scholarly journals Geochemistry of hematitite and itabirite, Quadrilátero Ferrífero, Brazil

2009 ◽  
Vol 62 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Moustafa Selmi ◽  
Leonardo E. Lagoeiro ◽  
Issamu Endo

Twenty-one samples of hematitite and twelve samples of itabirite were collected from different deposits of the Quadrilátero Ferrífero (QF) area and were analyzed for trace and rare earth elements. The purpose of the study is to understand the element distribution in the QF in comparison with other iron formations (IF) around the world. Trace element contents are relatively low with considerable variability, being lower than the contents in the Algoma IF, Anamikie IF, Maru IF in Nigeria and Orissa IF in India. REE's abundance is relatively low, but higher than REE's of Hamersley IF of Western Australia, Surgur belt in India and lower than Kuruman IF in South Africa. Chondrite normalized patterns show slight degrees of fractionation for LREE to HREE and slightly positive Eu anomalies coupled with positive values of (La/Yb)CN and (La/Sm)CN ratios.

Author(s):  
Le Zhang ◽  
Jia-Lin Wu ◽  
Yanqiang Zhang ◽  
Ya-Nan Yang ◽  
Pengli He ◽  
...  

Titanite is a widespread accessory nesosilicate with high trace-element contents including rare-earth elements, Th, and U, and is thus suitable for in situ isotopic and trace-element analyses and U–Pb dating....


2014 ◽  
Vol 6 (15) ◽  
pp. 6125-6132 ◽  
Author(s):  
Wenjun Li ◽  
Xindi Jin ◽  
Bingyu Gao ◽  
Changle Wang ◽  
Lianchang Zhang

Comparison between the REE data of this work and literature values by Z. S. Yu et al., Sampaio et al., Dulski et al., and Bau et al. in reference materials FER-2 (a) and FER-3 (b) using PAAS-normalized REE patterns.


2019 ◽  
Vol 56 (7) ◽  
pp. 693-714 ◽  
Author(s):  
David J. Good ◽  
Peter C. Lightfoot

A diverse suite of tholeiitic to alkaline basalt and gabbroic intrusions located in the Coldwell Complex on the northern margin of the Midcontinent Rift exhibit unusual trace element signatures that show enriched large ion lithophile elements and light rare earth elements with negative Nb and Zr anomalies. These features are not typical of magmas derived by partial melting within or above a rising mantle plume, as might be expected in an early Midcontinent Rift magmatic event. In this paper, we provide a detailed geochemical study of a 500 m thick sequence of metabasalt that represents the earliest stage of magmatism in the Coldwell Complex. We show that contamination or crystallization processes or subsequent metasomatism cannot explain the trace element variations. Instead, we propose partial melting in a metasomatized Subcontinental Lithospheric Mantle source to explain the decoupled behavior of large ion lithophile elements from light rare earth elements and heavy rare earth elements and rare earth elements from high field strength elements and the enriched Nd isotope signature of metabasalt. Similar features occur in unit 5b of the Mamainse Point Volcanic Group located at the northern margin of the Rift. An objective of this paper is to relate Two Duck Lake gabbro, host rock for low-sulfur, high precious metal sulfide mineralization at the Marathon deposit, to the metabasalt sequence. The excellent match of trace element abundances in Two Duck Lake gabbro to metabasalt unit 3 confirms an early Coldwell Complex age for metabasalt and a Subcontinental Lithospheric Mantle source for Cu – platinum group element mineralized gabbros.


2009 ◽  
Vol 15 (3) ◽  
pp. 222-230 ◽  
Author(s):  
Colin M. MacRae ◽  
Nicholas C. Wilson ◽  
Joel Brugger

AbstractA method for the analysis of cathodoluminescence spectra is described that enables quantitative trace-element-level distributions to be mapped within minerals and materials. Cathodoluminescence intensities for a number of rare earth elements are determined by Gaussian peak fitting, and these intensities show positive correlation with independently measured concentrations down to parts per million levels. The ability to quantify cathodoluminescence spectra provides a powerful tool to determine both trace element abundances and charge state, while major elemental levels can be determined using more traditional X-ray spectrometry. To illustrate the approach, a scheelite from Kalgoorlie, Western Australia, is hyperspectrally mapped and the cathodoluminescence is calibrated against microanalyses collected using a laser ablation inductively coupled plasma mass spectrometer. Trace element maps show micron scale zoning for the rare earth elements Sm3+, Dy3+, Er3+, and Eu3+/Eu2+. The distribution of Eu2+/Eu3+ suggests that both valences of Eu have been preserved in the scheelite since its crystallization 1.63 billion years ago.


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