The micromorphology and non-clay mineralogy of a red-brown earth profile from Pyramid Hill, Vic., have been examined in order to test Butler's postulated genesis based on field criteria. The profile includes four separate parent material layers. The lowest layer appears to have been derived mainly from in situ weathering of granite. The upper three layers have been derived mainly from a source other than the local granite and have microscopic characteristics comparable to those of altered parna, viz. a non-clay fraction which shows a marked peak in the 30-60 �m range, which consists of quartz and felspar with magnetite, ilmenite, leucoxene and titanite and which has a zircon/tourmaline ratio of about 0.5. As well as a solum developed in the upper two parna layers, there appears to be a buried truncated soil associated with the third parna layer. In both soils there has been significant translocation and deposition of carbonates, iron oxides and hydroxides, manganese oxides and hydroxides and clay, with somewhat more material segregated in the lower solum. Weathering and water-table effects at some depth below a prior surface appear to have been responsible for segregations within the lower layer derived from granite. The data support the concepts of Butler, and in addition indicate contamination of the surface layer by reasonably fresh minerals.
Summary A broad group of pedological features has been recognized by their occurrence as three‐dimensional entities embedded in the matrix of soil materials. They have been named glaebules and are divided into sub‐groups on their internal fabric, mineralogy, distinctness as a unit, and shape. These features include nodules, concretions, and septaria which have all been recognized by the petrologist, and pedodes, papules, and glaebular haloes which are newly recognized features. An attempt is made to interpret the origin of these features in terms of processes of formation and inheritance versus formation in situ. This is based on interpretation of the characteristics used for their classification.
Stereomicroscopic and thin-section studies of structure and fabric features of two red-brown earth profiles from the Riverine Plain of south eastern Australia are assessed in relation to depositional layering and soil formation as suggested by field evidence. Internal fabric in relation to mode of occurrence suggests that some of these features are inherited from, and characteristic of, the original depositional layer whilst others have been formed or accumulated during soil formation subsequent to the cessation of deposition. Trends in the degree of development of these features with increasing depth suggest that the Hanwood profile consists of five depositional layers with evidence for a depositional time break, accompanied by soil formation, at the top of the fourth layer below the present surface. The Deniboota profile includes three depositional layers with evidence for a time break at the top of the second layer below the present surface.
Vertisols are important agricultural soils that have a unique morphology resulting from episodic intermixing of topsoil and subsoil. When examined a feature at a time, however, one finds that these soils have morphological features in common with many other soils. The micromorphological evidence of argillipedoturbation was examined in a paper presented at the International Working Meeting on Micromorphology at London. This chapter examines the morphological features of Vertisols that have been reported in the literature and compares to similar features in other soils. Morphological features of Vertisols from Sudan, the United States, and Australia have been examined by the authors. Descriptions and characterization data for the Vertisols of the Sudan were presented in the tour guide for the Fifth International Soil Classification Workshop. Data for the Vertisols of the United States are in Soil Survey Investigations Reports, The Desert Project Monograph, various bulletins, and various unpublished reports of the National Soil Survey Laboratory.
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