Mathian M., Aufort J., Braun Jean-Jacques, Riotte Jean, Selo M., Balan E., Fritsch Emmanuel, Bhattacharya S., Allard T. (2019). Unraveling weathering episodes in Tertiary regoliths by kaolinite dating (Western Ghats, India). Gondwana Research, 69, p. 89-105. ISSN 1342-937X.
Titre du document
Unraveling weathering episodes in Tertiary regoliths by kaolinite dating (Western Ghats, India)
Mathian M., Aufort J., Braun Jean-Jacques, Riotte Jean, Selo M., Balan E., Fritsch Emmanuel, Bhattacharya S., Allard T.
Source
Gondwana Research, 2019,
69, p. 89-105 ISSN 1342-937X
Secondary minerals in soils can record climatic changes affecting continental surfaces over geological times. Their dating should refine our present knowledge about their potential periods of formation as well as their relations with the ongoing change of climate and erosion/weathering regimes. In the present study, twenty kaolinite samples from two lateritic profiles of the Karnataka plateau, an intensively studied area in the southern India, have been dated using electron paramagnetic resonance (EPR) spectroscopy. Kaolinite ages vary between 0.229(+/- 0.24) Ma to 40.73(+/- 15.37) Ma. Four different groups of age can be identified with ages clustered around 1.0, 3.5, 9.0 and 39.0 Ma. These groups of age indicate local preferential weathering periods that coincide with distinct Indian climatic events described in independent studies, such as monsoon strengthening. Thus, regional or subcontinental factors likely prevailed over global forcing in the imprint of climatic events in the regolith profiles. These results confirm that despite their simple mineralogy, laterites can contain several relictual and coexisting generations of secondary minerals and that EPR dating of kaolinite contributes to unraveling the complex history of continental surfaces over geological periods.
Plan de classement
Sciences du milieu [021]
;
Géologie et formations superficielles [064]
;
Pédologie [068]
