Rare earth element-thorium correlations in sedimentary rocks, and the composition of the continental crust

1980 ◽  
Vol 44 (11) ◽  
pp. 1833-1839 ◽  
Author(s):  
Scott M. McLennan ◽  
W.B. Nance ◽  
S.R. Taylor
Keyword(s):  
Rare Earth ◽  
Continental Crust ◽  
Rare Earth Element ◽  
Earth Element ◽  
Sedimentary Rocks

The tonalite–trondhjemite–granodiorite (TTG) to granodiorite–granite (GG) transition in the late Archean plutonic rocks of the central Wyoming Province

2006 ◽  
Vol 43 (10) ◽  
pp. 1419-1444 ◽  
Author(s):  
Carol D Frost ◽  
B Ronald Frost ◽  
Robert Kirkwood ◽  
Kevin R Chamberlain
Keyword(s):  
Rare Earth ◽  
Continental Crust ◽  
Rare Earth Element ◽  
Earth Element ◽  
Gradual Transition ◽  
Heavy Rare Earth Element ◽  
Isotopic Compositions ◽  
Similar Range ◽  
Wyoming Province ◽  
Ree Patterns

The 2.95–2.82 Ga quartzofeldspathic gneisses and granitoids in the Bighorn, western Owl Creek, and northeastern Wind River uplifts in the central Wyoming Province include low-K tonalite–trondhjemite–granodiorite (TTG) and high-K granodiorite–granite (GG) rocks. Both types of granitoids were intruded contemporaneously, although TTGs are more abundant in the older gneisses. The TTG suite consists of calcic to marginally calc-alkalic rocks that straddle the boundaries between metaluminous and peraluminous and between ferroan and magnesian compositions. Rare-earth element (REE) patterns of these rocks may be highly fractionated with low heavy rare-earth element (HREE) contents and modest to absent Eu anomalies but may also be less strongly HREE depleted. These rocks do not represent first-generation continental crust: most have unradiogenic Nd and radiogenic 207Pb/204Pb isotopic compositions that require the incorporation of isotopically evolved sources. The GG suite has compositions that are transitional between Archean TTG and modern, continental margin calc-alkalic rocks. The GG suite is characterized by higher alkali contents relative to CaO than the TTG suite and higher K/Na ratios but exhibits a similar range in REE patterns. The Nd, Sr, and Pb isotopic compositions of the GG suite are slightly less variable but lie within the range of those of the TTG suite. We interpret them as having a source similar to that of the TTG, perhaps forming by partial melting of preexisting TTG. The shift from TTG-dominated to GG-dominated continental crust was a gradual transition that took place over several hundred million years. Clearly subduction-related calc-alkalic magmatism is not recognized in the Wyoming Province prior to 2.67 Ga.

Eu anomaly- reliability of the proxy in inferring source composition of clastic Sedimentary rocks: A case study from western Dharwar craton, Karnataka, India

2020 ◽  
Author(s):  
Anirban Mitra ◽  
Sukanta Dey
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Sedimentary Rocks ◽  
Dharwar Craton ◽  
Source Rocks ◽  
Granitic Rocks ◽  
Negative Anomaly ◽  
Eu Anomaly ◽  
Ree Pattern

<p>Use of trace and rare earth element concentration of terrigenous sedimentary rocks to deduce the composition of their source rocks in the hinterland is a very common and efficient practice. The results of geochemical analysis of the metaquartzarenites located at the basal part of Bababudan and Sigegudda belt, late Archean greenstone sequences of western Dharwar craton show that the sediments were most possibly supplied from Paleo to Mesoarchean granitoids of western Dharwar Craton. Rare earth element patterns of these basal quartzites display fractionated REE pattern in variable degree (La<sub>N</sub>/Yb<sub>N</sub> =1.47-10.63) with moderate to highly fractionated LREE (La<sub>N</sub>/Sm<sub>N</sub>=2.67-8.93) and nearly flat to slighly elevated HREE (Gd<sub>N</sub>/ Yb<sub>N</sub>=0.62-1.29) and a significant Eu negative anomaly (avg. Eu/Eu*=0.67). In general, presence of negative Eu anomaly in clastic rocks reflect the widespread occurrence of granitic rocks in the source area, which possess negative Eu anomaly. On the other hand, mechanical enrichment of zircon (having negative Eu anomaly, high HREE concentration and low La<sub>N</sub>/Yb<sub>N</sub>), if present, will hamper the whole REE pattern of the sediments and necessarily, do not actually mimic the source composition. Here, in our study, the Th/Sc vs Zr/Sc diagram show mineral Zircon has been concentrated by mechanical concentration in the sedimentary rocks. Few quartzite samples which have high Zr content typically exhibit low La<sub>N</sub>/Yb<sub>N</sub> values, reflecting pivotal role of mineral zircon in controlling the REE pattern of the sediments. Hence, in this case, we should be cautious in interpreting of the Eu negative anomaly of the basal quartzites for meticulously identifying their source rock composition. More geochemical and other analytical approaches are required in this regard.</p>

EVIDENCE OF RARE EARTH ELEMENT ENRICHMENT IN SEDIMENTARY ROCKS FROM PENNSYLVANIA

2016 ◽  
Author(s):  
Tracy L. Bank ◽  
◽  
Elliot Roth ◽  
Bret Howard ◽  
Evan Granite
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Sedimentary Rocks ◽  
Element Enrichment

scholarly journals Trace Element and Stable Isotope Geochemistry of Lwamondo and Zebediela Kaolins, Limpopo Province, South Africa: Implication for Paleoenvironmental Reconstruction

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 93
Author(s):  
Avhatakali Raphalalani ◽  
Georges-Ivo Ekosse ◽  
John Odiyo ◽  
Jason Ogola ◽  
Nenita Bukalo
Keyword(s):  
Trace Elements ◽  
Rare Earth ◽  
Stable Isotope ◽  
Trace Element ◽  
Continental Crust ◽  
Rare Earth Element ◽  
Earth Element ◽  
Paleoenvironmental Reconstruction ◽  
Δ18o And Δd ◽  
Ree Patterns

The aim of the present study was the paleoenvironmental reconstruction of the prevailing environment under which the Lwamondo and Zebediela kaolin deposits were formed. Hence, this study reports deuterium and oxygen stable isotope values and trace and rare earth element concentrations for two samples of kaolin. Upper continental crust-normalised trace-element patterns reveal that large ion lithophile elements and high-field-strength elements are generally depleted in Lwamondo and Zebediela kaolins, whereas transition trace elements are generally enriched in these kaolins. Upper continental crust-normalised rare earth element (REE) patterns show that there is a slight enrichment of heavy REEs (HREEs) compared to light REEs (LREEs) in these kaolins. The δ18O and δD stable isotope values for kaolinite from Lwamondo ranged from 17.4‰ to 19.1‰ and from −54‰ to 84‰, respectively, whereas those values for kaolinite from Zebediela varied from 15.6‰ to 17.7‰ and from −61‰ to –68‰ for δ18O and δD, respectively. The REE patterns and the content of other trace elements indicate ongoing kaolinitisation in the Lwamondo and Zebediela kaolins with minimum mineral sorting. The sources of the kaolins varied from basic to acidic and these were derived from an active margin tectonic setting. Lwamondo kaolin was deposited in an oxic environment whereas Zebediela kaolin was deposited under suboxic/anoxic conditions. Based on the δ18O and δD values of the kaolinite, they formed in a supergene environment at temperatures generally below 40 °C.

scholarly journals Sources and Level of Rare Earth Element Contamination of Atmospheric Dust in Nigeria

2021 ◽  
Vol 11 (30) ◽  
Author(s):  
Tesleem O. Kolawole ◽  
Omowunmi S. Olatunji ◽  
Olumuyiwa M. Ajibade ◽  
Charles A. Oyelami
Keyword(s):  
Rare Earth ◽  
Continental Crust ◽  
Rare Earth Element ◽  
Earth Element ◽  
Industrial Area ◽  
Residential Area ◽  
Remote Area ◽  
Atmospheric Dust ◽  
Minimum Value ◽  
Traffic Area

Background. Rare earth element (REE) composition of atmospheric dust has recently been used to trace potential sources of dust pollution. Objective. The present study aimed to determine the sources of atmospheric pollution in the study area using REE patterns and determine their level of pollution. Methods. Twenty-five (25) atmospheric dust samples were collected in the study area, with five samples each from an industrial area, traffic area, dumpsite area, residential area and remote area in Ibadan, southwestern Nigeria. In addition, five (5) topsoil and two (2) rock samples (granite gneiss) were collected for comparison. Concentrations of REE were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results. The ratio of lanthanum/cerium (La/Ce), especially in some locations in industrial area (1.5), traffic area (1.5) and to some extent dumpsite area (1.1) was higher than in soil (0.2), upper continental crust (0.5) and the minimum value of fluid catalytic crackers (1.0). Generally, the respective average values of the ratios of La/praseodymium (Pr), La/neodymium (Nd) and La/samarium (Sm) in industrial area (32.1, 7.8 and 52.6) and traffic area (14.9, 4.4 and 26.8) were higher than their respective averages in soil (4.4, 1.1 and 6.2), rock (5.7, 1.9 and 14.1), upper continental crust (4.4, 1.1 and 6.6) and the minimum value in fluid catalytic crackers (5.8, 3.7 and 37.0). Meanwhile, their corresponding value in the dumpsite area, residential area and remote area were lower or similar to the geological background levels. Discussion. The contamination factors of REEs in the atmospheric dust of the industrial area and traffic area were classified as heavily contaminated, especially with light lanthanoid elements in REE. The degree of contamination of REEs in the atmospheric dust of industrial area (30.9) and traffic area (18.8) fell within the considerable contamination category. The high values of the light lanthanoid ratio and the contamination indices were attributed to their emission from the fired-power plant and vehicular exhaust. Conclusions. Most of the composition of the atmospheric dust was sourced from the local geology of the study area as observed in the residential area and remote area, while the contamination in the industrial area and traffic area was attributed to human activities. Competing Interests. The authors declare no competing financial interests.

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