The table below includes specific environments where various types of sediments are deposited and common rocks, structures, and fossils that aid in deducing the depositional environment from examining a sedimentary rock outcrop. Although this is not a complete list, it is a good introduction to depositional environments.
| Environment Name | Common Sedimentary Rock Types | Common Sedimentary Structures | Common Fossils |
|---|---|---|---|
| stream - channel | conglomerate, sandstone | cross-beds,ripple marks | high energy, oxidizing environment with few fossils |
| stream - floodplain | shale | mud cracks | terrestrial plants and animals |
| alluvial fan | conglomerate, arkose | poorly sorted, cross-beds | high energy, oxidizing environment with few fossils |
| desert dune (aeolian) | sandstone | well sorted, large scale cross-beds | terrestrial reptile traces |
| glacier - till | tillite | angular to rounded grains, poorly sorted, unstratified (massive) | high energy environment with few fossils |
| glacier - outwash | sandstone, conglomerate | ripple marks, cross-beds, similar to stream channel | high energy, oxidizing environment with few fossils |
| swamp | coal | cross-beds, ripple marks, mud cracks | plant fossils |
| lake | silt, shale, freshwater limestone | graded beds, thin beds, varves, ripple marks, mud cracks | lake dwelling organisms |
| Environment Name | Common Sedimentary Rock Types | Common Sedimentary Structures | Common Fossils |
| delta | marine and nonmarine mudstone, siltstone, sandstone, coal | possible cross-beds, ripple marks | terrestrial plants, mollusk shells, bioturbation |
| beach | sandstone | fine to medium-grained, well-sorted, cross-beds | mollusk shells, bioturbation |
| tidal flat | mudstone, siltstone, sandstone, possible evaporites | fine-grained, ripple marks, cross-beds, mud cracks | mollusk shells, bioturbation |
| Environment Name | Common Sedimentary Rock Types | Common Sedimentary Structures | Common Fossils |
| shelf/platform | limestone, shale, sandstone | cross-beds, ripple marks | fish, coral, mollusk shells, sponges, echinoderms |
| reef | limestone | massive | coral |
| slope/rise | mudstone, graywacke | graded beds, turbidites | microscopic plankton |
| deep marine | chert, chalk, limestone, mudstone | thin beds | microscopic plankton |
| shallow restricted circulation in arid hot climate | gypsum, anhydrite, halite | mud cracks, thin beds, salt casts | extreme chemical environment with few fossils |
Geology 101 - Introduction to Physical Geology
Basics Table--Depositional Environments
Created by Ralph L. Dawes, Ph.D. and Cheryl D. Dawes, including figures unless otherwise noted
updated: 7/10/11
Basics Table--Depositional Environments
Created by Ralph L. Dawes, Ph.D. and Cheryl D. Dawes, including figures unless otherwise noted
updated: 7/10/11
Unless otherwise specified, this work by Washington State Colleges is licensed under a Creative Commons Attribution 3.0 United States License.