منابع مشابه
Fractals in petrology
A fractal (power-law) distribution is the only statistical distribution applicable to a scale-invariant process. One of the major problems in petrology is the distribution of trace elements in the Earth’s crust. Extreme values of this distribution result in ore deposits. There is accumulating observational evidence that tonnage–grade statistics of ore deposits are often fractal (powerlaw). Rayl...
متن کاملPetrology and Stratigraphic Setting
anomolously low A1203, low Ti02 and are enriched in chromium and nick~A We present petrographic and chemical c ata on the Kamloops Lake picritic tmalts as we1 I as the stratigraphic setting for thwe ultramafic lavas. Age constraints derive From field relationships, Mineral chemistry indicates th 31 these ultramafic rocks represent mantle-deri.ed material which has undergone: minimal differentia...
متن کاملMidocean Ridge Geochemistry and Petrology
The most volcanically active regions of our planet are concentrated along the axes of the globe, encircling midocean ridges. These undersea mountain ranges, and most of the oceanic crust, result from the complex interplay between magmatic (i.e., eruptions of lavas on the surface and intrusion of magma at depth) and tectonic (i.e., faulting, thrusting, and rifting of the solid portions of the ou...
متن کاملContributions to mineralogy and petrology
High-silica topaz-bearing rhyolites of Cenozoic emplaced as domes, lava flows or shallow intrusions. They age are widely distributed across the western USA and may also contain Fe-Mn garnet, beryl, bixbyite, pseudoMexico. They are characteristically enriched in fluorine brookite, hematite and fluorite in miarolitic cavities or with(>0.2 wt.%) and incompatible lithophile elements (e.g. Li, in th...
متن کاملContributions to mineralogy and petrology
A geochemically and mineralogically diverse group neous aspect can form as products of different proof granitoids is present within an area of 900 km2 in the cesses . . . " Within an area of 900 km2 in the southern Snake southern Snake Range of eastern Nevada. The granitoids Range, White Pine County, Nevada, six igneous masses exposed range in age from Jurassic through Cretaceous to are well ex...
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ژورنال
عنوان ژورنال: Nature
سال: 1973
ISSN: 0028-0836,1476-4687
DOI: 10.1038/244057b0