Fate of calcite, apatite and feldspars in an ombrotrophic peat bog, Black Forest, Germany

Abstract

The distribution of primary minerals in a peat profile was investigated in a dated core ( 210 Pb, 14 C) taken from the upper part of an ombrotrophic bog. Using XRD, the most abundant minerals present in the peat were those of the local granite, suggesting that the dust entering the bog is mainly of local origin. Apatite and calcite are restricted to the top 8 cm of the profile, which suggests rapid dissolution. The release of P by apatite dissolution is possibly the main source of plant-available P to the oligotrophic waters. In contrast, quartz and feldspars appear to be preserved for thousands of years despite the low pH and abundance of organic acids. This study suggests that ombrotrophic peat bogs could be valuable archives of aluminosilicate deposition since the Late Glacial.

Stable (206Pb, 207Pb, 208Pb) and radioactive (210Pb) lead isotopes in 1year of growth of Sphagnum moss from four ombrotrophic bogs in southern Germany: Geochemical significance and environmental implications

“…In both of these cases (natural Pb from soil dust and anthropogenic Pb from combustion processes), the Pb is physically incorporated in the aerosol. Whereas silicates minerals and glass shards are resistant to chemical weathering and are well preserved in acidic bogs (Le Roux et al, 2006), it may be that 210 Pb undergoes some detachment from the surface of the host aerosol, either in response to the low pH (typically 4) of bog water or the acidic pH of rainwater.…”

Rare earth element and Pb isotope variations in a 52 kyr peat core from Lynch’s Crater (NE Queensland, Australia): Proxy development and application to paleoclimate in the Southern Hemisphere

“…Experimental systems differ considerably from natural conditions however, where mineral dissolutions occur at reduced rates due to the presence of coatings and the near equilibrium conditions (Mö ller et al, 1998;Ganor et al, 2005). Feldspars are quite resistant to mild acid leaching in both experimental and natural settings (Mö ller et al, 1997;Bau et al, 1998) and in peats quartz and felspars are preserved for thousands of years even in acid (pH 4-4.5), organic rich environments (Steinmann and Shotyk, 1997;Le Roux et al, 2006). Ylirukanen and Lehto (1995) observed REE concentrations in peats varied in conjunction with ash content and that the REE patterns were similar to those of the rocks surrounding the peatland.…”

A Comparison of Tree Rings and Peat Deposit Geochemical Archives in the Vicinity of a Lead Smelter

“…The content of metals in peat depends mainly on the input of rain water, dissolution of solids transported through the dry deposition, and partly on ionic exchange and biological transformation processes (Shotyk 1997;Le Roux et al 2006). Since the 1950s, the deposition rates of Pb compounds and other accompanying metals changed significantly in the studied mining/smelting district (Vurm 2001).…”

“…It is probable that the cycling of major compounds in minerotrophic peat deposits is related to the lithogenic admixture or to the deposition of dust particles (Le Roux et al 2006), and that the basic cations content in tree rings are rather related to their content and availability from the exchangeable complex in soils. Higher concentrations of basic cations in the youngest part of the peat cores are probably related to the uptake of these nutrients by plants (Steinmann and Shotyk 1997).…”