The Relationship of the Relative Abundance of Masses of Granites and Rhyolites in the Earth’s Crust with the Patterns of the Rheology of the Granitic Magmas

Petrology ◽  
2019 ◽  
Vol 27 (5) ◽  
pp. 460-466
Author(s):  
E. S. Persikov
1914 ◽  
Vol 1 (2) ◽  
pp. 65-67 ◽  
Author(s):  
L. Leigh Fermor

The recent discussion on the origin of the Himalaya, initiated by Colonel S. G. Burrard in his paper “On the Origin of the Himalaya Mountains”, has centred in the theories of isostasy and mountain compensation advocated by the Rev. O. Fisher and Mr. J. F. Hayford.In his latest contribution to the subject Colonel Burrard states very clearly the problem of isostasy now requiring solution—“Continents and mountains have been found to be compensated by underlying deficiencies of density; how has this condition resembling hydrostatic equilibrium arisen upon a solid globe of rock?”In a recent paper I have advanced reasons for believing in the existence in the earth's crust at a certain depth, at present unknown, of a highly garnetiferous shell of rock, for which the name infra-plutonic zone or shell is suggested. This zone is situated at such a depth that pressure becomes a dominant factor in mineral transformations, the accompanying high temperature ensuring a sufficient degree of molecular mobility. It is suggested that under the influence of these high pressures (and temperatures) reactions will ensue between the various ferromagnesian silicates—micas, amphiboles, pyroxenes, olivines—and anorthite felspar, with the formation of garnet as a characteristic mineral: the reason assigned is that a reduction of volume accompanied by an absorption of heat is thereby effected, it being accepted that the garnet-forming reactions are endothermic.If one can accept the philosophical necessity for the existence of this infra-plutonic shell, then some theory of isostasy seems logically to follow, with the garnetiferous plastic-solid shell as the cushion upon which the isostatic adjustments of the earth's crust have their foundation.


2021 ◽  
Vol 11 (3) ◽  
pp. 375-385
Author(s):  
M.Y. Nilov ◽  
◽  
L.I. Bakunovich ◽  
N.V. Sharov ◽  
B.Z. Belashev ◽  
...  

An important task for the White Sea region, Russia’s second largest diamond-producing province, is the search for magmatic bodies overlapped by sedimentary cover via magnetometer survey. The models, linking local and magnetic anomalies with their sources, are essential for interpretation of search results. The aim of the study is to build a 3D magnetic model of the Earth’s crust for the White Sea region using aeromagnetic data and the modeling technologies of the Integro software package. The simulation is basing on a digital map of the pole-reduced anomalous magnetic field. The sources of magnetic anomalies are believed to be located in the Earth’s crust. The researchers obtained 3D distribution of the relative magnetic susceptibility of rocks by solving the inverse problem of magnetic prospecting. To separate the magnetic sources by spatial frequencies and depth, the model magnetic field was recalculated upward, as well as the TDR derivatives, which determine the lateral boundaries of the sources of positive magnetic field anomalies, were calculated. The researchers further analyzed 2D distributions of the magnetic sources of the model for vertical and horizontal sections with depths of 10, 15 and 20 km, thus proving the relationship between the surface and deep structures of the magnetic sources of the Earth’s crust in the region.


2021 ◽  
Vol 254 ◽  
pp. 02003
Author(s):  
Elena Bataleva

The paper presents the results of experiments carried out at the regime points of magnetotelluric monitoring both on the territory of the Bishkek geodynamic test site (Northern Tien Shan) and on a series of monitoring profiles in various geological conditions. Previous studies indicate the relationship of variations in the electromagnetic and seismic fields, lunisolar tidal effects, seismic regime with the processes of fracturing. The purpose of this work is to establish the features of the relationship between the spatio-temporal distribution of seismicity and the distribution of geoelectric inhomogeneities in the Earth’s crust (fault-block tectonics of the region). Based on the analysis of the results of the interpretation of magnetotelluric data (2D inversion) and new detailed seismotomographic constructions, the verification of geoelectric models was carried out, the analysis of the distribution of hypocenters of seismic events was carried out. Special attention was paid to the confinement of earthquakes to listric fault structures. The relationship between the distribution of the hypocenters of seismic events and the spatial position of the electrical conductivity anomalies is confirmed by the authors explanation of the physical nature of the identified conducting structures, based on hypotheses of fluidization and partial melt of the Earth’s crust.


1894 ◽  
Vol 1 (11) ◽  
pp. 502-505
Author(s):  
Mark Stirrup

In a paper published in the Geological Magazine, September, 1894, Sir Henry Howorth expatiates on recent changes of the relative level of land and sea in support of his views on the Mammoth age and his diluvial catastrophe,inwhich there seems to me some very extraordinary confusion in the matter of geological chronology and sequence of events. The first paragraph reads as follows:—“In some recent papers published in the Geological Magazine, I have endeavoured to show that at the close of the Mammoth age there was a very considerable dislocation of the Earth's crust, and that a consequence of it was the upheaval of Some of the highest masses of land on the earth, including the massive mountains of Asia and the American Cordillera. I now propose to show that (as is a priori probable) there was a concurrent collapse or sinking of the ground over large areas, which, as in the corresponding upheaval, was very rapid, if not sudden” (the italics are mine). The suggested relationship of these various events and their alleged catastrophic character, induces me to again enter this ever-expanding field of controversy.In support of his thesis Sir Henry first refers to the subsidences which resulted in the separation of England from the Continent, and consequent extinction of the Mammoth. Assuming that the course of things was as stated, when it is further suggested that this event was contemporaneous with great dislocation of the Earth's crust, resultinginstupendous upheavals of mountain ranges in Asia and America, he attempts more than can well be proved.


Sign in / Sign up

Export Citation Format

Share Document