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Onaga

Submitted by Raven Mueller on Thu, 2014-07-10 09:18
Stone Type (Commercial): 
Quarry: 
Availability: 
Available
Physical Data
Color: 
Munsell Color(s): 
Absorption (%): 
7.60
Density (lb/cf): 
132.00
Modulus of Rupture, Dry (psi): 
1,649
Compressive Strength, Dry (psi): 
3,883
Bulk Specific Gravity: 
1.95
Geology
Stone Type (Lithologic): 
Chronostratigraphy: 
Grain Shape: 
Subrounded
Rounded
Grain Sorting: 
Poorly-Sorted
Grain Size: 
Coarse
Fine
Petrographic Description: 

Specimen: 2014-038-1
This specimen is a minimally fossiliferous limestone. The limestone is grain supported with a predominantly sparite cement matrix. Intraclasts constitute about 10 of slide area. Allochems comprise approximately 70 percent of slide area. These estimates identify the limestone as a grainstone. The most predominate allochem are peloids, which are often only faintly distinguishable from the cementing medium and make up about 50 percent of all allochems. Ooids contribute about 30 percent to allochem total with intraclasts at 15 percent, and bioclasts representing about 5 percent. These estimates and degree of sorting indicate this limestone is classified as an unsorted oosparite. Intraclasts often have significant iron hydroxide staining with a maximum dimension around 1.5 mm. Peloids have a maximum dimension around .6 mm with a modal range around .25 to .15 mm. Some peloids may actually be of intraclast origin. Ooids have a maximum dimension near .3 mm and a modal range around .15 mm. Ooids are often poorly preserved, in most cases they are identifiable by iron hydroxide stained rinds. This material is easily weathered and creates halo voids around many grains. In the hand sample this dissolution lead to complete removal of the grain at the rock’s surface. Bioclasts are rare and most reflect complete replacement of the original, presumably aragonite, material. Micritic envelopes are common and bound the replacement calcite. Bioclasts are mostly bivalves with a maximum dimension of 4.5 mm. Some foraminifera may also have been present, as suggested by patterns of discoloration, but are not adequately preserved for definitive identification. One example of secondary, cryptocrystalline quartz is present with a maximum dimension of .75 mm. Extant voids constitute about 3 percent of slide area. Void character is mostly interparticle and likely formed from dissolution of iron hydroxide rich rinds around ooids as noted above. Lithification appears to have occurred prior to significant compaction.
MP 7/21/2015

See also Susan Ward Aber and David A. Grisafe, "Petrographic Characteristics of Kansas Building Limestones," Kansas Geological Survey Bulletin 224 ([Lawrence, KS], 1982), available online at http://www.kgs.ku.edu/Publications/Bulletins/224/

Images

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Specimen ID
2014-038-1 Image of specimen in dry conditions.download image Close-up image of specimen in dry conditions.download image Close-up image of specimen in wet conditions.download image
2014-038-2 No image available.
2014-038-3 No image available.

Thin Sections

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Specimen ID Non-polarized Cross-polarized
2014-038-1 Specimen shown in non-polarized light.download image Specimen shown in cross-polarized light.download image
2014-038-2 No image available.
2014-038-3 No image available.

Quarry

NOTE: Quarry locations are approximate.

Onaga Quarry
St. Marys , Kansas
United States
39° 15' 10.6776" N, 96° 5' 18.312" W
Kansas US

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