Topic
Petrography
About: Petrography is a research topic. Over the lifetime, 7449 publications have been published within this topic receiving 102018 citations.
Papers published on a yearly basis
Papers
More filters
01 Jan 2016
TL;DR: The RILEM AAR 1.2 Atlas as discussed by the authors was designed and intended to assist in the identification of alkali-reactive rock types in concrete aggregate by thin-section petrography.
Abstract: This RILEM AAR 1.2 Atlas is complementary to the petrographic method described in RILEM AAR 1.1. It is designed and intended to assist in the identification of alkali-reactive rock types in concrete aggregate by thin-section petrography. Additional issues include: optical thin-section petrography conforming to RILEM AAR 1.1 is considered the prime assessment method for aggregate materials, being effective regarding cost and time. Unequivocal identification of minerals in very-fine grained rock types may however require use of supplementary methods. the atlas adheres to internationally adopted schemes for rock classification and nomenclature, as recommended in AAR 1.1. Thus, rock types are classified as igneous, sedimentary or metamorphic based upon mineral content, microstructure and texture/fabric. in addition, the atlas identifies known alkali-reactive silica types in each rock type presented. It also identifies consistent coincidence between certain lithologies and silica types; however, it refrains from attributing alkali-reactivity to a specific silica property or quality. operator skill and experience remain essential for reliable assessment by thin-section petrography. aggregate materials must be classified according to local criteria, based on regional experiences with ASR-damaged field structures and geology. Access to additional data may be relevant for the assessment of imported materials. mere application of rock nomenclature does not provide any sort of warranty to the development of deleterious alkali-reaction. Such may result in either rejection of a suitable aggregate material, thus wasting a valuable resource, or acceptance of an unsuitable material leading to concrete damage, both of which are undesirable
31 citations
TL;DR: Fluid inclusions in granite quartz from SW England provide a record of the complex and protracted hydrothermal history of this important metallogenic province as mentioned in this paper, where the types of fluid inclusion most commonly related to Sn-W-Cu mineralization are halite-free, moderate temperature inclusions.
Abstract: Fluid inclusions in granite quartz from SW England provide a record of the complex and protracted hydrothermal history of this important metallogenic province. Regional variations in terms of the different types of inclusions can be correlated on an inter-pluton scale with both the texture of the host granite and the extent to which it is mineralized. On an intra-granite scale those areas where mineralization is particularly pronounced show a higher overall inclusion abundance than areas where little or no mineralization is known to occur. The types of fluid inclusion most commonly related to Sn-W-Cu mineralization are halite-free, moderate temperature inclusions. Inclusions containing visible CO2 at room temperature are restricted to two localities in SW England. Both of these contain stockwork/vein-swarm tungsten mineralization. These regional ‘fluid inclusion anomalies’ show that fluid inclusion petrography using a simple petrographic microscope has potential application in the field of mineral exploration.
31 citations
TL;DR: Petrographic and geochemical analysis of recent fluvial, beach, and dune sediments derived from the same source terrane was carried out in the western Gulf of Mexico to show the usefulness of the these three environments in determining the tectonic setting of the source as discussed by the authors.
Abstract: Petrographic and geochemical analysis of recent fluvial, beach, and dune sediments derived from the same source terrane was carried out in the western Gulf of Mexico to show the usefulness of the these three environments in determining the tectonic setting of the source. Petrographic analysis showed that dunes concentrate the less heavy minerals and quartz grains by means of the selectiveness of the wind as a transport agent. In contrast, the heavier grains, such as the rock fragments remain in the beach and fluvial environments because of the high transport energy. Beach and dune sands do not define a particular tectonic setting because of the selective wind action of the backshore of the beach and the dune environments and the less intense chemical weathering. The fluvial sands are the most representative in terms of interpretation of tectonic setting because they reflect the volcanic domain of the source rocks of the Trans-Mexican Volcanic Belt. The geochemical results of all three sedimentary environments reflect the calcalkaline character of the igneous source rocks of the Trans-Mexican Volcanic Belt. The samples fall in a continental island-arc-margin field with basaltic and andesitic source rocks. A correlation and factor analysis indicates an alkali-basalt source that contributes to the composition of the beach, dune, and fluvial sediments. The geochemical analysis of the sediments more accurately reflects the tectonic setting regardless of the depositional setting of the sediments.
31 citations
Journal Article•
TL;DR: In this paper, the Majhgawan and Hinota pipes are olivine lamproite lapilli tuffs and not kimberlites as suggested elsewhere, and the Wajrakarur/Lattavaram bodies are classified as kimbersites.
Abstract: New petrographic and mineral chemistry data are presented to show that the Majhgawan and Hinota pipes are olivine lamproite lapilli tuffs and not kimberlites as suggested elsewhere. These bodies, therefore, comprise a newly recognized province of diamondiferous olivine lamproites. Other intrusions in India have been proposed in the literature as being lamproites or kimberlites. Available information for these localities is discussed and, where possible, augmented by new data (Wajrakarur/Lattavaram, Angor, Jungel, Chelima). The Wajrakarur/Lattavaram bodies are classified here as kimberlites. Although two of these bodies appear to be extreme varieties they do not represent a different rock type and are not lamproites. The Chelima and Gondwana coalfields dyke swarms could include lamproites. There are no data to support suggestions of other lamproites or kimberlites in India. This study highlights the need for further detailed petrological investigations of many of these localities.
31 citations
TL;DR: In this paper, the physical and chemical properties of concrete aggregates which significantly affect concrete are outlined, and methods employed and the point of view adopted in performance of the petrographic examination are discussed.
Abstract: Petrographic examination of concrete aggregates proposed for use on projects of the Bureau of Reclamation has assumed great importance as a supplement to standard, empirical, acceptance tests which are almost universally applied by large and progressive engineering organizations. Petrographic examinations entail visual inspection and lithologic segregation of various size-fractions of the aggregate, and they may be rapidly made by petrographers experienced in problems of concrete. Physical and chemical properties which are not determinable by any standard tests are estimated and qualitatively evaluated in terms of their effects upon concrete. Methods employed and the point of view adopted in performance of the petrographic examination are discussed in this paper. Physical and chemical properties of aggregates which significantly affect concrete are outlined.
31 citations