Results 181 to 190 of about 3,752 (234)

Lamprophyres of Kayla pipe and their mantle xenocrysts, SE Yakutia

2021
<p>The bulk rock and geochemistry of the Kayla and Khatastyr lamproites is similar to other Aldan lamproites and lamprophyres.  The ultramafic varieties are close to cratonic Ol- lamproites and alkaline Al, Si-rich varieties are closer to orogenic type.</p><p>Trace element bulk rock trace element ...
Nikolai Vladykin, Igor Ashchepkov, Irina Sotnikova, Nikolai Mevedev   +3 more
openaire   +1 more source

Garnet xenocrysts in the Mashhad granite, NE Iran

Geologische Rundschau, 1980
Garnet-bearing tonalite is present within 300 m of the contact with garnet-rich hornfels. It is suggested that the almandine xenocrysts in the tonalite are of accidental origin and represent residuals from the assimilation of garnet-rich hornfels by tonalite.
Moazez-Lesco, Z., Plimer, I. R.
openaire   +1 more source

Zircon xenocryst evidence for crustal recycling at the Mid-Atlantic Ridge

Lithos, 2020
Abstract The presence of zircon xenocrysts in Mid Atlantic Ridge (MAR) rocks poses essential questions concerning the path they have followed from their sources, how they have survived transport through the mantle, and why they are much more abundant than in any other ocean. Sixteen out of twenty-five seafloor samples collected between S 21° to N 42°
Bea Barredo, Fernando, Bortnikov, Nikolay, González Montero, María Del Pilar, Zinger, Tatiana, Sharkov, Evgenii, Silanteev, Silanteev, Sergei, Skolotnev, Sergei, Trukhalev, A., Molina Palma, José Francisco   +8 more
openaire   +2 more sources

Evidence for Archean crust in Iran provided by ca 2.7 Ga zircon xenocrysts within amphibolites from the Sanandaj–Sirjan zone, Zagros orogen

Precambrian Research, 2019
High-precision secondary-ion mass spectrometry (SIMS) U–Pb and Hf–O isotopic microanalyses of zircons from the central Sanandaj–Sirjan metamorphic zone (SSMZ) of the Zagros orogen, Iran, provide evidence of the presence of 2.7 Ga xenocrystic zircons ...
Farzaneh Shakerardakani, Xianhua Li, Xiao-Xiao Ling, Jiao Li, G. Tang, Yu Liu, B. Monfaredi   +6 more
semanticscholar   +1 more source

Pyroxene xenocryst geotherms: Techniques and application

Lithos, 2009
Abstract Pyroxene thermobarometry of mantle materials has matured with time, experimental investigation and experience to encompass solutions for both pressure and temperature based on the composition of garnet-facies peridotitic clinopyroxene alone.
openaire   +1 more source

Xenocrysts in Eocene Camptonites from Taourirt, Northern Morocco

Mineralogical Magazine, 1988
AbstractA study of xenocrystic material included in 57 Ma igneous rocks that outcrop in the Taourirt area of north-east Morocco has been made. The mineralogy of the host rocks is essentially clinopyroxene, rare olivine, titanomagnetite and either kaersutite or biotite.
Abdelkader Mokhtari, Danielle Velde
openaire   +1 more source

Low-δ18O zircon xenocrysts in alkaline basalts; a window into the complex carbonatite-metasomatic history of the Zealandia lithospheric mantle

Geochimica et Cosmochimica Acta, 2019
Megacrystic zircon grains from alkaline basaltic fields are rare but can provide fundamental insights into mantle metasomatic processes. Here, we report in-situ U-Pb ages, trace element concentrations and hafnium and oxygen isotopes for fourteen zircon ...
Q. V. D. van der Meer, J. Scott, S. Serre, M. Whitehouse, M. Kristoffersen, P. L. le Roux, E. Pope   +6 more
semanticscholar   +1 more source

Cathodoluminescence and trace element zoning in quartz phenocrysts and xenocrysts

Geochimica et Cosmochimica Acta, 1997
Abstract Quartz phenocrysts and xenocrysts are a common component of volcanic rocks but rarely contribute to our understanding of magmatic or eruptive processes due to an apparent internal chemical and structural homogeneity. Scanning electron microscopy cathodoluminescence imaging (SEM-CL) and secondary ion mass spectroscopy (ion microprobe ...
Gordon R. Watt, Paul Wright, Simon Galloway, Chris McLean   +3 more
openaire   +1 more source

Age of xenocrystic zircon from diatremes of western Canada

Canadian Journal of Earth Sciences, 1991
Numerous diatremes of middle and late Paleozoic age intrude miogeoclinal middle and lower Paleozoic strata in the Canadian Cordillera. In addition to abundant crustal xenoliths and conspicuous mantle-derived mineral xenocrysts, rare zircon grains are present. U–Pb dating of single zircon crystals from many of these diatremes has failed to identify the
R. R. Parrish, I. Reichenbach
openaire   +1 more source

40Ar/39Ar ages of alkali feldspar xenocrysts constrain the timing of intraplate basaltic volcanism

Quaternary Geochronology, 2018
Intraplate continental basaltic volcanic provinces (ICBVPs) occur on all continents and represent some of the most enigmatic volcanic systems. Constraints on the origin(s) and evolution of ICBVPs are predicated on detailed knowledge of eruption histories,
E. L. Matchan, David Phillips, E. Traine, D. Zhu   +3 more
semanticscholar   +1 more source