Naming Rocks !!! Flashcards
Igneous Phaneritic Rocks
G.D.G
Granite, Diorite, Gabbro
Igneous Aphanitic Rocks
B.A.R
Basalt, Andesite, Rhyolite
Felsic Igneous Rocks
Rhyolite, Granite
Intermediate Igneous Rocks
Andesite, Diorite
Mafic Igneous Rocks
Basalt, Gabbro
G.P.F
Granite = phaneritic, felsic
R.A.F
Rhyolite = aphanitic, felsic
D.P.I
Diorite = phaneritic, intermediate
A.A.I
Andesite = aphanitic, intermediate
G.P.M
Gabbro = phaneritic, mafic
B.A.M
Basalt = aphanitic, mafic
Add vesicular or
porphyritic in front of the base name of igneous rocks if present!
Naming Clastic Sedimentary Rocks Based on Grain Size
Clast name + rock name = name of rock
Clast names of clastic sedimentary rocks
Conglomerate (rounded clasts) or Breccia (angular clasts) for sizes: boulder to granule
Sandstone for very coarse sand to very fine sand
Siltstone/Mudstone/Shale for microscopic grain sizes
Naming Sandstones (for very coarse sand to very fine sand sedimentary rocks!!!!)
Feldspathic arenite, quartz arenite, lithic (rock) arenite INCLUDE GRAIN SIZE MODIFIER
Classification of Carbonate Rocks
- Use Dunham classification of limestones diagram
- All have modifier i.e oolitic or fossiliferous or dolomitic if including dolomite/calcite followed by type of stone: mudstone, wackestone, packstone, grainstone, or boundstone
Metamorphic: if protolith is mudstone
Slate, phyllite, schist, or gneiss
Naming Schists
HIGHEST-GRADE MINERAL then MOST-ABUNDANT MINERAL schist
Non-foliated metamorphic: if protolith is quartz sandstone
Quartzite
Non-foliated metamorphic: if protolith is conglomerate
Metaconglomerate
Non-foliated metamorphic: if protolith is carbonate rock
Marble
Non-foliated metamorphic: if protolith is mafic igneous rock
Amphibolite
