نتایج جستجو برای: geological boundaries

تعداد نتایج: 87690  

2018
Jan Zalasiewicz Will Steffen Reinhold Leinfelder Mark Williams Colin Waters

The Anthropocene concept arose within the Earth System science (ESS) community, albeit explicitly as a geological (stratigraphical) time term. Its current analysis by the stratigraphical community, as a potential formal addition to the Geological Time Scale, necessitates comparison of the methodologies and patterns of enquiry of these two communities. One means of comparison is to consider some...

2008
M. Zhdanov

of the traditional smooth inversion this information is provided as [2J The two-dimensional (2-D) magnetotelluric inverse problem an assumption that the solution, the geoelectrical model in the MT has been addressed by several authors. The most well-known case, should be represented by smooth functions. At the same time, approaches are the search for a smooth model [de Groot-Hedlin in some geol...

Journal: :Frontiers in Earth Science 2022

The spatial position and dip feature of the density boundary are significant to study fault tectonic frameworks. Edge detection methods generally attach importance horizontal boundary, but it is difficult determine expressly. A gradient inversion method was proposed based on corresponding relationship among gravity forward field, kernel matrix, model attributes. result this that value different...

2016
Nicholas J. Gardiner Christopher L. Kirkland Martin J. Van Kranendonk

Hf isotope ratios measured in igneous zircon are controlled by magmatic source, which may be linked to tectonic setting. Over the 200-500 Myr periodicity of the supercontinent cycle - the principal geological phenomenon controlling prevailing global tectonic style - juvenile Hf signals, i.e. most radiogenic, are typically measured in zircon from granites formed in arc settings (crustal growth),...

Journal: :فیزیک زمین و فضا 0
علی نجاتی کلاته استادیار، دانشکده معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود، ایران امین روشندل کاهو استادیار، دانشکده معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود، ایران

potential field images obtained in potential field data measurements are suitable tools for mineral and hydrocarbons resources explorations. these images consist of different anomalies which in many cases are contaminated with noise. the horizontal location of the boundaries of potential field anomaly sources is of interest in potential field interpretation. however, the edge of potential field...

امامعلی پور, علی, میرمحمدی, میرصالح,

The Heydarabad bauxite-laterite deposit is located in 63 km southeast of Urmia city. This ore deposit occurs as a concordant layer within the boundaries of Upper Permian and Lower Triassic carbonate units (limestone and dolomite), although it has been suffered some tectonic displacements along its direction. The studied horizon varies from 15-20 m in thickness and has an east-west trend with a ...

Journal: :Environmental monitoring and assessment 2009
Janet A Nestlerode Virginia D Engle Pete Bourgeois Paul T Heitmuller John M Macauley Yvonne C Allen

The Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) initiated a two-year regional pilot survey in 2007 to develop, test, and validate tools and approaches to assess the condition of northern Gulf of Mexico (GOM) coastal wetlands. Sampling sites were selected from estuarine and palustrine wetland areas with herbaceous, forested, and shrub/scrub habitats delineated by the ...

Journal: :Science 1979
M A Carpenter

Combined annealing experiments and observations by transmission electron microscopy show that in natural pigeonite crystals antiphase domains coarsen approximately according to a rate law in which the tenth power of the average domain size is proportional to time. This result suggests that certain cations (possibly Ca(2+)) were segregated preferentially onto the antiphase boundaries. The domain...

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