EASC TUT 3

Rock 1

Conglomerate

• Composition

  • Assorted

  • Lots of lithic (rock) fragments

• Clastic

  • Gravel (>2 mm)

  • rounded grains

  • poorly sorted

• Characteristics

  • Rounded gravel size grains (clasts)

Rock 2

Quartz sandstone

• Composition

  • Quartz

  • 2a: Silica cement

  • 2b: Iron oxide cement

• Clastic

  • Sand (1/16-2 mm)

  • Well sorted 

  • Rounded grains

• Characteristics

  • Abundance of quartz sand grains

Rock 3

Arkose

• Composition

  • Feldspar

  • Quartz

• Clastic

  • Sand & granules

  • Angular grains

  • Moderate sorting

• Characteristics

  • Moderately sorted sandstone with obvious feldspar

Rock 4

Lithic sandstone

• Composition

  • Quartz

  • Lithic fragments

• Clastic

  • Sand

  • Moderate/well rounded

  • Moderate/well sorted

• Characteristics

  • Lots of dark lithic (rock) fragments (ex. basalt) & lots of quartz sand grans

Rock 5

Mudstone & shale

• Composition

  • Microscopic

• Clastic

  • Clay/silt (mud)

• Characteristics

  • Mudstone is lumpy. Shale breaks along flat layers. May contain plant fossils (terrestrial)

Rock 6

Chalk

• Composition

  • Microscopic

  • Reacts with acid (calcite)

• Nonclastic

  • Microcrystalline 

  • Coccolithophorids

• Characteristics

  • Soft & dull, can wrote with it

Rock 7

Oolithic limestone

• Composition

  • Reacts with acid (calcite)

• Nonclastic

  • Microcrystalline

  • Calcite ooid

• Characteristics

  • Rounded ooids like pearls

Rock 8

Micrite

• Composition

  • Microscopic

  • Reacts with acid (calcite)

• Nonclastic

  • Microcrystalline

  • Calcite

• Characteristics

  • Reacts with acid, dark in color, microscopic grains

Rock 9

Coal

• Composition

  • Carbon

• Nonclastic

  • Microcrystaline

• Characteristics

  • Low density, shiny

Rock 10

Chert

• Composition

  • Microscopic

  • Silica/quartz

• Nonclastic

  • Microcrystalline

  • Silica/quartz

• Characteristics

  • Conchoidal fractures & hard