Abstract

GARCIA-RODRIGUEZ, Manuel et al. Influence of temperature on the asymmetry of weathering pits in a granitic environment. Implementation of a linear regression model. Bol. Soc. Geol. Mex [online]. 2017, vol.69, n.2, pp.479-494. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2017v69n2a11.

Weathering pits represent a kind of geological form present in almost all climatic environments. This manuscript explores the role of thermal cycles as important agents in the modelling and asymmetry of the walls of weathering pits in a temperate-cold Mediterranean climate. This study has been developed in the granite massif from La Pedriza in Manzanares which is a protected area, with a great environmental value, allocated in the National Park Sierra de Guadarrama (Madrid, Spain). The analysis of thermal variability was approached using periodic multiple regression that showed the influence of daily and annual cycles depending on the north and south orientation of the pit walls. A mathematical model of linear regression revealed the influence of the daily thermal variability on the alteration of the pit walls generating flat surfaces or a more or less pronounced concavity. This study also established relationships between the alteration degree of different areas of the pits with the lichen presence and with the relative hardness of the rock. The results support the hypothesis of a causal relationship between thermal variability and the shaping of the weathering pits depending on their north or south orientation.

Keywords : gnamma; mathematical modelling; weathering granite; La Pedriza de Manzanares.

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