GEOL 107 - GENERAL GEOLOGY - LABORATORY OUTLINE SEDIMENTARY AND METAMORPHIC ROCKS LAB Material covered Chapters 6 & 7 in Ludman & Marshak Laboratory Manual for Introductory Geology Topics: I. Definition of a sedimentary rock II. Textures of sedimentary rocks III. Compositions of sedimentary rocks IV. Using the various textures and compositions be able to identify the following sedimentary rocks: Bituminous Coal Breccia Chert Conglomerate Coquina Fossiliferous Limestone Lignite Coal Micrite Peat Sandstone Shale V. Definition of a metamorphic rock VI. Textures of metamorphic rocks VII. Compositions of metamorphic rocks VIII. Using the various textures and compositions be able to identify the following metamorphic rocks: Anthracite Coal Gneiss Marble Phyllite Quartzite Schist Slate
Definition of a sedimentary rock - rocks whose origin is from the erosion, transportation, deposition, and subsequent lithification of pre-existing rocks under conditions normal near, or at, the surface of the earth, or from organic (biochemical) or inorganic chemical reactions, or are the lithified accumulations of organic debris. The different types of textures of sedimentary rocks are: clastic - aggregate of mineral grains/rock particles or fragments of organic remains crystalline - composed of interlocking crystals The different types of compositions of sedimentary rocks are: carbonate - mainly the mineral fragments of calcite or dolomite, or chemical precipitates of calcite, or calcite plant or animal remains siliceous - mainly quartz grains, or a precipitate of silica, or an accumulation of siliceous plant or animal remains evaporites - formed by chemical precipitation when saltwater evaporates e.g., gypsum or halite organics contain remnants of organic chemicals and may be more than 90% carbon argillaceous - rocks contain mostly clay The sedimentary rock names are based on the texture and composition of the rocks: conglomerate - clastic texture with large (bigger than sand-size), rounded rock fragments breccia - clastic texture with large (bigger than sand-size), angular rock fragments sandstone - clastic texture with sand-sized particles siltstone - clastic texture with silt-sized particles shale - clastic texture with clay-sized (not visible with the naked eye, less than 1/256 mm in diameter) particles, argillaceous composition limestone crystalline or clastic texture containing calcite with carbonate composition fossiliferous limestone - contains fossils crystalline limestone - crystalline texture coquina - clastic texture with calcite material chert - crystaline texture containing silica with siliceous composition
peat clastic texture with accumulation of organic material, can see plant fragments, easily broken into pieces lignite coal clastic texture with accumulation of organic material, more lithified than peat, usually brown color bituminuous coal crystalline texture with accumulation of organic material, more lithified than lignite, usually shiny black color Definition of a metamorphic rock - rock whose origin is from the physical and/or chemical change of pre-existing rocks by exposing them to higher temperatures and/or pressures, and/or the passage of fluids The different types of textures of metamorphic rocks are: foliated - parallel arrangement of minerals into distinct layers or bands non-foliated - does not show foliated texture The different types of compositions of metamorphic rocks are based on the minerals in the preexisting rocks that have been metamorphosed and on the new minerals that might have been formed during metamorphism The names of the metamorphic rocks are based on the textures and compositions of the rocks: gneiss - foliated texture schist - foliated texture phyllite - foliated texture slate - foliated texture quartzite - non-foliated, quartz composition marble - non-foliated, carbonate (calcite or dolomite) composition anthracite coal - non-foliated, organic matter (metamorphosed bituminous coal)