PETROGRAPHIC CHARACTERIZATION AND U-Pb DATING OF THE LAMPA METARHYOLITES FROM THE TSHELA AREA (Kongo Central Province, Democratic Republic of the Congo)
Abstract
The Lampa metarhyolites, exposed in the Tshela region and assigned to the Inga Formation (Seke-Banza Group, West Congo Supergroup, Democratic Republic of the Congo), form part of a probably Tonian felsic volcanic succession developed along the western margin of the Congo Craton. Although this succession is recognized at the regional scale, its internal petrographic variability and subsequent tectono-metamorphic evolution remain poorly constrained. This study integrates field observations, petrography, and in situ LA-ICP-MS U-Pb titanite geochronology to reassess the nature and evolution of these felsic volcanic rocks. Three relict volcanic facies are identified: matrix-rich metarhyolites, (pheno)crystal-rich metarhyolites, and distinct pyroclastic facies recognized here for the first time. These facies preserve primary volcanic characteristics despite variable degrees of sericitization, chloritization, recrystallization, and deformation associated with Pan-African reworking during the development of the West Congo Belt. Titanite grains from two of our samples yield a combined U-Pb age of 559 ± 15 Ma, interpreted as the timing of titanite crystallization during this orogenic event. These results provide new petrographic and geochronological constraints on the evolution of rocks derived from felsic magmatism in the Tshela region
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BibTeX
@article{hubert2026petrographic,
title = {{PETROGRAPHIC CHARACTERIZATION AND U-Pb DATING OF THE LAMPA METARHYOLITES FROM THE TSHELA AREA (Kongo Central Province, Democratic Republic of the Congo)}},
author = {Trésor Kawaya Hubert and Yann Waku Mpaka and Luc Tack and Marc Poujol and Mathias Potvin and Augustin Dekoninck and Albert Tienge Ongendangenda and Ridi Diakondua and Nicole Kitambala and Camille François},
journal = {Journal Africain des Sciences},
year = {2026},
month = oct,
doi = {10.70237/jafrisci.2026.v3.i11.04},
url = {https://insu.hal.science/insu-05780157v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - PETROGRAPHIC CHARACTERIZATION AND U-Pb DATING OF THE LAMPA METARHYOLITES FROM THE TSHELA AREA (Kongo Central Province, Democratic Republic of the Congo)
AU - Trésor Kawaya Hubert
AU - Yann Waku Mpaka
AU - Luc Tack
AU - Marc Poujol
AU - Mathias Potvin
AU - Augustin Dekoninck
AU - Albert Tienge Ongendangenda
AU - Ridi Diakondua
AU - Nicole Kitambala
AU - Camille François
PY - 2026
DA - 2026/10/06
JO - Journal Africain des Sciences
DO - 10.70237/jafrisci.2026.v3.i11.04
UR - https://insu.hal.science/insu-05780157v1
AB - The Lampa metarhyolites, exposed in the Tshela region and assigned to the Inga Formation (Seke-Banza Group, West Congo Supergroup, Democratic Republic of the Congo), form part of a probably Tonian felsic volcanic succession developed along the western margin of the Congo Craton. Although this succession is recognized at the regional scale, its internal petrographic variability and subsequent tectono-metamorphic evolution remain poorly constrained. This study integrates field observations, petrography, and in situ LA-ICP-MS U-Pb titanite geochronology to reassess the nature and evolution of these felsic volcanic rocks. Three relict volcanic facies are identified: matrix-rich metarhyolites, (pheno)crystal-rich metarhyolites, and distinct pyroclastic facies recognized here for the first time. These facies preserve primary volcanic characteristics despite variable degrees of sericitization, chloritization, recrystallization, and deformation associated with Pan-African reworking during the development of the West Congo Belt. Titanite grains from two of our samples yield a combined U-Pb age of 559 ± 15 Ma, interpreted as the timing of titanite crystallization during this orogenic event. These results provide new petrographic and geochronological constraints on the evolution of rocks derived from felsic magmatism in the Tshela region
SN - 3006-3760
SN - 3107-0949
ER -