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Автор(ы):Collignon M.
Издание:Imprimerie nationale, Paris, 1950 г., 106 стр.
Язык(и)Французский
Annales geologiques du service des mines. Recherches sur les faunes albiennes de Madagascar

Dans un mémoire, qui a été publié dernièrement dans les Annales géologiques du Service des Mines de Madagascar (1), j'ai décrit une faune albienne remarquable, caractérisée par l'abondance des Ammonites des Genres Douvillei-ceras, Lemuroceras et Brancoceras, et j'ai donné une coupe, selon Henri Besairie, du gisement principal de ces fossiles, situé dans la région d'Ambarimaninga, cercle de Sitampiky (Madagascar).

Au sommet de la coupe, c'est-à-dire au-dessus des couches principales à Ammonites que j'ai rapportées au sommet de l'Albien inférieur (Dou-villeicératien) et à la base de l'Albien moyen (partie inférieure de l'Oxytropidocératien) suivant l'échelle stratigraphique établie par Maurice Breistroffer (2), existe un banc fossilifère à Echinides épais de 1 m, où Henri Besairie a recueilli de très nombreux Oursins qui font l'objet du présent mémoire.

Автор(ы):Cooper S.P., Lorenz J.C.
Издание:Wiley Blackwell, 2020 г., 221 стр.
Язык(и)Английский
Applied Concepts in Fractured Reservoirs /  Прикладные концепции в трещиноватых коллекторах

This book is a companion to our previous Atlas of Natural and Induced Fractures in Core, moving on from the basic recognition of fracture types described in that volume, which must be the foundation of any fracture study, to explanations of how those fractures form, how they are measured, how they can be assessed, and how they affect reservoirs.

This volume is the summary of decades of experience with industry doing applied fracture studies. It brings together numerous fracture-related topics that are not collected elsewhere. We hope that it will be useful to both academia and industry, and that it is not in the vein of the apocryphal third-grader doing a book report on penguins, who concluded that “This book tells me more than I want to know about penguins.” <...>

Издание:Elsevier, 2020 г., 210 стр., ISBN: 978-0-12-819495-9
Язык(и)Русский
Applied geochemistry. Advances in mineral exploration techniques / Прикладная геохимия. Достижения в области методов разведки полезных ископаемых

Successful exploration for mineral resources depends on integrated application of our understanding of the geology that hosts ore deposits, and their geochemical and geophysical expressions. Geochemistry is one of the oldest exploration techniques, but it is also one of the most modern. In its earliest form, it involved tracing alluvial minerals, especially gold, back to their source. Over time, it has developed as a result of improved analytical techniques, different sampling media, changes in extraction methods, and improvements in data processing and presentation to become the versatile and sophisticated suite of methods available to modern explorers.

Автор(ы):Daly R.A.
Издание:D.Appleton-century company Inc., New York - London, 1938 г., 211 стр.
Язык(и)Английский
Architecture of the earth

The magical instruments of the astronomer reveal no element new to chemistry and show the earth to be a marvellously complete sample of the universe of matter, whether in planet, star, nebula, galaxy, or super-galaxy. Thus from earth science comes a better understanding of the universe. Geology, tracing the dramatic history of one of the celestial wanderers, deepens our concept of Time and still further broadens the foundation of a sound philosophy. Pierre Termier meant much when he wrote: "The earth declares the glory of God." He had devoted his life to a study of the stately processes that have governed the evolution of our globe through two billions of years. Yet, like other professional geologists, he found ordinary words inadequate for the new, unfamiliar ideas. Technical terms have had to be invented. Here is a difficulty when the geologist attempts to tell his story. Technicality puts a barrier between the specialists and the great public or even the beginner in the professional study of earth's history. For this trouble there is only one medicine—good-will. However, with good-will on both sides the geologist can share with others the thrills that spring from an incomparable moving picture.

Автор(ы):Reyment A.R., Savazi E.
Издание:Elsevier, 1999 г., 285 стр., ISBN: 0-444-82568-1
Язык(и)Английский
Aspects of multivariate statistical analysis in geology

Multivariate statistical methods have become commonplace in the Earth Sciences. What was once an exclusive area of activity is now within the reach of Everyman, owing to the ubiquitousness of mini-computers and the ready availability of software for doing the computing. In the days when one was required to do one's own programming, it was necessary to acquire considerable proficiency in linear algebra and one or more programming languages. Today, the vast majority of the people who use multivariate methods to analyse geological data have little or no idea of the matrix operations underlying a particular method, nor, for that matter, what the program is actually supposed to be doing. This situation can be both good and bad. It can do no harm if everything goes according to schedule, the program being used is competently constructed, which, alas, is far from being the general case, and there are no strong deviations from standard statistical theory in the data under examination. It is bad if the data do not fit the theoretical requirements of a particular method and even worse if the method of computation used is inappropriate. It is an inescapable and sad fact of life that much geological and biological material deviates in some manner or other from the theoretical requirements of a multivariate statistical procedure. The immediate relevance of this observation is that there are many sources of error in doing an analysis of geological data by means of standard statistical software.

Том 17, Выпуск 3
Издание:Stratigraphy and Geological Correlation, 2009 г., 16 стр.
Язык(и)Английский
Assembly and Breakup of Rodinia (Some Results of IGCP Project 440)

The principal results of project 440 “Assembly and Breakup of Rodinia” of the International Geological Correlation Programme (IGCP) are reviewed in this work. A map of that supercontinent compiled using geological and paleomagnetic data describes global paleogeography 900 Ma ago. The assembly of Rodinia, which comprised most of Precambrian continental blocks, lasted ca. 400 m.y. (from 1300 to 900 Ma). Its breakup presumably triggered by mantle superplume took place between 830 and 650 Ma. The correlation between tectonic events in different continental blocks is considered. Some problems concerning the Rodinia reconstruction and history, e.g., the slow growth of juvenile crust and effects of mantle-plume events during the amalgamation period and of glaciations at the breakup time, are discussed. The latter caused changes in the biosphere and climate, whereas postglacial periods stimulated progress in biota evolution

Выпуск 38
Издание:Палеонтологический институт РАН, Москва, 2002 г., 75 стр.
Язык(и)Английский
Astrovioidea: a new superorder of paleozoic cephalopods

A new superorder of Paleozoic eclochochlian eephalopods, Aslrovioidea superordo nov., is designated. A distinctive feature of this superorder is that the soft eameral tissue enters the siphon cavity and secrets calcareous eameral deposits. This resulted in the destruction of the connecting rings that previously constituted, in conjunction with the septal necks, the compound wall of the siphon. In early (Ordovician) representatives of this superorder, the soft eameral tissue passed through the siphon to destroy, either partially or completely, the connecting rings and to progress occasionally along the internal surface of those rings that remained unde-stroyed as far as several chambers (the order Lituilida Starobogalov, 1983).

Редактор(ы):Thompson A.J.B., Thompson J.F.H., Dunne K.P.E.
Издание:Mineral deposits division, 1996 г., 119 стр., ISBN: 978-0919216594
Язык(и)Английский
Atlas of alteration. A field and petrographic guide to hydrothermal alteration minerals

Secondary alteration of rocks and their contained minerals is common in nature. Alteration reflects the interaction of fluid, typically dominated by water, with rock at temperatures that range from warm (< 100°C) to hot (>500°C). For geologists who wish to study the primary mineralogy and chemistry of rocks, alteration is a nuisance to be avoided. Alteration mineralogy, however, documents the post-formation history of the rock, information that has practical implications. In particular, alteration is ubiquitous in and around hydrothermal mineral deposits. The distribution and mineralogy of this alteration relates to the hydrothermal environment, and hence, the type of mineral deposit. More importantly for mineral exploration, hydrothermal alteration around mineral deposits commonly forms halos that provide a target which is much larger than the deposit itself. The mineralogy and in some environments the chemical composition of the alteration provide an indication of the proximity of mineralization, or in the ideal case, a vector towards mineralization. Interpretation of alteration is, therefore, a routine part of exploration for hydrothermal mineral deposits. Similarly, as a product of geothermal activity, the mineralogy of hydrothermal alteration provides information on reservoir and fluid characteristics, and the evolution of the geothermal system. These data are used in conjunction with other information to evaluate potential geothermal resources.

Издание:148 стр.
Язык(и)Английский
Atlas of Igneous Rocks and their Textures

Atlas of igneous rocks and their textures A companion volume to the Atlas of Rock-forming Minerals in Thin Section, this full-colour handbook is designed to be used as a laboratory manual both by elementary students of earth sciences undertaking a study of igneous rocks in thin section under the microscope, and by more advanced students and teachers as a reference work. The book is divided into two parts — Part One is devoted to photographs of many of the common textures found in igneous rocks with brief descriptions accompanying each photograph. Part Two illustrates the appearance of examples of some sixty of the commonest (and a few not so common) igneous rock types; each photograph is accompanied by a brief description of the field of view shown. Nearly 300 full-colour photographs are included, and in many cases the same view is shown both in plane-polarized light and under crossed polars. A brief account of how thin sections can be prepared is included as an appendix. It is believed that the amateur geologist using these instructions will be able to make his own thin sections and, with the aid of a relatively simple microscope, enjoy the study of rocks in thin section.

Источник:Интернет
Выпуск 102
Издание:Economic geology, 2007 г., 27 стр.
Язык(и)Английский
Bald mountain gold mining district, Nevada: a Jurassic reduced intrusion-related gold system

The Bald Mountain mining district has produced about 2 million ounces (Moz) of Au. Geologic mapping, field relationships, geochemical data, petrographic observations, fluid inclusion characteristics, and Pb, S, O, and H isotope data indicate that Au mineralization was associated with a reduced Jurassic intrusion. Gold deposits are localized within and surrounding a Jurassic (159 Ma) quartz monzonite porphyry pluton and dike complex that intrudes Cambrian to Mississippian carbonate and clastic rocks. The pluton, associated dikes, and Au mineralization were controlled by a crustal-scale northwest-trending structure named the Bida trend. Gold deposits are localized by fracture networks in the pluton and the contact metamorphic aureole, dike margins, high-angle faults, and certain strata or shale-limestone contacts in sedimentary rocks. Gold mineralization was accompanied by silicification and phyllic alteration, ±argillic alteration at shallow levels. Although Au is typically present throughout, the system exhibits a classic concentric geochemical zonation pattern with Mo, W, Bi, and Cu near the center, Ag, Pb, and Zn at intermediate distances, and As and Sb peripheral to the intrusion. Near the center of the system, micron-sized native Au occurs with base metal sulfides and sulfosalts. In peripheral deposits and in later stages of mineralization, Au is typically submicron in size and resides in pyrite or arsenopyrite. Electron microprobe and laser ablation ICP-MS analyses show that arsenopyrite, pyrite, and Bi sulfide minerals contain 10s to 1,000s of ppm Au. Ore-forming fluids were aqueous and carbonic at deep levels and episodically hypersaline at shallow levels due to boiling. The isotopic compositions of H and O in quartz and sericite and S and Pb in sulfides are indicative of magmatic ore fluids with sedimentary sulfur. Together, the evidence suggests that Au was introduced by reduced S-bearing magmatic fluids derived from a reduced intrusion. The reduced character of the intrusion was caused by assimilation of carbonaceous sedimentary rocks.

Tertiary faults dismember the area and drop down the upper part of the mineralizing system to the west. The abundant and widespread kaolinite in oxide ores is relatively disordered (1A polytype) and has δD and δ18O values suggestive of a supergene origin. The deep weathering and oxidation of the ores associated with exhumation made them amenable to open-pit mining and processing using cyanide heap leach methods.

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