Glauconite


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Related to Glauconite: Glaucophane, glauconitic sandstone

glauconite

[′glȯ·kə‚nīt]
(mineralogy)
K15(Fe,Mg,Al)4-6(Si,Al)8O20(OH)4 A type of clay mineral; it is dioctohedral and occurs in flakes and as pigmentary material.

Glauconite

 

a mineral, hydrated iron aluminosilicate belonging to the hydromica group. It is characterized by variable and complex chemical composition; its main components are silica (49-56 percent), ferrous and ferric oxides (up to 21 percent), aluminum oxide (up to 18 percent), potassium oxide (up to 10 percent), magnesium oxide (up to 7 percent), and water (up to 13 percent). It crystallizes in the monoclinic system.

The color of glauconite is green (from dark green, almost black, to olive green). Its hardness on the mineralogical scale is 2-3, and its density is 2,200-2,300 kg/m3. Its capacity for absorbing water, as well as for ion exchange, is considerable. It is found among sedimentary rocks as round grains of cryp-tocrystalline structure, less frequently as small crystals of roughly hexagonal shape. It is formed at the bottom of the sea, where it settles as a gel. Cases of the formation of glauconite through the substitution of grains of biotite and other minerals in marine ooze are known. Glauconite is widespread in sedimentary rocks of various ages, mainly Mesozoic and Cenozoic.

Because of its capacity for cation exchange, glauconite is used to soften water and, since it contains a considerable amount of potassium oxide, as a soil fertilizer. It is also used for making green paint.

References in periodicals archive ?
2+] on the synthesized ion exchanger which is an analogue of the mica mineral Glauconite [[Na.
Other diagenetic minerals include trace amounts of glauconite, pyrite, and anhydrite.
Large amounts of sediment near the impact could have slumped or washed into the hole in hours or days, glauconite layers and all.
The well was drilled to a depth of approximately 2,800 meters and is being cased as a Glauconite gas well and an Elkton oil and gas well.
The survey is located southwest of Edmonton and is designed to evaluate multiple zones from Cretaceous to Devonian, including currently producing formations such as Cardium, Glauconite, Nordegg, Pekisko and Duvernay.
Those interbeds might also host a higher amount of other minor authigenic compounds typical for GA--phosphates (mainly apatite as biogenic detritus and nodules), carbonates (calcite and dolomite as cement and concretions), barite and glauconite.
There are several productive and producing hydrocarbon zones in the area of interest including (starting from the shallowest formation), the Milk River, Second White Specks, Barons, Bow Island, Glauconite and the Lower Mannville sandstones plus the Livingston Carbonate.
The presence of fresh water fish, plant debris, and thin pedogenic carbonate layers suggests that the fine-grained beds were deposited in a lacustrine environment; however, the presence of thin horizons with glauconite grains, marine-affinity bivalves, arenaceous foraminifera, and one specimen of a trilobite (Weir 2002; Tibert and Scott 1999) suggest a distal marine influence (Martel and Gibling 1996; Ryan 1998; Tibert and Scott 1999).
Sandstones with glauconite containing remnants of complete echinoderms, bryozoans, and sedimentary structures such as cross-bedding.
However, the presence of glauconite is an indication of either shelf or shallow marine environments.
He observed (Beall, 1964) that the Marlbrook Formation (upper Taylor Marl) was composed mostly of montmorillonite with different amounts of calcite fragments, quartz silt, glauconite, pyrite, and locally high amounts of phosphatic material.