Geochemistry of Upper Birimian sediments (major and trace elements and Nd–Sr isotopes) and implications for weathering and tectonic setting of the Late Paleoproterozoic crust

Roddaz, Martín; Debat, Pierre; Nikiéma, Serge

doi:10.1016/j.precamres.2007.06.008

Cited by 55 publications

(45 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…La géochimie des roches sédimentaires clastiques est prouvée être un bon outil dans l'étude de la provenance, du contexte tectonique et des conditions paléo-climatiques des anciennes séquences sédimentaires (McLennan et al, 1993, Roddaz et al, 2007. Les terres rares, le thorium, les éléments à forte affinité lithophile (HFSE) ainsi que les ratios Th/Sc, Cr/Th et l'anomalie Eu (exprimée telle que Eu/Eu*) ont été utilisés pour déterminer la composition de la zone source des roches sédimentaires (Condie et Wronkiewicz, 1990).…”

Section: Discussionunclassified

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Sinare¹

2013

View full text Add to dashboard Cite

JANVIER 2013 RÉSUMÉLe présent projet d'étude a été financé par SEMAFO Inc. et la Fondation SEMAFO. Son but principal est : 1) établir les processus de formation du gisement aurifère de Yaho à travers sa caractérisation pétrographique, structurale et métallogénique ; 2) établir des bases de comparaison avec certains gisements aurifères proximaux et 3) proposer des guides d'exploration afin de rendre l'exploration minière plus efficace.Le gisement aurifère de Yaho est localisé au sein des roches vertes de la ceinture birimienne de Houndé, à environ 320 km à l'ouest de Ouagadougou, la capitale du Burkina Faso. Une différence notable est observée entre les spectres en terres rares des clastes de PQF et l'intrusion felsique à phénocristaux de feldspath et de quartz, dénotant ainsi l'absence d'une relation génétique entre eux. Le bassin de Yaho a donc été formé par un apport externe, continu ou ponctuel, de produits d'érosion. Les données de la géochimie sur roche totale montrent une source mafique pour les pélites et une source mixte à dominance felsique pour les wackes lithiques. Les différentes intrusions présentent les caractéristiques de granitoïdes d'îles-en-arc volcaniques et sont des témoins indirects d'un contexte tectonique d'une zone de subduction.Les gisements aurifères de Yaho et de Wona sont localisés sur un même couloir de déformation ductile-cassant orienté NNE au nord et NNW au sud. Les structures observées sur le terrain sont compatibles avec deux déformations superposées D1 et D2 qui impriment le grain tectonique globalement N340. La D1 serait principalement le résultat d'une déformation coaxiale tandis que la D2 serait liée à une déformation dominante non-coaxiale. Cette dernière produit une zone de cisaillement qui est reconnue à l'échelle de la ceinture comme la principale structure hôte des minéralisations aurifères. La D3 est un mouvement compressif N-S qui génère le clivage de crénulation (Sp+1 = N270) particulièrement bien développé dans les pélites.

show abstract

Section: Discussionunclassified

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Sinare¹

2013

View full text Add to dashboard Cite

show abstract

“…The chemical index of alteration (CIA = Al 2 O 3 /Al 2 O 3 + CaO* + Na 2 O + K 2 O × 100 in molar proportions) of sedimentary rocks (Nesbitt and Young, 1982) is widely used to constrain the palaeoweathering conditions of ancient sedimentary sequences (Fedo et al, 1995;Hassan et al, 1999;Lee, 2002;Hofmann et al, 2003;Roddaz et al, 2006Roddaz et al, , 2007. CaO* represents Ca in silicate minerals.…”

Section: Source Area Weatheringmentioning

confidence: 99%

“…These enrichments suggest that they could have experienced some K and Na metasomatism during post-depositional period. Post-depositional K metasomatism is common in Archaean (e.g., Fedo et al, 1995Fedo et al, , 1997 and in post-Archaean sedimentary rocks (e.g., Roddaz et al, 2007). Paleoweathering conditions as well as post depositional K metasomatism can be evaluated by plotting the data in Al 2 O 3 -CaO* + Na 2 O-K 2 O (A-CN-K) compositional space (Fig.…”

Section: Source Area Weatheringmentioning

confidence: 99%

“…8). This can be considered a primary weathering trend departing from a composition of original protolith (e.g., Roddaz et al, 2007) that lies near tonalite composition. The pre-metasomatism CIA values obtained for our samples ranges from 46-92.…”

Section: Source Area Weatheringmentioning

confidence: 99%

“…Therefore, it is possible that many provenance signatures have been altered. In such cases the REE, Th and HFSE as well as Th/Sc, Cr/Th ratios and Eu-anomaly (expressed as Eu/Eu*) have long been proven to be useful tools for determining the composition of the source area (Taylor and McLennan, 1985;Roddaz et al, 2007). Although concentrations of HFSE and REE might have been reduced due to quartz dilution, their inter-element relationships, i.e., ratios and normalized patterns, are mostly preserved.…”

Section: Provenance Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Provenance and weathering history of Archaean Naharmagra quartzite of Aravalli craton, NW Indian shield: Petrographic and geochemical evidence

et al. 2010

View full text Add to dashboard Cite

The petrography as well as major, trace and rare earth element (REE) compositions of Mesoarchaean Naharmagra quartzite of Aravalli Craton have been investigated to determine influence of sorting and recycling, source area weathering and provenance composition. The quartzites are mineralogically mature, medium to coarse grained quartz arenite with minor medium grained arkose. Petrographic analysis revealed that the quartzites were primarily derived from granite and metamorphic basement rocks of typical cratonic interior. All samples have SiO 2 /Al 2 O 3 > 10 (average ~31), which indicates high maturity consistent with petrographical results. Quartzites are depleted in many major and trace elements due to quartz dilution. Many of the samples have undergone postdepositional K metasomatism. The calculated premetasomatic CIA values (46-92) indicate highly variable degree of source weathering compatible with non-steady state weathering. CIA and PIA values in combination with petrographic evidence favour intense chemical weathering probably under warm and humid climate. Provenance modeling indicates that the quartzites can be best modeled with a mixture having 50% tonalite-trondhjemite-granodiorite, 40% granite and 10% basalt. Probably, the sedimentation of these rocks took place in a stable and young cratonic basin evolved through accretion and tectonic amalgamation of pre-existing continental arcs comprising TTG and granitic bodies.Keywords: geochemistry, crustal evolution, Aravalli craton, Rajasthan, Indian shield greenstone tectonics and the upper crust was predominantly mafic in composition. Condie (1993Condie ( , 1997 suggested that upper crustal geochemical changes at APT can be related to four evolutionary changes of earth history i.e., (i) komatiite effect, (ii) tonalite-trondhjemitegranodiorite (TTG) effect, (iii) subduction effect, and (iv) weathering effect. The komatiite effect is preserved in the sedimentary rock records in terms of high Ni-Cr contents, flat REE patterns and no Eu-anomaly in Archaean sedimentary rocks. The sedimentary rocks derived from TTG sources will display highly fractionated REE patterns with high (La/Yb)n ratios and Y depletion. The subduction effect is preserved in terms of less fractionated REE patterns and less depleted large ion lithophile elements (LILE) in comparison to TTG derived sediments. Some geochemical changes across APT may be related to palaeoweathering effects, since in some cases the intensity of chemical weathering decreased during postArchaean period. Therefore, the geochemistry of clastic sedimentary rocks is particularly helpful in constraining the crustal evolution during Archaean (McLennan et al.,

show abstract

Geochemical and Sr‐Nd isotopic records of Paleoproterozoic metavolcanics and mafic intrusive rocks from the West African Craton: Evidence for petrogenesis and tectonic setting

Sakyi

Anum

et al. 2017

Geological Journal

View full text Add to dashboard Cite

Metavolcanics and mafic intrusive rocks of the Paleoproterozoic Birimian terrane in the southeastern part of the West African Craton, Ghana, were analyzed for major and trace elements and Nd and Sr isotopic data to constrain the geodynamic evolution of the Birimian Supergroup. The metavolcanic rocks consist of metabasalts, meta‐andesites, and amphibolites, whereas the mafic intrusions are mainly gabbros, hornblendites, and dolerites. The rocks are tholeiitic in composition and show the classic features of arc magmatism. The metavolcanics display significant enrichments in large ion lithophile elements (LILE) and light rare earth elements, relative to high field strength elements (HFSE) and heavy rare earth elements. The multielement patterns of the rocks also show positive Pb, Ba, Th, and Sr and negative Nb, Ta, and Ce anomalies that are typical characteristics of subduction‐related magmas. They also have La/Nb ratios <3 and La/Ta ratios <43 that are similar to other Archean and Birimian greenstone belts in West Africa. The rocks have εNd (2.1 Ga) values of −0.96 to +2.60, and Nd model ages of 2.24–2.51 Ga (TDM1) and 2.16–2.45 Ga (TDM2), indicating their juvenile character with possible contributions from pre‐Birimian crustal materials in their sources. The εNd values suggest a depleted source and further indicate that they were probably produced in an almost entirely oceanic environment with minor influence from the continental crust. The Nd isotopic results are consistent with the island arc model, which views Paleoproterozoic terranes of the West African Craton in the context of subduction–accretion processes. Accordingly, these processes may have played a role in the formation of the Columbia supercontinent during the Paleoproterozoic (2.1–1.8 Ga) orogenic events.

show abstract

Geochemistry of Upper Birimian sediments (major and trace elements and Nd–Sr isotopes) and implications for weathering and tectonic setting of the Late Paleoproterozoic crust

Cited by 55 publications

References 56 publications

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Provenance and weathering history of Archaean Naharmagra quartzite of Aravalli craton, NW Indian shield: Petrographic and geochemical evidence

Geochemical and Sr‐Nd isotopic records of Paleoproterozoic metavolcanics and mafic intrusive rocks from the West African Craton: Evidence for petrogenesis and tectonic setting

Contact Info

Product

Resources

About