Igneous Rocks Research Paper
Igneous Textures
Cooling rates influence igneous rock textures. Rapid cooling at the earth's surface results in tiny mineral crystals that can only be seen under a microscope. The resulting extrusive igneous rocks have an aphanitic texture. Rocks that form as magma cools slowly underground (intrusive igneous rocks) develop phaneritic textures, in which individual mineral crystals can be seen without a microscope.
Some igneous rocks exhibit visible crystals (phenocrysts) in a matrix of tiny crystals (groundmass), or a porphyritic texture. The magma cooled slowly underground (allowing the larger crystals to form) and then quickly at the Earth's surface (where the tiny crystals formed). When magma cools too quickly for any crystals to grow, the resulting texture is glassy.
Some magma contains large …show more content…
Organize the specimen into three piles in front of you. Then write down the ID numbers of specimens 40-52 in the three rows below. Felsic specimens: _40__ _43___ _46___ _51___
Intermediate specimens: __45__ _52___ _50___ __48__
Mafic specimens: __42__ _41___ _49__ __47__
Igneous rocks are identified by their texture and composition (see Tables 3-1 and 3-2). First identify the texture of each specimen: aphanitic, phaneritic, porphyritic, glassy, vesicular aphanetic or vesicular glassy. The next step is to identify the composition (Table 3-1 and 3-2) in each specimen. Place each specimen on Table 3-2 with respect to its texture and composition.
Q3-3: Use Table 3-2 to identify the names of specimens 40-52; then enter the names of the specimen on Table 3-3
Q3-4: Next for specimen 40-52 based on your work in Q3-2 determining whether the specimens are felsic, intermediate, or mafic - place your final answers along with the name of the specimen on table 3-3.
Table 3-1. Igneous Rock Names, Texture, and Mineral Composition Felsic Intermediate Mafic
Cooling rates influence igneous rock textures. Rapid cooling at the earth's surface results in tiny mineral crystals that can only be seen under a microscope. The resulting extrusive igneous rocks have an aphanitic texture. Rocks that form as magma cools slowly underground (intrusive igneous rocks) develop phaneritic textures, in which individual mineral crystals can be seen without a microscope.
Some igneous rocks exhibit visible crystals (phenocrysts) in a matrix of tiny crystals (groundmass), or a porphyritic texture. The magma cooled slowly underground (allowing the larger crystals to form) and then quickly at the Earth's surface (where the tiny crystals formed). When magma cools too quickly for any crystals to grow, the resulting texture is glassy.
Some magma contains large …show more content…
Organize the specimen into three piles in front of you. Then write down the ID numbers of specimens 40-52 in the three rows below. Felsic specimens: _40__ _43___ _46___ _51___
Intermediate specimens: __45__ _52___ _50___ __48__
Mafic specimens: __42__ _41___ _49__ __47__
Igneous rocks are identified by their texture and composition (see Tables 3-1 and 3-2). First identify the texture of each specimen: aphanitic, phaneritic, porphyritic, glassy, vesicular aphanetic or vesicular glassy. The next step is to identify the composition (Table 3-1 and 3-2) in each specimen. Place each specimen on Table 3-2 with respect to its texture and composition.
Q3-3: Use Table 3-2 to identify the names of specimens 40-52; then enter the names of the specimen on Table 3-3
Q3-4: Next for specimen 40-52 based on your work in Q3-2 determining whether the specimens are felsic, intermediate, or mafic - place your final answers along with the name of the specimen on table 3-3.
Table 3-1. Igneous Rock Names, Texture, and Mineral Composition Felsic Intermediate Mafic