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Petrography

About: Petrography is a research topic. Over the lifetime, 7449 publications have been published within this topic receiving 102018 citations.


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Book ChapterDOI
01 Jan 2000
TL;DR: A survey of sandstone units of widely varying age, location, and burial history suggests that quartz-lined and quartz-filled microfractures are nearly ubiquitous in lithified quartzose sandstones.
Abstract: The stable observing conditions, high magnifications, and sensitive light detection that are characteristic of scanning electron microscope-based cathodoluminescence (scanned-CL) imaging overcome several of the disadvantages of conventional light microscope-based CL systems, allowing more routine application of this petrographic method for description of micron-scale textural relationships between detrital grains, cements, and fractures in sandstones. Scanned-CL imaging has great utility for documenting the interrelation between deformation and diagenesis at the micrometer scale in siliciclastic rocks. A survey of sandstone units of widely varying age, location, and burial history suggests that quartz-lined and quartz-filled microfractures are nearly ubiquitous in lithified quartzose sandstones. Because fractures formed in association with quartz precipitation are prevalent in quartz-cemented siliciclastic hydrocarbon reservoir rocks, scanned-CL imaging of microfractures can potentially yield important information on subsurface fracture populations that have economic significance.

72 citations

Journal ArticleDOI
01 Dec 1998-Catena
TL;DR: In this paper, the main sources of pedogenic clay minerals are phyllosilicates in the silt fractions and vermiculites are the dominant pedogenetically formed clay minerals in the B or Bt horizons of the Holocene climaphytomorphic soils and in all the pedocomplexes in Karamaydan and Chashmanigar.
Abstract: The upper part of the Karamaydan section, Tadjikistan, shows the most detailed loess–paleosol sequence yet known for the Brunhes chron, and the central and lower parts of the Chashmanigar section provide similar detail for most of the Matuyama chron. To enable paleoclimates to be deduced, the primary and secondary minerals in the silt and clay fractions must be determined separately to evaluate the type and intensity of mineral weathering and clay mineral formation. To distinguish between inherited and pedogenetically formed clay minerals, the original petrographic homogeneity of the parent material from which a soil developed must be established. The main sources of pedogenic clay minerals are phyllosilicates in the silt fractions. Illites and vermiculites are the dominant pedogenetically formed clay minerals in the B or Bt horizons of the Holocene climaphytomorphic soils and in all paleosols (S) and pedocomplexes (PK) in Karamaydan and Chashmanigar, except S XVII in which large amounts of smectites were formed. There is little difference in the type and amount of pedogenic clay mineral formation between the Holocene soils and the paleosols in the Brunhes epoch at Karamaydan as well as during most of the Matuyama epoch at Chashmanigar. These results indicate that the climates of the interglacials represented by the B or Bt horizons of the buried paleosols of young, mid and old Pleistocene age were similar to that of the Holocene.

72 citations

Journal ArticleDOI
TL;DR: The Upper Hance coal seam in southeastern Kentucy was used as a template to examine the spatial distribution of ash yield, sulfur content and petrographic constituents relative to the geometry of the deposit as mentioned in this paper.

71 citations

Journal ArticleDOI
TL;DR: In this article, textural and mineral-chemical data on freeze-thaw disaggregated refractory inclusions from the Murchison meteorite were obtained with neutron activation analysis, SEM, and spectroscopy, revealing corundum-bearing inclusions, spinel-hibonite aggregates and spherules, and spinel pyroxene and elivine-pyroxene inclusions.
Abstract: Textural and mineral-chemical data on freeze-thaw disaggregated refractory inclusions from the Murchison meteorite are reported. The data were obtained with neutron activation analysis, SEM, and spectroscopy, the study revealed corundum-bearing inclusions, spinel-hibonite aggregates and spherules, and spinel-pyroxene and elivine-pyroxene inclusions. One of the three spinel-, pyroxene-, forsterite-rich inclusions had an amoeba-shaped spinel-pyroxene core, implying vapor-to-solid condensation and therefore crystallization from a melt. It is concluded that the meteorite formation encompassed diverse nebular materials, and that further studies of the meteorite will enhance the data base on the planetary nebular processes.

71 citations

Journal ArticleDOI
TL;DR: The Adigrat Sandstone in northern Ethiopia was sampled for chemical and mineralogical analysis using petrographic microscopes and XRD and the results were used to infer the provenance and geotectonic setting of the depositional basin this article.

71 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023551
20221,098
2021370
2020344
2019310
2018291