EART1104 Rock Identification

Nautiloid assemblage time span

Paleozoic - Mesozoic, deep marine

Cyanobacteria assemblage time span

Archaean - Present

Mollusca Gastropoda assemblage time span

Paleozoic - Present

Crinoid assemblage time span

Paleozoic - Present

Byrozoan assemblage time span

Mesozoic - Present

Icthyosaur/Dinosaur bones assemblage time span

Mesozoic

Arthropod (Trilobita) assemblage time span

Paleozoic, deep marine

Mollusca (Cephalopodea) assemblage time span

Paleozoic - Mesozoic, deep marine

Mollusca (Bivalva) assemblage time span

Paleozoic - Present

Brachiopoda assemblage time span

Paleozoic - Present

Mollusca vs Brachiopoda

Mollusc: two mirror halves, growth rings

Brachiopod: one big one small half, long lines

Crinoid (stem) assemblage time span

Paleozoic - Present, shallow marine

Dark-coloured, fine grains, foliated, some felsic crystals

Amphibolite

White, fine grains, non-foliated, sugary texture

Marble

Grey-white-coloured, medium grained, sugary, non-foliated, lustrous

Quartzite

Grey-coloured, ultra-fine grained, fine foliation, cleavage, less lustrous than phyllite

Slate

Shiny grey, ultra-fine grains, fine foliation, semi-lustrous, exhibits cleavage

Phyllite

Light-coloured, fine-medium grains, fine foliation, black crysts, metallic lustre

Schist

Light-coloured, fine-medium grains, foliated (igneous features), felsic minerals

Gneiss

What does basalt metamorphose into?

Amphibolite

What does limestone metamorphose into?

Marble (Calcium carbonate molecules)

What does sandstone metamorphose into?

Quartzite (Silicon molecules)

What does granite metamorphose into?

Gneiss

What does mudstone metamorphose into?

Shale —> Slate —> Phyllite —> Schist —> Gneiss

Pinkish, moderately sorted, coarse sand

Arkose (>25% feldspar)

Well-sorted, ultra-fine, organic/bioclastic origin

Mudstone

Moderately-sorted, moderately sized, large biogenous remains, uncemented

Coquina

Moderately-sorted, moderately sized, CEMENTED

Fossiliferous limestone

Poor-moderately sorted, moderate-large size, brown matrix, ANGULAR

Breccia

Poor-moderately sorted, moderate-large size, brown matrix, ROUNDED

Conglomerate

Mafic, intrusive igneous, medium grains

Gabbro

Mafic (more white than gabbro), intrusive igneous, medium grains

Dolerite

Mafic, intrusive, very large grains, green crysts

Dunite

Mafic, extrusive, small grains, small greyish phenocrysts

Basalt

Basalt intrusive equivalent

Gabbro, dolerite

Mafic/felsic (grey), intrusive, moderate phenocrysts

Dacite

Dacite intrusive equivalent

Granodiorite

Felsic (can be mafic but usually pink), fine grained

Rhyolite (metarhyolite if black)

Rhyolite intrusive equivalent

Granite

Mafic/felsic (grey), extrusive, small-mod phenocrysts

Andesite

Andesite intrusive equivalent

Diorite

Grey-brown, ultra-fine grain, sedimentary

Mudstone

Grey-brown, very fine, sedimentary

Siltstone

Siltstone vs Mudstone

Mudstone has smaller grains

Black, small sugary grains, non-foliated, small shiny crysts

Amphibolite

White, small sugary grains, non-foliated, small shiny crysts

Marble

White, medium sugary grains, non-foliated, some layer colouring

Quartzite

Grey, planar sheets, no crystals,

Slate

Black/white striped, medium grains, foliated

Slate

Shiny grey, fine grained, foliated, tiny black crysts

Phyllite

Very shiny grey, fine grained, foliated, larger black crysts

Schist

White w/black stripes, small grains, foliated

Gneiss

Shale undergoes increasing grades of metamorphism. What is this order?

Shale —> Slate —> Phyllite —> Schist —> Gneiss

Blue mineral, AlSiO5, long crysts

Kyanite

Pinkish/yellow, AlSiO5, square/rectangle shape crysts

Andalusite

White-grey, AlSiO5, long + thin crysts

Silimanite

Brown, Fe-Al complex, long + rectangular, sometimes cross-shaped crysts

Staurolite

Red, broad silicate group, rounded crysts

Garnet

Clear (can be light or dark), K-Al silicate group, flat planar sheets

Mica (ie: Muscovite: K-rich, pink)