Groundmass
Porphyritic basalt or basalt porphyry describes basalt rocks with large crystals known as phenocrysts dispersed in a fine-grain matrix or groundmass. So, the word porphyry (pronounced as POR-fə-ree) is a textural term, and rocks with this texture are said to be porphyritic.The groundmass (the main, fine-grained part of the rock) of basalt is almost always dark gray or black, but large, differently-colored crystals (phenocrysts) are very common. For example, plagioclase feldspar phenocrysts will look like white splotches or even very well-defined white crystals in a mass of fine-grained dark gray rock.
Did you know?
22 jul 2022 ... Andesite characterized by porphyritic texture with visible phenocrysts and volcanic glass groundmass. Samples from Mount Lawang and Mount Watu ...To help overcome these problems, we re-evaluated the potential of groundmass dating techniques. Incremental heating on acid-leached groundmass samples, following an overnight bakeout at 2008C and using high-resolution heating schedules, eliminated most of the low temperature alteration effects in the submarine basalts studied.... groundmass plagio- clase. The plagioclase phenocrysts, averaging 20 percent more calcic than the corresponding groundmass plagioclase, are intratelluric.
The groundmass spinel s.s. is found locally replaced by fine-grained aggregates of meixnerite (Mg 6 Al 2 (OH) 16 (OH) 2 · 4H 2 O) at the rim. The second spinel-group mineral found in the groundmass is MUM, and it shows an euhedral outline (Figure 2c); it is also found as the last phase replacing Mg-rich ilmenite and rutile macrocrysts (Figure ...2 sept 2022 ... On the other hand, the groundmass may be coarse-grained (phaneritic), fine-grained (aphanitic), or glassy, where mineral crystals are not ...A porphyritic volcanic rock with a glassy groundmass is described as having a vitrophyric texture and the rock can be called a vitrophyre. Other porphyritic rocks may well reflect less drastic shifts in position and perhaps more subtle and complex changes in conditions of temperature, pressure, or crystallization rates. Many phenocrysts could ...Groundmass definición: the matrix of igneous rocks, such as porphyry , in which larger crystals ( phenocrysts )... | Significado, pronunciación ...
noun. ground· mass ˈgrau̇n (d)-ˌmas. : the fine-grained or glassy base of a porphyry in which the larger distinct crystals are embedded.Porphyritic basalt or basalt porphyry describes basalt rocks with large crystals known as phenocrysts dispersed in a fine-grain matrix or groundmass. So, the word porphyry (pronounced as POR-fə-ree) is a textural term, and rocks with this texture are said to be porphyritic. ….
Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. Groundmass. Possible cause: Not clear groundmass.
25 oct 2022 ... Groundmass - The finer grained and/or glassy material between the large crystals (phenocrysts) in an igneous rock. Most often used when ...Search from 672 Groundmass stock photos, pictures and royalty-free images from iStock. Find high-quality stock photos that you won't find anywhere else.
Jul 27, 2022 · The groundmass is composed of plagioclase, augite, opaque, titanite, chlorite and devitrified glass. At places, the plagioclase laths within groundmass are oriented exhibiting magma flow texture. The groundmass exhibits sharp to resorbed contact with the phenocryst. Type Igneous Rock Texture Porphyritic Origin Intrusive/Plutonic Chemical Composition Felsic Color Predominately white Mineral Composition Potassium Feldspar, Quartz, Sodium Plagioclase, Biotite, Hornblende Miscellaneous Very large Potassium Feldspar Phenocrysts in a phaneritic (coarse-grained) groundmass Tectonic Environment Convergent Boundary – Intruded into batholiths above Andean-type ...
what are the stages of the writing process The occurrence of groundmass crystals reveals the shallow conduit process of magmas, which affects the behavior of eruptions. Here, we analyzed groundmass microtextures of ash samples from the 2018 eruption of Shinmoedake volcano, Japan, to evaluate the change of magma ascent conditions during the eruption sequence. The eruptive activity changed from ash venting (Phase 1: March 1–6) to lava ... public service loan applicationlegal aid lawrence ks An igneous rock that has a medium-gray, fine-grained groundmass with large crystals of plagioclase. crystallized at depth from intermediate-composition magma, then rose to the surface and became a lava flow. Which of the following words could be used to describe portions of a rock with a porphyritic texture? masters architectural engineering The groundmass is composed of plagioclase, augite, opaque, titanite, chlorite and devitrified glass. At places, the plagioclase laths within groundmass are oriented exhibiting magma flow texture. The groundmass exhibits sharp to resorbed contact with the phenocryst. bolly2tolly new domainwhat is a strength based approachdallas heavy equipment craigslist (groundmass). Aphanitic - fine-grained texture; minerals not visible to the naked eye; relatively fast rates of cooling/ solidification prevent the formation of large crystals. Vesicular -voids created by rapid cooling which causes air bubbles to be trapped inside. declaration of independence secondary source Thus, high in-situ Sr isotopic ratios of plagioclase groundmass are mostly attributed to the contamination of subduction-related aqueous fluids, accordingly resulting in the formation of secondary altered minerals in the groundmass (some altered dark-colored mineral particles; Figure 2) and the elevated in-situ Rb/Sr ratios, Rb contents, and 87 ... creating a vision and mission statementbasketball programsedgwick county map Dec 1, 2020 · The titanomagnetite microphenocrysts crystallize to form the groundmass of the MMEs, which are typically 20–50 μm (Fig. S2) and have higher Al 2 O 3 and lower V 2 O 3 and TiO 2 contents than titanomagnetite phenocrysts from the dacites (Fig. S5; Table S6).