2. depth of emplacement is used to divide rocks in which major group? nese 3 a reck with angular clasts and a matrix of finer sand or silt is a 4 what sedimentary rock is a precursor to an argillite? 5. fractional crystallization implies a magma does what during cooling? 6. a gneiss often forms by metamorphism of which igneous rock? 7. a limestone with > 10% grains and mud-supported is a s. a limest 9. is sediment that is not lithified considered a sedimentary rock? tone that is grain-supported and does not have a mud matrix is a