aphanitic


Also found in: Dictionary, Thesaurus.

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.
Mentioned in ?
References in periodicals archive ?
Ls = sedimentary aphanitic lithic grains + extrabasinal carbonate
L = Lvm + Lsm###where###Lvm = volcanic, hypabasal and metavolcanic aphanitic lithic grains
Lithostratigraphy, petrology and sedimentary facies of the Late Cretaceous- Palaeocene Ispikan Group, southwestern Makran, Pakistan
2000; Kershaw & Da Silva 2013) and an aphanitic structure dominated by micrite, e.
Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian) at Whitman's Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics
4h) is medium grey, and has hornblende phenocrysts ranging from 3 to 5 mm in size in an aphanitic groundmass.
Precise age and petrology of Silurian-Devonian plutons in the Benjamin River--Charlo area, northern New Brunswick
The aphanitic variety displays a typical trachytic texture with flow-aligned feldspars (0.
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
However, contacts between coarse and fine-grained to aphanitic felsic rocks are always sharp where exposed, and where intrusive relations can be determined, the coarse-grained phase invariably cuts the fine-grained one.
Emplacement of the Fogo Island Batholith, Newfoundland
It is reasonable to conclude that in the case of the San Martino porphyry with its aphanitic matrix, the coarser grain size of the more mafic enclaves suggests that they arrived as solids or near-solids (crystal mushes) rather than crystallizing after emplacement even at the level of the deepest feeder dykes.
When and where did hybridization occur? The case of the Monte Capanne pluton, Italy
They are commonly intruded by aphanitic diabase with plagioclase porphyritic interiors.
Mafic intrusions on Campobello Island: implications for New Brunswick--Maine correlations
5-foot thick aphanitic layer of calcarenitic limestone, commonly marly and fossi-liferous; (2) a 233-foot thick aphanitic limestone; and (3) a 110.
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
Venugopal (1979) reported that the rhyolite contains plagioclase, alkali feldspar, and embayed quartz phenocrysts set in a partially sericitized, aphanitic groundmass; a late phase of devitrification is indicated by oval patches of radiating plagioclase scattered throughout the finer groundmass.
Stratigraphy and geochemistry of Ordovician volcanic rocks of the Eel River area, west-central New Brunswick

Encyclopedia browser ?
Full browser ?