Fig 1.
Experimental Station of Caldeirão, Central Amazon—Brazil.
The base image is LANDSAT 5 image (2011). The Landsat images were downloaded from USGS.
Fig 2.
(A) Pretic Anthrosol (Orthodystric, Clayic) (P1); (B) Pretic Anthrosol (Lixic, Orthoeutric, Clayic) (P2); (C) Haplic Xanthic Acrisol (Hyperdystric, Clayic) (P3).
Central Amazon—Brazil.
Table 1.
Some morphological and physical properties in (A) Pretic Anthrosol (Orthodystric, Clayic), (B) Pretic Anthrosol (Lixic, Orthoeutric, Clayic) and (C) Haplic Xanthic Acrisol (Hyperdystric, Clayic).
Central Amazon—Brazil.
Table 2.
Chemical properties in (A) Pretic Anthrosol (Orthodystric, Clayic), (B) Pretic Anthrosol (Lixic, Orthoeutric, Clayic) and (C) Haplic Xanthic Acrisol (Hyperdystric, Clayic).
Central Amazon—Brazil.
Table 3.
Summary of the micromorphological description of the Pretic Anthrosol (Orthodystric, Clayic).
Central Amazon—Brazil.
Table 4.
Summary of the micromorphological description of the Pretic Anthrosol (Lixic, Orthoeutric, Clayic).
Central Amazon—Brazil.
Table 5.
This is the Table 5 Summary of the micromorphological description of the Haplic Xanthic Acrisol (Hyperdystric, Clayic).
Central Amazon—Brazil.
Fig 3.
Different color of the fine material (melanization) in Pretic Anthrosol (Orthodystric, Clayic) (OIL).
(A) Au1: single fine material dark gray (10YR 4/1); (B) Au2: 60% brownish yellow (10YR 6/8), 30% yellow (10YR 8/8) and 10% dark gray; (C) Au3: 80% brownish yellow and 20% yellow; (D) Au4: 45% brownish yellow, 35% dark gray and 20% yellow; (E) Au5: 50% yellow, 35% dark gray and 15% brownish yellow; (F) Bt1 exclusively yellow. q: quartz; v: voids; c: charcoal.
Fig 4.
(A and B) granular microstructure of Au1 horizons; (C) subangular block microstructure of non-anthropic A; (D) different types of microaggregates in pretic horizons. q: quartz; v: voids; a: oval microaggregates with well-sorted quartz; b: oval microaggregates with or without poorly-sorted quartz; c: polyhedral microaggregates.
Fig 5.
Textural pedofeatures in pretic horizons (A and B—XPL) (C and D—PPL).
(A) typical yellow red microlaminated (m) and non-laminated (nl) clay coatings with strong continuous orientation and extinction bands (Au4); (B) illuvial clay coating on ceramic fragment; (C) non-laminated reddish yellow hypo-coating (detail); (D) fragment of clay coatings (papule) with moderately continuous orientation and diffuse extinction (Au5).
Table 6.
Chemical composition by EDS-SEM of nodules and micromass associated to biological channels in (A) Pretic Anthrosol (Orthodystric, Clayic), (B) Pretic Anthrosol (Lixic, Orthoeutric, Clayic) and (C) Haplic Xanthic Acrisol (Hyperdystric, Clayic).
Central Amazon—Brazil.
Fig 6.
Amorphous pedofeatures (nodules) in Pretic Anthrosol (Lixic, Orthoeutric, Clayic).
(A and B) irregular, orthic and concentric nodules with very small voids, spongy-like (ultraviolet light); (C and D) nodules formed of several smaller entities each separated by adjacent groundmass (disjointed morphology) (OIL).
Fig 7.
The xanthization process at different stages in the nodules.
(A and B) dark red (PPL) and yellow (OIL) nodules with a strongly impregnative core and a weaker impregnative cortex (dissolution); (C) detail of nodule with internal fabric severed at the boundaries with groundmass and serrated edges (degradation) (OIL); (D) hematite nodule at intermediate degradation stage with yellowish red infillings; (E) highly changed nodule, predominantly yellow with yellowish red edges (OIL); (F) nodule completely changed, yellowish and without reddish material (OIL).