scholarly journals Magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace-element discriminant diagrams

2009 ◽  
Vol 46 (11) ◽  
pp. 823-839 ◽  
Author(s):  
Pierre-Simon Ross ◽  
Jean H. Bédard
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Volcanic Rocks ◽  
Total Iron ◽  
Calc Alkaline ◽  
Overall Performance

When dealing with ancient subalkaline volcanic rocks, the alkali – total iron – magnesium (AFM) diagram is of limited use in assigning a tholeiitic versus calc-alkaline affinity because these elements are often mobile during alteration and metamorphism. Classification diagrams using immobile trace elements are preferable but need to be tested and optimized on unaltered rocks. To this end, a geochemical database containing over a thousand, presumed unaltered, subalkaline volcanic samples from young oceanic arcs was assembled. The data were classified using both major and trace-element approaches, and the results were compared. If the calc-alkaline and tholeiitic fields on the AFM diagram are used to define magmatic affinity, then the commonly used Zr versus Y, La versus Yb, and Th versus Yb discriminant diagrams misclassify 39%, 24%, and 28% of samples, respectively. After optimization (using a number of criteria), all three trace-element classification diagrams produce results that are generally consistent with the AFM diagram. The optimized diagrams only misclassify 7%, 11%, and 12% of the samples, respectively. A new Th/Yb versus Zr/Y diagram has a better overall performance than any single ratio diagram and may prove helpful in assigning magmatic affinities to volcanic rocks in ancient successions.

scholarly journals Pyrite Textures, Trace Elements and Sulfur Isotope Chemistry of Bijaigarh Shales, Vindhyan Basin, India and Their Implications

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 588
Author(s):  
Indrani Mukherjee ◽  
Mihir Deb ◽  
Ross R. Large ◽  
Jacqueline Halpin ◽  
Sebastien Meffre ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Sulfur Isotope ◽  
Volcanic Rocks ◽  
Central India ◽  
High Energy ◽  
Vindhyan Basin ◽  
Mean Values ◽  
Fine Grained ◽  
Sedimentary Pyrite

The Vindhyan Basin in central India preserves a thick (~5 km) sequence of sedimentary and lesser volcanic rocks that provide a valuable archive of a part of the Proterozoic (~1800–900 Ma) in India. Here, we present an analysis of key sedimentary pyrite textures and their trace element and sulfur isotope compositions in the Bijaigarh Shale (1210 ± 52 Ma) in the Vindhyan Supergroup, using reflected light microscopy, LA-ICP-MS and SHRIMP-SI, respectively. A variety of sedimentary pyrite textures (fine-grained disseminated to aggregates, framboids, lags, and possibly microbial pyrite textures) are observed reflecting quiet and strongly anoxic water column conditions punctuated by occasional high-energy events (storm incursions). Key redox sensitive or sensitive to oxidative weathering trace elements (Co, Ni, Zn, Mo, Se) and ratios of (Se/Co, Mo/Co, Zn/Co) measured in sedimentary pyrites from the Bijaigarh Shale are used to infer atmospheric redox conditions during its deposition. Most trace elements are depleted relative to Proterozoic mean values. Sulfur isotope compositions of pyrite, measured using SHRIMP-SI, show an increase in δ34S as we move up stratigraphy with positive δ34S values ranging from 5.9‰ (lower) to 26.08‰ (upper). We propose limited sulphate supply caused the pyrites to incorporate the heavier isotope. Overall, we interpret these low trace element signatures and heavy sulfur isotope compositions to indicate relatively suppressed oxidative weathering on land during the deposition of the Bijaigarh Shale.

Immobile trace elements and Archean volcanic stratigraphy in the Timmins mining area, Ontario

1979 ◽  
Vol 16 (2) ◽  
pp. 305-311 ◽  
Author(s):  
J. F. Davies ◽  
R. W. E. Grant ◽  
R. E. S. Whitehead
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
No Value ◽  
Volcanic Rocks ◽  
Mining Area ◽  
Stratigraphic Correlation ◽  
Trace Element Data ◽  
Volcanic Stratigraphy ◽  
Lithostratigraphic Units ◽  
Hydrolysis Of

Carbonate alteration and hydrolysis of mafic volcanic rocks in the Timmins area have been accompanied by mobilization and redistribution of alkalies, CaO, MgO, and FeO. These major oxides are of dubious value in classifying the volcanic rocks, and are of no value in identifying and correlating lithostratigraphic units. The trace elements Y, Zr, TiO2, and Cr, whose fractionation tendencies parallel those of the alkalies, FeO and MgO, are relatively immobile and display characteristic patterns within different volcanic units. The trace-element patterns are highly diagnostic, and their distribution corresponds to the distribution of lithostratigraphic units. Immobile trace-element data represent a potentially valuable tool in stratigraphic correlation of Archean volcanic rocks, whether altered or unaltered.

Mineralogical composition of and trace-element accumulation in lower Toarcian anoxic sediments: a case study from the Bilong Co. oil shale, eastern Tethys

2015 ◽  
Vol 153 (4) ◽  
pp. 618-634 ◽  
Author(s):  
XIUGEN FU ◽  
JIAN WANG ◽  
XINGLEI FENG ◽  
WENBIN CHEN ◽  
DONG WANG ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Oil Shale ◽  
Volcanic Rocks ◽  
Mineralogical Composition ◽  
Geochemical Data ◽  
Anoxic Sediments ◽  
Marine Influence ◽  
High Concentrations ◽  
Element Enrichment

AbstractThe sediments of organic-rich oil shales in the Bilong Co. area can be correlated with those of the early Toarcian anoxic black-shale events in Europe. The Bilong Co. sediments are rich in trace elements Se, Mo, Cd, As and Ni, and, to a lesser extent, Li, F, V, Co, Cu, Cs, Hg and Bi, in comparison to the upper continental crust. Thirty-two oil shale samples were collected from the Bilong Co. oil shale to evaluate the controlling factors of trace-element enrichment in the lower Toarcian anoxic sediments. Minerals identified in the Bilong Co. oil shale include calcite, quartz, illite, feldspar and dolomite, and trace amounts of siderite, magnesite, halite, haematite, zeolite, amphibole, gypsum, anhydrite, apatite, pyrite, sphalerite, barite and mixed-layer illite/smectite. Mineralogical and geochemical data show that seawater and hydrothermal activities are the dominant influences on the mineralogical composition and elevated trace-element concentrations in the oil shale. The clay minerals, quartz and feldspar in the Bilong Co. oil shale were derived from the Nadi Kangri volcanic rocks. Input of sediment from this source may have led to enrichment of trace elements Li, Cr and Cs in the oil shale. Carbonate minerals and nodular- and framboidal-pyrite are authigenic phases formed from seawater. The enrichment of V, Co, Ni, Cu, Mo, As, Se, Bi and U in the oil shale was owing to marine influence. Barite, sphalerite and fracture-filling pyrites were derived from hydrothermal solutions. High concentrations of F, Zn and Cd were probably derived from hydrothermal fluids.

Further immobile element data from altered volcanic rocks, Timmins mining area, Ontario

1980 ◽  
Vol 17 (3) ◽  
pp. 419-423 ◽  
Author(s):  
J. F. Da Vies ◽  
R. E. S. Whitehead
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Volcanic Rocks ◽  
Mining Area ◽  
Trace Element Data ◽  
Element Data ◽  
Lithostratigraphic Units

The relatively immobile trace elements TiO2, Zr, and Y prove useful for determining the original identity of, and for correlating, metamorphosed and metasomatized Archean volcanic rocks. More than 95% of 366 samples from the Timmins area were found to correspond to the lithostratigraphic units determined independently from structural and stratigraphic decisions based on lithology and top determinations. Trace-element data can be used for distinguishing volcanic units and as an aid in correlation regardless of any petrogenetic interpretations.

Rare-earth and other trace-element distributions in the calc-alkaline volcanic rocks from deep boreholes in the Phlegrean Fields, Campania (south Italy)

1980 ◽  
Vol 28 ◽  
pp. 123-133 ◽  
Author(s):  
A. Albini ◽  
R. Cristofolini ◽  
P. Di Girolamo ◽  
D. Stanzione
Keyword(s):  
Rare Earth ◽  
Trace Element ◽  
Volcanic Rocks ◽  
Calc Alkaline ◽  
South Italy ◽  
Phlegrean Fields ◽  
Deep Boreholes

scholarly journals Trace Element Distribution in Magnetite Separates of Varying Origin: Genetic and Exploration Significance

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 759 ◽  
Author(s):  
Demetrios G. Eliopoulos ◽  
Maria Economou-Eliopoulos
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Precious Metals ◽  
Trace Element Content ◽  
Element Distribution ◽  
Ore Deposits ◽  
Trace Element Distribution ◽  
Calc Alkaline ◽  
Porphyry Cu ◽  
Volcanic Source

Magnetite is a widespread mineral, as disseminated or massive ore. Representative magnetite samples separated from various geotectonic settings and rock-types, such as calc-alkaline and ophiolitic rocks, porphyry-Cu deposit, skarn-type, ultramafic lavas, black coastal sands, and metamorphosed Fe–Ni-laterites deposits, were investigated using SEM/EDS and ICP-MS analysis. The aim of this study was to establish potential relationships between composition, physico/chemical conditions, magnetite origin, and exploration for ore deposits. Trace elements, hosted either in the magnetite structure or as inclusions and co-existing mineral, revealed differences between magnetite separates of magmatic and hydrothermal origin, and hydrothermal magnetite separates associated with calc-alkaline rocks and ophiolites. First data on magnetite separates from coastal sands of Kos Island indicate elevated rare earth elements (REEs), Ti, and V contents, linked probably back to an andesitic volcanic source, while magnetite separated from metamorphosed small Fe–Ni-laterites occurrences is REE-depleted compared to large laterite deposits. Although porphyry-Cu deposits have a common origin in a supra-subduction environment, platinum-group elements (PGEs) have not been found in many porphyry-Cu deposits. The trace element content and the presence of abundant magnetite separates provide valuable evidence for discrimination between porphyry-Cu–Au–Pd–Pt and those lacking precious metals. Thus, despite the potential re-distribution of trace elements, including REE and PGE in magnetite-bearing deposits, they may provide valuable evidence for their origin and exploration.

scholarly journals Petrogenesis of Magnesian High-K Granitoids From Bitkine (Centrechad Massif): Major and Trace Elements Constraints

2020 ◽  
Vol 1 (5) ◽  
Author(s):  
Mbaihoudou Diontar ◽  
Jean Claude Doumnang ◽  
Maurice Kwékam ◽  
Zagalo Al-hadj Hamid ◽  
Armand Kagou Dongmo ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Fractional Crystallization ◽  
Major And Trace Elements ◽  
Trace Element Data ◽  
Calc Alkaline ◽  
Element Data ◽  
High K ◽  
Microgranular Enclaves ◽  
Mantle Magma

Major and trace element data were used to constrain the nature and origin of the Bitkine gabbro-diorite magma.The gabbro-diorites of Bitkine within the Guéra Massif, and associated microgranular enclaves consist of plagioclase, k-feldspar, clinopyroxene, amphibole, biotite and quartz. Gabbro-diorites and enclaves are basic to intermediate rocks. They are high-K magnesian calc-alkaline with shoshonite affinity. ΣREE range from 132 to 436 ppm in gabbro-diorites, while they are from 134 to 207 ppm in enclaves. LREE are weakly enriched compared to HREE (La/Yb)N = (12.23 -41.40) and (6.20-31.86) respectively in gabbro-diorites and enclaves. These rocks show a weak negative anomaly in europium (Eu/Eu* = 0.78-1.07). They are rich in Ba and Sr, and show negative anomalies in Nb, Ta and Ti. The Nb/Ta, Rb/Cs and Ba/Nb ratios of the Bitkine gabbro-diorites and their enclaves indicate that they are derived from mantle magma modified by subducted fluids. This magma during its evolution by fractional crystallization was contaminated by crustal materials.

Methylmercury and Trace Element Distribution in the Organs of Stenella coeruleoalba Dolphins Stranded on the French Mediterranean Coast

2014 ◽  
Vol 8 (1) ◽  
pp. 35-48 ◽  
Author(s):  
Emmanuel Wafo ◽  
Véronique Risoul ◽  
Thérèse Schembri ◽  
Véronique Lagadec ◽  
Frank Dhermain ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Marine Pollution ◽  
Element Distribution ◽  
Mediterranean Coast ◽  
Trace Element Distribution ◽  
Slight Reduction ◽  
Stenella Coeruleoalba ◽  
Contamination Levels

The main objective of this study was to evaluate the contamination by mercury (Hg), methylmercury (Me-Hg), cadmium (Cd), selenium (Se), zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in dolphins stranded on the French Mediterranean coast. The distributions of these contaminants in the organs of dolphins have also been studied. Overall, contamination levels varied according to the following sequence: liver > kidney > lung > muscle, except for cadmium (kidney > liver > lung > muscle). Size and sex of animals were also considered. Young dolphins were less impacted with trace elements than adults, except for copper. Among the studied parameters, the most important appeared to be the size of mammals. In addition, in the case of mercury and selenium, the sex of mammals seemed to be also relevant. The correlations between the concentrations of trace elements suggest the existence of detoxification processes. Since 1990s, using dolphins for tracing marine pollution, a slight reduction in the burden of the considered trace elements could be noted.

scholarly journals Spatial distribution and potential ecological risk assessment of some trace elements in sediments and grey mangrove (Avicennia marina) along the Arabian Gulf coast, Saudi Arabia

2020 ◽  
Vol 18 (1) ◽  
pp. 77-96
Author(s):  
Hameed Alsamadany ◽  
Hassan S. Al-Zahrani ◽  
El-Metwally M. Selim ◽  
Mohsen M. El-Sherbiny
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Ecological Risk ◽  
Oil Pollution ◽  
Gulf Coast ◽  
Arabian Gulf ◽  
Avicennia Marina ◽  
Potential Ecological Risk ◽  
Average Concentration ◽  
Grey Mangrove

AbstractTo assess trace element concentrations (Zn, Cu, Pb, Cr, Cd and Ni) in the mangrove swamps along the Saudi coast of the Arabian Gulf, thirteen samples of surface sediment and leaves of grey mangrove, Avicennia marina were collected and analyzed. The detected trace element contents (μg g-1) in surface sediments were in the following descending order according to their mean values; Cr (49.18) > Zn (48.48) > Cu (43.06) > Pb (26.61) > Ni (22.88) > Cd (3.21). The results showed that the average concentrations of Cd and Pb exceeded their world average concentration of shale. The geo-accumulation, potential ecological risk and toxicity response indices demonstrated that trace elements have posed a considerable ecological risk, especially Cd. The inter-relationships between physico-chemical characters and trace elements suggests that grained particles of mud represent a noteworthy character in the distribution of trace elements compared to organic materials. Moreover, the results revealed that Zn was clearly bioaccumulated in leaf tissues A. marina. Dredging, landfilling, sewage effluents and oil pollution can be the paramount sources of pollution in the area under investigation.

Early Cretaceous crust–mantle interaction linked to rollback of the Palaeo-Pacific flat-subducting slab: constraints from the intermediate–felsic volcanic rocks of the northern Great Xing’an Range, NE China

2021 ◽  
pp. 1-22
Author(s):  
Jia-Hao Jing ◽  
Hao Yang ◽  
Wen-Chun Ge ◽  
Yu Dong ◽  
Zheng Ji ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Volcanic Rocks ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Ne China ◽  
Asthenospheric Mantle ◽  
High K ◽  
Wide Range ◽  
Great Xing’An Range ◽  
Subducting Slab

Abstract Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time (c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵHf(t) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵHf(t) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.

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