Classification of Sedimentary Rocks Flashcards

Questions and Answers

What is detrital sedimentary rock?

Sedimentary rocks made from the broken fragments of other rocks that are compacted and cemented together.

What characterizes conglomerate?

Abraded (rounded) pebbles in sandstone; resembles concrete; coarse (>2mm).

What are the characteristics of breccia?

Angular fragments show no signs of abrasion; coarse (>2mm) pebbles and cobbles.

Describe graywacke sandstone.

Dark sand-size rock fragments impart a salt-and-pepper appearance; usually rich in clay; medium (1/16-2mm) like coarse sandpaper. Signup and view all the answers

What is arkose sandstone primarily composed of?

Abundant grains of feldspar that are typically weathered to dull white or dull pink; commonly with some amount of clay. Signup and view all the answers

What defines quartz sandstone?

Relatively pure content of quartz grains; some examples are porous and permeable. Signup and view all the answers

What is the texture of siltstone?

Gritty to the touch; grains barely detectable with the unaided eye; like fine sandpaper; fine (1/256-1/16). Signup and view all the answers

What are the characteristics of claystone?

Smooth to very slightly gritty; grains hardly detectable with the unaided eye; slick when wet; very fine. Signup and view all the answers

Study Notes

Classification of Sedimentary Rocks

Detrital sedimentary rocks consist of fragments from other rocks, compacted and cemented together.
Conglomerate features rounded pebbles and cobbles, has a texture similar to concrete, and is classified as coarse (>2mm).
Breccia is characterized by angular fragments with no signs of abrasion, also classified as coarse (>2mm) in size.
Graywacke sandstone is identified by its dark sand-sized rock fragments, which create a salt-and-pepper appearance and is medium-grained (1/16-2mm).
Arkose sandstone contains abundant feldspar grains, typically weathered to dull white or pink, and may contain some clay, also classified as medium-grained (1/16-2mm).
Quartz sandstone is relatively pure, primarily composed of quartz grains, and may exhibit porosity and permeability, classified as medium-grained (1/16-2mm).
Siltstone has a gritty texture, with grains that are barely visible to the naked eye, resembling fine sandpaper, and is fine-grained (1/256-1/16mm).
Claystone features a smooth or slightly gritty texture, with grains nearly invisible to the naked eye, and feels slick when wet, classified as very fine.

Description

This quiz covers flashcards related to the classification of sedimentary rocks. Learn about various types such as detrital rocks, conglomerates, and breccia through concise definitions. Perfect for geology students and enthusiasts looking to enhance their understanding of sedimentary rock types.