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.

Постаккреционная металлогения Восточной Якутии характеризуется доминирующим развитием эпитермальной Au-Hg минерализации (Суплецов, 2001).  Конформные металлогенические зоны золотоносного Hg оруденения, контролируемые продольными разломами, расположены в структурах Колымо-Омолонского микроконтинента и Верхоянского складчатого пояса. Данные разломы, как правило, трассируются свитами кайнотипных даек щелочных базальтоидов. Металлогенические построения позволили выделить две генетически близкие группы Au-Hg месторождений, локализованные в карбонатных и терригенных комплексах пород, отличающихся морфоструктурой, гидротермальными изменениями и масштабами оруденения. Ртути и сурьме в данных месторождениях, скорее всего, принадлежит второстепенное значение, и они выступают в качестве бипродукта.

Приведены сведения о современном состоянии отечественной золотодобывающей промышленности и ее проблемах. Изложены методы оптимизации параметров эксплуатационной разведки. Рассмотрены технологические схемы ведения добычных работ открытым и подземным способами. Уделено внимание технологаи повторной разработки остаточных запасов подземных рудников открытым способом. Описаны методы взрывной отбойки пород, а также методы управления сдвижением массива горных пород и горным давлением.

Для инженерно-технических работников золотодобывающей промышленности.

In 1997 the British Columbia Geological Survey (BCGS) initiated a project to identify prospective areas for sediment-hosted gold mineralization. The inspiration for the project came from presentations and articles by Howard Poulsen of the Geological Survey of Canada (1996a, 1996b). He pointed out that there is potential to find hypogene, sediment-hosted gold mineralization in Canada akin to deposits found in Nevada. He mentioned that if an intrusive association is important to generate the mineralization, then two different geological environments might host this style of mineralization. Accreted terranes with a basement containing carbonate lithologies intruded by Mesozoic or Cenozic plutonism would be a prospective geological setting, specifically the Stikine and Quesnel terranes. The second favourable environment is within the sediments deposited along the continental margin of ancestral North America which have been cut by Mesozoic magmas, such as are found in the Kootenay Arc and Selwyn Basin (Figure 1).

Others have considered British Columbia as prospective territory for sediment-hosted gold. Early work by companies focused on the Insular Belt rocks exposed on Vancouver Island and the Queen Charlottes. These exploration programs were based largely on an epithermal-style model for the mineralization which was in favour at the time. The discovery of the Babe deposit (now called the Specogna or Cinola) in the Queen Charlotte Islands in 1970 increased the interest in this model because it was initially identified as a Carlin-type deposit (Richards et al, 1976; Champigny  and Sinclair,   1982). <...>

The Carlin trend contains the largest concentration of Carlin-type gold deposits in the world. Two major controversies about these giant gold deposits have been their age, which is now firmly established as Eocene, and the source of heat, fluids, and metals, which remains debated. We present data that demonstrate an intense period of Eocene magmatism coincided in time and space with deposit formation and was arguably the primary heat source. Geologic studies over the last 40 years have emphasized the stratigraphy and structure of Paleozoic sedimentary rocks, which are the major ore hosts. However, four igneous episodes affected the Carlin trend, in the Jurassic, Cretaceous, Eocene, and Miocene. A Jurassic diorite-granodiorite laccolith and related dikes were emplaced at about 158 Ma in the northern Carlin trend. A Cretaceous granite intruded the northcentral part of the trend at 112 Ma. Abundant Eocene dikes intruded along most of the trend and were accompanied by lavas in a large volcanic field along the southwest edge of the trend between ~40 and 36 Ma. Miocene rhyolite lavas erupted just west of and across the southern part of the trend at ~15 Ma.