Biogenic · Cross section
Geopetal structures
A cavity, such as inside a shell, partly filled with sediment at the bottom and with cement (for example calcite) above.
- How it forms
- Sediment settles to the floor of the cavity under gravity, and cement later fills the remaining space.
- Typical setting
- Fossiliferous limestones; vesicles in lavas can behave similarly
- Way up
- The sediment fill marks the bottom, and its surface records the original horizontal and later tilt.
- Flow direction
- No.
Photo examples
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