Shock Metamorphism (Impact Metamorphism) When an extraterrestrial body, such as a meteorite or comet impacts with the Earth or if there is a very large volcanic explosion, ultrahigh pressures can be generated in the impacted rock.
What are the main features of metamorphosed rocks?
Metamorphic rocks were once igneous or sedimentary rocks, but have been changed (metamorphosed) as a result of intense heat and/or pressure within the Earth’s crust. They are crystalline and often have a “squashed” (foliated or banded) texture.
Which of the following changes may occur during metamorphism?
Metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids.
What is the importance of metamorphism in the Earth’s processes?
This fluid phase may play a major role in the chemical reactions that are an important part of how metamorphism occurs. The fluid usually consists largely of water. Metamorphic rocks provide a record of the processes that occurred inside Earth as the rock was subjected to changing physical and chemical conditions.
What are the 4 main types of metamorphism?
Top 4 Types of Metamorphism| Rocks | Geography
- Type # 1. Contact Metamorphism:
- Type # 2. Regional Metamorphism:
- Type # 3. Hydro-Metamorphism:
- Type # 4. Hydro-Thermo-Metamorphism:
What are the main factors of contact metamorphism?
Contact metamorphism occurs due to heating, with or without burial, of rocks that lie close to a magma intrusion. It is characterized by low P/T gradients, as strong thermal gradients between an intruding magma and adjacent country rock are best established at shallow crustal levels.
What are the 5 characteristics of rocks?
Physical Characteristics of Rocks – Cleavage, Streak, Hardness, Fracture, Luster.
What are 5 facts about metamorphic rocks?
The word metamorphic literally means “changed form”. Slate, a metamorphic rock, can form from shale, clay or mudstone. The Taj Mahal in India is made entirely of different types of marble, a metamorphic rock. Serpentine is a type of metamorphic rock that originates as the igneous rock periodite.
What are the three processes of metamorphism?
The three types of metamorphism are Contact, Regional, and Dynamic metamorphism. Contact Metamorphism occurs when magma comes in contact with an already existing body of rock. When this happens the existing rocks temperature rises and also becomes infiltrated with fluid from the magma.
What are the two processes of metamorphism?
Equally as significant are changes in chemical environment that result in two metamorphic processes: (1) mechanical dislocation where a rock is deformed, especially as a consequence of differential stress; and (2) chemical recrystallization where a mineral assemblage becomes out of equilibrium due to temperature and …
What are the two major types of metamorphism?
There are two main types of metamorphism:
- Contact metamorphism—occurs when magma contacts a rock, changing it by extreme heat (Figure 4.14).
- Regional metamorphism—occurs when great masses of rock change over a wide area due to pressure exerted on rocks at plate boundaries.
What are some of the effects of shock metamorphism?
These effects include fracturing, the formation of planar deformation features (PDF), the formation of high-pressure phases, melting, and vaporization.
What causes a rock to become a metamorphic rock?
The pressure and heat that drive metamorphism are consequences of three forces: (a) internal heat of the Earth. (b) weight of the overlying rock. (c) horizontal or tectonic forces that cause the rocks to deform.
When does diagenesis turn into burial metamorphism?
Burial Metamorphism (Fig. 8.3): occurs when sedimentary rocks that had undergone diagenesis are buried even deeper. Diagenesis grades into burial metamorphism, a relatively mild type of metamorphism resulting from the heat and pressure exerted by overlying sediments and sedimentary rocks.
How many GPA does a meteorite need to have to be shock metamorphic?
The resultant impact pressure of about 1 GPa for an impact on rock is too low to produce shock metamorphic effects other than fracture. Thus, 20 GPa shock metamorphic effects found in some small meteorites may be interpreted as the result of impacts on a meteorite parent body.
