BETA

Lazonby

Submitted by Ed FitzGerald on Tue, 2015-03-10 09:43
Stone Type (Commercial): 
Description: 

A Permian Triassic sandstone extracted from a quarry located near Penrith in Cumbria, UK, quarry records date from 1878.

Availability: 
Available
Physical Data
Color: 
Geology
Stone Type (Lithologic): 
Chronostratigraphy: 
Grain Shape: 
Subrounded
Rounded
Grain Sorting: 
Well-Sorted
Grain Size: 
Medium
Petrographic Description: 

Specimen: 2015-005
This specimen is a sandstone. Detrital grains constitute about 60 to 70 percent of slide area, void space is approximately 15 to 20 percent, and the remaining area is occupied by fine cementing matrix. Much of the void space is potentially the result of recent weathering or even slide preparation, formally filled by matrix. Most grains are rounded to subrounded. Of the detrital grains, quartz comprises about 80 to 90 percent of grains. Sutured plutonic/metamorphic quartz-feldspar lithic fragments predominate among the remaining portion with monomineralic feldspars, opaques, and fine grained lithic fragments contributing a lesser amount. Based on these estimates this sandstone is classified as a lithic greywacke (this assumes much of the void space was originally fine-grained matrix). The constituent grains are well sorted. These observations suggest the parent material of detrital grains was mineralogically mature. Textural maturity is also mature. Maximum grain size is .6 mm and minimum is .04 mm. The modal size is around .4 mm. Matrix cement is predominantly silica, producing distinct, presumably hematite delineated, overgrowth rims. Some other less durable cementing medium may have once filled many of the pore spaces. There are a few areas with an iron oxyide/hydroxide and clay/micaceous filling. No visible macrostructure, such as bedding is visible in thin section. The hand sample presents only faint banding that is unlikely to be evident in a thin section.

Images

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Specimen ID
2015-005 Image of specimen in dry conditions. Finish: Smooth sawndownload image Image of specimen in wet conditions. Finish: Smooth sawndownload image

Thin Sections

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Specimen ID Non-polarized Cross-polarized
2015-005 Specimen shown in non-polarized light.download image Specimen shown in cross-polarized light.download image

Quarry

NOTE: Quarry locations are approximate.

Lazonby Quarry
Penrith , Cumbria
United Kingdom
54° 43' 53.8824" N, 2° 44' 56.418" W
Cumbria GB

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