Aspectos Sedimentológicos E Geoquímicos Do Testemunho Anp 1040, Do Talude Continental, Porção Oeste Do Estado Do Ceará

Abstract

The ANP 1040 core analyzed was collected at a depth of 1900 m in the Equatorial Atlantic Ocean, around 100.8 km from the coastline of the municipality of Itapipoca, Ceará. Particle size analyzes, geochemistry by X-ray fluorescence, calcium carbonate, organic matter and total nitrogen contents were performed. The data show that the ANP 1040 core contains the mud, sandy mud and muddy facies, composed of bioclastic sediments classified as limestone. The decrease of the marine influence on the sedimentation was observed in the intermediate interval of the core because it presented high levels of Ti/Ca and Fe/Ca ratios. In addition, this interval was correlated to high values of mud, organic matter, and low percentage of carbonate content. The high values of these ratios (Ti/Ca and Fe/Ca) are related to an increase of the continental sedimentary contribution, denoting a period of a greater precipitation in the region, indicating a humid tropical climate that increased the flow of the continental drainages and, consequently, the supply of terrestrial sediments to the continental slope. In addition, the high values of the Ti/Al ratio at the base of the core are related to a supply of eolian sediments, while low values of Ti/Al at the top of the core indicated a fluvial source. This work contributes to the knowledge of the Quaternary Geology of the Icaraí sub-basin, Ceará Basin, Brazilian Equatorial Margin.

Paleoenvironmental significance of Benthic Foraminifera and Ostracoda from the late Quaternary of the Ceará Basin, Brazilian Equatorial Margin

“…This taxon is often abundant in regions with low organic matter input and strong bottom currents (Schmiedl et al 1997, Nees andStruck 1999). According to Noucoucouk et al (2020Noucoucouk et al ( , 2021, conditions of increased organic matter influx predominated in the study area, during the Holocene, causing environmental variations and affecting the distribution of the biota.…”