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Geology Lab Test #2
Term | Definition |
---|---|
Conglomerate | Type: Clastic Texture: Clastic Identifying Characteristics: Gravel sized rounded clasts |
Breccia | Type: Clastic Texture: Clastic Identifying Characteristics: Gravel sized angular clasts |
Sandstone | Type: Clastic Texture: Clastic Identifying Characteristics: Sand sized clasts |
Mudstone | Type: Clastic Texture: Clastic Identifying Characteristics: Small mud-sized silty clasts |
Shale | Type: Clastic Texture: Clastic Identifying Characteristics: Small mud-sized clasts, fissile (easy split), fossil |
Bituminous Coal | Type: Organic Texture: Bioclastic Identifying Characteristics: Compacted plant debris |
Halite | Type: Evaporite Texture: Crystalline Identifying Characteristics: Precipitation of ocean water, rock salt |
Micrite | Type: Carbonate Texture: Crystalline Identifying Characteristics: Shallow water deposition, fine-grained carbonate mud, effervescent |
Oolitic Limestone | Type: Carbonate Texture: Oolitic Identifying Characteristics: Shallow water deposition, small spheroidal particles, effervescent |
Intraclast Limestone | Type: Carbonate Texture: Clastic Identifying Characteristics: Shallow water deposition, chucks of carbonate rock, effervescent |
Fossiliferous Limestone | Type: Carbonate Texture: Bioclastic Identifying Characteristics: Shallow water deposition, fossil imprints, effervescent |
Coquina | Type: Carbonate Texture: Bioclastic Identifying Characteristics: Shallow water deposition, conglomeration of broken shells, effervescent |
Chalk | Type: Carbonate Texture: Bioclastic Identifying Characteristics: Deep water deposition, effervescent |
Gneiss | Texture: Foliated Protolith: Shale, Slate, Phyllite, Schist, Granite Characteristics: Alternating dark- and light-colored layers (gneissic banding) |
Anthracite Coal | Texture: Non-Foliated Protolith: Bituminous Coal Characteristics: Semi-metallic luster |
Marble | Texture: Non-Foliated Protolith: Limestone Characteristics: Variety of colors, effervesces |
Quartzite | Texture: Non-Foliated Protolith: Quartz Sandstone Characteristics: Variety of colors |
Hornsfels | Texture: Non-Foliated Protolith: Mudstone Characteristics: Fine-grained |
Schist | Texture: Foliated Protolith: Shale, Slate, Phyllite Characteristics: Medium-coarse grained, large mica flakes |
Phyllite | Texture: Foliated Protolith: Shale, Slate Characteristics: Fine-grained, tiny mica flakes |
Slate | Texture: Foliated Protolith: Shale Characteristics: Finest grained |
Amphibolite | Texture: Non-Foliated Protolith: Basalt, gabbro Characteristics: Coarse-grained, dark in color |
Basalt | Texture: Aphanitic Composition: Mafic Visible Minerals: None How Did the Rock Form? Fast cooling at the surface |
Andesite | Texture: Aphanitic Composition: Intermediate Visible Minerals: Feldspar, Pyroxene, Hornblende How Does the Rock Form? Fast cooling at the surface |
Rhyolite | Texture: Aphanitic Composition: Felsic Visible: Feldspar, Quartz How Did the Rock Form? Fast cooling at the surface |
Obsidian | Texture: Glassy Composition: Felsic Visible Minerals: None How Did the Rock Form? Very fast cooling at the surface |
Pegmatite | Texture: Pegmatitic Composition: Felsic Visible Minerals: Feldspar, Biotite Mica, Hornblende How Did the Rock Form? Slow cooling beneath the surface |
Granite | Texture: Phaneritic Composition: Felsic Visible Minerals: Feldspar, Biotite Mica, Hornblende, Quartz How Did the Rock Form? Melting of rock, then rise of magma that cooled slowly in a magma chamber beneath the surface |
Diorite | Texture: Phaneritic Composition: Intermediate Visible Minerals: Feldspar, Hornblende, Quartz How Did the Rock Form? Slow cooling beneath the surface |
Gabbro | Texture: Phaneritic Composition: Mafic Visible Minerals: Feldspar, Olivine, Pyroxene How Did the Rock Form? Slow cooling beneath the surface |
Porphyritic Rhyolite | Texture: Porphritic Composition: Felsic Visible Minerals: Feldspar, Biotite Mica How Did the Rock Form? Slow cooling beneath the surface, then fast cooling at the surface |
Porphyritic Basalt | Texture: Porphritic Composition: Mafic Visible Minerals: Feldspar, Pyroxene |
Porphyritic Andesite | Texture: Porphritic Composition: Intermediate Visible Minerals: Feldspar, Pyroxene, Hornblende How Did the Rock Form? Slow cooling beneath the surface, then fast cooling at the surface |
Porphyritic Gabbro | Texture: Porphyritic Composition: Mafic Visible Minerals: Feldspar, Olivine, Pyroxene How Did the Rock Form? Slow cooling beneath the surface, then fast cooling at the surface |
Tuff | Texture: Pyroclastic Composition: Felsic Visible Minerals: Made of rock fragments How Did the Rock Form? Explosive volcanic eruption with fast cooling at surface |
Ash | Texture: Pyroclastic Composition: Intermediate Visible Minerals: None How Did the Rock Form? Explosive volcanic eruption with fast cooling at the surface |
Scoria | Texture: Vesicular Composition: Mafic Visible Minerals: None How Did the Rock Form? Fast cooling at the surface with release of gas due to pressure drop |
Pumice | Texture: Vesicular Composition: Felsic Visible Minerals: Feldspar How Did the Rock Form? Very fast cooling at the surface with release of gas due to pressure drop |
Vesicular Basalt | Texture: Vesicular Composition: Mafic Visible Minerals: None How Did the Rock Form? Very fast cooling at the surface with release of gas due to pressure drop |