Inland Seas and Lakes

• What is an inland sea and lake

  • An inland sea is a shallow sea that covers central areas of continents during periods of high sea level that result in marine transgressions
  • Whereas a lake is an inland body of water occupying a depression in the Earth’s crust formed from processes such as impacts, tectonics, fluvial, aeolian, glacial or volcanic
  • Economic importance of lakes and inland seas: flood, water, mineral and hydrocarbons
• Lake Hyrdology

  • Water balance for lakes is influenced heavily by the hydrological cycle and the transportation of water through this. It is a budget affected by the surface water, ground water as well as precipitation and evaporation of an area
  • Most lakes on Earth’s surface are glacial and periglacial lakes
• Classifications of Lakes


  • Perennial – water is maintained throughout the year
  • Ephemeral – water bodies are seasonal and experience variations in respect to the precipitation and other run off
  • A subset of these is endorheic lakes which do not drain to any other source (e.g., river or ocean), these lakes can be used to determine the nature of precipitation, evaporation, ground water and surface water in an area
• Lake Sedimentary Environments

  • Sediment sources: clastic sediments from river influx, atmospheric input, intake sediment production, erosion, hillslope sediments
  • Sediment dispersion:  Determined by lake circulation and stratification for fine sediments, and longshore drift for coarser sediments
  • Sediment sinks: depositional environments include: deltaic deposition, beach deposition, and near shore or far shore fallout
  • Lake sediments play an important role as a paleo archive to reconstruct the past
• Lake Sedimentary Models

  • River driven waterbodies- Variable depth with fluvial deposition features such as deltas and horizontal cross shore transport  
  • Wind driven waterbodies- Shallow depth with wave related features, beaches or spits, and intense bottom currents
  • Gravity driven waterbodies- Deeper depth with mass wasting lobes
• Features of Wind Driven Lakes

  • Paleo shorelines show wave cut benches
  • These terraces show past lake levels through changing levels of erosion
• Lake level variability


  • Hydrology and bathymetry impact lake level and changes in the area
  • Humans and climate have a distinct effect on hydrology, so the levels of lakes are expected to change rapidly
  • Sequence stratigraphy in past lake sediments allows us to reconstruct past lake levels. Sand = shoreline sediments, mud = suspension sediments
• Playa landscapes

  • Flat, dry, expansive barren surfaces of a dried-up basin. Usually in closed lakes so there are high levels of salt concentrates
  • They are classified based on groundwater and surface water interactions
  • Dynamics: They vary seasonally to long term. Dynamics is based on flooding, evaporation concentration, the brine and then desiccation of water level
  • They can have active beaches, and experience longshore drift during floods