Geological knowledge advances on the Alto Rio Negro region, northwestern Amazonian Craton, Brazil: a review

Mendes, Tulio; Nascimento, Rielva Solimairy Campelo do; Veras, Renata da Silva; Almeida, Marcelo Esteves; Knauer, Luiz Guilherme

doi:10.29396/jgsb.2021.v4.n3.2

Cited by 3 publications

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“…In the review by Berzas Nevado et al ( 2010 ), blood mercury concentrations in fish-eating populations varied from 36.1 to 90.4 µg/L. Recent studies continue to report on relatively high levels of blood mercury from these populations (i.e., range 19.6–105.0 µg/L) (Mendes et al 2021 ). These blood mercury values among fish consumers are higher than those reported (12.2 µg/L) in gold-prospectors or garimpeiros (Berzas Nevado et al 2010 ).…”

Section: To 2000: Toxicological Studies On Highly Exposed Populationsmentioning

confidence: 99%

“…Frequency of fish intake in subsistence populations are for the most part reported daily, and some families may have more than one meal containing fish per day. The mean daily fish consumption as reviewed recently may range from 30 to 406 g/day for different types of populations and measured by different methods (Mendes et al 2021 ). Furthermore, among traditional villagers, mercury hair concentrations in traditional mothers are good predictors of family mercury hair concentrations (Mendes et al 2021 ).…”

Section: To 2000: Toxicological Studies On Highly Exposed Populationsmentioning

confidence: 99%

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Our evolved understanding of the human health risks of mercury

Basu

Bastiansz

Dórea

et al. 2023

Ambio

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Mercury (Hg) is a chemical of health concern worldwide that is now being acted upon through the Minamata Convention. Operationalizing the Convention and tracking its effectiveness requires empathy of the diversity and variation of mercury exposure and risk in populations worldwide. As part of the health plenary for the 15th International Conference on Mercury as a Global Pollutant (ICMGP), this review paper details how scientific understandings have evolved over time, from tragic poisoning events in the mid-twentieth century to important epidemiological studies in the late-twentieth century in the Seychelles and Faroe Islands, the Arctic and Amazon. Entering the twenty-first century, studies on diverse source-exposure scenarios (e.g., ASGM, amalgams, contaminated sites, cosmetics, electronic waste) from across global regions have expanded understandings and exemplified the need to consider socio-environmental variables and local contexts when conducting health studies. We conclude with perspectives on next steps for mercury health research in the post-Minamata Convention era.

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Section: To 2000: Toxicological Studies On Highly Exposed Populationsmentioning

confidence: 99%

Section: To 2000: Toxicological Studies On Highly Exposed Populationsmentioning

confidence: 99%

Our evolved understanding of the human health risks of mercury

Basu

Bastiansz

Dórea

et al. 2023

Ambio

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“…The Mesoproterozoic orogenic events that affected the area stand out as plausible candidates. These events were responsible for generating the extensive NW-SE and NE-SW-trending foliation in the granitic rocks, and were associated with elevated temperatures, reaching amphibolite to granulite conditions (e.g., Mendes et al, 2021).…”

Section: Comparative Analysis Across West Gondwana Cratonic Segmentsmentioning

confidence: 99%

Extensional exhumation of cratons: insights from the Early Cretaceous Rio Negro-Juruena belt (Amazonian Craton, Colombia)

Fonseca,

Nachtergaele,

Bonilla

et al. 2023

Preprint

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Abstract. This study presents results from apatite fission track (AFT) thermochronology to investigate the thermal history and exhumation dynamics of the Rio Negro-Juruena basement, situated within the western Guiana Shield of the Amazonian Craton. AFT dating and associated thermal history modelling in South America has largely been restricted to the plate’s margins (e.g. Andean active margin, Brazilian passive margin and others). Our paper reports on low-temperature thermochronological data from the internal part of the western Guiana Shield for the first time. This area is part of a vast cratonic lithosphere that is generally thought to be stable and little influenced by Mesozoic and Cenozoic tectonics. Our data however show AFT central ages ranging from 79.1 ± 3.2 Ma to 177.1 ± 14.8 Ma with mean confined track lengths of ca. 12 µm. Contrary to what might be expected of stable cratonic shields, inverse thermal history modeling indicates a rapid basement cooling event in the early Cretaceous. This cooling is interpreted as a significant exhumation event of the basement that was likely driven by the coeval extensional tectonics associated with back-arc rifts in the Llanos and Putumayo-Oriente-Maranon basins. The extensional tectonics facilitated both basement uplift and subsidence of the adjoining basins, increasing erosional dynamics and consequent exhumation of the basement rocks. The tectonic setting shifted in the late Cretaceous from extensional to contractional, resulting in reduced subsidence of the basins and consequential diminishing cooling rates of the Guiana Shield basement. Throughout the Cenozoic, only gradual, slow subsidence occurred in the study area due to regional flexure linked to the Andean orogeny. Comparative analysis with low-temperature thermochronology data from other West Gondwana cratonic segments highlights that exhumation episodes are highly controlled by tectonic inheritance, lithospheric strength, and proximity to rift zones. This study underscores the complex interplay between tectonic events and the response of cratonic lithosphere over geological time scales and highlights extensional settings as an important geological context for craton exhumation.

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Extensional exhumation of cratons: insights from the Early Cretaceous Rio Negro–Juruena belt (Amazonian Craton, Colombia)

Fonseca,

Nachtergaele,

Bonilla

et al. 2024

Solid Earth

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Abstract. This study presents results from apatite fission track (AFT) thermochronology to investigate the thermal history and exhumation dynamics of the Rio Negro–Juruena basement, situated within the western Guiana Shield of the Amazonian Craton. AFT dating and associated thermal history modeling in South America has largely been restricted to the plate's margins (e.g., Andean active margin, Brazilian passive margin, and others). Our paper reports on low-temperature thermochronological data from the internal part of the western Guiana Shield for the first time. This area is part of a vast cratonic lithosphere that is generally thought to be stable and little influenced by Mesozoic and Cenozoic tectonics. Our data, however, show AFT central ages ranging from 79.1 ± 3.2 to 177.1 ± 14.8 Ma, with mean confined track lengths of ca. 12 µm. Contrary to what might be expected of stable cratonic shields, inverse thermal history modeling indicates a rapid basement cooling event in the early Cretaceous. This cooling is interpreted as a significant exhumation event of the basement that was likely driven by the coeval extensional tectonics associated with back-arc rifts in the Llanos and Putumayo–Oriente–Maranon basins. The extensional tectonics facilitated both basement uplift and subsidence of the adjoining basins, increasing erosional dynamics and consequent exhumation of the basement rocks. The tectonic setting shifted in the late Cretaceous from extensional to contractional, resulting in reduced subsidence of the basins and consequential diminishing cooling rates of the Guiana Shield basement. Throughout the Cenozoic, only gradual, slow subsidence occurred in the study area due to regional flexure linked to the Andean orogeny. Comparative analysis with low-temperature thermochronology data from other west Gondwana cratonic segments highlights that exhumation episodes are highly controlled by tectonic inheritance, lithospheric strength, and proximity to rift zones. This study underscores the complex interplay between tectonic events and the response of cratonic lithosphere over geological timescales and highlights extensional settings as an important geological context for craton exhumation.

show abstract

Geological knowledge advances on the Alto Rio Negro region, northwestern Amazonian Craton, Brazil: a review

Cited by 3 publications

References 0 publications

Our evolved understanding of the human health risks of mercury

Our evolved understanding of the human health risks of mercury

Extensional exhumation of cratons: insights from the Early Cretaceous Rio Negro-Juruena belt (Amazonian Craton, Colombia)

Extensional exhumation of cratons: insights from the Early Cretaceous Rio Negro–Juruena belt (Amazonian Craton, Colombia)

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