نتایج جستجو برای: type flood basalts

تعداد نتایج: 1365507  

2013
A. L. Fagan A. Simonetti

Apollo 14 (A-14) impact melt olivine vitrophyres (OVs), composed of olivine phenocrysts in an opaque glass matrix with minor amounts of pyroxene and plagioclase, are petrographically similar to pristine quenched A-14 high-alumina (high-Al) and Apollo 12 (A-12) basalts. Textural and chemical analyses have been conducted on olivines within impact melt and pristine mare basalt clasts from A-14 bre...

2013
Lara S. Wagner Maureen D. Long

[1] The Pacific Northwest (PNW) has experienced voluminous intraplate volcanism over the past 17 Ma, beginning with the Steens/Columbia River flood basalts and continuing with the stillongoing volcanism in the High Lava Plains (HLP) and eastern Snake River Plain (SRP). Here we present two complementary datasets (SKS splitting and Rayleigh wave phase velocity anisotropy) that place constraints o...

2013
Elli McKinley

The Basalt of Summit Creek is an enigmatic basalt unit that is about 55 million years (Ma) in age, located south of Mount Rainier. These basalts formed in a transitional time between the formation of the Coastal Range Basalts and the present Cascade arc. Through geochemical and paleomagnetic techniques, samples were collected and analyzed. Paleomagnetic samples showed nearly complete post erupt...

2008
Georgiana Y. Kramer Bradley L. Jolliff Clive R. Neal

[1] High-alumina (HA) mare basalts are a unique group of the lunar sample collection. Sample geochemistry indicates that these basalts are derived from sources composed of late-stage cumulates from the Lunar Magma Ocean (LMO). Their aluminous nature suggests their sources contained significant plagioclase, which has implications regarding the efficiency of plagioclase separation from earlier fo...

2005
Matthias Willbold

Trace elements (elements that constitute less than 0.1 wt.% of the analyzed sample) are important tracers for a great variety of processes in many research areas, such as biochemistry, medicine, semi-conductor and nano-technology, environmental science and geosciences (e.g., Anitha et al. [2002]; Becker et al. [2004]; Barbante et al. [2004]; Tibi and Heumann [2003]). Accordingly, much scientifi...

2000
Mei-Fu Zhou Tai-Ping Zhao John Malpas Min Sun

Abundant mafic and ultramafic rocks including basalts, komatiitic basalts, and peridotites occur in the Proterozoic Sibao Group, northern Guangxi Province, China. Whereas the basalts are generally pillow lavas, the komatiitic basalts are typically spinifex-textured and, in a few cases, show pyroxene accumulation associated with Ni Cu (PGE) sulfide deposits. The peridotites occur in the lower po...

2015
Xun Yu Cin-Ty A. Lee Li-Hui Chen Gang Zeng

Eruptive sequences can be used as windows into the thermal and chemical evolution of magma chambers. We examined a continuous vertical section of the Baichahe basalt flow associated with the late Cenozoic Chifeng flood basalt in Inner Mongolia, North China. From oldest to youngest, MgO increases, K2O, light rare earths and other incompatible elements decrease, and Nb/La and radiogenic Pb isotop...

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