EARS 1 Lab 4 Name___________________________ SEDIMENTARY ROCK GUIDE Rock Name Composition Clast Size Possible Depositional Environment Arkose (sandstone) Feldspar (orthoclase mostly), quartz, some Medium to Alluvial fan, river (fluvial) iron-oxides coarse Arenite (sandstone) >90% quartz Medium to River (fluvial), aeolian, beach, shallow coarse water marine Greywacke Rock (lithic) fragments and quartz in a muddy Medium to Shallow water to deep water marine fan (sandstone) matrix coarse Mudstone Clay Very fine River (fluvial) floodplain, delta, lagoon Shale Clay, quartz, some iron-oxides Very fine Lake, delta, deep marine Siltstone Quartz, clay Fine River, shallow marine Sandstone Various Medium to Alluvial fan, river (fluvial), beach, aeolian, coarse others Conglomerate Various Coarse to very Alluvial fan, river (fluvial), glacier coarse Breccia Various Coarse to very Alluvial fan, river (fluvial), glacier coarse Fossiliferous Calcium carbonate, pieces of marine shells, - Shallow water marine limestone corals Chert Cryptocrystalline quartz (has characteristic - Deep water marine, evaporate, chemical conchoidal fracture) precipitation in other rocks Bituminous coal Organic matter, clay - Swamp/Lagoon EARS 1 Lab 4 Name___________________________ METAMORPHIC ROCK GUIDE Rock Name Mineralogy Diagnostic textures Metamorphic grade Protolith (slatey cleavage, compositional (low, medium, high) banding, schistosity, etc.) Slate Clay, quartz, micas Slatey cleavage (breaks into flat Low Shale planes) Phyllite Micas, quartz, garnet Sheen, medium-to-well developed Medium Shale porphyroblasts foliation Schist (include Micas, garnet Schistosity (shiny and well-foliated) Medium-High Shale dominant porphyroblast, quartz mineralogy) Gneiss Orthoclase feldspar, Compositional banding High Granite, shale/siltstone quartz, amphibole Quartzite Quartz Massive Low-High Quartz sandstone Marble Calcite, variable Massive (fizzes in HCl) Low-High Limestone or dolostone impurities Amphibolite Amphiboles, feldspar Commonly massive, also can be High Basalt or gabbro compositionally banded Anthracite - - Low-High Peat, coal .