Search Results

You are looking at 1 - 10 of 40 items for :

  • "similarity" x
  • Earth and Environmental Sciences x
  • All content x
Clear All

36 297 312 Venikov V A 1976: Similarity and Modeling Theory (in Russian). University textbook, Moscow

Restricted access

monitoring locations on the small rivers of Hungary. The waters are classified according to similarities in physico-chemical patterns. Inter-group and intra-group differences are quantified. Based on these measurements, answers to the following questions are

Open access

waters are classified according to similarities in physico-chemical patterns. Inter-group and intra-group differences are quantified. Based on these measurements, answers to the following questions are sought. Is it true that more monitoring efforts are

Open access

Abstract

The Mesozoic stratigraphic record of northern Eurasia includes a total of 1,739 formations. The proportion of conglomerate, sandstone + siltstone, shale, carbonates, evaporites, siliceous rocks, and volcanics + volcaniclastics among sedimentary complexes are evaluated for each epoch of the Mesozoic. Sandstone, shale, and conglomerate occur in 86%, 71%, and 42% of formations respectively. Less common are carbonates (28%) and volcanics and volcaniclastics (24%), whereas evaporites and siliceous rocks are rare (< 5%). The proportion of particular sedimentary rock types fluctuates throughout the Mesozoic. The proportion of sandstone + siltstone changes quite similarly to that of shale. A comparison of stratigraphic data from northern Eurasia and North America reveals some similarities, including a Lower Triassic increase in the conglomerate proportion, a Middle-Upper Triassic increase in the proportion of siliceous rocks, Upper Triassic-Lower Jurassic and Upper Jurassic-Lower Cretaceous “clastic spikes”, and a Middle-Upper Jurassic “carbonate-evaporite spike”. They may reflect any global-scale processes. Increases in clastic deposition coincided with eustatic lowstands, whereas voluminous accumulation of carbonates and evaporites tended to coincide with global sea-level rises. It remains unclear whether global climate was responsible for changes in the proportion of sedimentary rock types.

Restricted access

In a basic problem of geodesy the directions from points with known coordinates to an unknown (new) point are measured, and then the resulting angles are used to compute the coordinates of the new point. The relations between angles and lengths lead to a system of nonlinear equations of the form f i = 0 ( i = 1, 2, 3), where each f i is a second degree polynomial of the unknown distances x 1 , x 2 , x 3 . Two different direct (non-iterative) solutions are discussed: one is based on the Sylvesterdeterminant of the resultant (this is a new result), the other on the Gröbner-bases. We show that in the general case both methods lead to the same equations in one variable and of fourth degree, but in a special case the equations obtained from Sylvester-determinant are of second degree. As a numerical example, three known points and an unknown point were selected in the city of Sopron. The required space angles were used to make the computations yielding the X, Y, Z coordinates of the unknown point.We show that the direct solution of the 2D similarity transformation leads to the same result as applying the Gröbner-bases.

Restricted access

Magma/wet sediment interaction (e.g. autobrecciation, magma-sediment mingling, hyaloclastite and peperite-forming, etc.) is a common phenomenon, where hot magma intrudes into unconsolidated or poorly consolidated water saturated sediment. In the Eastern Borsod Basin (NE-Hungary) relatively small (2–30 m) subvolcanic bodies, sills and dykes with contact lithofacies zones were found generated by mechanical stress and quenching of the magma, and interacting with unconsolidated wet andesitic lapilli-tuff and tuff-breccia. Close to the contact between sediment and intrusions, thermal and mechanical effects may occur in the host sediment. Hydrothermal alteration and stratification of the host sediment were developed only locally along the contact zone, probably due to the paleo-hydrogeologic and paleo-rheological inhomogeneities of the lapilli-tuff–tuff-breccia deposits. Processes of magma/wet sediment interaction may be difficult to recognize because of limited exposure and/or certain similarities of the brecciated intrusions to the characteristics of the host sediment; hence detailed field work (geologic mapping or profiling) was required to demonstrate the subvolcanic origin of the brecciated andesite bodies.

Open access

). In fact, clustering is the process of dividing a data set or sample into a bunch of K groups or clusters based on their similarity or dissimilarity ( Yaghini et al. 2012 ). This technique is a statistical method, in which similar groups or clusters

Open access

). In fact, clustering is the process of dividing a data set or sample into a bunch of K groups or clusters based on their similarity or dissimilarity ( Yaghini et al. 2012 ). This technique is a statistical method, in which similar groups or clusters

Open access
Central European Geology
Authors: Ildikó Gyollai, Ákos Kereszturi, and Elias Chatzitheodoridis

crystallized last from residual melt on Mars, and their coexistence with zircon shows similarity with frictional pseudotachilite of a terrestrial impact craters (Morokweng structure; Reimold et al. 1999 ). Such zircon- and apatite-bearing pseudotachylite

Open access
Central European Geology
Authors: Mir Ali Asghar Mokhtari, H. Moinvaziri, M. R. Ghorbani, and M. Mehrpartou

Abstract

The Kamtal Intrusion is located in Eastern Azarbaijan province, northwestern Iran, near the Armenian border. This body consists of an acidic part of monzogranitic composition, and an intermediate-basic part which is composed of quartz-monzonite and gabbro. The gabbro forms lenses within the intermediate rocks. Monzogranite has been intruded into the quartz-monzonite. Both monzogranites and quartz-monzonites are high-K calk-alkaline and metaluminous in composition and can be classified as I-type granitoids, while the gabbro has tholeiitic affinity.

Monzogranite and quartz-monzonite are characterized by LREE-rich patterns and high LREE/HREE ratios. The similarities of their REE patterns suggest a genetic relationship among these rocks. The geochemical characters of the gabbro types indicate two different patterns: a flat pattern with low LREE/HREE ratio, and a steep pattern with high LREE/HREE ratio. The former was probably produced by high melting ratio of a depleted mantle source, and the steep pattern probably was the result of a low melting ratio of this mantle source. Negative anomalies of Nb and Ti can be seen in all rock types of the Kamtal Intrusion, which is indicative of subduction zones. The comparison of trace element variations with granitoid rocks of different tectonic settings allows observing a similarity between the Kamtal Intrusion and Andean volcanic arc granitoids.

The Kamtal body is related to the VAG tectonic setting and was probably produced as a result of Khoy back-arc basin subduction beneath the Azerbaijan continental crust.

Restricted access