New evidence of Nontronite as Rhyodacite alteration product, Nefza area, Northern Tunisia

Randa Ben Abdallah; M. Medhioub; Béchir Moussi; Johan Yans; N. HATIRA; H.-R. Chaftar; W. Hajjaji; Jean Marc Baele; Fakher Jamoussi

New evidence of Nontronite as Rhyodacite alteration product, Nefza area, Northern Tunisia

Randa Ben Abdallah, M. Medhioub, Béchir Moussi, Johan Yans, N. HATIRA, H.-R. Chaftar, W. Hajjaji, Jean Marc Baele, Fakher Jamoussi

Research output: Contribution to journal › Article

Abstract

The magmatic rocks of the Nefza district located in the NW part of Tunisia belong to a Neogene volcanic complex. It includes fresh rhyodacites weathered into kaolinite and/or halloysite, and nontronite. Chemical analyses of rhyodacites compared to the nontronite phase reveal an evolution in the composition in term of loss in Na, Ca, K. The values of CIW (Chemical Index of Weathering) and the AI index (Alteration Index of Ishikawa) show that the rhyodacite experienced chemical changes due to the leaching of the fresh rocks by meteoric and hydrothermal waters.

Original language	English
Pages (from-to)	178-194
Journal	European Journal of Scientific Research
Volume	122
Issue number	2
Publication status	Published - May 2014

Keywords

Tunisia
kaolinite
Nontronite
weathering indexes
rhyodacite
Nefza

1 Article

Mixed hydrothermal and meteoric fluids evidenced by unusual H- and O-isotope compositions of kaolinite-halloysite in the Fe(-Mn) Tamra deposit (Nefza district, NW Tunisia)
Dekoninck, A., Moussi, B., Vennemann, T., Jamoussi, F., Mattielli, N., Decrée, S., Chaftar, H-R., Hatira, N. & Yans, J., 17 Jul 2018, In: Applied Clay Science. 163, p. 33-45 13 p., 10.1016/j.clay.2018.07.007.
Research output: Contribution to journal › Article › peer-review

Open Access

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@article{f631ea6186964772982f194b92af5a0c,

title = "New evidence of Nontronite as Rhyodacite alteration product, Nefza area, Northern Tunisia",

abstract = "The magmatic rocks of the Nefza district located in the NW part of Tunisia belong to a Neogene volcanic complex. It includes fresh rhyodacites weathered into kaolinite and/or halloysite, and nontronite. Chemical analyses of rhyodacites compared to the nontronite phase reveal an evolution in the composition in term of loss in Na, Ca, K. The values of CIW (Chemical Index of Weathering) and the AI index (Alteration Index of Ishikawa) show that the rhyodacite experienced chemical changes due to the leaching of the fresh rocks by meteoric and hydrothermal waters.",

keywords = "Tunisia, kaolinite, Nontronite, weathering indexes, rhyodacite, Nefza",

author = "{Ben Abdallah}, Randa and M. Medhioub and B{\'e}chir Moussi and Johan Yans and N. HATIRA and H.-R. Chaftar and W. Hajjaji and Baele, {Jean Marc} and Fakher Jamoussi",

year = "2014",

month = may,

language = "English",

volume = "122",

pages = "178--194",

journal = "European Journal of Scientific Research",

issn = "1450-216X",

publisher = "European Journals Inc.",

number = "2",

}

TY - JOUR

T1 - New evidence of Nontronite as Rhyodacite alteration product, Nefza area, Northern Tunisia

AU - Ben Abdallah, Randa

AU - Medhioub, M.

AU - Moussi, Béchir

AU - Yans, Johan

AU - HATIRA, N.

AU - Chaftar, H.-R.

AU - Hajjaji, W.

AU - Baele, Jean Marc

AU - Jamoussi, Fakher

PY - 2014/5

Y1 - 2014/5

N2 - The magmatic rocks of the Nefza district located in the NW part of Tunisia belong to a Neogene volcanic complex. It includes fresh rhyodacites weathered into kaolinite and/or halloysite, and nontronite. Chemical analyses of rhyodacites compared to the nontronite phase reveal an evolution in the composition in term of loss in Na, Ca, K. The values of CIW (Chemical Index of Weathering) and the AI index (Alteration Index of Ishikawa) show that the rhyodacite experienced chemical changes due to the leaching of the fresh rocks by meteoric and hydrothermal waters.

AB - The magmatic rocks of the Nefza district located in the NW part of Tunisia belong to a Neogene volcanic complex. It includes fresh rhyodacites weathered into kaolinite and/or halloysite, and nontronite. Chemical analyses of rhyodacites compared to the nontronite phase reveal an evolution in the composition in term of loss in Na, Ca, K. The values of CIW (Chemical Index of Weathering) and the AI index (Alteration Index of Ishikawa) show that the rhyodacite experienced chemical changes due to the leaching of the fresh rocks by meteoric and hydrothermal waters.

KW - Tunisia

KW - kaolinite

KW - Nontronite

KW - weathering indexes

KW - rhyodacite

KW - Nefza

M3 - Article

SN - 1450-216X

VL - 122

SP - 178

EP - 194

JO - European Journal of Scientific Research

JF - European Journal of Scientific Research

IS - 2

ER -

New evidence of Nontronite as Rhyodacite alteration product, Nefza area, Northern Tunisia

Abstract

Keywords

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Research output

Mixed hydrothermal and meteoric fluids evidenced by unusual H- and O-isotope compositions of kaolinite-halloysite in the Fe(-Mn) Tamra deposit (Nefza district, NW Tunisia)

Cite this