نتایج جستجو برای: basalts

تعداد نتایج: 2061  

2017
Rahul Das Gupta Anupam Banerjee Steven Goderis Philippe Claeys Frank Vanhaecke

The 1.88 km diameter Lonar impact crater formed 570 ka ago and is an almost circular depression hosted entirely in the Poladpur suite of the 65 Ma old basalts of the Deccan Traps. To understand the effects of impact cratering on basaltic targets, commonly found on the surfaces of inner Solar System planetary bodies, major and trace element concentrations as well as Nd and Sr isotopic compositio...

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...

Journal: :Eos, Transactions American Geophysical Union 2006

2010
YAN SONG

The Cenozoic Hannuoba basaltic province, 200 km northwest of Beijing, China, is composed of intercalated tholeiitic, transitional and alkalic basalts. Although the alkalic basalts contain abundant upper mantle xenoliths, they range in MgO content from 5.7 to 10.6% MgO. Most of the major and trace element abundance variations in the alkalic basalts can be explained by segregation of a clinopyrox...

2007
R. A. Duncan

Determination of reliable crystallization ages by K-Ar methods for young (<1 Ma), fresh basalts from the seafloor has been frustrated by several effects. The small amounts of radiogenic 4øAr developed over these timescales in such 10w-K rocks are difficult to resolve from predominantly atmospheric 4øAr. An additional concern is that mantle-derived 4øAr may not be totally outgassed when magmas q...

2010
Chu-Yung Chen

Haleakala volcano on East Maui, Hawaii, consists of a tholeiitic basalt shield which grades into a younger alkalic series that was followed by a post-erosional alkalic series. Fresh, stratigraphically controlled samples from the three volcanic series were analyzed for major element abundances, Sr and Nd isotopic ratios and trace element (K, Rb, Sr, Ba, Th, Ta, Nb, REE, Hf, Zr, Sc, V, Cr, Co, Ni...

2018
Katherine E. Potter John W. Shervais Eric H. Christiansen Scott K. Vetter

Citation: Potter KE, Shervais JW, Christiansen EH and Vetter SK (2018) Evidence for Cyclical Fractional Crystallization, Recharge, and Assimilation in Basalts of the Kimama Drill Core, Central Snake River Plain, Idaho: 5.5-Million-Years of Petrogenesis in a Mid-crustal Sill Complex. Front. Earth Sci. 6:10. doi: 10.3389/feart.2018.00010 Evidence for Cyclical Fractional Crystallization, Recharge,...

2013
Fang-Zhen Teng Nicolas Dauphas Shichun Huang Bernard Marty

The iron isotopic compositions of 93 well-characterized basalts from geochemically and geologically diverse mid-ocean ridge segments, oceanic islands and back arc basins were measured. Forty-three MORBs have homogeneous Fe isotopic composition, with dFe ranging from +0.07& to +0.14& and an average of +0.105 ± 0.006& (2SD/ p n, n = 43, MSWD = 1.9). Three back arc basin basalts have similar dFe t...

2010
J. A. Bryant G. M. Yogodzinski T. G. Churikova

Primitive arc magmatism and mantle wedge processes are investigated through a petrologic and geochemical study of high-Mg# (Mg/Mg ? Fe [ 0.65) basalts, basaltic andesites and andesites from the Kurile-Kamchatka subduction system. Primitive andesitic samples are from the Shisheisky Complex, a field of Quaternary-age, monogenetic cones located in the Aleutian–Kamchatka junction, north of Shiveluc...

2017
Yunzhao Wu Lin Li Xiaoxing Luo Yu Lu Yuan Chen Carle M. Pieters Alexander T. Basilevsky

The objective of this study is to explore the regional geology of the northwest Imbrium region in which the Chang’E-3 (CE-3) landing site is located. CE-3 successfully landed on December 14, 2013 on the unsampled Eratosthenian basalts whose study is important for understanding the evolution of the Moon. New geologic and structural maps of the research area were produced through the integrated a...

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