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Our knowledge of the Earth's magnetic field has developed over many centuries, originating from some of the earliest scientific investigations. The first scientific treatise ever written is generally recognized as being the geomagnetic text Epistola de Magnete written by Petrus Peregrinus in 1269. This was followed more than three centuries later by the classical work De Magnete by William Gilbert in 1600.
Magnetism is one of the most pervasive features of the Universe, with planets, stars and entire galaxies all having associated magnetic fields. All of these fields are generated by the motion of electrically conducting fluids, via the so-called dynamo effect. The basics of this effect are almost trivial to explain: moving an electrical conductor through a magnetic field induces an emf (Faraday’s law), which generates electric currents (Ohm’s law), which have associated magnetic fields (Ampere’s law). The hope is then that with the right combination of flows and fields the induced field will reinforce the original field, leading to (exponential) field amplification <...>
The approximately 1000 Mt @ 0.6% Cu, 0.3-0.4 g/t Au Majdanpek porphyry copper is the most northerly deposit within the Timok Magmatic Complex (TMC) which also hosts the exploited Bor and producing Veliki Krivelj deposits. Slightly older, but similar magmatic rocks southeast of the region host the significant porphyry-high sulphidation mineralisation at Elatsite and Chelopech in neighbouring Bulgaria. Similar porphyry deposits are also known in Romania, across the Danube river to the north of Majdanpek. The TMC igneous rocks show clear evidence of crustal contamination and thus likely relate to an eastward dipping subduction zone beneath a continental margin located to the west. Mineralisation is related to sparse and narrow north-south trending andesitic dykes dated at 83 Ma. These dykes intrude along a north-south trending fracture zone cutting Proterozoic and Palaeozoic metamorphic rocks, and Jurassic limestones. Extrusive facies of the TMC are rare at Majdanpek, although they are common farther to the south of the region. Mineralisation is typicaly developed as stockworks, the bulk of which are actually within the metamorphic aureole of the andesitic dykes. There are also numerous skarns and replacement bodies flanking the intrusives, while more distal replacement bodies are found in the Jurassic limestones. The highest copper grades relate to K-silicate alteration and zones of strong silicification. Mo grades are very low throughout the deposit, while the Cu%;Au g/t ratio is approximately 2:1. PGEs occur as minor phases accompanying the copper mineralisation and are recovered at the smelter. Significant supergene upgrading is recorded in an oxidation blanket that was 25 m thick in the north and covered the deposit.
The modern image of the Geological Society owes much to William Smith whom the Society used, in 1831, to claim ascendency over European rivals. At its birth, however, the Society pursued a science adopted from the Continent, which privileged field data and saw mineralogy and chemistry as the sciences of the Earth. The Society’s birth mobilized the nation; its co-operative, mobile, investigative, subtly theoretical and didactic vigour materialized in the production of Greenough’s geological map of England.
Geotechnical engineering differs from other forms of engineering by the composition of ground, which is composed of a wide range of solids with discontinuities, pores fluids and structures. These different elements composing the ground interact with one another increasing the complexity of any prediction. In traditional geotechnical analysis, limit equilibrium methods (LEM) are useful techniques for estimating the onset of failure.
Under the low-temperature and pressure conditions of Earth’s upper lithosphere, silicate rock responds to large strains by brittle fracture. The mechanism of brittle behavior is by the propagation of cracks, which may occur on all scales. We begin by studying this form of deformation, which is fundamental to the topics that follow. <...>
This book derives from the Integrated Basin Studies Project (IBS), which ran during the years 1992-1995 with the support of the European Commission DGXII. The papers produced by the IBS group have been complemented by eight papers arising from the conference 'Mediterranean Basins: Tertiary Extension within the Alpine Orogen', held in Cergy-Pontoise, France, 11-13 December 1996. The title of this conference has also been retained as the title of the book. The papers included here collectively cover the majority of the Mediterranean Tertiary extensional basins, with the exception of those in the SW of the region. <...>
It is an old wisdom that metals are indispensable for life. Indeed, several of them, like sodium, potassium, and calcium, are easily discovered in living matter. However, the role of metals and their impact on life remained largely hidden until inorganic chemistry and coordination chemistry experienced a pronounced revival in the 1950s. The experimental and theoretical tools created in this period and their application to biochemical problems led to the development of the field or discipline now known as Bioinorganic Chemistry, Inorganic Biochemistry, or more recently also often addressed as Biological Inorganic Chemistry.
By 1970 Bioinorganic Chemistry was established and further promoted by the book series Metal Ions in Biological Systems founded in 1973 (edited by H.S., who was soon joined by A.S.) and published by Marcel Dekker, Inc., New York, for more than 30 years. After this company ceased to be a family endeavor and its acquisition by another company, we decided, after having edited 44 volumes of the MIBS series (the last two together with R.K.O.S.) to launch a new and broader minded series to cover today’s needs in the Life Sciences. Therefore, the Sigels new series is entitled <...>
It is a daunting task for any geologist to understand gold genesis and to find exploration guidelines in the enormous volume of literature. From the perspective of the exploration geologist, this is worth tackling because there is still a large dichotomy when it comes to their genesis, epigenetic-structural aspects and syngenetic concepts. While the targets will not change with the model (Colvine et al., 1984), a better overall understanding will clearly aid target selection and exploration techniques <...>
Of all the materials used as gemstones, diamond stands out from the crowd for many reasons. One of these is that more is published about diamond than all the other gem materials placed together. So why do we have here yet another cauldron of diamond information?
