Diabase normally has a fine, but visible texture of euhedral lath shaped plagioclase crystals (62%) set in a finer matrix of clinopyroxene, typically augite (2029%), with minor olivine (3% up to 12% in olivine diabase), magnetite (2%) and ilmenite (2%).
texture /ˈtɛkstʃə/ CET6 TEM4 ( textures ) 1. NVAR The texture of something is the way that it feels when you touch it, for example, how smooth or rough it is.
Diabasic texture is (name and describe): Ophitic to subophitic texture in which lathshaped plagioclase crystals are partially or completely included in pyroxene crystals, typically augite 20.
The texture is termed diabasic and is typical of diabases. This diabasic texture is also termed interstitial [ 4 ] . The feldspar is high in anorthite (as opposed to albite ), the calcium endmember of the plagioclase anorthitealbite solid solution series, most commonly labradorite .
Olivinebearing Diabasic Shergottite Northwest Africa 5990: Petrology and Composition of a New Type of Depleted Martian Igneous Rock Article (PDF Available) · March 2010 with 69 Reads Cite this ...
textures. Matrix is 5050 quartz and probable albitic plagioclase. Muscoviterich bands are present in varying proportion. The rocks appear to be metarhyolite flows. One sample contains poorly formed sparse garnets and finegrained biotite, indicating transition of metamorphic conditions to the uppermost greenschist facies.
(3) Be on the lookout for reaction textures (resorption, overgrowths), multiple phenocryst populations, reverse compositional zoning, zones of melt inclusions, etc., which might be evidence of magma mixing. (4) Determine as far as possible the paragenesis (sequence of formation of the minerals) and display this schematically on a diagram.
Description: Breccia composed of sparse lithic eucrite clasts (with fineintersertal, microgabbroic and diabasic textures) and related crystalline debris, plus ~5 vol.% polycrystalline diogenite and diogenitic orthopyroxene clasts, in a finer matrix. Minerals include exsolved pigeonite, calcic plagioclase, silica polymorph, ilmenite and chromite.
A second clast has a diabasic texture and consists of 86% bytownite (An 85Ab12Or1), 7% pyroxene (mainly augite, En45Fs13Wo42), and 7% mesostasis (containing normative silica, .
relict chill margin, and relict diabasic texture visible in thin section. Resting on this basement is a 1316 ft (45 m) sequence of Early Proterozoic conglomerate, quartzite, limestone, and lean cherty ironformation, possibly correlative with the upper part of the Michigamme Formation of .
The texture is termed diabasic and is typical of diabases. This diabasic texture is also termed interstitial . [2] The feldspar is high in anorthite (as opposed to albite ), the calcium endmember of the plagioclase anorthitealbite solid solution series, most commonly labradorite .
(a) Typical diabasic texture. Columnar plagioclase grains are randomly distributed; the frame spaces of plagioclase grains are filled with augite grains of similar sizes. Zhuang1 well, m, crosspolarized light (CPL hereinafter); (b) Intensive chloritization at the intrusion margins.
relict diabasic texture (mafic volcanic or hypabbysal intrusive) is present from 163 to 166 feet. Biotite is altered to chlorite and plagioclase to epidote. All the bedrock has a moderately to strongly developed S^ fabric. OB502 Pink to tan, mediumcoarse grained biotitebearing syenite.
acterized by this texture and grain size. The specimen for Figure 6 has a diabasic texture. The center of a flowunit is in general char acterized by this texture and grain size. It is apparent that the grain of Figure 6 is coarser than the grain of Figure 5, and that the augite
The texture is termed diabasic and is typical of diabases. This diabasic texture is also termed interstitial [ 4 ] . The feldspar is high in anorthite (as opposed to albite ), the calcium endmember of the plagioclase anorthitealbite solid solution series, most commonly labradorite .
The texture is termed diabasic and is typical of diabases. This diabasic texture is also termed interstitial. [4] The feldspar is high in anorthite (as opposed to albite), the calcium endmember of the plagioclase anorthitealbite solid solution series, most commonly labradorite. Diabase/dolerite
Textures of Igneous Rocks. The main factor that determines the texture of an igneous rock is the cooling rate (dT/dt) . Other factors involved are: The diffusion rate the rate at which atoms or molecules can move (diffuse) through the liquid.
NEW MEXICO GEOLOGICAL SOCIETY • FIFTEENTH FIELD CONFERENCE 5 mm Hb = Hornblende Ca = Calcite O = Olivine Or = Orthoclase P1 = Plagioclase P = Pyroxene G Figure 1. — Photomicrographs (crossed nicols) or rock types from a dikeswarm complex in Capitan quadrangle. Specimens from road cuts on Highway 380 west of Indian Divide.