نتایج جستجو برای: geological boundary
تعداد نتایج: 183188 فیلتر نتایج به سال:
The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter r...
Texture-based methods have proven to be useful in the detection of salt bodies in seismic data. In this abstract, we present three computationally inexpensive texture attributes that strongly differentiate salt bodies from other geological formations. The proposed method combines the three texture attributes along with region boundary smoothing for delineating salt boundaries. Our first propose...
We report on the second and final year of geological mapping in the Nakina area, conducted under the Atlin Targeted Geoscience Initiative (TGI). Principal aims of the TGI are to create a legacy of high quality geoscience data that will stimulate geological resource exploration, and regional economic development (see Atlin TGI Part I). Geological maps produced as part of the project portray base...
The usefulness of online geological maps is hindered by linguistic barriers. Multilingual geoscience thesauri alleviate linguistic barriers of geological maps. However, the benefits of multilingual geoscience thesauri for online geological maps are less studied. In this regard, we developed a multilingual thesaurus of geological time scale (GTS) to alleviate linguistic barriers of GTS records a...
Based on the precipitating factors of geological disasters in complex mountainous regions, this paper took geological disaster distribution, seismic intensity, fracture, engineering petrofabric, river distance, slope and precipitation as the risk indicators of geological disasters. Next, a mathematical model was established by using the analytical hierarchy process. The weight of above seven ri...
It is related to the realization of the benefit of state-owned resources and the long retainable development of the country to evaluate the mining property rights to improve the using rate of the mineral resources. Guided by the principle of prospective return, a method for evaluating geological potential value was put forward which emphasized on the valuation of geological techniques. A coeffi...
The theories of porous materials represent a material length scale and are quite sufficient for a large number of the solid mechanics applications. In the following, we restrict our attention to the behavior of the porous solids in which the matrix material is elastic and the interstices are voids of material. The intended applications of this theory are to the geological materials, like rocks ...
The analysis of seismic wave propagation and amplification in complex geological structures requires efficient numerical methods. In this article, following up on recent studies devoted to the formulation, implementation and evaluation of 3D singleand multi-region elastodynamic fast multipole boundary element methods (FM-BEMs), a simple preconditioning strategy is proposed. Its efficiency is de...
A 1.5‰ to 2‰ carbon isotope shift in surface ocean dissolved inorganic carbon has been reported stratigraphically above the Cretaceous-Tertiary (K-T) boundary in the global stratotype section at El Kef, Tunisia, and in many other marine sections worldwide. Because a change in the dC value of paleoatmospheric CO2 would have accompanied the marine surface carbon isotope shift, the K-T carbon isot...
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