TITLE:
Mineralogical Horizon (A) Evaluation of a Toposequence of Soils Derived from Basalt by Thermal Analysis
AUTHORS:
Wilson Sacchi Peternele, Antonio Carlos Saraiva da Costa
KEYWORDS:
Toposequence, Soil, Clay Minerals, TG, DTG
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.2 No.5,
August
5,
2014
ABSTRACT: Thermogravimetry (TG) is a technique where the mass change of a substance is evaluated in function of temperature or time at a constant temperature while submitted to a controlled program in a specific environment. The minerals obtained from a clay fraction are highly susceptible to significant changes in composition as a response to thermal processes in function of temperature or dynamic as a function of time at a constant temperature. Thermogravimetric curves (TG) show mass changes preferentially during the heating processes. The DTG curve derived from the TG curve, shows changes in the inclination that are not exposed in the TG curve. DTG curve thus can show higher values of mass loss which are associated to an elevated degree of weathering for those reactions which involve mass changes, such as desorption, dehydration and reactions of dehydroxilation, observed in clay fraction without iron oxide-hydroxide, indicating kaolinite as a dominant mineral, with higher value 70.97% of the fraction to soil class LVdf.