aphanitic

[‚af·ə′nid·ik]

(petrology)

Referring to the texture of an igneous rock in which the crystalline components are not distinguishable by the unaided eye.

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References in periodicals archive ?

###Ls = sedimentary aphanitic lithic grains + extrabasinal carbonate

Lithostratigraphy, petrology and sedimentary facies of the Late Cretaceous- Palaeocene Ispikan Group, southwestern Makran, Pakistan

The aphanitic microcracks inside the columns are small joint planes between the two crystal grains.

Application of D-CRDM method in columnar jointed basalts failure analysis

The unit forms an argillaceous part within micritic (aphanitic) limestones of the Geidziunai Member below and the Smilgiai Member above.

The Pirgu regional stage (Upper Ordovician) in the East Baltic: lithostratigraphy, biozonation, and correlation/Pirgu regionaalne lade (Ulem-Ordoviitsium) Baltikumis: litostratigraafia, biotsonaalsus ja korrelatsioon

2000; Kershaw & Da Silva 2013) and an aphanitic structure dominated by micrite, e.g.

Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian) at Whitman's Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics

The trachyte occurs in two varieties, porphyritic and aphanitic, the latter of which is dominant.

Geochemistry of Carboniferous peralkaline felsic volcanic rocks, central New Brunswick, Canada: examination of uranium potential

The matrix is composed of an aphanitic quartz-feldspar mosaic.

Archived U-Pb (zircon) dates from southern New Brunswick

Within 50 m of the main body, some centimetre-scale beds appear to have melted to thin layers of brownish aphanitic material which locally forms a selvedge around blocks.

Emplacement of the Fogo Island Batholith, Newfoundland

At Ain Khuff the Khuff formation is 562 feet thick, with alternating lithology from top to bottom being as follows: (1) a 92.5-foot thick aphanitic layer of calcarenitic limestone, commonly marly and fossilifer-ous; (2) a 233-foot thick aphanitic limestone; and (3) a 110.5-foot thick layer of dolomite and shale, with angular granitic sand and fine conglomerate at the bottom.

ABU DHABI - The Geology

The locality consists of broken outcrop and rubble of weakly cleaved, massive, light yellow-grey felsic tuff, aphanitic to sand-size and aphyric, of the Lower Birch Island Member, in a partly slumped half-metre wall along a roadside ditch on the south (uphill) side of the road.

Arenig volcanic and sedimentary strata, central New Brunswick and eastern Maine

The remainder of the formation comprises intensely recrystallized, black aphanitic siliceous rocks that contain fa int pink to grey siliceous blotches (relict fragments) up to 5 cm in length, which are probably siliceous lapilli.

Mafic intrusions on Campobello Island: implications for New Brunswick--Maine correlations

At Ain Khuff in Saudi Arabia the Khuff formation is 562 feet thick, with alternating lithology from top to bottom being as follows: (1) a 92.5-foot thick aphanitic layer of calcarenitic limestone, commonly marly and fossi-liferous; (2) a 233-foot thick aphanitic limestone; and (3) a 110.5-foot thick layer of dolomite and shale, with angular granitic sand and fine conglomerate at the bottom.

ABU DHABI - Geology - The Permian - Gas-Rich Khuff Formation

The subvolcanic rhyolite porphyry has a red, aphanitic matrix and typically contains small rounded quartz phenocrysts and feldspar laths.

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in Southern New Brunswick and Maine

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