Dunham's Classification Flashcards

Mudstone

• Allochthonous sedimentary rock
• Contains less than 10% of components larger than 2 mm
• Composed primarily of lime mud
• Mud supported, indicating a matrix of fine particles
• Contains less than 10% grains within the 0.3-2 mm size range

Wackestone

• Allochthonous sedimentary rock
• Similar to mudstone with less than 10% of components larger than 2 mm
• Contains lime mud
• Mud supported but with greater than 10% grains present

Packstone

• Allochthonous sedimentary rock
• Contains less than 10% of components larger than 2 mm
• Composed of lime mud
• Grain supported, meaning grains are more prominent compared to the mud matrix

Grainstone

• Allochthonous sedimentary rock
• Contains less than 10% of components larger than 2 mm
• Does not contain lime mud, distinguishing it from packstone and wackestone
• Grain supported, suggesting an abundance of grains

Floatstone

• Allochthonous sedimentary rock
• Contains greater than 10% of components larger than 2 mm
• Matrix supported, where the larger components are embedded in a finer-grained matrix

Rudstone

• Allochthonous sedimentary rock
• Contains greater than 10% of components larger than 2 mm
• Component supported, indicating that larger fragments contribute significantly to the structure

Bafflestone

• Autochthonous sedimentary rock
• Formed by organisms that act as baffles, influencing sediment accumulation and distribution

Bindstone

• Autochthonous sedimentary rock
• Created by organisms that encrust and bind sediments together

Framestone

• Autochthonous sedimentary rock
• Formed by organisms that build a rigid framework, serving as a structural foundation in marine environments

Test your knowledge of Dunham's classification of sedimentary rocks with these flashcards. Each card features key terms such as Mudstone, Wackestone, and Packstone, along with their definitions. Perfect for geology students seeking to master this important classification system.