|Geological history of coastal lagoons|In: Kjerfve, B. (Ed.) (1994). Coastal lagoon processes. Elsevier Oceanography Series, 60. Elsevier Science: Amsterdam. ISBN 0-444-55556-0. xx, 577 pp., more
In: Elsevier Oceanography Series. Elsevier: Oxford; New york; Amsterdam. ISSN 0422-9894, more
|Authors|| || Top |
- Martin, L.
- Landim Dominguez, J.M.
This paper discusses the geological processes controlling the origin and evolution of coastal lagoons. The study of a lagoon is intimately connected with the barrier island enclosing it-one cannot exist without the other. Three main factors control the origin and maintenance of sandy barriers and thus determine the ultimate fate of coastal lagoons: (1) sea-level history; (2) shoreface dynamics; and (3) tidal range. The history of infilling of coastal lagoons is controlled primarily by rates of sediment supply relative to rates of sea-level rise. In areas of high relative sediment supply, such as on mesotidal coasts or where rivers empty directly into lagoons, the lagoon floor is rapidly brought to the intertidal level. Thus, sediments deposited in the intertidal zone will dominate the sedimentary record of the lagoons. In areas of low sediment supply, lagoons will be characterized by unobstructed water bodies and the lagoonal sedimentary record will be dominated by sediments deposited in sub-tidal environments. The effects of sea-level history and rates of sediment supply on the evolution and infilling of ‘fossil’ coastal lagoons along the eastern coast of Brazil are documented and discussed for three major scenarios: (1) lagoons formed on a low-relief coastal plain during a sea-level rise; (2) lagoons formed on a low-relief coastal plain during a sea-level drop; and (3) lagoons formed on a high-relief coastal plain during a sea-level rise.