Morphological and sedimentary patterns of a semi-arid shelf, Northeast Brazil

Depositional and geomorphic patterns of mixed calciclastic‐siliciclastic systems on a deep‐water Equatorial Margin

“…(2015) and Morais et al. (2019) (Figure 1c). In this work, we utilised a combination of multispectral satellite imagery with bands B4‐Red, B3‐Green, and B1‐Ultra blue (coastal aerosol) provided by the Sentinel‐2 mission (Figure 1c).…”

“…The modern carbonate shelf of Equatorial Brazil is itself considered to be a major supplier of carbonate deposits to more distal regions as its middle and outer parts record typical autochthonous carbonate sedimentation (de Morais et al., 2019). The inner continental shelf is characterised by the mixing of siliciclastic and carbonate sediment, especially during maximum freshwater discharges from suspended sediment released from river mouths (de Morais et al., 2019). An exception to this setting is the Foz do Amazonas Basin, which is dominated at present by the large siliciclastic input from the Amazon River and Delta, feeding sediment into deep waters via a large submarine channel (Figure 1a).…”

“…The PAMA continental shelf is a tectonically steepened carbonate ramp with no rimmed reef along its margin (Alves et al., 2020). The study area has been considered as a mixed carbonate‐siliciclastic shelf in all similar to the analogous Ceará Basin (de Morais et al., 2019) (Figure 1a).…”

“…Recent data from Ceará identified three main depositional systems on its continental shelf: (a) siliciclastic, located near the shoreface and river mouths, (b) mixed, comprising biolithoclastic and lithobioclastic facies and (c) carbonate, revealing the predominance of an autochthonous carbonate supply, mainly derived from calcareous algae (de Morais et al., 2019). The modern carbonate shelf of Equatorial Brazil is itself considered to be a major supplier of carbonate deposits to more distal regions as its middle and outer parts record typical autochthonous carbonate sedimentation (de Morais et al., 2019). The inner continental shelf is characterised by the mixing of siliciclastic and carbonate sediment, especially during maximum freshwater discharges from suspended sediment released from river mouths (de Morais et al., 2019).…”

Pedodiversity and environmental degradation in the lower course of Acaraú river, Ceará State, Northeastern Brazil

“…The sediments of the Barreiras Formation are made by clays and sands, with little or no lithification, with reddish, cream or yellowish coloration, sometimes mottled and with ferruginous cement(e.g. Morais et al, 2019). The grain size varies from thin to medium, containing interceptions of conglomerate levels consisting of rounded to smoothly rounded quartz pebbles and quartzite, besides other rocks with indistinct stratification (Ximenes Neto et al, 2018).…”