SESQUIOXIDE-CEMENTED SOIL HORIZONS IN NORTHERN QUEBEC: THEIR DISTRIBUTION, PROPERTIES AND GENESIS

Abstract

Cemented subsoil horizons are observed in soils along the St. Lawrence North Shore, as far north as Esker. Cementation is mostly strongly developed at depths of 30–90 cm in freely drained soils of sand texture containing large amounts of amphibole minerals. The cemented horizons contain generally small quantities of extractable iron, aluminum and organic matter, though larger than their non-cemented counterparts. A slaking experiment indicates that amorphous iron and aluminum are the main cementing agents. Three hypotheses for the genesis of these cemented horizons are examined; it is proposed that iron and aluminum are released in the Ae horizon, translocated in a basically inorganic form, and precipitated in the B horizons as cementing agents. Study of a chronosequence of soils suggests that 5,000–6,000 yr are required for the formation of strong cementation. The new chemical criteria established for the Podzolic Order of the Canadian Classification System work well in these soils.