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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 |