Limestone weathering rates accelerated by micron-scale grain detachment

Geology ◽  
2014 ◽  
Vol 42 (9) ◽  
pp. 751-754 ◽  
Author(s):  
Simon Emmanuel ◽  
Yael Levenson
Keyword(s):  
Weathering Rates ◽  
Limestone Weathering

scholarly journals Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

2019 ◽  
Vol 527 ◽  
pp. 118774 ◽  
Author(s):  
Xiaoli Dong ◽  
Matthew J. Cohen ◽  
Jonathan B. Martin ◽  
Daniel L. McLaughlin ◽  
A. Brad Murray ◽  
...  
Keyword(s):  
Soil Thickness ◽  
Weathering Rates ◽  
Karst Landscape ◽  
Limestone Weathering

25 Jahre nationale Bodenbeobachtung im Schweizer Wald | 25 years of soil monitoring at forest sites in Switzerland

2010 ◽  
Vol 161 (12) ◽  
pp. 517-523
Author(s):  
Reto Giulio Meuli ◽  
Peter Schwab
Keyword(s):  
Organic Pollutants ◽  
Monitoring Network ◽  
Soil Protection ◽  
Soil Monitoring ◽  
Guide Value ◽  
Sampling Campaign ◽  
Forest Sites ◽  
Limestone Weathering ◽  
Guide Values ◽  
Jurassic Limestone

The national soil monitoring network (Nabo) consists of 105 sites across Switzerland, 28 of which are located in forests. After 25 years already seven forest sites (25%) were more or less damaged by storms. Two of them had to be abandoned for a decade to recover. Concerning precautionary soil protection the legal guide value is exceeded at three forest sites for cadmium and at one site also for chromium. These sites are all based on Jurassic limestone, and it is well known that residuals of limestone weathering can be rich in cadmium. Hence, the enrichment is supposed to be of geogenic origin. In the Canton Ticino the top soil at Novaggio site exceeds the guide value for lead. Here, anthropogenic origin is very likely. The analysis of the organic pollutants PAH and PCB in the third sampling campaign revealed moderate concentrations with a maximum lower than or equal to ⅔ of the corresponding guide value. Based on the results of the first four sampling campaigns it can be concluded that only small changes in the measured heavy metal concentrations in the top soils at the 28 Nabo sites were found. The most dynamic element is lead. Most of the concentrations are far below the guide values, the same holds for the organic pollutants PAH and PCB.

Calcium Budgets for Catchments as Interpreted by Strontium Isotopes

1989 ◽  
Vol 20 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Gunnar Jacks ◽  
Göran Åberg ◽  
P. Joseph Hamilton
Keyword(s):  
Steady State ◽  
Forest Ecosystem ◽  
Coniferous Forest ◽  
Strontium Isotopes ◽  
Runoff Water ◽  
Weathering Rate ◽  
Weathering Rates ◽  
Exchangeable Calcium

Strontium isotopes in precipitation, soil and runoff water can be used to establish a ratio of wet plus dry deposited Sr to Sr released by weathering. This ratio is especially enhanced in areas with old acid Proterozoic rocks (0.6-2.5 Ga) and Archean rocks (>2.5 Ga). Since Sr and Ca behave in an analogous way in the coniferous forest ecosystem the results for Sr can be used for the determination of Ca. If the deposition of calcium can be calculated reasonably accurately the weathering rate can also be estimated. Five catchments have been investigated using this approach. Three of them seem to be close to a steady state, wherein the losses and gains of calcium to the system are equal. In the two southern-most catchments there seems to be an ongoing loss of exchangeable calcium. The loss by runoff occurs with sulphate being the dominant anion. Weathering rates of 1.5 to 4.8 kg Ca/ha year have been estimated.

scholarly journals Co-variation of silicate, carbonate and sulfide weathering drives CO2 release with erosion

2021 ◽  
Vol 14 (4) ◽  
pp. 211-216
Author(s):  
Aaron Bufe ◽  
Niels Hovius ◽  
Robert Emberson ◽  
Jeremy K. C. Rugenstein ◽  
Albert Galy ◽  
...  
Keyword(s):  
Erosion Rate ◽  
Global Climate ◽  
Stream Water ◽  
Sulfide Oxidation ◽  
Silicate Weathering ◽  
Emission Rates ◽  
Mountain Ranges ◽  
Weathering Rates ◽  
Southern Taiwan ◽  
Co2 Release

AbstractGlobal climate is thought to be modulated by the supply of minerals to Earth’s surface. Whereas silicate weathering removes carbon dioxide (CO2) from the atmosphere, weathering of accessory carbonate and sulfide minerals is a geologically relevant source of CO2. Although these weathering pathways commonly operate side by side, we lack quantitative constraints on their co-variation across erosion rate gradients. Here we use stream-water chemistry across an erosion rate gradient of three orders of magnitude in shales and sandstones of southern Taiwan, and find that sulfide and carbonate weathering rates rise with increasing erosion, while silicate weathering rates remain steady. As a result, on timescales shorter than marine sulfide compensation (approximately 106–107 years), weathering in rapidly eroding terrain leads to net CO2 emission rates that are at least twice as fast as CO2 sequestration rates in slow-eroding terrain. We propose that these weathering reactions are linked and that sulfuric acid generated from sulfide oxidation boosts carbonate solubility, whereas silicate weathering kinetics remain unaffected, possibly due to efficient buffering of the pH. We expect that these patterns are broadly applicable to many Cenozoic mountain ranges that expose marine metasediments.

scholarly journals Current, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: a comparison of three methods

2020 ◽  
Vol 17 (2) ◽  
pp. 281-304 ◽  
Author(s):  
Sophie Casetou-Gustafson ◽  
Harald Grip ◽  
Stephen Hillier ◽  
Sune Linder ◽  
Bengt A. Olsson ◽  
...  
Keyword(s):  
Steady State ◽  
Soil Depth ◽  
Base Cations ◽  
Base Cation ◽  
Mineral Weathering ◽  
Soil Horizon ◽  
Soil Horizons ◽  
Weathering Rate ◽  
Weathering Rates ◽  
Forest Sites

Abstract. Reliable and accurate methods for estimating soil mineral weathering rates are required tools in evaluating the sustainability of increased harvesting of forest biomass and assessments of critical loads of acidity. A variety of methods that differ in concept, temporal and spatial scale, and data requirements are available for measuring weathering rates. In this study, causes of discrepancies in weathering rates between methods were analysed and were classified as being either conceptual (inevitable) or random. The release rates of base cations (BCs; Ca, Mg, K, Na) by weathering were estimated in podzolised glacial tills at two experimental forest sites, Asa and Flakaliden, in southern and northern Sweden, respectively. Three different methods were used: (i) historical weathering since deglaciation estimated by the depletion method, using Zr as the assumed inert reference; (ii) steady-state weathering rate estimated with the PROFILE model, based on quantitative analysis of soil mineralogy; and (iii) BC budget at stand scale, using measured deposition, leaching and changes in base cation stocks in biomass and soil over a period of 12 years. In the 0–50 cm soil horizon historical weathering of BCs was 10.6 and 34.1 mmolc m−2 yr−1, at Asa and Flakaliden, respectively. Corresponding values of PROFILE weathering rates were 37.1 and 42.7 mmolc m−2 yr−1. The PROFILE results indicated that steady-state weathering rate increased with soil depth as a function of exposed mineral surface area, reaching a maximum rate at 80 cm (Asa) and 60 cm (Flakaliden). In contrast, the depletion method indicated that the largest postglacial losses were in upper soil horizons, particularly at Flakaliden. With the exception of Mg and Ca in shallow soil horizons, PROFILE produced higher weathering rates than the depletion method, particularly of K and Na in deeper soil horizons. The lower weathering rates of the depletion method were partly explained by natural and anthropogenic variability in Zr gradients. The base cation budget approach produced significantly higher weathering rates of BCs, 134.6 mmolc m−2 yr−1 at Asa and 73.2 mmolc m−2 yr−1 at Flakaliden, due to high rates estimated for the nutrient elements Ca, Mg and K, whereas weathering rates were lower and similar to those for the depletion method (6.6 and 2.2 mmolc m−2 yr−1 at Asa and Flakaliden). The large discrepancy in weathering rates for Ca, Mg and K between the base cation budget approach and the other methods suggests additional sources for tree uptake in the soil not captured by measurements.

The significance of mid-latitude rivers for weathering rates and chemical fluxes: Evidence from northern Xinjiang rivers

2013 ◽  
Vol 486 ◽  
pp. 151-174 ◽  
Author(s):  
Bingqi Zhu ◽  
Jingjie Yu ◽  
Xiaoguang Qin ◽  
Patrick Rioual ◽  
Ziting Liu ◽  
...  
Keyword(s):  
Weathering Rates ◽  
Northern Xinjiang

Base cation and silicon biogeochemistry under pine and scrub oak monocultures: implications for weathering rates

Geoderma ◽  
2005 ◽  
Vol 126 (3-4) ◽  
pp. 353-365 ◽  
Author(s):  
J.L. Johnson-Maynard ◽  
R.C. Graham ◽  
P.J. Shouse ◽  
S.A. Quideau
Keyword(s):  
Base Cation ◽  
Weathering Rates ◽  
Scrub Oak ◽  
Silicon Biogeochemistry

scholarly journals Hydrochemistry, weathering and weathering rates on Madeira island

2003 ◽  
Vol 283 (1-4) ◽  
pp. 122-145 ◽  
Author(s):  
Cornelis H Van der Weijden ◽  
Fernando A.L Pacheco
Keyword(s):  
Weathering Rates ◽  
Madeira Island
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