نتایج جستجو برای: basalts

تعداد نتایج: 2061  

2009
Jeffrey Taylor

Lars Borg (Lawrence Livermore National Laboratory, LLNL) and colleagues at LLNL, the University of New Mexico, the University of California, Berkeley, and Arizona State University have made detailed measurements of trace elements and isotopes in Northwest Africa (NWA) 032, a lunar basaltic meteorite. Previous studies had already shown that the rock is a low-titanium mare basalt. Among other thi...

Journal: :Science 2007
Alexander V Sobolev Albrecht W Hofmann Dmitry V Kuzmin Gregory M Yaxley Nicholas T Arndt Sun-Lin Chung Leonid V Danyushevsky Tim Elliott Frederick A Frey Michael O Garcia Andrey A Gurenko Vadim S Kamenetsky Andrew C Kerr Nadezhda A Krivolutskaya Vladimir V Matvienkov Igor K Nikogosian Alexander Rocholl Ingvar A Sigurdsson Nadezhda M Sushchevskaya Mengist Teklay

Plate tectonic processes introduce basaltic crust (as eclogite) into the peridotitic mantle. The proportions of these two sources in mantle melts are poorly understood. Silica-rich melts formed from eclogite react with peridotite, converting it to olivine-free pyroxenite. Partial melts of this hybrid pyroxenite are higher in nickel and silicon but poorer in manganese, calcium, and magnesium tha...

Journal: :Science 1989
M A Richards R A Duncan V E Courtillot

Continental flood basalt eruptions have resulted in sudden and massive accumulations of basaltic lavas in excess of any contemporary volcanic processes. The largest flood basalt events mark the earliest volcanic activity of many major hot spots, which are thought to result from deep mantle plumes. The relative volumes of melt and eruption rates of flood basalts and hot spots as well as their te...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
J Marvin Herndon

Nuclear georeactor numerical simulation results yield substantial (3)He and (4)He production and (3)He(4)He ratios relative to air (R(A)) that encompass the entire 2-SD (2sigma) confidence level range of tabulated measured (3)He(4)He ratios of basalts from along the global spreading ridge system. Georeactor-produced (3)He(4)He ratios are related to the extent of actinide fuel consumption at tim...

Seyyed Mohammad Hashemi,

Introduction: Quaternary basalts are one of the last signs of magmatism in Iran, some of which are related to deep fractures and active faults in the Quaternary. Quaternary basalts of Tabas are very important due to their high expansion and location in eastern Iran, and are located 140 km south east of Tabas city and according to the proposed divisions are part of the Lut zone. The aim of this...

Journal: :Geophysical Journal International 1997

2013
Gero Kurat

für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

2004
E. Jerby

The paper presents two experimental methods for basalt processing by microwaves, and their results. One method employs a single-mode cavity to melt basalt, and to produce a volcanic glass (obsidian). The other method uses an open-end applicator (i.e. a microwave drill [1]) to form holes in basalt rocks. Experimental observations of the basalt interactions with microwaves in these two schemes ar...

2007
P. B. Kelemen

3.18.3 CHARACTERISTICS OF ARC MAGMAS 7 3.18.3.1 Comparison with MORBs 7 3.18.3.1.1 Major elements 7 3.18.3.1.2 We are cautious about fractionation correction of major elements 9 3.18.3.1.3 Distinctive, primitive andesites 11 3.18.3.1.4 Major elements in calc-alkaline batholiths 11 3.18.3.2 Major and Trace-Element Characteristics of Primitive Arc Magmas 18 3.18.3.2.1 Primitive basalts predominat...

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