The Chalice gold deposit (~ 20 t Au produced), in the southwestern portion of the Late-Archean Norseman-Wiluna greenstone belt of the Yilgarn Craton, Western Australia, is hosted both in a sequence of intercalated mafic and ultramafic amphibolites and a post-peak metamorphism monzogranite dike. The deposit is flanked on the western side by calc-alkaline plutonic rocks, and to the east by a predominantly monzogranitic pluton, with at least four generations of monzogranitic dikes that intrude the local mine stratigraphy. Locally, four deformation events (D1–D4) have affected this sequence of amphibolites, and two stages of gold mineralisation are recognised, controlled by the progressive D2 event.

В вопросе о планировании проспекторских работ на Алтае всегда значительную роль играло противопоставление Рудного Алтая, района издавна обжитого, известного многочисленными полиметаллическими месторождениями, всей остальной территории этой горной страны—Горному Алтаю, потенциальные возможности которого в деле выявления промышленных рудных м-ний оценивались в общем очень низко. Совершенно понятно, что геологическими учреждениями Рудный Алтай изучался в значительной степени интенсивнее. Понятным является также и то обстоятельство, что исторически сложившееся представление об особом богатстве Рудного Алтая месторождениями цветных металлов нашло свое отражение в работах геологов, исследовавших этот район. Беглый маршрутный объезд Горного Алтая, проделанный В. П. Нехорошевым в 1925 и 1926 г. г., хотя и позволил ему обнаружить и описать ряд м-ний полезных ископаемых этого района, но не дал повидимому убедительных доказательств для изменения создавшейся неблагонадежной репутации Горного Алтая. Напротив, анализируя собранный в этих исследовательских об'ездах материал, В. П. Нехорошее подводит теоретическую базу под прочно установившееся мнение о бедности Горного Алтая полезными ископаемыми, отмечая слабое развитие в этом районе рудоносных для Рудного Алтая интрузивных порфиров. <...>

The Gold Bar district contains five Carlin-type gold deposits and four resources for a combined gold endowment of 1.6 M oz [50 t]. The gold deposits are hosted in Devonian carbonate rocks below parautochthonous and allochthonous Paleozoic siliciclastic rocks emplaced during the Early Mississippian Antler orogeny. The district is in the Battle Mountain-Eureka trend, a long-lived structural feature that localized intrusions and ore deposits of different types and ages.

Выполнен фрактальный анализ данных разведки и эксплуатации 15 жил четырех золоторудных месторождений России. Измерены фрактальные размерности контуров изоконцентрат золота на продольных вертикальных проекциях, рассчитаны природные порции (кванты) дискретной структуры запасов, определен коэффициент перехода между квантами запасов разных масштабных уровней. Установлено постоянство величин квантов запасов и фрактальной размерности запасов для всех рудных тел каждого месторождения.

The Bendigo goldfield, which has produced most of Victoria’s gold 22 million ouncess684.3 ton., consists of numerous deposits located mainly along narrow, parallel-trending anticlinal domes separated by 100 to 400 m. The individual domes are parts of a regional anticlinorium in Lower Ordovician sedimentary rocks. Highest gold ore values are generally located in the eastern limbs and particularly in the apical areas of the smaller individual anticlinal domes and in the central part of the more regional-anticlinorium.

Alteration present in metasandstone units in the Nell Gwynne anticline consists of phengitic sericite to 15 vol%., chlorite to 7%., carbonates siderite, sideroplesite, ankerite and calcite, to 10%. and sulphides arsenopyrite, pyrite, chalcopyrite and sphalerite, to 5%.. The alteration generally follows the trend of the structure extending upward and above mineralisation in anticlinal areas and below largely unmineralised synclinal areas. Phengitic sericite extends furthest, to at least 150 m above mineralised saddle reef positions, chlorite to 130 m, sulphides to 80 m and carbonate to 50 m. Chlorite geothermometry suggests temperatures of 260 to 2908C for the alteration. The sequence of carbonate precipitation generally is from siderite early., sideroplesite, ankerite and calcite. The more Fe-rich carbonates tend to occur near the apical parts of the anticlinal domes. Arsenopyrite occurs within 10 m of the veins, while hydrothermal pyrite, chalcopyrite and sphalerite all extend to 50 m. Framboidal pyrite possibly greigite. present in unaltered metasediments becomes progressively recrystallised and replaced by hydrothermal pyrite, chalcopyrite and sphalerite as mineralisation is approached. Hydrothermal pyrite is generally euhedral and anomalous in having high As contents when compared to framboidal pyrite. Maximum Au grades 205 ppm. occur in the saddle reef position and below a thick shale unit. Lower-grade mineralisation 0.5–6.0 ppm. occurs above this in the overlying stratigraphy. As and Pb anomalies cross cut the alteration zoning and occur as plume-like dispersion haloes above the mineralisation. The Au occurs in and near the As ‘plume’. Cu concentrations reach their maximum values adjacent to high Au values. Measured CO2 values confirm the observed carbonate distributions. H2Oq and Zn values in the section show relatively random distributions. Two separate stages of mineralisation are indicated, the earlier localised within classic saddle reef structures and containing the highest Au, Cu and some As and a later, cross-cutting stage of mineralisation associated with high As. The alteration is mainly associated with the former. q1998 Elsevier Science B.V. All rights reserved

Систематизированы данные о составе и строении аномальных геохимических полей, специализированных на широкий круг полезных ископаемых (Au, Ag, Pb, Zn, Сu, Mo, W, Sb, Bi, Sn). Охарактеризованы общие и частные закономерности эволюции многоуровневых геохимических систем, выделена универсальная объемная геохимическая зональность. Рассмотрены строение и формирование вещественно-минеральных эквивалентов геохимических полей— гидротермально-мета-соматических систем. Разработан способ геометризации зональных геохимических полей, усовершенствована методика геохимического прогноза и оценки ресурсов продуктивных гидротермально-метасоматических систем на всех стадиях поискового процесса, опирающаяся на серию традиционно используемых концентрационных и выделяемых структурно-геохимических признаков.

Для геохимиков и геологов, ведущих поиски месторождений полезных ископаемых.

Since the freeing of the market price of gold in 1971. exploration for epithermal gold deposits in the southwest Pacific region has been intense, and has been encouraged by some major successes. Sufficient discoveries have been made to summarise what has been found to date, and to assess what implications may be drawn for future exploration. Data are tabulated for 137 epithermal precious metal deposits and prospects in Australia (30), Fiji (2). Indonesia (43 ). New Zealand (22), Palau and Yap (2), Papua New Guinea (18), the Philippines (19), and Solomon Islands (1).

Comparison of the character of epithermal deposits in the southwest Pacific with those in other regions (e.g., the northeastern Pacific margin) suggests that they are in most respects similar with, however, three differences: (i) through much of the region (especially the Philippines and Indonesia) low-sulfidation style deposits commonly show characteristics suggestive of formation at deeper levels than is typical elsewhere; (ii) high-sulfidation deposits appear to be more common than along the northeast Pacific margin; (iii) many of the largest deposits show atypical features, particularly those suggestive of a transition to porphyry or mesothermal conditions, or indicating overprinting of an epithermal system on a porphyry environment. These differences can be partly understood in terms of the tectonic setting and evolution of the volcanic arcs of the southwest Pacific, and the consequent hydrological conditions that existed during mineralization.

The results of exploration in the southwest Pacific indicate that, while the principles of formation of epithermal deposits still apply, deposit models developed in other tectonic/volcanic settings should not be rigidly applied. Gold explorers should first consider the character of the geologic environment at the time of mineralization to try to predict the hydrological conditions during mineralization. Once the likely volcanic environment and paleorelief have been established, then the types, distribution, and zoning of hydrothermal alteration, coupled with observations of deposit form, vein textures and mineralogy, will allow a judgement to be made on the level of system that is now exposed, and on the probable controls that localized mineralization.

The very dynamic character of the tectonic and volcanic setting throughout much of the southwest Pacific has resulted in deposits that reflect changes in the environment of the deposit, in some cases even while deposition was occurring. This has produced some deposits with unusual characteristics which could not have been predicted before exploration.

Sediment-hosted disseminated gold deposits in NW Sichuan China have many features in common with the well-known Carlin-type deposits in the western United States. They are hosted by Middle–Upper Triassic turbidites composed of 1300–4300 m of rhythmically interbedded, slightly metamorphosed calcareous sandstone, siltstone, and slate. The ore bodies are typically layer- or lens-like in shape and generally extend parallel to the stratification of the host sedimentary rocks, with a strike length of tens to several hundreds of meters. The immediate host rocks consist mainly of calcareous slate and siltstone characterized by high contents of organic matter and diagenetic pyrite. The main primary ore minerals associated with gold mineralization include pyrite, arsenopyrite, realgar, and stibnite. Gangue minerals comprise mostly quartz, calcite and dolomite. Gold is extremely fine-grained, usually less than 1 Am, and cannot be seen with an electron microscope.

The paper records the first occurrence of dolomite-hosted, disseminated gold mineralization at Barhi and Jhal, in a Late Archean-Early Proterozoic metavolcano-sedimentary belt ŽMahakoshal fold belt. in central India. Gold mineralization is hosted by dolomite that occurs as discontinuous bands interbedded with phyllite. Hydrothermal alteration styles of the host rock include decalcification, silicification, and argillization. Pyrite is the most common sulfide, whereas stibnite and realgar are rare. Mineralization is characterized by persistent gold from 0.20 to 0.62 ppm and a consistent association of anomalous arsenic, antimony, and mercury with gold.

Книга написана группой авторов, имеющих самое непосредственное отношение к проблемам золота и драгоценных камней. В первую очередь будет полезна ювелирам-профессионалам, банкирам, банковским работникам, менеджерам, поставщикам золотого лома и неограненных алмазов.

В книге приведены новые сведения, о которых ранее не всегда могли знать даже специалисты. Известно, что во времена социализма все то, что было связано с золотом и алмазами, носило достаточно секретный характер или предназначалось для служебного пользования. Теперь представилась возможность рассказать об этом. Тем не менее, авторы не претендуют на полные, энциклопедические знания в этой области, однако то, о чем читатель прочтет в книге, достоверно.

Книга производит впечатление бестселлера, особенно для молодежи.

Издание предполагается как пробное. В нем использованы справочные и другие материалы из латвийских и зарубежных изданий.