scholarly journals Micromorphological evidence for mineral weathering pathways in a coastal acid sulfate soil sequence with Mediterranean-type climate, South Australia

Soil Research ◽  
2009 ◽  
Vol 47 (4) ◽  
pp. 403 ◽  
Author(s):  
R. M. Poch ◽  
B P. Thomas ◽  
R. W. Fitzpatrick ◽  
R. H. Merry
Keyword(s):  
Organic Matter ◽  
Sulfide Oxidation ◽  
South Australia ◽  
Thermal Conditions ◽  
Mineral Weathering ◽  
Solution Chemistry ◽  
Local Source ◽  
Coastal Environments ◽  
Calcareous Sand ◽  
Acid Sulfate

Soil micromorphology, using light microscopy and scanning electron microscopy (SEM), was used to describe detailed soil morphological and compositional changes and determine mineral weathering pathways in acid sulfate soils (ASS) from the following 2 contrasting coastal environments in Barker Inlet, South Australia: (i) a tidal mangrove forest with sulfidic material at St Kilda, and (ii) a former supratidal samphire area at Gillman that was drained in 1954 causing sulfuric material to form from sulfidic material. Pyrite framboids and cubes were identified in sulfidic material from both sites and are associated with sapric and hemic materials. Gypsum crystals, interpreted as a product of sulfide oxidation, were observed to have formed in lenticular voids within organic matter in the tidal mangrove soils at St Kilda. Sulfide oxidation was extensive in the drained soil at Gillman, evidenced by the formation of iron oxyhydroxide pseudomorphs (goethite crystallites and framboids) after pyrite and jarosite, and of gypsum crystals. Gypsum crystals occur where a local source of calcium such as shells or calcareous sand is present. Sporadic oxidation episodes are indicated by the formation of iron oxide and jarosite coatings around coarse biogenic voids. These observations indicate that mineral transformation pathways are strongly influenced by soil physico-chemical characteristics (i.e. oxidation rate, Eh, pH, soil solution chemistry, mineralogy, and spatial distribution of sulfides). This information has been used to illustrate the interrelationships of pyrite, carbonate, gypsum, jarosite, and organic matter and help predict soil evolution under changing hydro-geochemical, redoximorphic, and thermal conditions in soils from coastal environments.

The response of partially oxidised acid sulfate soil materials to anoxia

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 515 ◽  
Author(s):  
Nicholas J. Ward ◽  
Leigh A. Sullivan ◽  
Richard T. Bush
Keyword(s):  
Organic Matter ◽  
Sulfide Oxidation ◽  
Management Strategies ◽  
Oxidation Products ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Anoxic Conditions ◽  
Inorganic Sulfur

Four acid sulfate soil (ASS) materials were subjected to anoxia after varying periods of oxidation to determine the geochemical response of these types of soils to flooding. The response of the partially oxidised ASS materials to the exclusion of oxygen was variable. The rate of sulfide oxidation, acidification, and the production of soluble oxidation products such as sulfate, iron, and aluminium generally decreased markedly when subjected to anoxia. However, especially in the highly acidic ASS materials (i.e. pH <3.5), sulfide oxidation and acidification generally continued (albeit at much slower rates), most probably due to oxidation by Fe3+. Rapid sulfide re-formation occurred in the peat ASS material that had been oxidised for 63 days, with 0.47% reduced inorganic sulfur (SCR) formed over 60 days of anoxia. This substantial sulfide re-formation was accompanied by only a slight increase in pH. Minimal sulfide re-formation occurred in 2 of the ASS materials when placed in anoxic conditions, most likely due to a lack of readily available organic matter in these materials. The results show that the imposition of anoxic conditions on partially oxidised ASS materials is generally effective in decreasing the rates of further sulfide oxidation, acidification, and the production of soluble sulfide oxidation products. Biogeochemical sulfide formation consumes acidity; however, sulfide re-formation was ineffective in reversing acidification under the conditions of this experiment. The results indicate that the treatment of sites containing actual ASS materials by management strategies relying on oxygen exclusion need to be accompanied by other strategies that include acidty neutralisation or containment.

Evolution of Holocene coastal environments near Robe, southeastern South Australia

1999 ◽  
Vol 56 (1) ◽  
pp. 81-97 ◽  
Author(s):  
J.H. Cann ◽  
C.V. Murray-Wallace ◽  
A.P. Belperio ◽  
A.J. Brenchley
Keyword(s):  
South Australia ◽  
Coastal Environments

Role of natural organic matter (NOM), colloidal particles, and solution chemistry on ultrafiltration performance

2011 ◽  
Vol 78 (2) ◽  
pp. 189-200 ◽  
Author(s):  
A.W. Zularisam ◽  
Anwar Ahmad ◽  
Mimi Sakinah ◽  
A.F. Ismail ◽  
T. Matsuura
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Colloidal Particles ◽  
Solution Chemistry

Interstadial Conifer Wood from Northern Maine

1988 ◽  
Vol 30 (1) ◽  
pp. 98-101
Author(s):  
R. Scott Anderson ◽  
Ronald B. Davis ◽  
Robert Stuckenrath ◽  
Harold W. Borns
Keyword(s):  
Organic Matter ◽  
New England ◽  
Lake Sediments ◽  
Lake Sediment ◽  
Radiocarbon Dating ◽  
Late Glacial ◽  
Local Source ◽  
Northern New England ◽  
Upper South ◽  
Conifer Wood

Conifer wood, probably spruce (Picea sp.), of middle Wisconsinan age (29,200 ± 500 yr B.P.) was recovered from late-glacial lake sediments from Upper South Branch Pond, Maine. If the wood was derived from a local source, deglaciation of part of northern New England is suggested for this time. The occurrence also has implications for understanding the problem associated with radiocarbon dating of bulk lake sediment containing small amounts of organic matter.

OIL GEOCHEMISTRY AND POTENTIAL SOURCE ROCKS OF THE OFFICER BASIN, SOUTH AUSTRALIA

1980 ◽  
Vol 20 (1) ◽  
pp. 68 ◽  
Author(s):  
D.M. McKirdy ◽  
A.J. Kantsler
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbonate Rocks ◽  
Depositional Environment ◽  
South Australia ◽  
Source Rocks ◽  
Potential Source ◽  
Playa Lake ◽  
Oil Source ◽  
Extractable Organic Matter

Oil shows observed in Cambrian Observatory Hill Beds, intersected during recent stratigraphic drilling of SADME Byilkaoora-1 in the Officer Basin, indicate that oil has been generated within the basin. Shows vary in character from "light" oils exuding from fractures through to heavy viscous bitumen in vugs in carbonate rocks of a playa-lake sequence.The oils are immature and belong to two primary genetic families with some oils severely biodegraded. The less altered oils are rich in the C13 - C25 and C30 acyclic isoprenoid alkanes. Source beds within the evaporitic sequence contain 0.5 - 1.0% total organic carbon and yield up to 1900 ppm solvent-extractable organic matter. Oil-source rock correlations indicate that the oils originated within those facies drilled; this represents the first reported examples of non-marine Cambrian petroleum. The main precursor organisms were benthonic algae and various bacteria.Studies of organic matter in Cambrian strata from five other stratigraphic wells in the basin reveal regional variations in hydrocarbon source potential that relate to differences in precursor microbiota and/or depositional environment and regional maturation. Micritic carbonates of marine sabkha origin, located along the southeast margin of the basin, are rated as marginally mature to mature and good to prolific sources of oil. Further north and adjacent to the Musgrave Block, Cambrian siltstones and shales have low organic carbon values and hydrocarbon yields, and at best are only marginally mature. Varieties of organic matter recognised during petrographic studies of carbonates in the Officer Basin include lamellar alginite (alginite B) and "balls" of bitumen with reflectance in the range 0.2 to 1.4%.

scholarly journals Geophysical prospection for late Holocene burials in coastal environments: Possibilities and problems from a pilot study in South Australia

2010 ◽  
Vol 25 (5) ◽  
pp. 645-665 ◽  
Author(s):  
Ian Moffat ◽  
Lynley A. Wallis ◽  
Mark W. Hounslow ◽  
Katrina Niland ◽  
Kate Domett ◽  
...  
Keyword(s):  
Pilot Study ◽  
Late Holocene ◽  
South Australia ◽  
Coastal Environments ◽  
Geophysical Prospection

Effect of fire intensity on solution chemistry of surface soil under a Eucalyptus pauciflora forest

Soil Research ◽  
1986 ◽  
Vol 24 (3) ◽  
pp. 423 ◽  
Author(s):  
PK Khanna ◽  
RJ Raison
Keyword(s):  
Organic Matter ◽  
Soil Layer ◽  
Solution Chemistry ◽  
Water Soluble ◽  
Fire Intensity ◽  
Soil Solutions ◽  
Soluble Silica ◽  
High Concentrations ◽  
One Year ◽  
Heated Soil

The chemical composition of soil solutions (field percolates collected in situ and laboratory saturation extracts) was measured at three sites subjected to widely varying fire intensity in subalpine Eucalyptus paucfiora forest near Canberra. The sites were unburnt forest, areas prescribed burnt resulting in almost complete canopy scorch, and ashbeds (intensely heated soil). Saturation extracts were obtained 1, 58, 375, 745 and 1095 days after the fire, and soil percolates were collected on 17 occasions during the initial year after burning. Large quantities of cations (Ca2+, Mg2+, K+ , NH+4) and anions (Cl-, SO24-) and soluble silica were mobilized by burning, especially under ashbeds. Mobilization resulted from deposition of water-soluble elements in ash, immediate effects of soil heating, and enhanced rates of mineralisation of soil organic matter indicated by high concentrations of NH+4 which persisted for more than one year in surface soils under the ashbeds. After burning Ca2+ became the dominant cation in saturation extracts of surface (0-5 cm) soils for the entire 3-year study period. In the 5-15 cm soil layer, firstly NH+4 and later K+ replaced some of the Na+ in the solution phase. Most of the Cl- deposited in ash was leached below 15 cm depth within one year and was probably accompanied by transport of K+, Mg2+, Na+ and NH+4, but very little transfer of Ca2+ occurred. Concentrations of NO-3 and phosphate were always low in saturation extracts and soil percolates, and levels were unaffected by burning, despite the presence of large amounts of exchangeable NH+4 in the soil and the deposition of significant amounts of phosphate in ash. Burning increased the concentrations of soluble silica and SO24- in saturation extracts for at least 3 years after the fire. Most of the changes in soil solution chemistry measured would increase nutrient availability to the vegetation during the initial year after burning, but these changes must be balanced against losses of organic matter and nutrients during and after fires.

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