A fragment of a shell or fossil forming part of a sedimentary rock.
- The erosive bases and stacking of bivalve shells indicate removal and redeposition, and suggest that these shells and other bioclasts were removed from the platform and redeposited on the slope by storms.
- Leperditiid shells are the dominant bioclasts and trilobite fragments are rare.
- The offset in these two curves reflects the lengthy residence time for bioclasts in this high wave energy coastal environment, and a component of sediment recycling from older barriers.
- Example sentences
- The middle member is dominated by gray silty shale grading upwards to bioclastic siltstone interbedded with bioclastic limestone.
- The lower part is a 6 m thick sandstone whose base is characterized by closely spaced erosion surfaces, common phosphate nodules, black quartz pebbles and fragmented bioclastic debris.
- The bioclastic facies of the Upper Domerian and Upper Toarcian Limestone Mbrs suggest periods of shallower sedimentation above storm wave base.
For editors and proofreaders
Line breaks: bio|clast
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