I am a Senior Researcher and Professor in the Coordination of Geophysics at Observatório Nacional (Rio de Janeiro, Brazil). My research interests are mostly focused in rock magnetism, paleomagnetism and magnetostratigraphy, as well as in cyclostratigraphy analysis of high-resolution sequences of enviromagnetic data. Phone: +55-21-3504-9293 Address: Department of Geophysics National Observatory R. Gal. Jose Cristino, 77, 20421-400 Rio de Janeiro (RJ) Brazil
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and... more The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and its record is punctuated by Oceanic Anoxic Events (OAEs). The timing and duration of these events are still contentious, particularly the age of the Barremian-Aptian boundary. This study presents a cyclostratigraphic evaluation of a high-resolution multiproxy dataset (δ13C, δ18O, MS and ARM) from the Poggio le Guaine core. The identification of Milankovitch-band imprints allowed us to construct a 405-kyr astronomically-tuned age model that provides new constraints for the Aptian climato-chronostratigraphic framework. Based on the astronomical tuning, we propose: (i) a timespan of ~7.2 Myr for the Aptian; (ii) a timespan of ~420 kyr for the magnetic polarity Chron M0r and an age of ~120.2 Ma for the Barremian−Aptian boundary; and (iii) new age constraints on the onset and duration of Aptian OAEs and the ‘cold snap’. The new framework significantly impacts the Early Cretaceous geological ...
The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and... more The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and its record is punctuated by Oceanic Anoxic Events (OAEs). The timing and duration of these events are still contentious, particularly the age of the Barremian-Aptian boundary. This study presents a cyclostratigraphic evaluation of a high-resolution multiproxy dataset (δ 13 C, δ 18 O, MS and ARM) from the Poggio le Guaine core. The identification of Milankovitch-band imprints allowed us to construct a 405-kyr astronomically-tuned age model that provides new constraints for the Aptian climato-chronostratigraphic framework. Based on the astronomical tuning, we propose: (i) a timespan of~7.2 Myr for the Aptian; (ii) a timespan of~420 kyr for the magnetic polarity Chron M0r and an age of~120.2 Ma for the Barremian−Aptian boundary; and (iii) new age constraints on the onset and duration of Aptian OAEs and the 'cold snap'. The new framework significantly impacts the Early Cretaceous geological timescale.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
The accumulation of heavy minerals along a part of the southeastern Brazilian coast (northern coa... more The accumulation of heavy minerals along a part of the southeastern Brazilian coast (northern coast of Rio de Janeiro State, Brazil) provides insight into sedimentary provenance and transport by longshore drift. In particular, recent work has focused on heavy minerals as tracers to determine sedimentary sources and transport pathways, indicating a mineral distribution according to the northward and southward coastal transport cells. There is also evidence of heavy-mineral transport by the Paraíba do Sul River. However, research has not been done in this area on the opaque fraction (iron oxides and oxyhydroxides), which are good tracers for provenance and distribution processes. Here we intend to: 1) characterize the spatial variation of the magnetic properties of heavy-mineral contents throughout a coastal area of the Itabapoana and Paraíba do Sul River mouths (state of Rio de Janeiro), 2) evaluate the contribution of coastal dynamics on the mineral distribution along this coastal a...
Abstract Cyclostratigraphy has revealed the quasi-periodic nature that globally distributed sedim... more Abstract Cyclostratigraphy has revealed the quasi-periodic nature that globally distributed sedimentary successions present through the Phanerozoic. This is mainly the case of the strong eccentricity-related greenhouse climate of the Cretaceous period, a time interval in which the long-eccentricity 405-kyr cycle has been routinely used to constrain high-resolution astronomical timescales. Despite the importance of the South Atlantic opening to the evolution of the Cretaceous climate and carbon cycle, few investigations have applied the modern cyclostratigraphic analysis to explore the eventual orbital pacing of the Cretaceous South Atlantic successions. We use geophysical and geochemical data analysis from the Petrobras well ES-1 (offshore Espirito Santo Basin to develop a floating and anchored astronomical timescale (ATS) and infer the relation between sedimentation rate and TOC accumulation. Additionally, we estimate the net primary productivity (NPP) during intervals of high TOC accumulation. Our results show a pervasive orbitally-driven forcing imprint according to the Milankovitch spectral peak ratio as predicted to Cretaceous times, with a prominent occurrence of a 405-kyr long-eccentricity cycle, being used to constrain the elapsed time. An abrupt shift in the GR data likely associated with the Cretaceous – Paleogene boundary was used to anchor our floating ATS. The evolutionary Average Spectral Misfit (eASM) and Correlation Coefficient (COCO/eCOCO) tests demonstrate that the sedimentation rate can have contrasting effects over the organic matter burial, which is likely related to the large-scale paleogeographic configuration. Our study exemplifies that orbitally-driven sedimentation can be used to build high-resolution chronology for Brazilian marginal basins.
<p&amp... more <p>The last glacial was an interval characterized by a sequence of abrupt millennial-scale events well documented mainly from the Greenland and Antarctica ice-cores. Although the triggers are not fully understood, most of the works agree that they occurred in consonance with oscillations in the strength of the Atlantic Meridional Overturning Circulation (AMOC). Paleoceanographic reconstructions have shown that cold millennial-scale stadials were accompanied by high temperatures in the subsurface to intermediate waters of the Atlantic Ocean that may have acted in both the basal melting of ice-sheets and in the rapid atmospheric warming during the onset of warm interstadials. Assuming that recent transient models indicated an accentuated response of the subsurface western South Atlantic to the millennial-scale disturbances, here we present a paleoceanographic reconstruction in this area based on the deep-dwelling planktic foraminifer Globorotalia inflata. Our high-resolution oxygen isotope (d<sup>18</sup>O) presents a sequence of millennial-scale variability that strongly resembles the structure of the Greenland Dansgaard-Oeschger cycles, mainly during Marine Isotope Stage (MIS) 5. On the other hand, during MIS 3, this millennial-scale feature is absent or weakly represented. Cross-spectral analyzes indicate a meaningful north-to-south forcing over the western South Atlantic subsurface during early-glacial. Mg/Ca-derived temperature and ice-volume free seawater d<sup>18</sup>O (d<sup>18</sup>O<sub>IVF-SW</sub>) executed for the MIS 5 interval demonstrated that the subsurface western South Atlantic was warmer and saltier (colder and fresher) during early glacial stadial (interstadials). We hypothesized that a wide reorganization of the northward heat transport throughout the last glacial occurred, in which regions so far south as 24 ºS worked as prominent heat reservoirs in periods of weakened AMOC during MIS 5 but not necessarily during MIS 3. Our data suggest that future impacts over the AMOC along the Brazilian margin will likely be recognized in the subsurface layers of the western South Atlantic.</p>
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and... more The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and its record is punctuated by Oceanic Anoxic Events (OAEs). The timing and duration of these events are still contentious, particularly the age of the Barremian-Aptian boundary. This study presents a cyclostratigraphic evaluation of a high-resolution multiproxy dataset (δ13C, δ18O, MS and ARM) from the Poggio le Guaine core. The identification of Milankovitch-band imprints allowed us to construct a 405-kyr astronomically-tuned age model that provides new constraints for the Aptian climato-chronostratigraphic framework. Based on the astronomical tuning, we propose: (i) a timespan of ~7.2 Myr for the Aptian; (ii) a timespan of ~420 kyr for the magnetic polarity Chron M0r and an age of ~120.2 Ma for the Barremian−Aptian boundary; and (iii) new age constraints on the onset and duration of Aptian OAEs and the ‘cold snap’. The new framework significantly impacts the Early Cretaceous geological ...
The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and... more The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and its record is punctuated by Oceanic Anoxic Events (OAEs). The timing and duration of these events are still contentious, particularly the age of the Barremian-Aptian boundary. This study presents a cyclostratigraphic evaluation of a high-resolution multiproxy dataset (δ 13 C, δ 18 O, MS and ARM) from the Poggio le Guaine core. The identification of Milankovitch-band imprints allowed us to construct a 405-kyr astronomically-tuned age model that provides new constraints for the Aptian climato-chronostratigraphic framework. Based on the astronomical tuning, we propose: (i) a timespan of~7.2 Myr for the Aptian; (ii) a timespan of~420 kyr for the magnetic polarity Chron M0r and an age of~120.2 Ma for the Barremian−Aptian boundary; and (iii) new age constraints on the onset and duration of Aptian OAEs and the 'cold snap'. The new framework significantly impacts the Early Cretaceous geological timescale.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
Logging data are measurements of physical properties of the formation surrounding a borehole, acq... more Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.
The accumulation of heavy minerals along a part of the southeastern Brazilian coast (northern coa... more The accumulation of heavy minerals along a part of the southeastern Brazilian coast (northern coast of Rio de Janeiro State, Brazil) provides insight into sedimentary provenance and transport by longshore drift. In particular, recent work has focused on heavy minerals as tracers to determine sedimentary sources and transport pathways, indicating a mineral distribution according to the northward and southward coastal transport cells. There is also evidence of heavy-mineral transport by the Paraíba do Sul River. However, research has not been done in this area on the opaque fraction (iron oxides and oxyhydroxides), which are good tracers for provenance and distribution processes. Here we intend to: 1) characterize the spatial variation of the magnetic properties of heavy-mineral contents throughout a coastal area of the Itabapoana and Paraíba do Sul River mouths (state of Rio de Janeiro), 2) evaluate the contribution of coastal dynamics on the mineral distribution along this coastal a...
Abstract Cyclostratigraphy has revealed the quasi-periodic nature that globally distributed sedim... more Abstract Cyclostratigraphy has revealed the quasi-periodic nature that globally distributed sedimentary successions present through the Phanerozoic. This is mainly the case of the strong eccentricity-related greenhouse climate of the Cretaceous period, a time interval in which the long-eccentricity 405-kyr cycle has been routinely used to constrain high-resolution astronomical timescales. Despite the importance of the South Atlantic opening to the evolution of the Cretaceous climate and carbon cycle, few investigations have applied the modern cyclostratigraphic analysis to explore the eventual orbital pacing of the Cretaceous South Atlantic successions. We use geophysical and geochemical data analysis from the Petrobras well ES-1 (offshore Espirito Santo Basin to develop a floating and anchored astronomical timescale (ATS) and infer the relation between sedimentation rate and TOC accumulation. Additionally, we estimate the net primary productivity (NPP) during intervals of high TOC accumulation. Our results show a pervasive orbitally-driven forcing imprint according to the Milankovitch spectral peak ratio as predicted to Cretaceous times, with a prominent occurrence of a 405-kyr long-eccentricity cycle, being used to constrain the elapsed time. An abrupt shift in the GR data likely associated with the Cretaceous – Paleogene boundary was used to anchor our floating ATS. The evolutionary Average Spectral Misfit (eASM) and Correlation Coefficient (COCO/eCOCO) tests demonstrate that the sedimentation rate can have contrasting effects over the organic matter burial, which is likely related to the large-scale paleogeographic configuration. Our study exemplifies that orbitally-driven sedimentation can be used to build high-resolution chronology for Brazilian marginal basins.
<p&amp... more <p>The last glacial was an interval characterized by a sequence of abrupt millennial-scale events well documented mainly from the Greenland and Antarctica ice-cores. Although the triggers are not fully understood, most of the works agree that they occurred in consonance with oscillations in the strength of the Atlantic Meridional Overturning Circulation (AMOC). Paleoceanographic reconstructions have shown that cold millennial-scale stadials were accompanied by high temperatures in the subsurface to intermediate waters of the Atlantic Ocean that may have acted in both the basal melting of ice-sheets and in the rapid atmospheric warming during the onset of warm interstadials. Assuming that recent transient models indicated an accentuated response of the subsurface western South Atlantic to the millennial-scale disturbances, here we present a paleoceanographic reconstruction in this area based on the deep-dwelling planktic foraminifer Globorotalia inflata. Our high-resolution oxygen isotope (d<sup>18</sup>O) presents a sequence of millennial-scale variability that strongly resembles the structure of the Greenland Dansgaard-Oeschger cycles, mainly during Marine Isotope Stage (MIS) 5. On the other hand, during MIS 3, this millennial-scale feature is absent or weakly represented. Cross-spectral analyzes indicate a meaningful north-to-south forcing over the western South Atlantic subsurface during early-glacial. Mg/Ca-derived temperature and ice-volume free seawater d<sup>18</sup>O (d<sup>18</sup>O<sub>IVF-SW</sub>) executed for the MIS 5 interval demonstrated that the subsurface western South Atlantic was warmer and saltier (colder and fresher) during early glacial stadial (interstadials). We hypothesized that a wide reorganization of the northward heat transport throughout the last glacial occurred, in which regions so far south as 24 ºS worked as prominent heat reservoirs in periods of weakened AMOC during MIS 5 but not necessarily during MIS 3. Our data suggest that future impacts over the AMOC along the Brazilian margin will likely be recognized in the subsurface layers of the western South Atlantic.</p>
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