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Автор(ы):Barker A.J.
Издание:CRC Press, 2014 г., 180 стр., ISBN: 978-1-315-77869-3
Язык(и)Английский
A key for identification of rock-forming minerals in thin-section / Ключ для идентификации породообразующих минералов в шлифе

Being able to accurately identify minerals in thin-section is an essential skill for any geologist, and is vital for the correct interpretation of rocks and their petrogenesis. It can be a particularly challenging prospect for students new to the subject. However, with a basic understanding of microscopy, petrology and optical mineralogy, coupled with some reference text books, it is soon possible to identify some of the major rock- forming minerals with confidence.

Издание:Geology Society of America, 2011 г., 49 стр., ISBN: 978-0-8137-2481-2
Язык(и)Английский
A new geological map of the Island of Syros (Aegean Sea, Greece): Implications for lithostratigraphy and structural history of the Cycladic Blueschist Unit / Новая геологическая карта острова Сирос (Эгейское море, Греция): значение для литостратиграфии

The Island of Syros (Cyclades, Greece) is a prime locality for the study of processes active in deep levels of orogens and is world famous for its exceptionally well preserved blueschist- to eclogite-facies lithologies. Syros Island was completely remapped at a scale of 1:25,000. Detailed lithostratigraphical observations and areawide, closely spaced structural measurements allowed a much more detailed depiction of the highly variable lithological assemblage, as well as of the complex structural evolution.

Том 39, Выпуск 4
Издание:Москва, 2005 г., 7 стр.
Язык(и)Английский
A New Record of an Azhdarchid (Pterosauria: Azhdarchidae) from the Upper Cretaceous of the Volga Region

A distal fragment of a radius of Azhdarchidae indet. from Upper Campanian (Upper Cretaceous) marine deposits of Saratov is described. The bone belongs to a large pterosaur, of about 4.3 m wing span. It differs from the radii of Azhdarcho, Montanazhdarcho, and cf. Quetzalcoatlus in the asymmetrical distal epi-physis and, in addition, from Montanazhdarcho and cf. Quetzalcoatlus in the absence of a pneumatic foramen on the posterior side. In its geographical and stratigraphical positions, this specimen is close to the azhdarchid Bogolubovia orientalis (3–4 m in wing span), known from a fragmentary cervical vertebra from the Campanian of the Penza Region, and may belong to this species.

Издание:Springer, 2014 г., 231 стр., ISBN: 978-81-322-1568-4
Язык(и)Английский
A Petrographic atlas of ophiolites. An example from the eastern India-Asia collision zone / Петрографический атлас офиолитов. Пример из восточной Индо-Азиатской колизионной зоны

The basic tenet of the plate tectonic paradigm is that a newly generated oceanic plate is subducted at a trench. However, it is widely accepted today that some material is not subducted, but is accreted to form an accretionary wedge or prism, within which there may be a preserved section of the oceanic crust/mantle, known as an ophiolite.

Автор(ы):Bridges S., Robinson L.
Издание:Elsevier, 2020 г., 593 стр., ISBN: 978-0-12-821341-4
Язык(и)Английский
A practical handbook for drilling fluids processing / Практическое руководство по буровым растворам

This book concentrates on properly treating drilling fluid in the surface systems including a detailed discussion of the three required sections: suction, addition, and removal. The single, most important function of a drilling fluid is to prevent ablowout and to be able to control a kick if one does occur. For this reason, the first subject addressed in this book is the fluid processing required to handle a kick. For safety, in anticipation of a kick, the drilling fluid within the drill pipe should have the same density avoiding sag, settling, and uneven density in the annulus that could lead to a kick. To achieve these conditions, the surface system must be able to blend a sufficient quantity of homogeneous fluid. The agitation and blending of this fluid is discussed and proper calculations related to ensuring the proper properties 

Выпуск 55
Автор(ы):Xiaoling W., Yinxiu L.
Издание:Journal of Geochemical Exploration, 1995 г., 5 стр.
Язык(и)Английский
A rapid field analytical method for gold in geochemical exploration

A rapid field method for gold analysis in geochemical exploration has been developed. Cold extraction of Au, at room temperature, using a mixture of sodium bromide, sulphuric acid, hydrogen peroxide is performed; the technique has the advantage of avoiding the irritating odour of commonly used aqua regia digestion. Polyurethane foam is used to concentrate gold from solution. After desorption of Au using mixed reagents (0.5% Na2S03-NaCl solution at pH 8), two sequential procedures, depending on the concentration, are followed for the determination of gold. (1) A 1 mL portion of desorbed solution is used to form Au-TMK-DBS (Thio Micher's Ketone and dodecyl benzene sodium sulphonate) ternary complex. Concentrations below 20 ng/g Au are determined by visual colour comparison of the organic layer with a series of standards. (2) If the concentration is greater than 20 ng/g Au, a complexation reaction using the same reagents is followed by fibre-optic colorimetry. The method is rapid and simple, and the tiresome operation of ashing the foam is avoided. The limit of detection is 0.5 ng/g Au and eighty determinations can be made in one working day. The method could be used for rapid follow-up of rock sample or in situ drill core analyses. About 600 samples from 5 gold districts were tested by this method. The results are very satisfactory.


Автор(ы):Steve C.Brown
Издание:PGS Publishing, Linden Park, 2005 г., 16 стр.
Язык(и)Английский
A Review of the Geology and Mineralisation of the Alumbrera Porphyry Copper-Gold Deposit, Northwestern Argentina.

The Bajo de la Alumbrera porphyry copper-gold deposit is located within the northern Sierras Pampeanas in the eastern Andes Mountains of northwestern Argentina. It formed in a tectonically favourable location within a major arc-oblique wrench fault system, the Tucuman Transfer Zone. Initial andesitic volcanism deposited on crystalline Lower Palaeozoic basement, and subsequently emplaced dacitic subvolcanic stocks are directly related to eastward subduction of the Nazca oceanic plate beneath the western continental margin of South America. Structural preparation and shallowing of the angle of subduction of the Nazca plate -related to the arc-normal Juan Fernandez Ridge on that plate - probably aided the ascent of calc-alkaline oceanic arc-related magma into the Tucuman Transfer Zone.

Издание:PGS Publishing, Linden Park, 2002 г., 11 стр.
Язык(и)Английский
A Short Review of Palaeozoic Hydrothermal Magnetite Iron-Oxide Deposits of the South and Central Urals, and their Geological Setting

The Urals orogen represents the site of Palaeozoic oceanic crust creation and subsequently a zone of arc development, arc-continent collision, continent-continent collision and post-orogenic collapse. The orogen is host to a number of world-class VMS deposits in the Silurian to Devonian arc sequences but in addition is host to highly significant iron oxide deposits of both hydrothermal and orthomagmatic origin. The hydrothermal ores are developed in Palaeozoic belts associated with rift-related, dominantly mafic, largely subaerial, alkaline volcanism intruded by comagmatic stocks of varying ages, from the Late Silurian to Early Carboniferous. Volcanism, sedimentation and mineralisation all seem to be controlled by major N to NNE trending structures. Much of the mafic volcanic sequence shows hematisation, which is evidence of early oxidation of the lava-tuff packages. Mineralisation comprises massive and disseminated magnetite bodies with elevated REE and ubiquitous accessory apatite. The deposits can be huge, as for example the giant Carboniferous Kachar deposit in Kazakhstan with reserves of over a billion tonnes of >45% Fe are defined. Some of the bodies are true contact skarns developed at the interface between intrusive bodies and volcano-sediments which include limestones. Other bodies, including Kachar, are distal to any possible related intrusions and are developed within regionally extensive scapolite alteration zones. A regionally consistent pattern of early feldspar ± biotite alteration followed by ore-stage pyroxene-garnet-scapolite followed by late hydrous silicate-carbonate alteration is repeated throughout the Urals. Regionally extensive scapolitisation is common in most of the belts. Base metals are generally present in the deposits, often appearing late in the paragenetic sequence, with some bodies having near economic copper grades (0.6% Cu) and significant precious metals.

Издание:Wiley, 2020 г., 591 стр., ISBN: 978-1-119-65097-3
Язык(и)Английский
A Study in Earth’s Geological Evolution. The Baltic Shield / Исследование геологической эволюции Земли. Балтийский щит

Understanding the basics of Earth’s emergence and evolution at every stage is a fundamental, almost philosophic problem comparable with the issues of the universe. On the other hand, it reflects an applied nature in substantiation of manifestation patterns of endogenous and exogenous processes affecting even the socioeconomic evolution of human society. The book begins with a brief description of Earth’s planetary evolution physical theory built based on an analysis of its energy balance. The theory is based on two source concepts. First, it is accepted that the Earth, according to O.Yu. Schmidt’s hypothesis, had emerged after homogenous accretion of a cold gas-dust proto-planetary cloud. Second, the Earth’s core is composed of an iron with its oxide alloy (on condition that the composition of the mantle and of the Earth’s crust is known). Both assumptions are currently most substantiated and accepted by most geophysicists. It turned out that these two assumptions are sufficient for constructing a self-consistent theory as they include all necessary information about the original Earth’s structure and its internal energy. Comparing based on experimental data equation of state for this matter and applying the laws of physics, it is possible to construct the theory itself. At that, the use of geological data is expedient as edge (boundary) conditions for the problem to be resolved. The young Earth’s evolution and its spinning around the axis of own revolution had substantially depended on tidal interaction of our planet with the Moon, and for this reason we had to review a model of its origin <...>

Издание:PGS Publishing, Linden Park, 2005 г., 18 стр.
Язык(и)Английский
A Tectonic Model for Porphyry Copper-Molybdenum-Gold Deposits in the Eastern Indo-Asian Collision Zone

Two Himalayan porphyry copper-molybdenum-gold belts have been developed in the eastern part of the Himalayan-Tibet orogenic zone related to the collision between the Indian and Asian Plates. Both were accompanied by the emplacement of high-level intracontinental, alkali-rich, potassic felsic magmas which produced a huge Cenozoic belt of potassic igneous rock. The emplacement of these magmas was controlled by large-scale strike-slip fault systems, orientated roughly orthogonal to the of the Indo-Asian continental convergence, which adjusted the collisional strain. The Jomda-Markam-Xiangyun copper-molybdenum belt is the western of the two, developed along a narrow zone following the Nanqian thrust, the Jinshajiang fault system, and the Red River shear zone, whereas the eastern, the Zhongdian-Yanyuan-Yao'an porphyry copper-gold-silver belt, was developed along the western margin of the Yangtze Craton. The ore-bearing porphyries have compositions which include granite, monzogranite, and monzonite, with a small amount of quartz-syenite porphyry. They are distinguished from barren porphyries by their higher Si02 (>63 wt %), lower Y (<20 ppm) and their adakitic magma affinity. All alkali-rich porphyries are relatively enriched in large-ion lithophile elements (K, Rb and Ba) and depleted in high-field strength elements (Nb, Ta, Ti and P) with a wide range of Nb/Y ratios.

1768.7