scholarly journals Multi-stage history of compound mantle xenoliths from Western USA: Implications for metasomatic processes in the deep mantle.

2016 ◽  
Vol 47 (1) ◽  
pp. 357
Author(s):  
I. Baziotis ◽  
P. D. Asimow ◽  
A. Koroneos ◽  
G. Poli ◽  
T. Ntaflos
Keyword(s):  
Partial Melting ◽  
Volcanic Field ◽  
Mantle Xenoliths ◽  
Basaltic Volcanism ◽  
Silicate Minerals ◽  
Western Usa ◽  
Multi Stage ◽  
Short Period ◽  
History Of ◽  
Cima Volcanic Field

The compound mantle xenoliths from Cima Volcanic Field and Chino Valley (Western U.S.A.) represent outstanding candidates to illustrate the processes that occur prior to their delivery to the surface by alkali-basaltic volcanism. The xenoliths share characteristics like pyroxene zonation, amphibole breakdown and formation of glass and armalcolite. Their petrogenetic evolution involved partial melting of the silicate minerals, infiltration of reactive melts and dissociation of minerals en route to the surface, suggesting that these rocks followed multi-stage histories that initiated deep in the mantle (>1.0 GPa) and proceeded during a very short period of time. 

Petrology of Lower Crustal and Upper Mantle Xenoliths from the Cima Volcanic Field, California

1991 ◽  
Vol 32 (1) ◽  
pp. 169-200 ◽  
Author(s):  
H. G. WILSHIRE ◽  
A. V. McGUIRE ◽  
J. S. NOLLER ◽  
B. D. TURRIN
Keyword(s):  
Upper Mantle ◽  
Volcanic Field ◽  
Mantle Xenoliths ◽  
Lower Crustal ◽  
Cima Volcanic Field

scholarly journals Evolution of intraplate alkaline to tholeiitic basalts via interaction between carbonated melt and lithospheric mantle

2021 ◽  
Author(s):  
Ze-Zhou Wang ◽  
Sheng-Ao Liu
Keyword(s):  
Partial Melting ◽  
Mantle Source ◽  
Lithospheric Mantle ◽  
Eastern China ◽  
Volcanic Field ◽  
Basaltic Volcanism ◽  
Element Abundances ◽  
Isotopic Compositions ◽  
Compositional Diversity ◽  
Basaltic Melts

Abstract Intraplate basaltic volcanism commonly exhibits wide compositional ranges from silica-undersaturated alkaline basalts to silica-saturated tholeiitic basalts. Possible mechanisms for the compositional transition involve variable degrees of partial melting of a same source, decompression melting at different mantle depths (so-called “lid effect”), and melt-peridotite interaction. To discriminate between these mechanisms, here we investigated major-trace elemental and Sr-Nd-Mg-Zn isotopic compositions of a suite of intraplate alkaline and tholeiitic basalts from the Datong volcanic field in eastern China. Specifically, we employed Mg and Zn isotope systematics to assess whether the silica-undersaturated melts originated from a carbonated mantle source. The alkaline basalts have young HIMU-like Sr and Nd isotopic compositions, lower δ26Mg (-0.42‰ to -0.38‰) and higher δ66Zn (0.40‰ to 0.46‰) values relative to the mantle. These characteristics were attributable to an asthenospheric mantle source hybridized by carbonated melts derived from the stagnant Pacific slab in the mantle transition zone. From alkaline to tholeiitic basalts, δ26Mg gradually increases from -0.42‰ to -0.28‰ and δ66Zn decreases from 0.46‰ to 0.28‰ with decreasing alkalinity and incompatible trace element abundances (e.g. Rb, Nb, Th and Zr). The Mg and Zn isotopic variations are significantly beyond the magnitude (<0.1‰) induced by different degrees of fractional crystallization and partial melting of a same mantle source, excluding different degree of partial melting and the “lid effect” as possible mechanisms accounting for the compositional variations in the Datong basalts. There are strong, near-linear correlations of δ26Mg and δ66Zn with 87Sr/86Sr (R2=0.75 − 0.81) and 143Nd/144Nd (R2=0.83 − 0.90), suggesting an additional source for the Datong basalts. This source is characterized by pristine mantle-like δ26Mg and δ66Zn values as well as EM1-like Sr-Nd isotopic ratios, pointing towards a metasomatized subcontinental lithospheric mantle (SCLM). Isotope mixing models show that mingling between alkaline basaltic melts and partial melts from the SCLM imparts all the above correlations, which means that the SCLM must have been partially melted during melt-SCLM reaction. Our results underline that interaction between carbonated silica-undersaturated basaltic melts and the SCLM acts as one of major processes leading to the compositional diversity in intracontinental basaltic volcanism.

Stepping up detection, response, preparedness and readiness measures for “COVID-19”- A Pandemic

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1042-1047
Author(s):  
Khushbu Balsara ◽  
Deepankar Shukla
Keyword(s):  
Health Care ◽  
Health Care Workers ◽  
Clinical History ◽  
Frontline Workers ◽  
Diagnostic Assays ◽  
Care Workers ◽  
Short Period ◽  
History Of ◽  
Detection Response ◽  
Care Worker

In a very short period of time, “COVID-19” has seized the consciousness globally by making remarkable changes in our day to day living and has superintended as a public health emergency globally. It has high radar of transmission, affecting an individual at work to frontline workers. The measures and planning for a response plays a key role from drawing up an emergency committee and this follows an equation which broadly deals with epidemiological to clinical history of the patient, management steps from isolation, screening, diagnostic assays for identification and treatment. The application of an organized plan with secure structure aids in better performance, increases efficacy of management and saves time. Also saves time for a health care worker to g through routine levels of channels of administration if already a familiar way of operation is known for such situations. Thus, planning and developing a ‘blueprint of approach’ towards management of patient while facing such situation is a must. This review provides an insight to the measures for detection, response and preparedness of the hospital and health care workers should largely be inclusive of; also highlights the measures to be taken at every step after coming in contact with a positive case of “COVID-19”.

“The last chord of the Silver Age”: science and culture in Crimea in 1920

2020 ◽  
Vol 2020 (10-4) ◽  
pp. 4-14
Author(s):  
Vladimir Kalinovsky ◽  
Alexander Puchenkov
Keyword(s):  
Civil War ◽  
The South ◽  
Silver Age ◽  
Russian Culture ◽  
Short Period ◽  
The Crimea ◽  
Science And Culture ◽  
History Of ◽  
Russian Intelligentsia

This article is devoted to the development of science and culture in the short period of the Wrangel Crimea - 1920. At this time, the brightest figures of Russian culture of that time worked on the territory of the small Peninsula: O. E. Mandelstam, M. A. Voloshin, B.D. Grekov, G.V. Vernadsky, V.I. Vernadsky and others. The article provides an overview of the life and activities of the Russian intelligentsia in 1920 in the Crimea, based on materials of periodicals as the most important source for studying the history of the Civil war in the South of Russia whose value is to be fully evaluated.

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