Feasibility of lime‐modified carbonate soil for highway subgrade filling

2020 ◽  
Vol 15 (S1) ◽  
Author(s):  
Yuxin Zheng ◽  
Chunyan Li ◽  
Qingqing Ma
Keyword(s):  
Carbonate Soil

The Behavior of Zinc-Iron Couples in Carbonate Soil

CORROSION ◽  
1945 ◽  
Vol 1 (4) ◽  
pp. 187-191
Author(s):  
T. H. Gilbert ◽  
Guy Corfield
Keyword(s):  
Carbonate Soil

The soils of Aldabra

1979 ◽  
Vol 286 (1011) ◽  
pp. 67-77 ◽  
Keyword(s):  
High Salinity ◽  
Mineral Soil ◽  
Soil Types ◽  
Organic Soils ◽  
Patchy Distribution ◽  
Soil Covers ◽  
Terrestrial Sediments ◽  
Soil Information ◽  
Carbonate Soil ◽  
Mineral Soils

The soils of Aldabra are of patchy distribution, consisting of pockets of either accumulated organic matter or of biogenic mineral detritus. The soils are shallow (10-20 cm) but locally deeper and more extensive soil covers do occur. Organic covers occur under well established Casuarina stands and mineral soil covers occur on the floors of rock basins or where sands are present. The organic soils originate from leaf litter, with local increments of faecal material and bird remains. The mineral soils are primarily carbonate and are derived mechanically from carbonate rocks, from windblown bioclastic carbonate grains or from terrestrial sediments. Solution residues and phosphatic particles also contribute to these soils. Attempts are made to cross-correlate existing soil information, and several organic and carbonate soil types can be recognized. These are: shallow organic (including litter, pellet and guano varieties); deep organic; calcarenaceous bioclastic soils; brown (silt or silt loam) carbonate soils (including a phosphatic variety) and a widespread organic brown carbonate soil. The soils may be slightly acid but are mostly circumneutral or alkaline; high salinity may occur in coastal locations. Phosphate levels are usually low. Insufficient profile data are available at present to define soil type in any rigorous way and the spatial distribution of soil types is only scantily known.

scholarly journals Groundwater residence time estimates obscured by anthropogenic carbonate

2021 ◽  
Vol 7 (17) ◽  
pp. eabf3503
Author(s):  
Alan M. Seltzer ◽  
David V. Bekaert ◽  
Peter H. Barry ◽  
Kathryn E. Durkin ◽  
Emily K. Mace ◽  
...  
Keyword(s):  
Residence Time ◽  
Open System ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Soil Amendments ◽  
Flow Models ◽  
Time Estimates ◽  
Drinking And Irrigation ◽  
Carbonate Soil ◽  
Agricultural Regions

Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. Here, we report measurements of multiple age tracers (14C, 3H, 39Ar, and 85Kr) and parameters relevant to dissolved inorganic carbon (DIC) from 17 wells in California’s San Joaquin Valley (SJV), an agricultural region that is heavily reliant on groundwater. We find evidence for a major mid-20th century shift in groundwater DIC input from mostly closed- to mostly open-system carbonate dissolution, which we suggest is driven by input of anthropogenic carbonate soil amendments. Crucially, enhanced open-system dissolution, in which DIC equilibrates with soil CO2, fundamentally affects the initial 14C activity of recently recharged groundwater. Conventional 14C dating of deeper SJV groundwater, assuming an open system, substantially overestimates residence time and thereby underestimates susceptibility to modern contamination. Because carbonate soil amendments are ubiquitous, other groundwater-reliant agricultural regions may be similarly affected.

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