What is lamination in geology?

In geology, lamination refers to a small-scale sequence of fine layers, known as laminae, found within sedimentary rocks. These planar structures are typically one centimeter or less in thickness and are usually smaller and less pronounced than larger bedding layers. A single sedimentary rock can contain both individual laminae and thicker beds.

What we know

• Lamination is a small-scale sequence of fine layers occurring in sedimentary rocks. [1, 2]
• Laminae are typically planar structures measuring one centimeter or less in thickness. [1, 2]
• Laminae are normally smaller and less pronounced than geological bedding layers. [2]
• A single sedimentary rock can feature both laminae and beds. [2]

Still open

• While laminae are usually regarded as being one centimeter or less in thickness, structures ranging from several millimeters to many centimeters have also been described as laminae.

Where to go next

• the bigger pictureHow do geological beds form?
• compared withWhat is a geological stratum?
• a case in pointHow does cross-bedding differ from standard bedding?
• what caused itWhat depositional environments create ripples and dunes?
• how it workedWhat separates successive beds in rock formations?
• an unexpected connectionHow are water and wind involved in creating layered structures?Flowing media like water and wind create tilted internal layers known as cross-bedding on the inclined surfaces of moving bedforms.

Sources

• [1]lamination (Wikidata Q1711375) · CC0 1.0
• [2]Lamination (geology) · CC BY-SA 4.0
• [3]Bed (geology) · CC BY-SA 4.0
• [4]Stratum · CC BY-SA 4.0
• [5]Cross-bedding · CC BY-SA 4.0