Sallow marine sediments in the bay of Callao, Perú. 1997

Abstract

During El Niño 1997, were studied shallow marine sediments of the bay of Callao (11°50’S to 12°06’S) 68 sampling stations were located within the bay, including Ventanilla. Additional 35 stations were placed between the mouths of rivers Rimac and Chillon, where the industrial, urban and port activities waste discharges are concentrated. Three transects were made: off Ventanilla beach, off the Comas and off Chucuito-La Punta beach. The beach front Marquez texture is sandy loam and north dominated the mud; off Oquendo beach, textures are muddy and sandy loam. Fine-grained sediments, clay and silt textured silty clay exist in the seabed and deeper areas offshore, but also near the coast, south and southwest of the port area of operations, off Chucuito and La Punta. Sand textures were recorded north of the river Chillon (La Pampilla and Ventanilla), and around Camotal bank, off La Punta. In the deeper areas and sheltered bay, sediments with fine grain size were negative asymmetry, characteristic of environments of sedimentation. In sectors where there are coarser sediment transport processes occur (type and form of waves) and erosion, appreciable background images, and analysis of statistical parameters. The high content of organic matter is associated with fine-grained sediments mainly. Its content is conditioned by both the rate of contribution and origin (anthropogenic, marine or continental) and by low oxygen conditions that favor its preservation. The lower organic content compared to the coastal area of Ventanilla, sediments are predominantly associated with fractions of sand and terrigenous origin and greater oxygenation