Results 21 to 30 of about 824 (171)

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

Mantle and Crustal Xenoliths in a Tephriphonolite From La Palma (Canary Islands): Implications for Phonolite Formation at Oceanic Island Volcanoes

Frontiers in Earth Science, 2022
The occurrence of mantle-derived peridotite xenoliths in phonolitic melts is a rare phenomenon, and is commonly ascribed to a mantle origin of the phonolite.
Andreas Klügel, Elmar Albers, Thor H. Hansteen   +2 more
doaj   +1 more source

MELTING CONDITIONS OF GRANITOID XENOLITHS IN CONTACT WITH ALKALINE MAFIC MAGMA (GUSINOOZERSKAYA DYKE, WESTERN TRANSBAIKALIA): TO THE PROBLEM OF THE ORIGIN OF ULTRAPOTASSIC ACID MELTS

Геодинамика и тектонофизика, 2017
The alkaline mafic (lamprophyric) Gusinoozerskaya dyke in West Transbaikalia is composed of partially melted granite xenoliths. Among the xenoliths, two melted substrates are observed: (1) plagioclase and quartz, and (2) alkaline feldspar and quartz. Few
V. B. Khubanov, T. T. Vrublevskaya, A. A. Tsygankov, A. G. Vladimirov, M. D. Buyantuev, E. N. Sokolova, V. F. Posokhov, E. A. Khromova   +7 more
doaj   +1 more source

Mantle Xenoliths from Huanul Volcano (Central-West Argentina): A Poorly Depleted Mantle Source under Southern Payenia

Geosciences, 2022
Huanul is a shield volcano with several lava flows hosting mantle xenoliths erupted during the Pleistocene (0.84 ± 0.05 Ma). It is located in the southern part of the Payenia Volcanic Province, which is among the largest Neogene-Quaternary volcanic ...
Gustavo W. Bertotto, Maurizio Mazzucchelli, Tommaso Giovanardi, Rommulo V. Conceiçao, Alberto Zanetti, Manuel E. Schilling, Mauro I. Bernardi, Alexis D. Ponce, Tiago Jalowitzki, Fernanda Gervasoni, Anna Cipriani   +10 more
doaj   +1 more source

Xenocrysts and megacrysts of alkaline olivine-basalt-basanite-nephelinite association Makhtesh Ramon (Israel): interaction with carrier magmas and crystallographic transformations

Литосфера, 2020
The article considers xenocrysts and megacrysts hosted in the rocks of Early Cretaceous olivine-basalt-basanite-nephelinite association that outcropped in the erosion crater of Makhtesh Ramon (Natural Reserve of Mishmar ha-Nagev, Israel).
Z. Yudalevich, Ye. Vapnik
doaj  

Age of the basement beneath the Mesozoic Lusitanian Basin revealed by granitic xenoliths from the Papôa volcanic breccia (West Iberia)

Geologica Acta, 2020
The dyke of the Papôa volcanic breccia cross-cutting the Lower Jurassic sequence of the Lusitanian Basin (West Iberia) contains granitic xenoliths. In this study, for the first time, U-Th-Pb zircon analysis of two xenoliths yielded 298±4Ma for biotite ...
M.F. Pereira, C. Gama, J.B. Silva, Í. Dias da Silva   +3 more
doaj   +1 more source

Geochemistry of spinels from xenoliths of mantle lherzolites (sverre Volcano, spitsbergen Archipelago)

Записки Горного института, 2017
The paper presents the results of a study (LA-ICP-MS method) of spinel from the collection of mantle xenoliths of lherzolites (seven xenoliths) selected in quaternary alkaline basalts of the Sverre volcano, the Spitsbergen archipelago.
D. S. Ashikhmin, Yu.-S. Chen, S. G. Skublov, A. E. Mel'nik   +3 more
doaj   +1 more source

Heterogeneous Exhumation Mechanisms in Neoproterozoic Collisional Metamorphism: P–T Constraints From Pelotas and Punta del Este Terranes, Southern Brazil and Uruguay

Geological Journal, EarlyView.
Petrography, thermobarometry, and pseudosection modelling reveal peak metamorphic conditions of 3–7.5 kbar and 520°C–800°C in Tonian‐Cryogenian orthogneisses of the Dom Feliciano Belt. Metamorphic field gradients of 27°C/km–39°C/km and variable exhumation mechanisms support correlation of these units as remnants of a Himalayan‐type Piratini Orogeny ...
Thaiane Niederauer‐Santos, Carla Cristine Porcher, Daniel Triboli Vieira, Edinei Koester, Diego Jaldín, Karina Luengo, Luisa Caon   +6 more
wiley   +1 more source

Geochemical Characterization of Intraplate Magmatism from Quaternary Alkaline Volcanic Rocks on Jeju Island, South Korea

Applied Sciences, 2021
The major and trace elements of Quaternary alkaline volcanic rocks on Jeju Island were analyzed to determine their origin and formation mechanism. The samples included tephrite, trachybasalts, basaltic trachyandesites, tephriphonolites, trachytes, and ...
Cheolhong Kim, Naing Aung Khant, Yongmun Jeon, Heejung Kim, Chungwan Lim   +4 more
doaj   +1 more source

Dispersal, source and glass chemistry of a third tephra unit within Iceland's Settlement Layer

Boreas, EarlyView.
Tephra layers may be studied to understand the dynamics and sequence of past explosive volcanism. In Iceland, the distinctive Settlement Layer (AD ~877) underlies almost all archaeological evidence for the Norse Settlement and is preserved in soils across Iceland and as cryptotephra overseas.
Conner A. G. Morison, GUÐRÚN LARSEN, Anthony J. Newton, Andrew J. Dugmore   +3 more
wiley   +1 more source