The Lanthanide Tetrad Effect in Argillic Alteration: An Example from the Jizvan District, Northern Iran

Abstract

Intrusion of quartz‐monzodioritic igneous bodies of Oligocene age into Eocene lithic crystal tuffs and trachy‐basalts resulted in the occurrence of a widespread argillic alteration zone in the Jizvan district (northern Iran). Mineralogically, the argillic alteration zone includes minerals such as kaolinite, quartz, smectite, pyrophyllite, muscovite‐illite, alunite, rutile, calcite, feldspar, chlorite, hematite and goethite. Therefore, the non‐CHARAC behaviour for trace elements in the argillic samples is reflected in the non‐chondritic Y/Ho and Zr/Hf ratios and the irregular REE patterns, which appear related to the tetrad effect phenomenon. The chondrite‐normalized REE distribution patterns indicate both concave (W‐shaped) and convex (M‐shaped) tetrad effects in the argillic samples. Based on the field evidence and the results from geochemical studies, it can be concluded that the samples from the argillic alteration zone having high fourth tetrad effect values (>0.30) were developed in the fault and breccia zones. The results indicate that factors such as preferential scavenging by Mn‐oxides, crystallization of clay minerals, fluid‐rock interaction, overprint of hypogene mineral assemblage by supergene ones, and the structural control, have all played an important role in the occurrence of tetrad effects in samples of the argillic zone in the Jizvan district.

Mineralogy and Geochemistry of Uraniferous Sandstones in Fault Zone, Wadi El Sahu Area, Southwestern Sinai, Egypt: Implications for Provenance, Weathering and Tectonic Setting

“…La/Y ratios less than unity are an indication of acidic environments, while the values higher than unity clearly signify an alkalic environment (Abedini et al, 2018). All samples of the El Sahu sandstones have La/Y ratios ˂1, suggesting prevalent acidic conditions in the relevant depositional environment.…”

Rare earth element geochemistry of altered pyroclastic rocks in the Hashtjin area of north-west Iran

“…1). Tetrad effects were also identified in magmatic rocks and hydrothermal ore deposits (Masuda & Akagi, 1989; Akagi et al , 1993, 1996; Lee et al , 1994; Kawabe, 1995; Bau, 1996; Lee et al , 2010), as well as in weathering and hydrothermal alterations (Masuda & Akagi, 1989; Takahashi et al , 2002; Monecke et al , 2007; Abedini et al , 2018; Li et al , 2020).…”

“…In these cases, the distribution patterns of REEs are generally controlled by weathering of terrestrial material, hydrothermal activities, scavenging, oxygen fugacity, proximity to source lithologies, deposition due The tetrad effect in REE patterns and non-chondritic Y/Ho ratios Normalized REE distribution diagrams produce smooth curves that remove variation due to lanthanide contraction, the Oddo-Harkins rule (Cantrell & Byrne, 1987) and charge radius control (CHARAC) behaviour (Lottermoser, 1992;Bau, 1996). Any remaining irregularities in normalized distribution patterns, such as the lanthanide tetrad effect, relate to the non-CHARAC behaviour of REEs and have been reported from various depositional environments (Censi et al, 2007;Feng et al, 2011;Nardi et al, 2012;Abedini et al, 2018). Such effects can be detected using index parameters, namely Y/Ho, Zr/Hf, Ce/Ce* and Eu/Eu* ratios (Kawabe, 1995).…”

“…REE s are also useful for assessing geochemical processes during the evolution of sediments in various environments (Chen & Zhao, 1997; Censi et al , 2007; Karadağ et al , 2009; Hannigan et al , 2010; Mongelli et al , 2016; Abedini et al , 2018). The distribution and differentiation of REE s have also been well studied in seawaters, marine sediments and weathering environments (Abedini & Calagari, 2013; Mongelli et al , 2014; Buccione et al , 2016; Liu et al , 2016; Long et al , 2017; Torr et al , 2017; Chen et al , 2018).…”

Correlating weathered, microphenocryst-rich, intermediate tephra: An approach combining bulk and single shard analyses from the Lepué Tephra, Chile and Argentina

“…extended groundwater interaction and alteration of granitic rocks (Masuda and Akagi, 1989;Takahashi et al, 2002); co-precipitation of REE in Fe-Mn oxyhydroxides from solution (Bau, 1999;Kawabe et al, 1999); processes occurring during argillic alteration (Abedini et al, 2018a) and the formation of Ti-rich bauxites (Abedini et al, 2018b), and during chemical weathering associated with the formation of terre rosse (Feng, 2010;Feng et al, 2011).…”