ISSN:0020-6814    

DOI:10.1080/00206819409465443

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

At the base of the sedimentary section of the Timan-Pechora basin are Late Precambrian rifts, which are filled by unmetamorphosed sedimentary rocks 10 km and more than 10 km thick. The upper parts of these rift deposits have potential for gas. Structurally the Phanerozoic sedimen tary fill of the basin is mildly deformed in the west and central parts into several broad depressions and more narrow intervening highs. The eastern part is strongly deformed by overthrusts that were emplaced in the Late Paleozoic in connection with development of the Ural fold belt. Eight oil-gas plays are recognized in the basin: 1—Ordovician-Lower Devonian, 2—Middle Devonian-lower Frasnian, 3—upper Frasnian-Tournaisian, 4—Lower Carboniferous, 5—upper Visean-Lower Permian, 6—Lower Permian, 7—Upper Permian, and 8—Triassic. The promising oil-gas basin is of great interest for global stratigraphy and tectonics as well as for petroleum exploration.

ISSN:0020-6814    

DOI:10.1080/00206819409465444

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Carboniferous-Lower Permian carbonate succession of the Timan-Pechora basin is a major hydrocarbonbearing complex, hosting about half of the oil and nearly a third of the gas reserves of the basin. The succession represents the last episode of carbonate deposition on the northeastern margin of the Russian platform before the closure of the Ural seaway in the mid- Permian.

ISSN:0020-6814    

DOI:10.1080/00206819409465445

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The bulk of the hydrocarbon resources of the Timan-Pechora basin on the northeastern margin of the Russian platform is hosted in reservoirs and traps in the Middle Devonian-Triassic stratigraphic interval, the second of three Phanerozoic first-order cycles. The stratigraphic positions of source rocks, reservoirs, and seals within this important first-order cycle bear specific and predictable relationships to stages within second-order transgressive-regressive cycles. Anticlinal traps constitute 12-15% of the surface area of the basin and host about 75% of the discovered reserves. In addition, numerous styles of stratigraphic and combination traps are recognized. Understanding of the stratigraphy of the basin points to many additional reservoirs and trap styles that as yet are underexplored. The prospects for significant future discoveries of oil and gas in the Timan-Pechora basin are high.

ISSN:0020-6814    

DOI:10.1080/00206819409465446

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Timan-Pechora basin, a promising hydrocarbon-producing region in the European part of Russia, reportedly has an estimated 1.3 billion tons of “proven” (A+B+C1) and 0.6 billion tons of C2 reserves of oil and 800 billion cubic meters of A+B+C2 reserves of natural gas. The distribution of the basin's reserves, embracing federally subordinated, republican, and autonomous jurisdictions, tends to create opportunities as well as additional complications for foreign developers. Harsh climatic conditions, swampy terrain, and other difficulties (e.g., heavy and paraffinic oils) have impeded rapid development. Nevertheless, the Timan-Pechora basin has become a major focus of joint venture activity involving, among other multinational oil companies, Conoco, Texaco, Exxon, and Amoco. New projects, with previously discovered fields containing an estimated 2 to 5 billion barrels of oil, appear to offer potential yields of about 6 million tons per annum by the year 2000.

ISSN:0020-6814    

DOI:10.1080/00206819409465447

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Xenoliths from the upper mantle have undergone a wide variety of processes at varied temperatures and pressures, as recorded by mineral compositions and textures. Eclogite xenoliths in kimberlites are a unique source from which to obtain information about such processes. Furthermore, eclogites that contain accessory diamond yield important compositional constraints on the deeper upper mantle. Whether eclogites have mantle or crustal origins is still a subject of controversy.

ISSN:0020-6814    

DOI:10.1080/00206819409465448

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Chert-plus-pyrite pebbles have been known for some time in a number of Witwatersrand conglomerates, but their distribution is highly variable. A wide variety of textures in chert-plus pyrite pebbles are documented here, and these textures place constraints on the origin of such pebbles. Replacement of chert pebbles by pyrite is indicated (pyrite grains and aggregates continue across many pebble boundaries), and both distributional and textural evidence favors a post-burial timing for this process. Significant mobility of sulfur after burial is indicated. Whether this replacement was diagenetic or metamorphic is not certain.

ISSN:0020-6814    

DOI:10.1080/00206819409465449

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Wenduermiao deposit, a large, low-grade iron ore deposit, occurs in the upper Proterozoic metavolcanic-sedimentary sequences of the Wenduermiao Group in south-central Inner Mongolia. The Wenduermiao Group consists mainly of metabasaltic rock, greenschist, marble, finely crystalline quartzite, and related metachemical sediments. Most of the iron ore occurs as stratiform and podiform deposits, or as massive lenses, along the transition zone of greenschist, chlorite-biotite-sericite-albite-quartz rocks, or calcite-amphibole-albite-quartz rocks. Two important ore types, chlorite-magnetite and calcite-magnetite, have been recognized and are interpreted as forming from different ore fluids. Primary mineralization in the deposit consists of martite and magnetite, with smaller amounts of specularite, goethite, and limonite.

ISSN:0020-6814    

DOI:10.1080/00206819409465450

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A survey of Russia's platinum-group metals examines a number of dimensions involved in their mining and processing. Estimates of reserves and production are assessed in light of deposit type (lode vs. placer) and relative abundance of various platinum-group metals in ores. Complex polymetallic sulfide ores in lode deposits at Noril'sk and Talnakh currently account for all commercial output of platinum group metals in Russia (as byproducts in the extraction of copper, nickel, cobalt, and other metals), but recent plans to develop osmium and iridium-rich placers in the Far East region and elsewhere are reviewed.

ISSN:0020-6814    

DOI:10.1080/00206819409465451

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor