124
3.2.5 Summary (Barrier Islands and Lagoons)
The facies association of barrier islands includes
coastal, beach, and foreshore sands, deltaic
sands and muds, and lagoonal or estuarine sands
and muds affected by tides. To identify ancient
examples this combination should be studied at
a large scale.
The upper portions of barrier islands are frequently not preserved. Shoreface sands of
transgressive barrier systems can directly overlie
back-barrier sands and lagoonal sediments.
Chapter 3 Coastal and Shallow Sea Sediments
- Lagoonal and estuarine sediments and their
biota, in particular, are strongly controlled by
climate and salinity. They render information
on the position of the paleo-coastline and the
paleo-climate of the region studied.
- The deposits of migrating tidal-channels between the islands can cover relatively large areas.
Drowned sand barriers can provide reservoirs
for hydrocarbons and groundwater.