How Minerals Work

2018 ◽  
Author(s):  
Alex Maltman
Keyword(s):  
Calcium Carbonate ◽  
Crystalline Structure ◽  
Three Dimensional ◽  
Regular Pattern ◽  
Silicate Minerals ◽  
For Profit ◽  
Geological Processes ◽  
The Earth ◽  
Ore Minerals

We might expect the ground of vineyards to consist of bewildering permutations of elements, but because its composition is dominated by just eight of them and there are chemical restrictions on how they can combine, the number of common minerals is not huge. Even so, their names are not particularly well known, even those of the very minerals that make the ground we live on and the soils that vines grow in. Mineral names that might spring to mind are more likely to be those used in jewelry or that are commercially mined. Such gemstones and ore minerals are not widespread, but geological processes have concentrated them in certain parts of the Earth, and if we can locate these accumulations, it may be worthwhile to extract them for profit. The rocks and soils that mainly concern us here are composed of silicate minerals, and Chapter 3 is devoted to these workhorses. They are sometimes called the “rock-forming minerals,” though there is an outstanding exception to this term: calcium carbonate, which makes the calcareous rocks. So in this chapter’s survey of the kinds of nonsilicate minerals we may come across in vineyards, we will pay particular attention to the carbonates. But first, let’s examine some fundamental concepts concerning the nature of minerals. As we saw in Chapter 1, minerals are made of ions bonded together through giving or sharing electrons. But to achieve this linkage, the ions cannot combine in some higgledy-piggledy fashion; rather, they have to organize themselves in a particular, symmetrical physical arrangement. It’s a bit like the sight of soldiers on formal parade. We call the three-dimensional framework of ions a lattice, and it’s this regular pattern that makes the material crystalline; it is a crystal. In other words, the pieces of mineral in a vineyard are crystalline. We may think of crystals as having the attractive, light- catching facets seen in gem shops and museums. Although this is a manifestation of the crystalline structure of the constituent ions, it is not what defines them as crystals. Consequently, minerals lying in a vineyard may be dull, shapeless chunks, but they are still crystals.

Forecast of manifestations of dangerous geological processes in Dnipropetrovsk with the use of methods of aerospace remote sensing of the Earth

2004 ◽  
Vol 10 (5-6) ◽  
pp. 194-196
Author(s):  
V.I. Voloshin ◽  
◽  
A.S. Levenko ◽  
N.N. Peremetchik ◽  
◽  
...  
Keyword(s):  
Remote Sensing ◽  
Geological Processes ◽  
The Earth

2D X-ray diffraction and molecular modelling of the crystalline structure of polyesters under uniaxial stress

2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck
Keyword(s):  
Crystalline Structure ◽  
Molecular Modelling ◽  
Three Dimensional ◽  
Uniaxial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Modelling Techniques ◽  
Diffraction Patterns

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.

scholarly journals Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Matthew J. Comeau ◽  
Michael Becken ◽  
Alexey V. Kuvshinov ◽  
Sodnomsambuu Demberel
Keyword(s):  
Electrical Resistivity ◽  
Crustal Structure ◽  
Three Dimensional ◽  
Suture Zone ◽  
Fault System ◽  
Magnetotelluric Data ◽  
Low Resistivity ◽  
Ophiolite Belt ◽  
Geological Processes ◽  
Metallogenic Belt

AbstractCrustal architecture strongly influences the development and emplacement of mineral zones. In this study, we image the crustal structure beneath a metallogenic belt and its surroundings in the Bayankhongor area of central Mongolia. In this region, an ophiolite belt marks the location of an ancient suture zone, which is presently associated with a reactivated fault system. Nearby, metamorphic and volcanic belts host important mineralization zones and constitute a significant metallogenic belt that includes sources of copper and gold. However, the crustal structure of these features, and their relationships, are poorly studied. We analyze magnetotelluric data acquired across this region and generate three-dimensional electrical resistivity models of the crustal structure, which is found to be locally highly heterogeneous. Because the upper crust (< 25 km) is found to be generally highly resistive (> 1000 Ωm), low-resistivity (< 50 Ωm) features are conspicuous. Anomalous low-resistivity zones are congruent with the suture zone, and ophiolite belt, which is revealed to be a major crustal-scale feature. Furthermore, broadening low-resistivity zones located down-dip from the suture zone suggest that the narrow deformation zone observed at the surface transforms to a wide area in the deeper crust. Other low-resistivity anomalies are spatially associated with the surface expressions of known mineralization zones; thus, their links to deeper crustal structures are imaged. Considering the available evidence, we determine that, in both cases, the low resistivity can be explained by hydrothermal alteration along fossil fluid pathways. This illustrates the pivotal role that crustal fluids play in diverse geological processes, and highlights their inherent link in a unified system, which has implications for models of mineral genesis and emplacement. The results demonstrate that the crustal architecture—including the major crustal boundary—acts as a first‐order control on the location of the metallogenic belt.

scholarly journals Ultrastructure of the earthworm calciferous gland. A preliminary study

2009 ◽  
Vol 15 (S3) ◽  
pp. 25-26
Author(s):  
J. Méndez ◽  
J. B. Rodríguez ◽  
R. Álvarez-Otero ◽  
M. J. I. Briones ◽  
L. Gago-Duport
Keyword(s):  
Calcium Carbonate ◽  
Crystalline Structure ◽  
Concentrated Suspension ◽  
Earthworm Species ◽  
Preliminary Study

AbstractThe earthworm species belonging to the Lumbricidae family (Annelida, Oligochaeta) posses a complex oesophageal organ known as “calciferous gland” which secretes a concentrated suspension of calcium carbonate. Previous studies have demonstrated the non-crystalline structure of this calcareous fluid representing an interesting example of biomineralisation.

Preparation and characterization of three-dimensional chrysanthemun flower-like calcium carbonate

2012 ◽  
Vol 27 (4) ◽  
pp. 708-714 ◽  
Author(s):  
Xianyong Chen ◽  
Qin Tang ◽  
Daijun Liu ◽  
Weibing Hu ◽  
Youmeng Dan
Keyword(s):  
Calcium Carbonate ◽  
Three Dimensional

Chapter 1 Introduction to Confocal Microscopy and Three-Dimensional Reconstruction

1993 ◽  
pp. 1-45 ◽  
Author(s):  
Shirley J. Wright ◽  
Victoria E. Centonze ◽  
Stephen A. Stricker ◽  
Peter J. DeVries ◽  
Stephen W. Paddock ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction

scholarly journals The particle and magnetic environments surrounding close-in exoplanets

2015 ◽  
Vol 11 (S320) ◽  
pp. 397-402
Author(s):  
A. A. Vidotto ◽  
R. Fares ◽  
M. Jardine ◽  
C. Moutou ◽  
J.-F. Donati
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Magnetic Field Intensity ◽  
Three Dimensional ◽  
Stellar Winds ◽  
Local Conditions ◽  
Hot Jupiters ◽  
The Earth ◽  
Weather Events ◽  
Host Stars

AbstractThe proper characterisation of stellar winds is essential for the study of propagation of eruptive events (flares, coronal mass ejections) and the study of space weather events on exoplanets. Here, we quantitatively investigate the nature of the stellar winds surrounding the hot Jupiters HD46375b, HD73256b, HD102195b, HD130322b, HD179949b. We simulate the three-dimensional winds of their host stars, in which we directly incorporate their observed surface magnetic fields. With that, we derive the wind properties at the position of the hot-Jupiters’ orbits (temperature, velocity, magnetic field intensity and pressure). We show that the exoplanets studied here are immersed in a local stellar wind that is much denser than the local conditions encountered around the solar system planets (e.g., 5 orders of magnitude denser than the conditions experienced by the Earth). The environment surrounding these exoplanets also differs in terms of dynamics (slower stellar winds, but higher Keplerian velocities) and ambient magnetic fields (2 to 3 orders of magnitude larger than the interplanetary medium surrounding the Earth). The characterisation of the host star's wind is also crucial for the study of how the wind interacts with exoplanets. For example, we compute the exoplanetary radio emission that is released in the wind-exoplanet interaction. For the hot-Jupiters studied here, we find radio fluxes ranging from 0.02 to 0.13 mJy. These fluxes could become orders of magnitude higher when stellar eruptions impact exoplanets, increasing the potential of detecting exoplanetary radio emission.

The partition coefficients of Nd and Sm for the sulphides: first data from Palaeoproterozoic layered Cu-Ni-PGE complexes of Fennoscandian Shield

2021 ◽  
Author(s):  
Pavel Serov ◽  
Tamara Bayanova
Keyword(s):  
Partition Coefficients ◽  
Sulfide Minerals ◽  
Spectrometric Method ◽  
New Mineral ◽  
Mass Spectrometric Method ◽  
Time Data ◽  
Mean Values ◽  
Geological Processes ◽  
Ore Minerals ◽  
Monchegorsk Pluton

&lt;p&gt;The Sm-Nd systematics is one of the most demanded isotope-geochronological tools to study ancient geological complexes. With the accumulation of knowledge about the REE in various geological processes, the question arises of extending the capabilities of the Sm-Nd method by using new mineral geochronometers. The research focused on defining the time of the ore process and its position in the general geochronological scale of formation of the geological site become particularly important. There is a pressing need for defining possible forms of REE occurrence in a lattice of geochronometer minerals in the Sm-Nd study of accessory minerals (e.g. fluorite, burbankite, eudialite, ruthile, etc.) and ore minerals (ilmenite, chrome-spinellid, sulfide minerals). The Sm-Nd method of dating ore processes using sulphide minerals, successfully used on several geological objects, made it possible to determine the main stages of ore formation and confirm geochronologically the conclusions about the syngenetic or epigenetic nature of the ore process.&lt;/p&gt;&lt;p&gt;Pyrite, pentlandite, chalcopyrite and pyrrhotite from the main industrial fields of the Fennoscandinavian shield were studied: Monchegorsk pluton, Fedorovo-Pansky intrusion, Pechenga, Penicat intrusion and Ahmavaara (Finland). Using a mass-spectrometric method 35 sulphide monofractions were analyzed. The partition coefficients for Nd and Sm were established: for pyrite - 0.229 (Nd) and 0.169 (Sm); for pyrrhotite - 0.265 (Nd) and 0.160 (Sm); for chalcopyrite - 0.229 (Nd) and 0.161 (Sm); for pentlandite &amp;#8211; 0.158 (Nd) and 0.082 (Sm). The mean values for D&lt;sub&gt;Nd&lt;/sub&gt; are 0.201, for D&lt;sub&gt;Sm&lt;/sub&gt;=0.145 and resulting D&lt;sub&gt;Nd&lt;/sub&gt;/D&lt;sub&gt;Sm&lt;/sub&gt; about 1.4.&lt;/p&gt;&lt;p&gt;Probably, the distribution of REE in sulfide minerals is inherited from fluids during sulfide formation. REE concentrations in sulphide may reflect the composition of the fluid.&lt;/p&gt;&lt;p&gt;Thus, for the first time data on Sm and Nd concentrations have been obtained by mass spectrometry. Coefficients of neodymium and samarium distribution in sulfides have been calculated for major Cu-Ni-PGE complexes of Fennoscandia.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;This study performed under the theme of scientific research 0226-2019-0053 and were supported by the RFBR &amp;#160;18-05-70082.&lt;/p&gt;

Seismic Rays

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Inverse Problem ◽  
Seismic Tomography ◽  
Seismic Waves ◽  
Seismic Station ◽  
Three Dimensional ◽  
Arrival Times ◽  
The Earth ◽  
Straight Lines ◽  
Ray Path ◽  
Uniform Composition

This chapter focuses on the underlying mathematics of seismic rays. Seismic waves caused by earthquakes and explosions are used in seismic tomography to create computer-generated, three-dimensional images of Earth's interior. If the Earth had a uniform composition and density, seismic rays would travel in straight lines. However, it is broadly layered, causing seismic rays to be refracted and reflected across boundaries. In order to calculate the speed along the wave's ray path, the time it takes for a seismic wave to arrive at a seismic station from an earthquake needs to be determined. Arrival times of different seismic waves allow scientists to define slower or faster regions deep in the Earth. The chapter first presents the relevant equations for seismic rays before discussing how rays are propagated in a spherical Earth. The Wiechert-Herglotz inverse problem is considered, along with the properties of X in a horizontally stratified Earth.

Earth as a Snowball

2012 ◽  
Author(s):  
Jan Zalasiewicz ◽  
Mark Williams
Keyword(s):  
Nineteenth Century ◽  
South African ◽  
War And Peace ◽  
Rock Fragments ◽  
Sedimentary Deposits ◽  
The Earth ◽  
Rock Strata ◽  
Louis Agassiz ◽  
Better Than

Our attempts to reconstruct the climate of the distant Archaean in Chapter 1 might seem a little like reading a volume of Tolstoy’s War and Peace recovered from a burnt-out house. Most of the pages have turned to ash, and only some scattered sentences remain on a few charred pages. The Proterozoic Eon that followed began 2.5 billion years ago, thus is not quite so distant from us in time. We know it a little better than the Archaean—at least a handful of pages from its own book have survived. And this book is long—the Proterozoic lasted nearly two billion years. This is as long as the Hadean and Archaean together, and not far short of half of Earth’s history. Like many a soldier’s account of war, it combined long periods of boredom and brief intervals of terror—or their climatic equivalents, at least. The latter included the most intense glaciations that ever spread across the Earth. Some of these may have converted the planet into one giant snowball. The earliest traces of glaciation on Earth are seen even before the Proterozoic, in rock strata of Archaean age, 2.9 billion years old, near the small South African town of Pongola. These rocks include sedimentary deposits called tillites, which are essentially a jumble of rock fragments embedded in finer sediment. The vivid, old-fashioned term for such deposits is ‘boulder clays’, while the newer and more formal name is ‘till’ for a recent deposit and ‘tillite’ for the hardened, ancient version. Many of the ancient blocks and boulders in the tillites of Pongola are grooved and scratched—a tell-tale sign that they have been dragged along the ground by debris-rich ice. This kind of evidence is among the first ever employed by scientists of the mid-nineteenth century, such as Louis Agassiz and William Buckland, to tell apart ice-transported sediments from superficially similar ones that had formed as boulder-rich slurries when rivers flooded or volcanoes erupted. Ice, then, appeared on Earth in Archaean times.

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