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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)