scholarly journals Errata: The distributions of two mantle sources based on the Sr-Nd isotopic compositions of late Cenozoic volcanic rocks from the northern Fossa Magna, central Japan

2016 ◽  
Vol 45 (1) ◽  
pp. 47-47
Author(s):  
Akiyuki NARITA ◽  
Masatsugu YAMAMOTO ◽  
Takahiro SASANUMA ◽  
Hiroaki KOMATSU
Keyword(s):  
Volcanic Rocks ◽  
Late Cenozoic ◽  
Central Japan ◽  
Isotopic Compositions ◽  
Mantle Sources ◽  
Northern Fossa Magna

Le terrane de Slide Mountain (Cordillères canadiennes) : une lithosphère océanique marquée par des points chauds

2003 ◽  
Vol 40 (6) ◽  
pp. 833-852 ◽  
Author(s):  
M Tardy ◽  
H Lapierre ◽  
D Bosch ◽  
A Cadoux ◽  
A Narros ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Oceanic Island ◽  
Light Rare Earth ◽  
Isotopic Compositions ◽  
Incompatible Elements ◽  
Depleted Mantle ◽  
Mantle Sources ◽  
British Colombia ◽  
Ultramafic Cumulates ◽  
Back Arc

The Slide Mountain Terrane consists of Devonian to Permian siliceous and detrital sediments in which are interbedded basalts and dolerites. Locally, ultramafic cumulates intrude these sediments. The Slide Mountain Terrane is considered to represent a back-arc basin related to the Quesnellia Paleozoic arc-terrane. However, the Slide Mountain mafic volcanic rocks exposed in central British Colombia do not exhibit features of back-arc basin basalts (BABB) but those of mid-oceanic ridge (MORB) and oceanic island (OIB) basalts. The N-MORB-type volcanic rocks are characterized by light rare-earth element (LREE)-depleted patterns, La/Nb ratios ranging between 1 and 2. Moreover, their Nd and Pb isotopic compositions suggest that they derived from a depleted mantle source. The within-plate basalts differ from those of MORB affinity by LREE-enriched patterns; higher TiO2, Nb, Ta, and Th abundances; lower εNd values; and correlatively higher isotopic Pb ratios. The Nd and Pb isotopic compositions of the ultramafic cumulates are similar to those of MORB-type volcanic rocks. The correlations between εNd and incompatible elements suggest that part of the Slide Mountain volcanic rocks derive from the mixing of two mantle sources: a depleted N-MORB type and an enriched OIB type. This indicates that some volcanic rocks of the Slide Mountain basin likely developed from a ridge-centered or near-ridge hotspot. The activity of this hotspot is probably related to the worldwide important mantle plume activity that occurred at the end of Permian times, notably in Siberia.

Age, geochemistry and Sr-Nd-Pb isotopic compositions of alkali volcanic rocks from Mt. Melbourne and the western Ross Sea, Antarctica

2015 ◽  
Vol 19 (4) ◽  
pp. 681-695 ◽  
Author(s):  
Mi Jung Lee ◽  
Jong Ik Lee ◽  
Tae Hoon Kim ◽  
Joohan Lee ◽  
Keisuke Nagao
Keyword(s):  
Ross Sea ◽  
Volcanic Rocks ◽  
Isotopic Compositions ◽  
Western Ross Sea

U-depleted versus U-enriched signatures in complementary crust-mantle sources of volcanic rocks from Asia

2021 ◽  
Author(s):  
Sergei Rasskazov ◽  
Irina Chuvashova ◽  
Tatiana Yasnygina ◽  
Elena Saranina
Keyword(s):  
Lower Mantle ◽  
Partition Coefficients ◽  
Volcanic Rocks ◽  
Anomalous Behavior ◽  
Water Soluble ◽  
Tien Shan ◽  
Mantle Sources ◽  
Continental Lower Crust ◽  
Morb Source ◽  
Transitional Processes

<p>The Nb/U~47 and Th/U~4 ratios are considered as indicative for the OIB source referred by some authors to lower mantle plumes that in fact have no specific geochemical signatures but HIMU component. The Th/U ratio may vary because of the different garnet–melt and/or clinopyroxene–melt partition coefficients of U and Th. Anomalously high or low Th/U values in rocks can also be related to the input or removal of U, the migration of which is controlled by its mobility under oxidizing conditions owing to the formation of water-soluble uranyl  compounds with hexavalent U. These variations definitely distinguish non-plume magmatic sources. The Th/U ratio decreases to 2.5 in the MORB source and increases to 6 in the continental lower crust one. We describe anomalous behavior of uranium in sources of Cenozoic basalts and basaltic andesites from Primorye, Lesser Khingan, Tunka Valley, as well as similar Cretaceous-Paleogene rocks from Tien Shan. Significant deviations of the Th/U and Nb/U ratios from the OIB values are characteristics mostly of garnet-free sources. The U-depleted and U-enriched signatures are used as sensitive indicators for deciphering crust–mantle transitional processes.</p><p>This work is supported by the RSF grant 18-77-10027.</p>

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