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What rock is produced by low-grade metamorphism of basalt?

What rock is produced by low-grade metamorphism of basalt?

Glaucophane schists are formed in a regional low-grade metamorphism of basalt, diabase, feldspar arenite, graywacke sandstone and marl sediments at relatively low temperatures and high directed pressure (Fig. 6.9).

What happens when basalt is metamorphosed?

Much of the basalt subjected to this type of metamorphism turns into a type of metamorphic rock known as greenschist. Greenschist contains a set of minerals, some of them green, which may include chlorite, epidote, talc, Na-plagioclase, or actinolite.

What is metamorphosed basalt called?

Basalt is the rock most typical of large igneous provinces. Ancient Precambrian basalts are usually only found in fold and thrust belts, and are often heavily metamorphosed. These are known as greenstone belts, because low-grade metamorphism of basalt produces chlorite, actinolite, epidote and other green minerals.

What is low grade metamorphic rock?

Low grade metamorphic rocks are generally characterized by an abundance of hydrous minerals. With increasing grade of metamorphism, the hydrous minerals begin to react with other minerals and/or break down to less hydrous minerals.

At what depth does low-grade metamorphism begin?

It takes ~10-12 km burial to reach low-grade metamorphic conditions. By contrast, lithification to form sedimentary rocks occurs at shallow depths.

Does basalt absorb water?

All natural stones are porous to some extent, which means they may absorb liquids and moisture if exposed. Basalt is one of the denser natural stones, as compared to a material like sandstone but can still absorb unwanted contaminants over time.

Is basalt porous?

Basaltic lavas tend to be fluid and form thin flows that have a considerable amount of primary pore space at the tops and bottoms of the flows. Basalts are the most productive aquifers of all volcanic rock types.

Why is basalt important?

Basalt is used for a wide variety of purposes. It is most commonly crushed for use as an aggregate in construction projects. Crushed basalt is used for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast, filter stone in drain fields, and may other purposes.

What are the 3 types of metamorphic rocks?

Common metamorphic rocks include phyllite, schist, gneiss, quartzite and marble. Foliated Metamorphic Rocks: Some kinds of metamorphic rocks — granite gneiss and biotite schist are two examples — are strongly banded or foliated.

What grade of metamorphism is phyllite?

Phyllites are said to have a texture called “phyllitic sheen,” and are usually classified as having formed through low-grade metamorphic conditions through regional metamorphism metamorphic facies. Phyllite has good fissility (a tendency to split into sheets).

What rock has the highest metamorphic grade?

Gneiss, the highest grade metamorphic rock, contains bands of easily visible quartz, feldspar, and/or mica.

What are some examples of low grade metamorphic rocks?

Typical low-grade metamorphic minerals are albite, muscovite, chlorite, actinolite and talc. The main and most widely spread metamorphic rocks from the group of low-grade schist metamorphism are argillaceous rocks namely slate, phyllites and schists as shown in Table 6.1.

Which is the most common metamorphic rock in basalt?

Metamorphism and weathering. Basalt metamorphoses to a number of different rock types, depending on pressure, temperature, and the nature of volatile compounds that react with minerals in basalt. Most common metamorphic rocks with basaltic protolith are chlorite schist, amphibolite, blueschist, and eclogite.

When does very low grade metamorphism take place?

Very-low-grade metamorphism comprises the lowermost temperature realm of metamorphic processes below ~ 300°C, i.e. where metamorphism starts during burial and first nucleation occurs, but replacement of the preserved protolith phases and fabrics can still be observed.

Why are some metamorphic rocks not foliated?

(However, if no flat or elongate minerals grow, the rock will not be foliated, even if forms under directed pressure during regional metamorphism.) Some metamorphic rocks form due to contactmetamorphism, as a result of heat from a nearby intrusion of magma.

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