Rare earth element, Sr- and Nd-isotope evidence for petrogenesis of Permian basaltic and K-rich volcanic rocks from south-west England

1986 ◽  
Vol 50 (357) ◽  
pp. 481-489 ◽  
Author(s):  
R. S. Thorpe ◽  
M. E. Cosgrove ◽  
P. W. C. van Calsteren
Keyword(s):  
High Field ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Transition Element ◽  
Oceanic Lithosphere ◽  
High Field Strength ◽  
Nd Isotope ◽  
South West ◽  
Isotope Evidence ◽  
South West England

AbstractPermian basic/ultrabasic lavas from south-west England may be divided into a ‘basaltic’ and a K-rich group. Both groups have enrichment of large-ion lithophile (LIL) elements relative to high field strength (HFS) elements, and the K-rich group show large degrees of LIL enrichment (c.50–500 times primordial mantle) in association with varied transition element concentrations. Samples from both groups 87Sr/86Sri = 0.704–0.705 and 143Nd/144Ndi = 0.5123–0.5127 and plot close to the mantle array on an ɛSr−ɛNd diagram. These data are interpreted in terms of derivation of the lavas from magmas resulting from partial melting of mantle which had experienced less (for the basaltic group) or more (for the K-rich group) enrichment in LIL elements as a result of migration of mantle melts. Such enrichment accompanied or followed subduction of oceanic lithosphere below south-west England. The resultant magmas experienced fractional crystallization of olivine and pyroxene prior to eruption.

Evolution of deep mantle sourced carbonated melt in the mantle lithosphere

2020 ◽  
Author(s):  
Guoliang Zhang
Keyword(s):  
Rare Earth ◽  
Field Strength ◽  
Rare Earth Elements ◽  
Lithospheric Mantle ◽  
High Field ◽  
Volcanic Rocks ◽  
Mantle Lithosphere ◽  
High Field Strength ◽  
Alkali Basalts ◽  
Deep Mantle

<p>Deep sourced magmas play a key role in distribution of carbon in the Earth’s system. Oceanic hotspots rooted in deep mantle usually produce CO<sub>2</sub>-rich magmas. However, the association of CO<sub>2</sub> with the origin of these magmas remains unclear. Here we report geochemical analyses of a suite of volcanic rocks from the Caroline Seamount Chain formed by the deep-rooted Caroline hotspot in the western Pacific. The most primitive magmas have depletion of SiO<sub>2</sub> and high field strength elements and enrichment of rare earth elements that are in concert with mantle-derived primary carbonated melts. The carbonated melts show compositional variations that indicate reactive evolution within the overlying mantle lithosphere and obtained depleted components from the lithospheric mantle. The carbonated melts were de-carbonated and modified to oceanic alkali basalts by precipitation of perovskite, apatite and ilmenite that significantly decreased the concentrations of rare earth elements and high field strength elements. These magmas experienced a stage of non-reactive fractional crystallization after the reactive evolution was completed. Thus, the carbonated melts would experience two stages, reactive and un-reactive, of evolution during their transport through in thick oceanic lithospheric mantle. We suggest that the mantle lithosphere plays a key role in de-carbonation and conversion of deep-sourced carbonated melts to alkali basalts. This work was financially supported by the National Natural Science Foundation of China (91858206, 41876040).</p>

scholarly journals VOLCANISM OF THE EARLY FORMATION STAGE OF ITURUP ISLAND (GREAT KURILE CHAIN)

2021 ◽  
pp. 87-98
Author(s):  
P.I. Fedorov ◽  
◽  
N.V. Tsukanov ◽  
A.R. Geptner ◽  
V.V. Petrova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Field Strength ◽  
Partial Melting ◽  
Upper Mantle ◽  
High Field ◽  
Middle Miocene ◽  
Volcanic Rocks ◽  
High Field Strength ◽  
Iturup Island ◽  
Formation Stage

The article presents new petrogeochemical data on the Middle Miocene-Pliocene volcanic rocks from central part of Iturup Island (Great Kurile Chain). It is shown that volcanism of the Middle Miocene-Early Pliocene age in the central part of the Iturup Island took place in a suprasubduction setting. The distribution of high field strength elements (HFSE) and their ratio in the basaltoids indicate their formation upon partial melting of the depleted upper mantle, while the enrichment of rocks with large ionic lithophilic elements (LILE) indicates both a fluid mantle additive introduced into the melts during the evolution of primary magma and the participation of a low-temperature suprasubduction fluid. The established differences in the composition of the basaltoids of the frontal and rear zones due to the limited number of analyzed samples are considered preliminary. Thus, basaltoids in the rear zone are distinguished by higher concentrations of Th, Pb, HFSE (Nb, Zr, Y, Hf), relative enrichment in LREE, pronounced negative Zr and Hf anomalies, and positive Eu.

scholarly journals Supplemental Material: Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas

2021 ◽  
Author(s):  
Krzysztof Sokół ◽  
et al.
Keyword(s):  
Rare Earth ◽  
Field Strength ◽  
High Field ◽  
Earth Element ◽  
Estimation Method ◽  
Model Description ◽  
High Field Strength ◽  
Data Standardization ◽  
Element Transport ◽  
Alkaline Magmas

Petrographic information, parameterization of the Grant model, description of the HFSE tonnage estimation method, and supplemental tables of whole-rock data, standardization, and HFSE volume-tonnage calculations.<br>

scholarly journals Zirconosilicates in the kakortokites of the Ilímaussaq complex, South Greenland: Implications for fluid evolution and high-field-strength and rare-earth element mineralization in agpaitic systems

2016 ◽  
Vol 80 (1) ◽  
pp. 5-30 ◽  
Author(s):  
A. M. Borst ◽  
H. Friis ◽  
T. Andersen ◽  
T. F. D. Nielsen ◽  
T. E. Waight ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Earth Element ◽  
Secondary Mineral ◽  
High Field Strength ◽  
Ree Mineralization ◽  
Subsequent Decrease ◽  
Fluoride Complexes ◽  
Mineral Assemblages ◽  
High Concentrations

AbstractThe layered agpaitic nepheline syenites (kakortokites) of the Ilímaussaq complex, South Greenland, host voluminous accumulations of eudialyte-group minerals (EGM). These complex Na-Ca-zirconosilicates contain economically attractive levels of Zr, Nb and rare-earth elements (REE), but have commonly undergone extensive autometasomatic/hydrothermal alteration to a variety of secondary mineral assemblages. Three EGM alteration assemblages are recognized, characterized by the secondary zirconosilicates catapleiite, zircon and gittinsite. Theoretical petrogenetic grid models are constructed to assess mineral stabilities in terms of component activities in the late-stage melts and fluids. Widespread alteration of EGM to catapleiite records an overall increase in water activity, and reflects interaction of EGM with late-magmatic Na-, Cl- and F-rich aqueous fluids at the final stages of kakortokite crystallization. Localized alteration of EGM and catapleiite to the rare Ca-Zr silicate gittinsite, previously unidentified at Ilímaussaq, requires an increase in CaO activity and suggests post-magmatic interaction with Ca-Sr bearing aqueous fluids. The pseudomorphic replacement of EGM in the kakortokites was not found to be associated with significant remobilization of the primary Zr, Nb and REE mineralization, regardless of the high concentrations of potential transporting ligands such as F and Cl. We infer that the immobile behaviour essentially reflects the neutral to basic character of the late-magmatic fluids, in which REE-F compounds are insoluble and remobilization of REE as Cl complexes is inhibited by precipitation of nacareniobsite-(Ce) and various Ca-REE silicates. A subsequent decrease in F– activity would furthermore restrict the mobility of Zr as hydroxyl-fluoride complexes, and promote precipitation of the secondary zirconosilicates within the confines of the replaced EGM domains.

scholarly journals Supplemental Material: Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas

2021 ◽  
Author(s):  
Krzysztof Sokół ◽  
et al.
Keyword(s):  
Rare Earth ◽  
Field Strength ◽  
High Field ◽  
Earth Element ◽  
Estimation Method ◽  
Model Description ◽  
High Field Strength ◽  
Data Standardization ◽  
Element Transport ◽  
Alkaline Magmas

Petrographic information, parameterization of the Grant model, description of the HFSE tonnage estimation method, and supplemental tables of whole-rock data, standardization, and HFSE volume-tonnage calculations.<br>

scholarly journals Supplemental Material: Reappraisal of the Mesozoic tectonic transition from the Paleo-Tethyan to Paleo-Pacific domains in South China

2021 ◽  
Author(s):  
Chengshi Gan ◽  
Yuzhi Zhang ◽  
et al.
Keyword(s):  
South China ◽  
High Field ◽  
South China Block ◽  
Loss On Ignition ◽  
High Field Strength ◽  
Nd Isotope ◽  
Mafic Rocks ◽  
Tectonic Transition ◽  
Major Oxide ◽  
Block Figure

Synthesis of the formation ages of the Triassic and Jurassic mafic rocks, shoshonitic rocks and granitoids in the Southeastern South China Block; Table S2: Major oxide (wt%) and trace element (ppm) compositions for the Triassic and Jurassic mafic rocks, shoshonitic rocks and high-Mg andesite and granitoids in the Southeastern South China Block; Table S3: Sr-Nd isotope compositions for the Triassic and Jurassic mafic rocks, shoshonitic rocks and high-Mg andesite and granitoids in the Southeastern South China Block; Table S4: Zircon Hf isotope compositions for the Triassic and Jurassic mafic and shoshonitic rocks and granitoids in the Southeastern South China Block; Figure S1: (A) Ta/Yb-Ce/Yb diagram for the Triassic and Jurassic shoshonitic rocks and (B) SiO2-MgO diagram for the Jurassic high-Mg andesite in the Southeastern South China Block; Figure S2: The variations of high field strength elements (HFSE) with loss on ignition (LOI) for the Jurassic mafic rocks in the Southeastern South China Block.<br>

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