Recycled subducted ocean crust has been traced by elevated 187Os/188Os in some studies and by high nickel and low manganese contents in others. Here, we show that these tracers are linked for Quaternary lavas of Iceland, strengthening the recycling model. An estimate of the osmium isotopic composition of both the recycled crust and the mantle peridotite implies that Icelandic Quaternary lavas are derived in part from an ancient crustal component with model ages between 1.1 _ 109 and 1.8 _ 109 years and from a peridotitic end-member close to present-day oceanic mantle.
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http://dx.doi.org/10.1126/science.1158452 | DOI Listing |
Sci Rep
May 2024
Université Paris-Saclay, CNRS, GEOPS, 91405, Orsay, France.
Large-scale flank collapses are one of the main hazards associated with the evolution of volcanic islands. Precisely dating such events is critical to evaluate the frequency of destabilization episodes and further assess the triggering mechanism(s) associated with internal and/or external factors, such as volcano dynamics, regional tectonics, and global paleoclimatic changes. Here, we constrain the age of a pumice-rich pyroclastic deposit exposed on the eastern flank of Flores Island (Azores), which we interpret as a co-blast deposit generated by a major flank collapse that destroyed the whole western flank of the former volcanic edifice.
View Article and Find Full Text PDFContrib Mineral Petrol
May 2024
Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Str. 49B, 50674 Cologne, Germany.
Unlabelled: Quaternary rocks from the East and West Eifel volcanic fields in western Germany are a key suite of intraplate volcanic rocks that can provide insights into volcanism of the Central European Volcanic Province (CEVP) and into continental intraplate volcanism in general. We present a comprehensive dataset for Eifel lavas including isotope as well as major and trace element data for 59 samples covering representative compositions of the different volcanic fields. In line with previous studies, the lavas are all SiO-undersaturated, alkaline-rich and mainly comprise primitive basanites, melilitites, and nephelinites (Mg# ≥ 57).
View Article and Find Full Text PDFHeliyon
December 2021
Department of Geology, College of Applied Sciences, Addis Ababa Science and Technology University, P.O. Box 16417, Addis Ababa, Ethiopia.
Major and trace element data are presented for basaltic lavas from western rift margin of central Main Ethiopian Rift located at Kella area to investigate the processes involved in the petrogenesis of the erupted magmas and the nature of mantle source compositions. Kella area is composed of Quaternary (<1.6 Ma), Miocene (10.
View Article and Find Full Text PDFNat Commun
July 2019
Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.
Recycling of Earth's crust through subduction and delamination contributes to mantle heterogeneity. Melt inclusions in early crystallised magmatic minerals record greater geochemical variability than host lavas and more fully reflect the heterogeneity of magma sources. To date, use of multiple isotope systems on small (< 300 μm) melt inclusions was hampered by analytical limitations.
View Article and Find Full Text PDFHeliyon
March 2019
Applied Research Centre Laboratory of Radiological Studies, Elevter Andronikashvili Institute of Physics of Ivane Javakhishvili Tbilisi State University, Georgia.
This study was performed to determine the distributions of radionuclides (U, Th and K naturally occurring in Khrami Late Variscan crystal massif and soils overlapping its adjacent territory built by Neogene and Quaternary lava using a gamma-ray spectrometry with an HPGe detector. By identification of artificial radionuclide Cs concentration revealed the character of radioactive contamination of the area under investigation. Based on the obtained results, the radiological parameters (outdoor absorbed gamma dose rate, annual effective dose; radium equivalent activity) were estimated to assess radiation hazards caused by use of industrial materials.
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