نتایج جستجو برای: volcanic

تعداد نتایج: 14735  

نقره‌ئیان, موسی, خدامی2, مهناز, داودیان دهکردی, علیرضا , شبانیان بروجنی, ناهید,

The Pliocene calc-alkaline volcanic rocks are exposed in two areas in southeast and northwest of Isfahan and consist of andesites and dacites. Based on geochemical data and multi- elements pattern, these rocks are medium to high calc-alkaline suite and they show LILE and LREE enriched normalized multi-element patterns, and negative Nb and Ti. Condrite-normalized REE patterns display a steep dec...

Journal: :international journal of environmental research 2011
o.i. shumilov e.a. kasatkina k. mielikainen m. timonen a.g. kanatjev

the paper deals with the analysis of the external factor (solar activity, volcanic eruptions) influence on tree growth at the kola peninsula, northwestern russia. pinus sylvestris l. (scots pine) tree-ring chronologies collected nearby the northern timberline (68.63n, 33.25e) include the oldest (1445-2005 ad) living pine tree found up to date in the kola peninsula. a total of 18 living trees p...

2002
DUMITRU BULGARIU

The separation and concetration of minerals from zeolitic volcanic tuffs represent one of the problems for which the literature not offer, to much practically solutions. The experimental strategy used by as, for the separation minerals from zeolitic volcanic tuffs to comprise the following methods: heavy liquids separation; magnetic separation and electrophoresis separation. For zeolites, silic...

1997
V. V. Zuev

The investigations of scattering and absorbing characteristics of stratospheric aerosol layer after high-power volcanic eruptions make it possible to separate out and evaluate the influence of anomalous high aerosol concentrations on the radiation transfer in the atmosphere and the general radiation balance of the Earth. The violent eruption of Mt. Pinatubo in the Philippines in June 1991 injec...

2017
Vaughan R. Pratt

Millisecond fluctuations in length of day over multiple decades may induce fluctuations in flow of magma to the surface. We propose that the same magmatic volatiles that greatly amplify volcanic eruptions can also amplify these minute magmatic fluctuations sufficiently to be detected in sea surface temperature.

2007
B. Mayer

The authors’ idea to use paintings to reconstruct time series of volcanic eruptions is highly ingenious. It is probably one of the most interesting applications of libRadtran so far and I admire the amount of work put into this analysis, by collecting this huge number of paintings and retrieving ancillary information such as the solar zenith angle etc. For the analysis the authors calculated re...

2014
Lucia Pappalardo Luca D'Auria Andrea Cavallo Stefano Fiore

Abrupt transitions in style and intensity are common during volcanic eruptions, with an immediate impact on the surrounding territory and its population. Defining the factors trigger such sudden shifts in the eruptive behavior as well as developing methods to predict such changes during volcanic crises are crucial goals in volcanology. In our research, the combined investigation of both petrolo...

2008
Robin S Waples George R Pess Tim Beechie

Contemporary evolution of Pacific salmon (Oncorhynchus spp.) is best viewed in the context of the evolutionary history of the species and the dynamic ecosystems they inhabit. Speciation was complete by the late Miocene, leaving c. six million years for intraspecific diversification. Following the most recent glacial maximum, large areas became available for recolonization. Current intraspecific...

Journal: :Science 1984
D B Campbell J W Head J K Harmon A A Hine

A new high-resolution radar image of Beta Regio, a Venus highland area, confirms the presence of a major tectonic rift system and associated volcanic activity. The lack of identifiable impact craters, together with the apparent superposition of the Theia Mons volcanic structure on the rift system, suggest that at least some of the volcanic activity occurred in relatively recent geologic time. T...

تاکی, سعید, قادری, مجید, خسروتهرانی, خسرو , درویش‌زاده, علی,

Deylaman area lies on Paleogene volcanic rocks in Western Alborz near the border between Central and Western Alborz structural zones. The succession of Paleogene rocks in the area is comprised of three separate phases each of which representing one stage of volcanic events. The main purpose of this paper is to study the lithologic sequence and geochemical characteristics of phase two volcanic r...

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