Incompatible element

About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.

Geochemical constraints on the genesis of the volcanic rocks in the southeast of Isfahan area, Iran

Abstract: Late Miocene–Pliocene to Quaternary calc-alkaline lava flows and domes are exposed in southeast of Isfahan in the Urumieh Dokhtar magmatic belt in the Central Iran structural zone. These volcanic rocks have compositions ranging from basaltic andesites, andesites to dacites. Geochemical studies show these rocks are a medium to high K calc-alkaline suite and meta-aluminous. Major element variations are typical for calc-alkaline rocks. The volcanic rocks have SiO2 contents ranging between 53.8% and 65.3%. Harker diagrams clearly show that the dacitic rocks did not form from the basaltic andesites by normal differentiation processes. They show large ion lithophile elements- and light rare earth elements (LREE)-enriched normalized multielement patterns and negative Nb, Ti, Ta, and P. Condrite-normalized REE patterns display a steep decrease from LREE to light rare earth elements without any Eu anomaly. These characteristics are consistent with ratios obtained from subduction-related volcanic rocks and in collision setting. The melting of a heterogeneous source is possible mechanism for their magma genesis, which was enriched in incompatible elements situated at the upper continental lithospheric mantle or lower crust. The geochemical characteristics of these volcanic rocks suggested that these volcanic rocks evolved by contamination of a parental magma derived from metasomatized upper lithospheric mantle and crustal melts.

The petrogenesis of impact basin melt rocks in lunar meteorite Shişr 161

Abstract: This study explores the petrogenesis of Shisr 161, an immature lunar regolith breccia meteorite with low abundances of incompatible elements, a feldspathic affinity, and a significant magnesian component. Our approach was to identify all clasts >0.5 mm in size in a thin section, characterize their mineral and melt components, and reconstruct their bulk major and minor element compositions. Trace element concentrations in representative clasts of different textural and compositional types indicate that the clast inventory of Shisr 161 is dominated by impact melts that include slowly cooled cumulate melt rocks with mafic magnesian mineral assemblages. Minor exotic components are incompatible-element-rich melt spherules and glass fragments, and a gas-associated spheroidal precipitate. Our hypothesis for the petrologic setting of Shisr 161 is that the crystallized melt clasts originate from the upper ~1 km of the melt sheet of a 300 to 500 km diameter lunar impact basin in the Moon’s feldspathic highlands. This hypothesis is based on size requirements for cumulate impact melts and the incorporation of magnesian components that we interpret to be mantle-derived. The glassy melts likely formed during the excavation of the melt sheet assemblage, by an impact that produced a >15 km diameter crater. The assembly of Shisr 161 occurred in a proximal ejecta deposit of this excavation event. A later impact into this ejecta deposit then launched Shisr 161 from the Moon. Our geochemical modeling of remote sensing data combined with the petrographic and chemical characterization of Shisr 161 reveals a preferred provenance on the Moon’s surface that is close to pre-Nectarian Riemann-Fabry basin.

Geochemistry and Sr-Nd-Pb isotopic systematics of the Ogcheon amphibolites from the central Ogcheon Belt, Korea: Implication for the source heterogeneity.

Abstract: A detailed geochemical and isotopic study was performed on the Ogcheon amphibolites from the central Ogcheon Belt, Korea, to investigate the source characteristics and petrogenesis Major and trace element data indicate that the parental rocks of the amphibolites are mostly transitional basalts, except for a few tholeiitic basalts The tholeiitic basalts are less enriched in incompatible elements than transitional basalts and are geochemically close to primary magmas Some transitional basalts with low SiO2 ( 16 wt%) are clearly distinguished from others and are believed to be derived from a ferro-basaltic magma On the basis of several contamination parameters (eg, La/Nb ratio, Nb/Th ratio, Nb and Ta anomaly), we suggest that crustal contamination has not significantly influenced the chemistry of the amphibolites All amphibolite samples are moderately enriched in incompatible elements and plot in within-plate fields on a number of tectonic discriminant diagrams, and are consistent with previous works The parental magmas of the amphibolites were derived from a heterogenous mantle source Sm-Nd isotope whole rock data define a poor linear array Considering variations in incompatible elements and Nd isotopes, the linear array may be not a true isochron but rather a mixing pseudoisochron due to source heterogeneity