Helenice Vital

• PhD
• Head of Department at Federal University of Rio Grande do Norte

The margins bounding the Equatorial Atlantic were formed during the Cretaceous due to the breakup of Gondwana. Rifting led to the development of sedimentary basins between West Africa and South America. We have used a grid of ~10,000 km of 2D seismic data to investigate the crustal structure along ~600 km of the NE Brazilian margin, containing the...

The Brazilian Equatorial Margin is formed by several basins and we have studied the East Ceará and Potiguar extending for over ~600 km with a seismic grid with >10k km of 2D lines. First part of our study supports that the rift evolution occurred in several extension phases with different characteristics and differences in sediment deposits. The de...

Na costa norte do estado do Rio Grande do Norte destaca-se a presença de um sistema de barreiras arenosas, que são corpos arenosos dispostos paralelos à linha de costa, que isolam áreas protegidas do impacto do mar aberto. Esse sistema apresenta em seu lado marinho e terrestre diferentes depósitos sedimentares, sendo a caracterização e análise dess...

The northeastern outer shelf in Brazil is a complex ecotone that holds significant information on Holocene sedimentary processes and evolution. X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) were employed to investigate bioclastic sedimentary facies and patches of relict...

The Brazilian Equatorial Margin (BEM) is interpreted as a transform margin, where the last segment opened during Gondwana rifting. However, margin evolution, and break‐up age remain unconstrained. We interpret >10k km of crustal‐scale seismic images extending along ∼600 km of the margin calibrated with drillholes. We determine the style and timing...

The Brazilian Equatorial Margin (BEM) is classically interpreted as a transform margin formed during the last phases of the Atlantic rifting of Gondwana. However, rift kinematics and subsequent continental break up has not been constrained. We present a new model based on the interpretation of a 2D seismic grid acquired along the BEM. The datasets,...

hallow and deep-water oceanographic influences over shelf-edge environments affect the development of benthic habitats. We investigated the influence of an offshore vortex on a narrow (6 km wide) and shallow (25-80 m water depth) outer shelf with warm waters (27-30°C) through 84 sediment samples, CTD profiles, and underwater photographs. We analyse...

We have studied seven symbiont-bearing foraminiferal species to evaluate the condition of sedimentary reef areas (Pirangi, Maracajaú, and Açu) in Rio Grande do Norte (RN, Brazil). The species are: Amphisorus hemprichii, Amphistegina gibbosa, Archaias angulatus, Borelis schlumbergeri, Heterostegina antillarum, Peneroplis carinatus, and Laevipeneropl...

Desde os anos 1950, ocorreram avanços significativos no mapeamento e interpretação das concentrações de gás no fundo do mar. Diversas técnicas, como batimetria, sonografia e sísmica, foram empregadas nesse processo. No entanto, os levantamentos sísmicos de alta resolução destacam-se como ferramentas cruciais para identificar e caracterizar com prec...

Sparse available data and lack of seafloor spreading magnetic lineaments during the Cretaceous Magnetic Quiet Zone have caused uncertainty on the kinematic of the rifting and age of break up along the Brazilian Equatorial Margin (BEM). Here we present some new interpretation results aiming discussing the basement structure, the style of the synrift...

The Parnaíba River Delta, located in northeastern Brazil, is one of the few examples of a deltaic depositional system with its pristine characteristics well preserved. This has placed it the spotlight of scientific research for the most diverse areas. The present work aimed to identify changes in the depositional environment based on stratigraphic...

The formation of the >1000 km long Brazilian Equatorial Margin (BEM) is not yet understood. Limited accessibility of data has caused its classification as a transform margin based on its geodynamic situation during the separation of Africa and South America. However, a newly available grid of seismic reflection lines imaging the entire crust along...

Este artigo representa a integração e interpretação de dados pretéritos, atividades de campo — com posterior análise laboratorial —, realizados na região costeira, litoral oriental do Rio Grande do Norte, entre os municípios de Baía Formosa e Natal, acerca do registro estratigráfico de um paleonível marinho pleistocênico. A variação da linha de cos...

Ongoing climate change has the potential to severely affect the tropical marine environments of Brazil. This chapter provides a brief overview of these environments with a major focus on deltas, mangrove forests, reefs, continental shelves, the zoo- and ichthyoplankton communities of pelagic ecosystems and major processes operating in the Tropical...

Continental shelves are areas of high heterogeneity that are poorly understood and increasingly influenced by anthropic activities. The tropical passive continental shelf of northeastern Brazil is the narrowest in the country and in some stretches is among the world’s narrowest. Narrow continental shelves are unusual features on passive continental...

This study evaluates Foraminiferal assemblages and their relation with grain size, calcium carbonate content, organic matter, and mineralogy of sediment samples collected at the sediment-water interface along a transect on the northern continental shelf of Rio Grande do Norte State, Brazil, adjacent to the city of Areia Branca. The sedimentary sequ...

We analyzed nine benthic foraminiferal species from the Açu Reef belonging to the orders Rotaliida and Miliolida, symbiont-bearing (Rotaliida: Amphistegina gibbosa, Heterostegina depressa; Miliolida: Peneroplis carinatus, Archaias angulatus, Amphisorus hemprichii, and Archaias compressus) and symbiont-barren (Rotaliida: Buccella peruviana, Pseudono...

The worst environmental oil spill disaster ever recorded in any tropical coastal region globally happened in 2019; severely affecting one of Brazil most famous northeast tourist area South Pirangi Reef area in the state of Rio Grande do Norte (RN). The oil, a complex chemical mixture of hydrocarbon including heavy metals spilled on beaches, in estu...

No início de setembro de 2019 manchas de petróleo cru chegaram na costa tropical do Brasil, em quatro meses 3.000 dos 8.000 km do litoral brasileiro foram atingidos. Desastres com petróleo são comuns em ambientes marinhos e, quando o petróleo atinge a zona costeira, os efeitos deletérios recaem sobre a multiplicidade de formas de vida e de ecossist...

Western boundary currents influence the global ocean circulation and climate, whereas it locally reaches out differently to the continental margins. This study investigates the response of the North Brazilian Undercurrent (NBUC) over their interactions with the eastern and northern margins of the northeastern Brazil. The data set comprises regional...

The link between major basement anisotropies and basin evolution is crucial for understanding the role of tectonic inheritance on continental margins. However, it is still a matter of debate how and why it happens, especially in the Equatorial Atlantic, where the interplay between Precambrian fabric and the shearing of major oceanic fractures has b...

The Rocas Atoll is in the Fernando de Noronha Fracture Zone South Atlantic Ocean and was developed on top of an ancient oceanic volcano, mainly during the Holocene. Quaternary sea-level fluctuations, especially during the last transgression, left geomorphic marks on the atoll and its surrounding shelf. This study investigated the shelf of Rocas Ato...

Rocas Atoll is a remote place and the only atoll in the southwestern Atlantic Ocean. This study presents new paleo-sea level reconstructions and a new interpretation on former ones. The new data indicate that sea level was higher at the Late-Holocene than it is at present and that the hydrodynamic factors overlap with sea-level changes, precluding...

This study aims to reconstruct the Holocene evolution of a semiarid tidal channel system in response to the deglacial sea-level rise and modern coastal processes. With a maximum water depth of approximately 10 m, this very shallow system is in the easternmost part of the Brazilian equatorial margin along a tide-dominated coast in a semidiurnal, mes...

We use the excellent sediment recovery of International Ocean Discovery Program (IODP) Exp. 363, in the Western Pacific Warm Pool (WPWP) to assess down-core variations in the abundance of warm versus cool benthic foraminiferal species through a warm benthic foraminifers (WBF) curve. The total percentage of the “warm” shallower species group (Latica...

The Parnaíba River Delta (PRD) is the second major delta in NE Brazil and occupies approximately 100 km of the Brazilian equatorial coast. This delta is highly asymmetric due to a large tidal channel complex in the western portion that has at present time no natural connection to the Parnaíba River (PR) and the actual PR mouth in the eastern part o...

In 2019, an oil spill in Brazil, of unknown origin, severely impacted coastal environs with the worst environmental disaster ever recorded in any tropical coastal region globally severely damaging South Pirangi Reef area in the state of Rio Grande do Norte (RN). Here we discuss acute and chronic impacts including chemical contamination and economic...

We use the excellent sediment recovery of International Ocean Discovery Program (IODP) Exp. 363, in the Western Pacific Warm Pool (WPWP) to assess down-core variations in the abundance of warm versus cool benthic foraminiferal species through a warm benthic foraminifers (WBF) curve. The total percentage of the “warm” shallower species group (Lati...

The regressive drift succession (late Campanian–Holocene) corresponds to the last major sedimentary cycle of the Potiguar Basin and includes shallow and deep-water deposits that have potential plays similar to other hydrocarbon discoveries in the Brazilian Equatorial Margin and the African conjugate margin. This study aimed to perform a stratigraph...

Single-channel seismic data is still a challenge to apply fundamental seismic processing techniques such as deconvolution and migration. This study proposes a processing workflow for high-resolution seismic data regarding problems of low signal/noise ratio, static variations, and multiples, which restrict the geological information of shallow strat...

The regressive drift succession (late Campanian–Holocene) corresponds to the last major sedimentary cycle of the Potiguar Basin and includes shallow and deep-water deposits that have potential plays similar to other hydrocarbon discoveries in the Brazilian Equatorial Margin and the African conjugate margin. This study aimed to perform a stratigraph...

The Amazon continental shelf extends from the mouth of the Amazon River to the border of Brazil with French Guiana. This shelf is under the influence of a unique dynamic environment, resulting from the superposition of several factors, such as geographic, physical, oceanographic, and climatic factors, adding to the fresh water and sedimentary disch...

This study investigated changes of the shoreline position in the Parnaíba River Delta (PRD), which is in an underdeveloped and sparsely populated area. The general behavior of the shoreline between 1984 and 2017 was analyzed using 12 Landsat satellite images and the Digital Shoreline Analysis System (DSAS) software. DSAS applied statistical methods...

Erosive processes at the Ponta Negra beach in Natal (RN), have been related to the low supply of terrestrial sediments and the predominantly carbonate substrate that favor the conditions of the starving shelf. In this work, the mapping of patterns and marine substrate features was carried out for the analysis of coastal and shelf sedimentary dynami...

High-resolution seismic stratigraphic analysis to reconstruct the depositional history of the inner shelf Holocene successions was performed on the northeastern Brazilian, adjacent to Natal City. Boomer seismic data was collected between the coastline up to ~ 15-m water depth. Three seismic units and three seismic surfaces were observed with region...

This study aimed to quantify the morphological variations of the tropical mesotidal barrier-spit systems (MBs) in Northeast Brazil to understand their evolution. Therefore, Landsat 5 TM and Landsat 8 OLI images were used to construct two multitemporal analyses: one in 4-year intervals (low frequency) and another in 1-year intervals (high frequency)...

The Brazilian Continental Margin (BEM) deep-water regions contain important geological features, although the area is poorly explored beyond the continental shelf-break. The main objective of this study is to seismically characterize syn- and post-rift sequences and certain seamounts that are part of the Fernando de Noronha Ridge (FNR) in deep-wate...

A Plataforma Continental Amazônica (PCA) estende-se da foz do rio Pará até a fronteira do Brasil com a Guiana Francesa e tem por limite externo a isóbata de 120m. Está sob influência de um ambiente dinâmico único, resultante da superposição de fatores geológicos, oceanográficos e climáticos, além das descargas hídrica e sedimentar do próprio Rio Am...

Morphological features on low-latitude continental shelves have recorded past sea level fluctuations. This study aims to recognize and interrogate, on the Rio Grande do Norte (RN, NE Brazil) outer shelves, specific seabed morphologies that could have been produced by the punctuated relative sea level rise of the last deglaciation. These sea floor m...

This study addresses the crustal segmentation of the Brazilian equatorial margin (BEM) controlled by the Romanche fracture zone (RFZ). It uses a combination of satellite and marine gravity anomalies and seismic reflection data to constrain the continent-ocean crust transition. We propose a simplified evolution model of the BEM that involves dextral...

Este documento apresenta as principais contribuições do Volume 2 do Primeiro Relatório de Avaliação Nacional - RAN1, do Painel Brasileiro de Mudanças Climáticas, que foi estruturado de acordo com o escopo previamente definido pelos Coordenadores e Autores Principais dos capítulos do Grupo de Trabalho 2 (GT2). Os levantamentos aqui sintetizados resu...

The Brazilian Continental Margin (BEM) deep-water regions contain important geological features that need advance in their characterization. Mass-transport deposits (MTD) are important not only by their significance in the sedimentary but also because of their negative impact economically. A slump is a coherent mass of sediment that moves on a conc...

We investigated benthic foraminiferal species as tracers for carbon export flux in the Indo-Pacific warm pool (International Ocean Discovery Program Expedition 363). In core tops, the distribution of lower bathyal and upper abyssal species can be separated into two distinct groups. Foraminifera belonging to the high carbon flux (>3.5 g C m−2 year−1...

Investigation of foraminifera assemblage through thirtyt-wo surface samples along the transect in Itapitangui river mangrove was done in july / 89. Foraminiferal fauna composed mainly of Ammotium salsum, Arenoparrella Mexicana, Haplophragmoides wilberti, Miliammina fusca and Trochammina inflata occur on mangrove area of Cananeia-Iguape estuary-lago...

This work consists of the analysis of the spatial distribution of foraminifera as bioindicators of environmental stress and pollution in the surface sediments of the Potengi River estuary and adjacent shelf. Forty-two samples were collected in the years 2011 and 2012, and univariate and multivariate statistical analyzes (diversity, dominance, eve-n...

Beachrock may be considered a reliable indicator of sea level, in addition to a reliable and recognizable source for onshore movement of beachrock clasts by overwash processes associated with extreme events. Key to this is its geomorphology and preservation potential, both of which are poorly understood. Here we examine the processes and deposits a...

The average contents F = 788 ppm and Cl < 45 ppm of the clay fraction from Amazon River mouth sediments represent the composition of a large portion of weathered South American continental crust prior to any contact with high salinity formation waters. The data show a large fractionation between F and Cl with the latter being strongly leached durin...

Bedforms, in shallow marine environments, have dimensions that depend on the sedimentary supply and texture, and hydrodynamic forcing (waves, tides and currents). A field of large sand ridges, found on the northern inner shelf of Rio Grande do Norte, adjacent to Galinhos, has morphology and distribution distinguished of others sedimentary features...

We examined the abundances of two species of benthic foraminifera that host algal endosymbionts (SBF) in two sedimentary reefal areas (Pirangi and Maracajaú) of Rio Grande do Norte (RN, Brazil). The original dataset is based on 95 samples collected in winter in 2013 and 2014 by divers or grab samplers, and is compared to other known Brazilian reefs...

Continuous coastal erosion has been observed on the shoreline of major river deltas worldwide as a result of relative sea level rise and anthropogenic impacts. However, the relative contribution of sea-level rise on deltaic coastline retreat (i.e. separately from anthropogenic interference) has not been clearly defined, due to a lack of research on...

The main scope of this paper is the analysis of seafloor classification using acoustic remote sensing data. These data were acquired in a hydroacoustic survey of bathymetry and sonography using an interferometric swath bathymetry system. The study area is a sector of the internal northeast Brazilian shelf adjacent to the Ponta Negra beach - Natal (...

The quality assessment of coastal and estuarine zone of Pium River Estuary and Pirangi coral reef area (inner shelf of Rio Grande do Norte) in recent and past environments is studied by organisms capable of: synthesizing the environmental characteristics (oceanographic and geological), highlighting the environmental variations of short periods and...

The agglutinated foraminifera Trochammina hadai Uchio (1962), a dominant species in Japan, first appeared as an invasive species in San Francisco Bay, US, in 1983. Trochammina hadai´s first appearance in the Brazilian coastal waters of Flamengo Inlet, Ubatuba, São Paulo State, is recorded nearly three decades later, in two of thirty-four sediment s...

Structural inheritance control of oceanic fracture zone formation by a large basement shear zone during continental breakup is still a matter of debate. In this research, we investigated the reactivation of Precambrian shear zones and their role in the formation of the Ascension and Fernando Poo fracture zones during the evolution of the South Atla...

Structural inheritance control of oceanic fracture zone formation by a large basement shear zone during continental breakup is still a matter of debate. In this research, we investigated the reactivation of Precambrian shear zones and their role in the formation of the Ascension and Fernando Poo fracture zones during the evolution of the South Atla...

The Rio Grande do Norte State’s coastal zone extends for 410km, constituted predominantly by sandy beaches (72%) and active sea cliff s carved into Cenozoic sediments mostly of the Barreiras Formation (26%). Generally, it is divided in two distinct sectors, according to the coastline orientation: The Eastern Littoral oriented N-S, and Equatorial Li...

A Bacia Potiguar encontra-se situada na intersecção entre as margens leste e equatorial brasileiras, abrangendo quase que totalmente o Estado do Rio Grande do Norte e ocupando apenas uma porção do Estado do Ceará. O registro sedimentar dessa bacia é representado por rochas que foram depositadas desde o Neocomiano até o Pleistoceno, no decorrer de d...

The evolution of a rifted and sheared continental margin may control the formation of marginal ridges, which are prominent morphostructural features located at the extremities of fracture zones. We investigate the Ceará Terrace, a marginal ridge located at the western limit of the Romanche Fracture Zone in the Brazilian Equatorial Margin. Our data...

Sedimentological aspects of northern continental slope of Rio Grande do Norte, NE of Brazil. The continental slopes of north and northeast regions of Brazil lack data and knowledge and they represent an ecosystem of economic and environmental importance. The aim of this study is to assess the sedimentology of the continental slope of Potiguar B...

This work characterizes the inner shelf circulation off Ponta Negra Beach, Rio Grande do Norte state (Brazil). Near-bottom currents and sea level data are analyzed along with wind data from the ERA-Interim dataset (ECMWF) and historical sea level data from the Port of Natal, provided by the National Oceanographic Database (BNDO). Time series are an...

A Margem Equatorial Brasileira (MEB) ainda é uma região vasta e pouco explorada, tanto científica quanto economicamente. Ao longo dos anos, a exploração da indústria petrolífera concentrou seus estudos sobre a Plataforma Continental. Assim, uma grande carência de informações existe quando se fala sobre mar profundo como, por exemplo, a existência d...

The continental slopes of north and northeast regions of Brazil lack data and knowledge and they represent an ecosystem of economic and environmental importance. The aim of this study is to assess the sedimentology of the continental slope of Potiguar Basin, NE Brazil. The samples were collected with box-corer and were analyzed for grain size, calc...

Propagation of acoustic waves in sediments using high-resolution seismic surveys, is strongly influenced by gas. Therefore, high resolution seismic provides evidence for gas accumulation within shallow seafloor sediments. The aim of this work is present patterns of sediments saturated with gas. The data were obtained in Canal do Varador, Amazon she...

This study examined sediments and foraminiferal assemblages on the inner continental shelf adjacent to Ponta Negra Beach, an important tourist destination in northeast Brazil. Eighteen sediment samples were collected in October 2013, nine each at depths of 5 m and 10 m. The predominance of sandy textures (64–99%), the very limited amounts of organi...

The Northern Shelf of Rio Grande do Norte (NSRN), between the cities of Areia Branca and São Bento do Norte, is characterized by its carbonatic-siliciclastic sedimentary coverage; mixed energy, dominated by waves and tides; and presence of geomorphological seabed features. These features include subaqueous dunes oblique to coastline, recovering a g...

This is the Strategic Document for the Brazilian Future Ocean Panel - PainelMar, an initiative that aims to " Perform as a multi-sectorial collaborative platform of individuals and organizations on the interface of knowledge and decision-making processes, aiming at qualifying policies for the sustainable use and health of the oceans" -illuminating,...

A Margem Equatorial Brasileira (MEB) é uma das mais vastas e menos conhecidas do País. Os estudos feitos ao longo dos anos são geralmente pontuais, baseados na exploração de hidrocarbonetos, refletindo a carência de informações regionais, principalmente quando se trata de águas profundas. A Plataforma Continental é, de certa forma, bem mais conheci...

A Plataforma Setentrional Potiguar é caracterizada por ter uma cobertura carbonática-siliciclástica, energia mista, dominada por ondas e marés, e pela presença de diferentes feições morfológicas de fundo, identificadas por imagem de satélite. Entre as diversas feições, dunas subaquosas oblíquas, longitudinais e perpendiculares a linha de costa se d...

The Ceará Plateau offshore Fortaleza holds some particular characteristics when compared to the other seamounts of the Brazilian Equatorial Margin (BEM). Not only it is the largest and the closest to the continent, it is also located at the boundary between the continental and the oceanic crusts, while all the others seamounts along the BEM are loc...

Carta geológica na escala 1:100.000. Programa Geologia do Brasil. CPRM/UFRN. 2011. Esta folha está inserida no Projeto Mapeamento Geológico e Levantamento de Recursos Minerais das folhas Mossoró, Jandaíra, Touros, Natal Pau dos Ferros e Apodi, em desenvolvimento através de convênio celebrado entre o Ministério das Minas e Energia, representado pelo...

Ostracods have an extensive fossil record and are widely applied in palaeoenvironmental reconstructions. Here, we investigate the biogeography of two common and widespread genera, Abyssocythere and Dutoitella. Both appeared in the Cretaceous and are widely distributed in modern deep seas, but all species are restricted in distribution. The earliest...

The Rio Grande do Norte coast extends 410 km, and consists of sandy beaches (72 %), active sea cliffs carved into Cenozoic sediments of the Barreiras and Tibau formations (26 %), and transgressive dune fields and beachrock. It comprises two different sectors: the northern (equatorial) coast trends east for 244 km, while the eastern (oriental) coast...

The late Pleistocene Holocene stratigraphic architecture on the northeastern Brazilian continental shelf off the Parnaíba Delta has been explored by high-resolution seismic profiles. The seismic surveys reveal the widespread distribution of incised valleys of different size in offshore continuation of the present-day Parnaiba delta. According to mo...