Middle Chesapeake Bay, core PC-6
Middle Chesapeake Bay (Maryland), United States
Sediments
- Type
- Sediment
Core collected in June 1989, far from any assumed anthropogenic source; sharp pollen discontinuity at 325 cm, read by the authors as an erosion gap. Recent levels carry anthropogenic Os transported from afar (down to 0.200 at 7.5 cm), while pre-settlement levels remain crustal (0.95 to 0.96). Helz et al. (2000).
187Os/188Os isotope ratio, no unit Values of the same system
Standard : Rapport absolu, sans standard de référence
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 0.6345 ± 0.2643 | 0.2001 / 0.9387 | 6 | core sediment, 7.5 to 302 cm (above the pollen discontinuity) Mean and standard deviation recalculated from 6 analyses, 0.2001 to 0.9387 (7.5 cm 0.2001; 30 cm 0.9387; 45 cm 0.6376; 167 cm 0.4856; 171 cm 0.7100; 302 cm 0.8349). 7.5 cm Os 0.747 ng/g, Re 2.64 ng/g; 30 cm Os 0.075 ng/g; 45 cm Os 1.056 ng/g; 167 cm Os 1.662 ng/g; 171 cm Os 0.121 ng/g; 302 cm Os 0.068 ng/g, Re 2.11 ng/g. Levels later than European agricultural settlement. | Helz et al. (2000), Osmium isotopes demonstrate distal transport of contaminated sediment… |
| 0.9594 ± 0.0039 | 0.9549 / 0.962 | 3 | core sediment, 429 to 481 cm (below the pollen discontinuity) Mean and standard deviation recalculated from 3 analyses, 0.9549 to 0.9620 (429 cm 0.9614; 434 cm 0.9620; 481 cm 0.9549). 429 cm Os 0.052 ng/g; 434 cm Os 0.051 ng/g; 481 cm Os 0.047 ng/g. Pre-settlement levels: regional crustal background. | Helz et al. (2000), Osmium isotopes demonstrate distal transport of contaminated sediment… |
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Cite this page
IsoFind Atlas (2026). Middle Chesapeake Bay, core PC-6, isotope signatures. https://www.isofind.tech/isotopes/en/sites/baie-de-chesapeake-moyenne-carotte-pc-6/ (accessed 2026-10-21).
@misc{isofind2026middlechesapeakebaycorepc6iso,
title = {Middle Chesapeake Bay, core PC-6, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/sites/baie-de-chesapeake-moyenne-carotte-pc-6/},
note = {Accessed 2026-10-21}
}Updated : 2026-10-21