Pedogeochemistry in NE-Brazil, in comparison to Australia and Europe  


Authors / CoAuthors

Schucknecht, A. | Matschullat, J. | de Caritat, P. | da Silva, J. | Melo, G. | Mello, J. | Plessow, A.

Abstract

A soil geochemical dataset (major and minor elements) is provided for NE-Brazil, based on low-density sampling. It covers an area from about 2°S to 12°S, and from 34°W to 49°W (ca. 1.7 million km2), and includes top (TOP: 0-20 cm) and bottom (BOT: 30-50 cm) mineral soil materials. Results are put in perspective using two recent and comparable studies, the National Geochemical Survey of Australia (NGSA) and the European Geochemical Mapping of Agricultural Soils (GEMAS). Cluster analysis revealed similar results for TOP and BOT samples, yielding three groups of elements/oxides displaying similar behaviour: Gr.1 comprising Al2O3, Fe2O3, TiO2, and P2O5; Gr.2 comprising CaO, K2O, MgO, MnO, and Na2O; and Gr.3 being SiO2. All median element concentrations in the Brazilian samples are depleted compared to World Soil Averages (WSA), except for Al2O3 and SiO2, which are respectively similar to WSA and enriched in Brazil. While this depletion is moderate for Fe2O3, MnO, P2O5, and TiO2, it reaches an order of magnitude and more for K2O, MgO, CaO, and Na2O. The difference between TOP and BOT concentrations is lower than the variation of either TOP or BOT concentrations between sample sites. Similar spatial distribution and the high correlation between TOP and BOT concentrations suggest that (1) similar processes and parameters are of general relevance for the geochemical composition of TOP and BOT samples, and (2) topsoil and subsoil in the investigation area are not decoupled. Weathering indicators are significantly and positively correlated and show similar spatial distributions in TOP and BOT samples. All elements deliver similar mass removal times (time to export all material from a 10 cm soil layer) and clearly discern between the regions: Europe with the fastest "depletion" (12,200 ± 300 years), followed by Australia (33,200 ± 3,000 years) and Brazil (86,700 ± 3,000 years). Similar results emerge when calculating denudation rates, using independent fluvial .../...

Product Type

nonGeographicDataset

eCat Id

73985

Contact for the resource

  Custodian

MNHD  

  Point of contact

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Keywords

  • External Publication
( Theme )
  • regolith
( Theme )
  • geochemistry
( Theme )
  • environmental
Australian and New Zealand Standard Research Classification (ANZSRC)
  • Earth Sciences
  • Published_Internal

Publication Date

2012-04-03T00:00:00

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

Access - restricted

Use - license

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Purpose

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unknown

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geoscientificInformation

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Unknown

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Extents

[-44.0, -10.0, 112.0, 154.0]

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