15.6719 ± 0.0059 | 15.6584 / 15.6773 | 8 | Mean and standard deviation recalculated from 8 levels, peat levels, before 2200 BCE (Neolithic to Chalcolithic), Table S4. Natural background according to the authors, who see it dominating before 2200 BCE: lead more radiogenic than later, in the direction of uncontaminated peatlands (206Pb/204Pb about 18.90 on average). Pb from 0.78 to 21.31 ppm. No isotope ratios: Di171, Di199. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6623 ± 0.005 | 15.6513 / 15.6682 | 13 | Mean and standard deviation recalculated from 13 levels, peat levels, Bronze Age (2200 to 800 BCE), Table S4. First mining imprints, increasing towards the end of the period. Pb from 0.02 to 3.76 ppm. No isotope ratios: Di49, Di76, Di79. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6587 ± 0.0036 | 15.6541 / 15.662 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Iron Age (800 to 50 BCE), Table S4. Pb from 2.31 to 3.24 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6522 ± 0.0066 | 15.643 / 15.6571 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Roman period (50 BCE to 500 CE), Table S4. First major peak of the European mining signal in the Early Roman period. Pb from 1.72 to 12.04 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6503 ± 0.0028 | 15.6483 / 15.6535 | 3 | Mean and standard deviation recalculated from 3 levels, peat levels, Middle Ages (500 to 1500), Table S4. One level per sub-period (Early, High and Late Middle Ages). Pb from 11.35 to 13.56 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6446 ± 0.0045 | 15.6364 / 15.6509 | 10 | Mean and standard deviation recalculated from 10 levels, peat levels, Industrial period (1750 to 1950), Table S4. No Early Modern level (1500 to 1750) in the core. Pb from 16.49 to 48.93 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 15.6115 ± 0.0124 | 15.5961 / 15.6293 | 6 | Mean and standard deviation recalculated from 6 levels, peat levels, Contemporary period (after 1950), Table S4. Mixture of coal, smelters and leaded gasoline; minimum 206Pb/204Pb (17.91) around 1994. Pb from 42.47 to 100.85 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
208Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 38.61 ± 0.059 | 38.519 / 38.679 | 8 | Mean and standard deviation recalculated from 8 levels, peat levels, before 2200 BCE (Neolithic to Chalcolithic), Table S4. Natural background according to the authors, who see it dominating before 2200 BCE: lead more radiogenic than later, in the direction of uncontaminated peatlands (206Pb/204Pb about 18.90 on average). Pb from 0.78 to 21.31 ppm. No isotope ratios: Di171, Di199. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.603 ± 0.031 | 38.523 / 38.645 | 13 | Mean and standard deviation recalculated from 13 levels, peat levels, Bronze Age (2200 to 800 BCE), Table S4. First mining imprints, increasing towards the end of the period. Pb from 0.02 to 3.76 ppm. No isotope ratios: Di49, Di76, Di79. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.598 ± 0.016 | 38.584 / 38.621 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Iron Age (800 to 50 BCE), Table S4. Pb from 2.31 to 3.24 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.589 ± 0.023 | 38.564 / 38.62 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Roman period (50 BCE to 500 CE), Table S4. First major peak of the European mining signal in the Early Roman period. Pb from 1.72 to 12.04 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.553 ± 0.009 | 38.547 / 38.563 | 3 | Mean and standard deviation recalculated from 3 levels, peat levels, Middle Ages (500 to 1500), Table S4. One level per sub-period (Early, High and Late Middle Ages). Pb from 11.35 to 13.56 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.495 ± 0.045 | 38.399 / 38.54 | 10 | Mean and standard deviation recalculated from 10 levels, peat levels, Industrial period (1750 to 1950), Table S4. No Early Modern level (1500 to 1750) in the core. Pb from 16.49 to 48.93 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 38.054 ± 0.177 | 37.884 / 38.321 | 6 | Mean and standard deviation recalculated from 6 levels, peat levels, Contemporary period (after 1950), Table S4. Mixture of coal, smelters and leaded gasoline; minimum 206Pb/204Pb (17.91) around 1994. Pb from 42.47 to 100.85 ppm. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
206Pb/207Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 1.1954 ± 0.0037 | 1.1888 / 1.2002 | 8 | Mean and standard deviation recalculated from 8 levels, peat levels, before 2200 BCE (Neolithic to Chalcolithic), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.1907 ± 0.003 | 1.1833 / 1.1951 | 13 | Mean and standard deviation recalculated from 13 levels, peat levels, Bronze Age (2200 to 800 BCE), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. The published 207Pb/206Pb of Di43 (0.84718) does not match its 204Pb ratios (0.8396): not used. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.1871 ± 0.0014 | 1.1862 / 1.1891 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Iron Age (800 to 50 BCE), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.1832 ± 0.0023 | 1.1808 / 1.1862 | 4 | Mean and standard deviation recalculated from 4 levels, peat levels, Roman period (50 BCE to 500 CE), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.1797 ± 0.0001 | 1.1796 / 1.1797 | 3 | Mean and standard deviation recalculated from 3 levels, peat levels, Middle Ages (500 to 1500), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.1782 ± 0.0021 | 1.1732 / 1.1795 | 10 | Mean and standard deviation recalculated from 10 levels, peat levels, Industrial period (1750 to 1950), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
| 1.157 ± 0.0087 | 1.1484 / 1.17 | 6 | Mean and standard deviation recalculated from 6 levels, peat levels, Contemporary period (after 1950), Table S4. Ratio recalculated from the 204Pb ratios, a common mixing tracer. | Delile et al. (2026), Rise and spread of lead-silver metallurgy deciphered from peatland … |
Deposits of the same type
- Marcenac reservoir on the Lot (reference) France
- Riou Mort and Riou Viou upstream of the Viviez plant France
- Riou Mort downstream of the Viviez plant France
- Cajarc reservoir on the Lot France
- Scheldt estuary Netherlands
- Natural Qaamarujuk fjord sediments (pre-mining) Greenland
- Keqikaer Glacier cryoconite China
- Ürümqi Glacier No. 1 cryoconite China
Cite this page
IsoFind Atlas (2026). Digonnière peatland (Dig1Ter core), isotope signatures. https://www.isofind.tech/isotopes/en/sites/tourbiere-de-la-digonniere-carotte-dig1ter/ (accessed 2026-10-13).
@misc{isofind2026digonnierepeatlanddig1tercore,
title = {Digonnière peatland (Dig1Ter core), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/sites/tourbiere-de-la-digonniere-carotte-dig1ter/},
note = {Accessed 2026-10-13}
}Updated : 2026-10-13