نتایج جستجو برای: igneous rock

تعداد نتایج: 40969  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده علوم انسانی و اجتماعی 1387

چکیده ندارد.

2012

There are growing concerns about Lead is the heaviest of the non-radioactive metals (atomic number 82; atomic weight 207) that naturally occur in substantial quantities in the earth’s surface. Lead is present in all soils, rivers, lakes, and seawater. Despite its weight, lead is also in the air, a component of dust and of sea spray. Lead is present in the proportion of 16 parts per million (ppm...

2005
D. Weis

Wrangellia consists largely of an oceanic plateau, a vast outpouring of basalt and more Mg-rich magma that erupted onto the ocean floor and was subsequently accreted to the western margin of the North American plate. Flood basalts form extensive sequences on Vancouver Island and are believed to have formed by melting in a mantle plume (an upwelling zone of hot mantle rock). They form the oceani...

Journal: :Science 2013
E M Stolper M B Baker M E Newcombe M E Schmidt A H Treiman A Cousin M D Dyar M R Fisk R Gellert P L King L Leshin S Maurice S M McLennan M E Minitti G Perrett S Rowland V Sautter R C Wiens

"Jake_M," the first rock analyzed by the Alpha Particle X-ray Spectrometer instrument on the Curiosity rover, differs substantially in chemical composition from other known martian igneous rocks: It is alkaline (>15% normative nepheline) and relatively fractionated. Jake_M is compositionally similar to terrestrial mugearites, a rock type typically found at ocean islands and continental rifts. B...

1996
Christian Koeberl Wolf Uwe Reimold Steven B. Shirey

The origin of granophyric rock dikes (the Vredefort Granophyre) at the 2 Ga Vredefort structure in South Africa has been controversial. They have been interpreted as either impact melt or igneous intrusions. Most Vredefort Granophyre samples have considerably higher Os contents than the country rocks and Re/Os and Os/Os ratios that scatter about a 2 Ga isochron. Their initial Os/Os ratios (at 2...

2012
Lorence G. Collins

In this presentation questions are raised about a melt-restite unmixing model proposed by Barton and Sidle (1994) for the myrmekite-bearing Waldoboro granite complex along the southeastern coast of Maine (USA). This complex consists mostly of granite/granodiorite gneiss and granite, but smaller masses of quartz diorite, aplite, pegmatite, leucogranite, tourmaline granite, and granite porphyry o...

2008
Erik Olstad Peggy O’Day

Background The ubiquity of nickel in the environment and its common presence in food and water mean that humans are constantly exposed to nickel. Although nickel is not acutely toxic at low levels, it is a carcinogen and has been linked to cellular oxidative stress [1]. Soils that develop on serpentinite, a metamorphic rock type derived from ultramafic igneous rocks (and the state rock of Calif...

Journal: :Plant biology 2004
M E Puente Y Bashan C Y Li V K Lebsky

Dense layers of bacteria and fungi in the rhizoplane of three species of cactus (Pachycereus pringlei, Stenocereus thurberi, Opuntia cholla) and a wild fig tree (Ficus palmeri) growing in rocks devoid of soil were revealed by bright-field and fluorescence microscopy and field emission scanning electron microscopy. These desert plants are responsible for rock weathering in an ancient lava flow a...

2013
R.Vinoth R.Srinivasan

The classification of natural images is an essential task in computer vision and pattern recognition applications. Rock images are the typical example of natural images, and their analysis is of major importance in rock industries and bedrock investigations. Rocks are mainly classified into three types. They are Igneous, Metamorphic and Sedimentary. They are further classified into Andesite, Ba...

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