Distribuição de dunas frontais no litoral setentrional do Ceará

Abstract

The study addresses the distribution of foredunes on the northern coast of the state of Ceará, ranging from the municipality of Acaraú to the municipality of Barroquinha. We seek to evaluate the distribution pattern of environmental systems with emphasis on the foredunes on this coast to understand their dynamics. The main hypothesis is that the foredunes, characterized as sand hills located generally at the upper limit of the beach strip, always occur and also maintain a direct connection with the active deflation surfaces. To this goal, fieldwork is carried out and specialized bibliography on the subject is used, associated with geoprocessing techniques for classification and evaluation of the distribution pattern of foredunes. The analytical results indicate that 18 environmental systems belonging to and associated with the coastal plain are identified on the northern coast of Ceará, while their physical-natural dynamics are characterized. In addition, 12 foredunes located from the extreme east to the extreme west of this coast are identified with different patterns of occurrence and maintaining connection with multiple environments. It is verified that where there is a predominance of well-developed foredunes, there is the presence of phytostabilizing vegetation of dunes and direct connections with dissipative beaches or close to estuaries, whose small waves with low speed and slow spreading, smaller sand grains and low slope of these environments contributes to the formation of these types of dunes. The foredunes still in the process of recent formation do not have evident spatial expressions of dune morphologies, although they are often associated with sediment-supplying environments, such as beach strips and active aeolian deflation surfaces. The study emphasizes the search for understanding the natural functionality of the systems with emphasis on the coastal dynamics of the foredunes that are less known, thus ending in the understanding of the distribution of the foredunes on the northern coast of Ceará.