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alkaline olivine basalt (thin section)-Silica under saturated. Interstices filled by alkali feldspar and felsphatoid. Olivine doesn't show reaction with orthopyroxene. It has olivine in the groundmass
Tholeiitic basalt (thin section ): Silica over-saturated. (>51%).Common Si-rich glassy mesostasis (Intersertal texture). Frequently contains pyroxene. Groundmass no olivine.
Olivine shows reaction to orthopyroxene.
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What is the difference between basalt and obsidian?
Basalt is a dark-colored volcanic rock formed from the rapid cooling of lava, while obsidian is a dark volcanic glass formed from the rapid cooling of lava with high silica content. Basalt has a crystalline structure, while obsidian is amorphous and often exhibits conchoidal fracturing. Basalt is typically denser and more resistant to weathering compared to obsidian.
What is the difference between basalt and quartz?
Basalt is a fine-grained volcanic rock that is typically dark in color and rich in iron and magnesium minerals. Quartz, on the other hand, is a mineral composed of silicon and oxygen atoms arranged in a continuous framework of SiO4 silicon–oxygen tetrahedra. Quartz is generally clear or translucent and has a glassy appearance, whereas basalt is typically dark and may contain small crystals of various minerals.
The specific gravity of basalt is about?
The density of basalt is normally between 2.8 and 3.0 g.cm-3. This density varies with the type of minerals that compose it.
What is the difference between gabbro and basalt?
Gabbro is a coarse-grained, intrusive igneous rock composed mainly of calcium-rich plagioclase feldspar, pyroxene, and sometimes olivine. Basalt, on the other hand, is a fine-grained, extrusive igneous rock composed mainly of plagioclase feldspar and pyroxene. Basalt is typically found on the Earth's surface, while gabbro is usually found beneath the surface as intrusive rock formations.
The distinction between the crust and mantle is primarily on the basis of a difference in?
composition — the crust is primarily composed of lighter, silicate minerals like granite and basalt, while the mantle is composed of denser minerals like peridotite. This compositional difference contributes to variations in density, temperature, and behaviour between the crust and mantle layers of the Earth.
What is an alkali basalt?
Alkali basalts are a type of basaltic rock that is enriched in alkali metals (such as potassium and sodium) compared to other basaltic rocks. They typically have a higher content of minerals like feldspar and pyroxene, and are associated with volcanic activity in rift zones and oceanic hotspots.
Why does alkalic basalt contain less silica than tholeiites?
The magma that forms alkalic basalt forms under conditions with a higher fraction of partial melting that the magma that forms tholeiitic basalt. This means that the resulting alkalic melt contains a higher percentage of the minerals with a low silica content.
What is the lava of surtsey?
the magma and lava in Surtsey are of alkali olivine basalt, which is the type of basalt found in Vestmannaeyjar (Westman Islands)
What is the lava composition for surtsey?
The magma and lava of Surtsey has a composition of alkali Olivine Basalt.
What type of magma is produced in the Kilauea?
Kilauea volcano typically produces tholeiitic basalt magma, which is low in silica content and flows easily. This type of magma is associated with shield volcanoes like Kilauea, known for their gentle eruptions and copious lava flows.
What is the difference between basalt and obsidian?
Basalt is a dark-colored volcanic rock formed from the rapid cooling of lava, while obsidian is a dark volcanic glass formed from the rapid cooling of lava with high silica content. Basalt has a crystalline structure, while obsidian is amorphous and often exhibits conchoidal fracturing. Basalt is typically denser and more resistant to weathering compared to obsidian.
What is the difference between vesicular basalt and non vesicular basalt?
Vesicular basalt has small rounded voids called vesicules formed by the molten rock cooling and freezing around pockets of gas. It looks a lot like a rock hard sponge. Non vesicular basalt is a normal solid rock.
What accounts for the difference between the oceanic crust and continental crust?
The oceanic crust is made up of basalt while continental crust is made up of mostly granite.
What is the difference between basalt and granite?
Granite is lighter in color than basalt. The color of the rocks is dependent on the mineral composition of the rock. Basalt is basic and contains a substantial amount of olivine whereas granite is acidic and is rich in quartz.Basalt is an extrusive igneous rock with small mineral crystals, formed when magma cools and solidifies rapidly; this is usually on the surface of Earth's crust, especially at incidents of seafloor spreading on the ocean floor as contact with seawater cools the magma rapidly.Granite is the foundation of the continental crust. Basalt is the foundation of oceanic crust.Granite is an intrusive igneous rock made from visible mineral crystals, a result of cooling over a longer period of time under the surface of the Earth.Another difference between basalt and granite include their joints. Basalt splits along columnar planes while granite splits along horizontal planes. This difference is due to the difference in their cooling process.granite is a sedimentary rock and basalt is a metamorphic rock
What is the similarity between granite and basalt?
Both are igneous rocks.
What is the igneous rock between granite and basalt?
Andesite is considered an intermediate rock between granite (felsic igneous rock) and basalt (mafic igneous rock), based on chemical composition.
How can you tell that the sandstone was not deposited on top of basalt layers?
The sandstone layer is older than the basalt. The older rock cannot be on top of the younger rock. The sandstone and the basalt (or basalt dike) are both deposited at the same depth.
