Magma mixing and the generation of isotopically juvenile silicic magma at Yellowstone caldera inferred from coupling 238U–230Th ages with trace elements and Hf and O isotopes in zircon and Pb isotopes in sanidine

2013 ◽  
Vol 166 (2) ◽  
pp. 587-613 ◽  
Author(s):  
Mark E. Stelten ◽  
Kari M. Cooper ◽  
Jorge A. Vazquez ◽  
Mary R. Reid ◽  
Gry H. Barfod ◽  
...  
Keyword(s):  
Trace Elements ◽  
Magma Mixing ◽  
Silicic Magma ◽  
Pb Isotopes ◽  
O Isotopes ◽  
Yellowstone Caldera

Metabentonite geochemistry: magmatic cycles and graptolite extinctions at Dob's Linn, southern Scotland

1988 ◽  
Vol 79 (1) ◽  
pp. 19-41 ◽  
Author(s):  
R. A. Batchelor ◽  
J. A. Weir
Keyword(s):  
Trace Elements ◽  
Deleterious Effect ◽  
Major Element ◽  
Magma Mixing ◽  
Volcanic Origin ◽  
Intermediate Composition ◽  
Ash Composition ◽  
Mineralogical Study ◽  
Local Extinctions ◽  
Phosphorus Levels

ABSTRACTThe Moffat Shale Group is a condensed, variable and partly pelagic sequence of mudrocks of Llandeilo—Llandovery age. The sequence has a five-fold lithological subdivision based mainly on the occurrence of grey mudstones within a succession otherwise dominated by fully euxinic black graptolitic mudrocks. Associated with the black mudrocks, especially in the Llandovery, are metabentonite beds which achieve a climax, both in thickness and in number, within the top quarter of the mudrock sequence. A geochemical and mineralogical study has confirmed a volcanic origin for the metabentonites. Major element data highlight a carbonate-dominated environment above the gregarius—convolutus Zones boundary. Phosphorus levels reach a peak at the same boundary, as well as at the Caradoc—Ashgill boundary where phosphorite horizons are known from Wales and Norway. Immobile trace elements have highlighted regular changes in source magma composition. Prolonged periods of crystal fractionation in magmas of intermediate composition gave rise, on eruption, to large volumes of silicic ash which had a deleterious effect on graptolite species and led to local extinctions. Regular fluctuations in ash composition from silicic to intermediate are ascribed to alternating fractionation and magma mixing cycles.

Petrology, geochemistry, and zircon U–Pb isotopes of Xintian Complex in Yanbian area, Northeast China: Evidence for magma mixing and geodynamics processes

2020 ◽  
Vol 55 (7) ◽  
pp. 5417-5431
Author(s):  
Yang Liu ◽  
Yong Zhang ◽  
Jinggui Sun ◽  
Zhikai Xu ◽  
Yuming Liu ◽  
...  
Keyword(s):  
Northeast China ◽  
Magma Mixing ◽  
Pb Isotopes

Geochemistry and Sr-Nd-Pb isotopes of Monte Amiata Volcano, Central Italy: evidence for magma mixing between high-K calc-alkaline and leucititic mantle-derived magmas

2015 ◽  
Vol 134 (2) ◽  
pp. 266-290 ◽  
Author(s):  
Sandro Conticelli ◽  
Elena Boari ◽  
Luca Burlamacchi ◽  
Francesca Cifelli ◽  
Francesco Moscardi ◽  
...  
Keyword(s):  
Magma Mixing ◽  
Central Italy ◽  
Pb Isotopes ◽  
Calc Alkaline ◽  
High K
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