Results 21 to 30 of about 5,310 (122)

XENOLITH GARNETS FROM MIR KIMBERLITE PIPE: CHEMICAL COMPOSITION AND EVIDENCE OF METASOMATIC PROCESSES IN THE LITHOSPHERE MANTLE

Геодинамика и тектонофизика, 2022
This paper reports the results on the composition of lithosphere mantle under the Mirny kimberlite field. The authors investigated 57 samples of the mantle xenoliths collected from the Mir pipe.
T. V. Kalashnikova, S. I. Kostrovitsky, K. A. Sinitsyn, E. E. Yudintseva   +3 more
doaj   +1 more source

The composition and distribution of the rejuvenated component across the Hawaiian plume: Hf‐Nd‐Sr‐Pb isotope systematics of Kaula lavas and pyroxenite xenoliths

Geochemistry, Geophysics, Geosystems, 2013
Rejuvenated volcanism refers to the reemergence of volcanism after a hiatus of 0.5–2 Ma following the voluminous shield building stage of Hawaiian volcanoes.
Michael Bizimis, Vincent J. M. Salters, Michael O. Garcia, Marc D. Norman   +3 more
doaj   +1 more source

Garnet pyroxenites explain high electrical conductivity in the East African deep lithosphere [PDF]

arXiv, 2021
A large contrast in electrical conductivity has been observed within the lithospheric mantle between the Tanzanian craton and the Mozambique belt at depths > 70 km. Such contrasts are typically attributed to changes in volatiles and/or melt content, with changes in mineralogy deemed insufficient to impact conductivity.
arxiv  

The Discovery and Geochemical Characteristics of an Eocene Peridotite Xenolith-Bearing Mafic Volcanic Neck in Coastal Southeast China

Frontiers in Earth Science, 2022
The mantle beneath coastal SE China evolved from enriched to depleted between the Cretaceous and the Neogene, although the precise timing of this change remains unclear.
Chuanshun Li, Xilin Zhao, Xilin Zhao, Xilin Zhao, Yang Jiang, Guangfu Xing, Minggang Yu, Zheng Duan   +7 more
doaj   +1 more source

Petrographical and Mineralogical Characteristics of Bengge Alkaline Igneous Complex in Zhongdian, Western Yunnan and Its Geological Significance

Kuangchan zonghe liyong, 2022
Bengge alkaline igneous complex in Zhongdian, Western Yunnan has the variety of rock types, which is production after a complex magma—fluid process. The petrographical and mineralogical analysis of the host rock and its xenolith suggests that the igneous
Yupeng Huang, Jinxi Zou, Qingqiang Liu, Chunzhang Wu, Xianfan Liu, Jianghong Deng, Kefa Ren   +6 more
doaj   +1 more source

Cold deep subduction recorded by remnants of a Paleoproterozoic carbonated slab

Nature Communications, 2018
The onset of modern-style plate tectonics remains under debate. Here, Xu et al. report a cold thermal-gradient recorded in an eclogite xenolith in Paleoproterozoic carbonatite from orogen, and propose that modern-style subduction has operated since at ...
Cheng Xu, Jindřich Kynický, Wenlei Song, Renbiao Tao, Zeng Lü, Yunxiu Li, Yueheng Yang, Miroslav Pohanka, Michaela V. Galiova, Lifei Zhang, Yingwei Fei   +10 more
doaj   +1 more source

Orthopyroxene-enrichment in the lherzolite-websterite xenolith suite from Paleogene alkali basalts of the Poiana Ruscă Mountains (Romania)

Geologica Carpathica, 2015
In this paper we present the petrography and geochemistry of a recently collected lherzolite-websterite xenolith series and of clinopyroxene xenocrysts, hosted in Upper Cretaceous–Paleogene basanites of Poiana Ruscă (Romania), whose xenoliths show ...
Nédli Zsuzsanna, Szabó Csaba, Dégi Júlia   +2 more
doaj   +1 more source

U-Pb Age and Hf Isotope Systematics of Zircon from Eclogite Xenoliths in Devonian Kimberlites: Preliminary Data on the Archaean Roots in the Junction Zone between the Sarmatian and Fennoscandian Segments of the East European Platform

Geosciences, 2021
The results of a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb dating and a Hf isotope study of zircon crystals separated from small eclogite xenoliths found in Devonian kimberlites within the Prypyat horst, Ukraine, have ...
Leonid Shumlyanskyy, Stepan Tsymbal, Monika A. Kusiak, Simon A. Wilde, Alexander A. Nemchin, Iryna Tarasko, Liudmyla Shumlianska, Mandy Hofmann   +7 more
doaj   +1 more source

Genesis of primitive Hawaiian rejuvenated-stage lavas: Evidence for carbonatite metasomatism and implications for ancient eclogite source [PDF]

arXiv, 2020
To constrain a contribution of deep carbonated mantle, to fractionation of Hf relative to rare earth elements (REE) in volcanic series, we examine available high-quality data on major, trace element and Nd-Hf isotope compositions of primitive lavas and glasses erupted during preshield, postshield and mostly rejuvenated stage of the Hawaiian hot spot ...
arxiv  

The Nitrogen Budget of Earth [PDF]

, 2015
We comprehensively compile and review N content in geologic materials to calculate a new N budget for Earth. Using analyses of rocks and minerals in conjunction with N-Ar geochemistry demonstrates that the Bulk Silicate Earth (BSE) contains \sim7\pm4 times present atmospheric N (4\times10^18 kg N, PAN), with 27\pm16\times10^18 kg N.
arxiv   +1 more source