Journal ArticleDOI
Formation of quartz overgrowths in the Penrith Sandstone (Lower Permian) of Northwest England as revealed by scanning electron microscopy
TLDR
The development of optically continuous quartz overgrowths is governed by the atomic structure and crystallographic orientation of the detrital quartz grains as mentioned in this paper, and growth is particularly rapid along the direction of the c-axis.Abstract:
SUMMARY
The development of optically continuous quartz overgrowths is governed by the atomic structure and crystallographic orientation of the detrital quartz grains. Initial growth commences with the appearance of numerous oriented projections, with rhombohedral and prismatic form, on grain surfaces. Merging and overlap of the projections results in the formation of large crystal faces whose form is dependent upon the initial location of the projections with respect to the internal crystallographic axes. Growth is particularly rapid along the direction of the c-axis. For unicrystalline quartz grains the ultimate growth phase is the production of polyhedral quartz crystals having the appearance of hexagonal dipyramids. In polycrystalline grains each quartz unit within a single grain develops a separate overgrowth, the form of which is similarly controlled by the internal structure of the individual quartz units. Hence, the completed overgrowth shows an irregular distribution of diversely oriented prism and rhombohedral faces.read more
Citations
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Journal ArticleDOI
Quartz cement in sandstones: a review
TL;DR: The main factors that control the amount of quartz cement in sandstones are: framework composition, residence time in the silica mobility window, and fluid composition, flow volume and pathways.
Book ChapterDOI
Sandstone Diagenesis: The Evolution of Sand to Stone
TL;DR: The classic transition from diagenesis to metamorphism was described eloquently in the Salton Sea geothermal field, south-east California, where sandstones of broadly similar composition are present over a temperature interval of 100°C to 350°C.
Journal ArticleDOI
How clay grain coats inhibit quartz cement and preserve porosity in deeply buried sandstones: Observations and experiments
TL;DR: In this paper, the authors investigated how clay grain coats inhibit quartz cement and preserve porosity in deeply buried sandstones and found that the fraction of grain surface coverage is the primary control on cement inhibition by coats, but at high temperatures, many coats permit quartz nucleation and preserves porosity by limiting cement growth.
Journal ArticleDOI
Textural and permeability characteristics of faulted, high porosity sandstones
Julian Fowles,S. D. Burley +1 more
TL;DR: In this paper, textural changes correlate with decreases in permeability and porosity of up to four orders of magnitude across cataclastic slip bands, which may have been sites of enhanced fluid flow during faulting.
Journal ArticleDOI
Optically continuous silcrete quartz cements of the St. Peter Sandstone: High precision oxygen isotope analysis by ion microprobe
TL;DR: A detailed oxygen isotope study of detrital quartz and authigenic quartz overgrowths from shallowly buried (<1 km) quartz arenites of the St. Peter Sandstone (in SW Wisconsin) constrains temperature and fluid sources during diagenesis as discussed by the authors.
References
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Journal ArticleDOI
Authigenesis in west virginia sandstones
TL;DR: The authigenic minerals in the Oriskany, Berea, and Big Injun sandstones are quartz, calcite, dolomite, orthoclase, microcline, albite, chlorite, kaolinite, and pyrite as discussed by the authors.
Journal ArticleDOI
Experimental Study of Quartz Overgrowths and Synthetic Quartzites
W. G. Ernst,Harvey Blatt +1 more
TL;DR: Synthetic overgrowths have been produced on both undulatory and non-undulatory detrital quartz grains using conventional hydrothermal techniques as discussed by the authors, and the enlargements were produced in quantity only in experiments in which silicic acid had been added and fluid pressure was equal to total pressure.
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