Metamoprhic Rock Lab Final
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School
Lone Star College System, North Harris *
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Course
1401
Subject
Geology
Date
Apr 3, 2024
Type
docx
Pages
2
Uploaded by CoachFinchMaster481
Directions
: Complete the following questions using three (3) reputable
online sources (not Wikipedia). All answers must at least two (2) complete sentences in length. Your responses must be in your own words. You will NOT
be awarded credit for copying and pasting directly from online sources.
•
Define metamorphic rocks.
Metamorphic rocks are formed from pre-existing rocks that undergo changes in mineral composition, texture, or both due to heat, pressure, or chemical reactions. These transformations occur deep within the Earth's crust and result in the development of new mineral structures and rock textures.
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How do metamorphic rocks form?
Metamorphic rocks form through the alteration of pre-existing rocks, called protoliths, due to high temperature, pressure, or chemical processes deep within the Earth's crust. These transformative conditions lead to changes in mineral composition and texture, resulting in the creation of metamorphic rocks.
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List and describe the two main textures of metamorphic rocks.
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Foliated textures involve the alignment of mineral grains in parallel layers or bands, commonly seen in rocks like slate, schist, and gneiss. •
Non-foliated textures lack a distinct layering and typically have equidimensional mineral grains, as observed in rocks such as marble and quartzite.
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What is a protolith?
A protolith is the original or parent rock from which a metamorphic rock forms through geological processes such as heat, pressure, or chemical alteration. The protolith undergoes changes in mineral composition, texture, or both, resulting in the creation of a metamorphic rock.
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List and describe the two most common types of metamorphism.
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Contact metamorphism occurs when rocks are subjected to high temperatures from nearby molten magma, leading to changes in mineralogy and texture. •
Regional metamorphism, on the other hand, is caused by intense pressure and heat over large areas due to tectonic forces, resulting in the transformation of rocks into new mineral assemblages and textures.
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Describe the characteristics of a foliated metamorphic rock.
Foliated metamorphic rocks exhibit a layered or banded structure due to the alignment of mineral
grains in parallel orientations. This texture is typically a result of directed pressure during metamorphism, and examples include rocks like slate, schist, and gneiss.
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Put the following metamorphic rocks in order from lowest to highest grade: Schist, Phyllite, Slate, Gneiss
Lowest Grade. Slate
Med-low Grade.
Phyllite Med-high Grade.
Schist Highest Grade Gneiss
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Site your sources:
“Metamorphic Rock.” Encyclopædia Britannica
, Encyclopædia Britannica, inc., 23 Feb. 2024, www.britannica.com/science/metamorphic-rock. “Protolith.” Protolith - an Overview | ScienceDirect Topics
, www.sciencedirect.com/topics/earth-and-planetary-sciences/protolith. Accessed 2 Mar. 2024. Types of Metamorphism
, www2.tulane.edu/~sanelson/eens212/typesmetamorph.htm. Accessed 2 Mar. 2024. •
Using Google Draw, or a similar drawing program, sketch an image of a metamorphic rock that clearly illustrates foliated texture
. You may insert your drawing at the end of this document or attach it separately to the assignment dropbox. Do the best you can here!
•
Using Google Draw, or a similar drawing program, sketch an image of a metamorphic rock that clearly illustrates a phaneritic non-foliated texture
. You may insert your drawing at the end of this document or attach it separately to the assignment dropbox. Do the best you can here!
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