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1.
Sci Rep ; 13(1): 13796, 2023 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-37652921

RESUMEN

Over the past century, understanding the nature of shock compression of condensed matter has been a major topic. About 20 years ago, a femtosecond laser emerged as a new shock-driver. Unlike conventional shock waves, a femtosecond laser-driven shock wave creates unique microstructures in materials. Therefore, the properties of this shock wave may be different from those of conventional shock waves. However, the lattice behaviour under femtosecond laser-driven shock compression has never been elucidated. Here we report the ultrafast lattice behaviour in iron shocked by direct irradiation of a femtosecond laser pulse, diagnosed using X-ray free electron laser diffraction. We found that the initial compression state caused by the femtosecond laser-driven shock wave is the same as that caused by conventional shock waves. We also found, for the first time experimentally, the temporal deviation of peaks of stress and strain waves predicted theoretically. Furthermore, the existence of a plastic wave peak between the stress and strain wave peaks is a new finding that has not been predicted even theoretically. Our findings will open up new avenues for designing novel materials that combine strength and toughness in a trade-off relationship.

3.
Mass Spectrom (Tokyo) ; 12(1): A0115, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37250597

RESUMEN

Northwest Africa (NWA) 2977 is a lunar basaltic meteorite that was found in 2005 and has been classified as an olivine cumulate gabbro. This meteorite contains a shock melt vein (SMV) induced by an intense shock event. We report herein on an in-situ analysis of phosphates in the host gabbro and the shock vein for the U-Pb dating of NWA 2977 using an ion microprobe, NanoSIMS. The majority of the analyzed phosphates, in both the SMV and host-rock, lie on a linear regression in 238U/206Pb-207Pb/206Pb-204Pb/206Pb three-dimensional space, indicating a total Pb/U isochron age of 3.15±0.12 Ga (95% confidence level), which is consistent ages determined in previous isotopic studies of NWA 2977 (Sm-Nd age of 3.10±0.05 Ga, Rb-Sr age of 3.29±0.11 Ga, and Pb-Pb baddeleyite age of 3.12±0.01 Ga), and identical to the age of the U-Pb phosphate in a paired meteorite NWA 773, 3.09±0.20 Ga, derived from our dataset. There was no clear difference in the formation age between the phosphates found in the SMV and host-rock, although the shape and size of the grains and the Raman spectra show the evidence of intense shock metamorphism. Based on these findings, the cooling rate of the phosphate was very rapid, constrained to be larger than 140 K/s.

4.
Sci Rep ; 13(1): 5051, 2023 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-37024563

RESUMEN

The helium isotope ratio (3He/4He), concentration ratio of neon-20 to helium-4 (20Ne/4He), argon (Ar), krypton (Kr), and xenon (Xe) concentrations were measured in the porewater of surface sediments of several submarine mud volcanoes. From the 3He/4He values (0.18-0.93RA), the estimated He origin is almost 90% crustal He, with little contribution from mantle-derived He. The determined Ar, Kr, and Xe concentrations lie within the solubility equilibrium range expected for temperatures from 83 °C up to 230 °C and are consistent with the temperature range of the dehydration origin of clay minerals. Considering the geothermal gradient in the investigated region (25 °C/km), these gases are considered to have reached dissolution equilibrium at a depth of about 3.3 km to 9.2 km below the seafloor. As the depth of the plate boundary is 18 km below the seafloor, the noble gas signatures are likely to originate from the crust, not from the plate boundary. This is consistent with the results presented by the He isotope ratios.

5.
Sci Rep ; 13(1): 3537, 2023 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-36864194

RESUMEN

Relative nitrogen abundance normalized by carbonaceous chondrites in the bulk silicate Earth appears to be depleted compared to other volatile elements. Especially, nitrogen behavior in the deep part of the Earth such as the lower mantle is not clearly understood. Here, we experimentally investigated the temperature dependence of nitrogen solubility in bridgmanite which occupies 75 wt.% of the lower mantle. The experimental temperature ranged from 1400 to 1700 °C at 28 GPa in the redox state corresponding to the shallow lower mantle. The maximum nitrogen solubility in bridgmanite (MgSiO3) increased from 1.8 ± 0.4 to 5.7 ± 0.8 ppm with increasing temperature from 1400 to 1700 °C. The nitrogen storage capacity of Mg-endmember bridgmanite under the current temperature conditions is 3.4 PAN (PAN: mass of present atmospheric nitrogen). Furthermore, the nitrogen solubility of bridgmanite increased with increasing temperature, in contrast to the nitrogen solubility of metallic iron. Thus, the nitrogen storage capacity of bridgmanite can be larger than that of metallic iron during the solidification of the magma ocean. Such a "hidden" nitrogen reservoir formed by bridgmanite in the lower mantle may have depleted the apparent nitrogen abundance ratio in the bulk silicate Earth.

6.
Nat Commun ; 13(1): 5265, 2022 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-36071036

RESUMEN

Identifying a strategy with strong efficacy against non-inflamed tumours is vital in cancer immune therapy. ERY974 is a humanized IgG4 bispecific T cell-redirecting antibody that recognizes glypican-3 and CD3. Here we examine the combination effect of ERY974 and chemotherapy (paclitaxel, cisplatin, and capecitabine) in the treatment of non-inflamed tumours in a xenograft model. ERY974 monotherapy shows a minor antitumour effect on non-inflamed NCI-H446 xenografted tumours, as infiltration of ERY974-redirected T cells is limited to the tumour-stromal boundary. However, combination therapy improves efficacy by promoting T cell infiltration into the tumour centre, and increasing ERY974 distribution in the tumour. ERY974 increases capecitabine-induced cytotoxicity by promoting capecitabine conversion to its active form by inducing thymidine phosphorylase expression in non-inflamed MKN45 tumour through ERY974-induced IFNγ and TNFα in T cells. We show that ERY974 with chemotherapy synergistically and reciprocally increases antitumour efficacy, eradicating non-inflamed tumours.


Asunto(s)
Anticuerpos Biespecíficos , Antineoplásicos , Neoplasias , Anticuerpos Biespecíficos/farmacología , Anticuerpos Biespecíficos/uso terapéutico , Antineoplásicos/farmacología , Capecitabina , Humanos , Neoplasias/tratamiento farmacológico , Linfocitos T
7.
Nat Commun ; 13(1): 4769, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35970934

RESUMEN

The origin of major volatiles nitrogen, carbon, hydrogen, and sulfur in planets is critical for understanding planetary accretion, differentiation, and habitability. However, the detailed process for the origin of Earth's major volatiles remains unresolved. Nitrogen shows large isotopic fractionations among geochemical and cosmochemical reservoirs, which could be used to place tight constraints on Earth's volatile accretion process. Here we experimentally determine N-partitioning and -isotopic fractionation between planetary cores and silicate mantles. We show that the core/mantle N-isotopic fractionation factors, ranging from -4‰ to +10‰, are strongly controlled by oxygen fugacity, and the core/mantle N-partitioning is a multi-function of oxygen fugacity, temperature, pressure, and compositions of the core and mantle. After applying N-partitioning and -isotopic fractionation in a planetary accretion and core-mantle differentiation model, we find that the N-budget and -isotopic composition of Earth's crust plus atmosphere, silicate mantle, and the mantle source of oceanic island basalts are best explained by Earth's early accretion of enstatite chondrite-like impactors, followed by accretion of increasingly oxidized impactors and minimal CI chondrite-like materials before and during the Moon-forming giant impact. Such a heterogeneous accretion process can also explain the carbon-hydrogen-sulfur budget in the bulk silicate Earth. The Earth may thus have acquired its major volatile inventory heterogeneously during the main accretion phase.

8.
Sci Rep ; 12(1): 12312, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35853994

RESUMEN

Currently, ERY974, a humanized IgG4 bispecific T cell-redirecting antibody recognizing glypican-3 and CD3, is in phase I clinical trials. After a first-in-human clinical trial of an anti-CD28 agonist monoclonal antibody resulting in severe life-threatening adverse events, the minimal anticipated biological effect level approach has been considered for determining the first-in-human dose of high-risk drugs. Accordingly, we aimed to determine the first-in-human dose of ERY974 using both the minimal anticipated biological effect level and no observed adverse effect level approaches. In the former, we used the 10% effective concentration value from a cytotoxicity assay using the huH-1 cell line with the highest sensitivity to ERY974 to calculate the first-in-human dose of 4.9 ng/kg, at which maximum drug concentration after 4 h of intravenous ERY974 infusion was equal to the 10% effective concentration value. To determine the no observed adverse effect level, we conducted a single-dose study in cynomolgus monkeys that were intravenously infused with ERY974 (0.1, 1, and 10 µg/kg). The lowest dose of 0.1 µg/kg was determined as the no observed adverse effect level, and the first-in-human dose of 3.2 ng/kg was calculated, considering body surface area and species difference. For the phase I clinical trial, we selected 3.0 ng/kg as a starting dose, which was lower than the first-in-human dose calculated from both the no observed adverse effect level and minimal anticipated biological effect level. Combining these two methods to determine the first-in-human dose of strong immune modulators such as T cell-redirecting antibodies would be a suitable approach from safety and efficacy perspectives.Clinical trial registration: JapicCTI-194805/NCT05022927.


Asunto(s)
Anticuerpos Biespecíficos , Glipicanos , Linfocitos T , Anticuerpos Biespecíficos/administración & dosificación , Relación Dosis-Respuesta Inmunológica , Glipicanos/inmunología , Humanos , Linfocitos T/inmunología
9.
Front Chem ; 10: 844953, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35360544

RESUMEN

We have developed a method to analyze all rare earth elements in silicate glasses and zircon minerals using a high lateral resolution secondary ion mass spectrometer (NanoSIMS). A 2nA O- primary beam was used to sputter a 7-8-µm diameter crater on the sample surface, and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV. A high mass resolving power of 9,400 at 10% peak height was attained to separate heavy REE from oxide of light REE. A multi-collector system combined with peak-jumping by magnetic field was adjusted to detect REEs and silicon-30 for calibration. Based on results of NIST SRM610 glass, sensitivities of REEs vary from 3 cps/ppm/nA of Lu to 13 cps/ppm/nA of Eu. Reproducibility of REE/Si ratios is better than 18% at 2σ. Secondary ion yields of REEs show positive relationships with their ionization potential of second valence. REEs of AS3, QGNG, and Torihama zircons were measured and calibrated against those of 91500 standard zircon. SIYs of REEs of zircon are identical to those of the glass standard. AS3 and QGNG data are generally consistent with those of previous work. Torihama REE data combined with the whole rock data provide partition coefficients of REEs between silicate melt and zircon. The relationship between these coefficients and ionic radius is explained by an elastic moduli model.

10.
Sci Rep ; 11(1): 19874, 2021 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-34615988

RESUMEN

We report here hourly variations of Mg/Ca, Sr/Ca, and Ba/Ca ratios in a Mediterranean mussel shell (Mytilus galloprovincialis) collected at the Otsuchi bay, on the Pacific coast of northeastern Japan. This bivalve was living in the intertidal zone, where such organisms are known to form a daily or bidaily growth line comprised of abundant organic matter. Mg/Ca ratios of the inner surface of the outer shell layer, corresponding to the most recent date, show cyclic changes at 25-90 µm intervals, while no interpretable variations are observed in Sr/Ca and Ba/Ca ratios. High Mg/Ca ratios were probably established by (1) cessation of the external supply of Ca and organic layer forming when the shell is closed at low tide, and (2) the strong binding of Mg to the organic layer, but not of Sr and Ba. Immediately following the great tsunami induced by the 2011 Tohoku earthquake, Mg/Ca enrichment occurred, up to 10 times that of normal low tide, while apparent Ba/Ca enrichment was observed for only a few days following the event, therefore serving a proxy of the past tsunami. Following the tsunami, periodic peaks and troughs in Mg/Ca continued, perhaps due to a biological memory effect as an endogenous clock.


Asunto(s)
Exoesqueleto/metabolismo , Mytilus/fisiología , Tsunamis , Exoesqueleto/química , Animales , Biomarcadores , Metales Alcalinotérreos/análisis , Metales Alcalinotérreos/metabolismo , Análisis Espectral , Factores de Tiempo
11.
Nat Commun ; 12(1): 4157, 2021 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-34230487

RESUMEN

The episodic growth of high-elevation orogenic plateaux is controlled by a series of geodynamic processes. However, determining the underlying mechanisms that drive plateau growth dynamics over geological history and constraining the depths at which growth originates, remains challenging. Here we present He-CO2-N2 systematics of hydrothermal fluids that reveal the existence of a lithospheric-scale fault system in the southeastern Tibetan Plateau, whereby multi-stage plateau growth occurred in the geological past and continues to the present. He isotopes provide unambiguous evidence for the involvement of mantle-scale dynamics in lateral expansion and localized surface uplift of the Tibetan Plateau. The excellent correlation between 3He/4He values and strain rates, along the strike of Indian indentation into Asia, suggests non-uniform distribution of stresses between the plateau boundary and interior, which modulate southeastward growth of the Tibetan Plateau within the context of India-Asia convergence. Our results demonstrate that deeply-sourced volatile geochemistry can be used to constrain deep dynamic processes involved in orogenic plateau growth.

12.
Sci Rep ; 11(1): 12026, 2021 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-34127710

RESUMEN

Plate bending-related normal faults (i.e. bend-faults) develop at the outer trench-slope of the oceanic plate incoming into the subduction zone. Numerous geophysical studies and numerical simulations suggest that bend-faults play a key role by providing pathways for seawater to flow into the oceanic crust and the upper mantle, thereby promoting hydration of the oceanic plate. However, deep penetration of seawater along bend-faults remains controversial because fluids that have percolated down into the mantle are difficult to detect. This report presents anomalously high helium isotope (3He/4He) ratios in sediment pore water and seismic reflection data which suggest fluid infiltration into the upper mantle and subsequent outflow through bend-faults across the outer slope of the Japan trench. The 3He/4He and 4He/20Ne ratios at sites near-trench bend-faults, which are close to the isotopic ratios of bottom seawater, are almost constant with depth, supporting local seawater inflow. Our findings provide the first reported evidence for a potentially large-scale active hydrothermal circulation system through bend-faults across the Moho (crust-mantle boundary) in and out of the oceanic lithospheric mantle.

13.
Int J Health Plann Manage ; 36(4): 1081-1106, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33786865

RESUMEN

Burundi is a fragile and conflict-affected state characterized by persistent conflict and political violence. Amid this conflict, Burundi has one of the highest maternal mortality rates globally-548 per 100,000 births as of 2017, such deaths could be prevented with antenatal care (ANC). This cross-sectional study aimed to examine the association between conflict and ANC and skilled birth attendant (SBA) utilization. Logistic regression analysis was conducted using the 2016-2017 Burundi Demographic and Health Survey (n = 8581), as well as a Near Analysis Geographic Information System exploration. Results show that women in extremely high conflict regions were less likely to have four antenatal visits (odds ratio [OR] = 0.79, p < 0.05). However, they were more likely to use a SBA (OR = 2.31, p < 0.001) and to deliver in a hospital (OR = 1.69, p < 0.001). As well, gender equality, education, and watching television were correlated with an increased likelihood of utilization. In contrast, unwanted pregnancies and increased parity were correlated with decreased use. Moreover, with renewed violence erupting in 2015, uptake of care has likely further stagnated or declined. If Sustainable Development Goal 3.1's objective of reducing maternal mortality globally is to be achieved, women's access to maternal healthcare services in conflicted-affected areas such as Burundi must be improved.


Asunto(s)
Servicios de Salud Materna , Atención Prenatal , Burundi , Estudios Transversales , Parto Obstétrico , Femenino , Humanos , Mortalidad Materna , Embarazo , Factores Socioeconómicos
14.
Environ Microbiol Rep ; 13(2): 98-103, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33196142

RESUMEN

Although sulfate ions are the main form of sulfur in the ocean, there is limited knowledge on their use by living organisms. Stable isotope labelling and NanoSIMS analysis were used in this study to clarify how sulfate, in seawater, is assimilated by corals and zooxanthellae at the cellular level. Aposymbiotic and symbiotic coral juveniles from the genus Acropora were incubated for 2 days in filtered seawater with 34 S-labelled sulfate. Further, the labelled corals were incubated for additional 2 days in natural seawater. Mapping of sulfur isotopes (34 S/32 S) showed that the 'hotspots' were enriched in 34 S on a sub-micro level and were heterogeneously distributed in the coral soft tissues. Specifically, 34 S hotspots were found in both the symbiotic zooxanthellae and coral host tissues. In aposymbiotic corals, 34 S was detected in the tissues, indicating that the host corals directly assimilated the sulfate ions without any aid from the zooxanthellae. Even after 2 days in normal seawater, the 34 S label was clearly seen in both symbiotic and aposymbiotic corals, indicating that the assimilated sulfur was retained for at least 2 days.


Asunto(s)
Antozoos , Animales , Agua de Mar , Azufre , Simbiosis
15.
J Agrar Chang ; 21(3): 604-619, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38607798

RESUMEN

The experiences of COVID-19 differ at both micro and macro levels. This emphasizes the need for differentiated responses that account for the varying vulnerabilities of diverse groups regarding the pandemic. In Ghana, much of the attention on COVID-19 has been on urban centres, particularly the country's two largest metropolises in southern Ghana. This has created a gap between national level policy and the experiences of COVID-19 among rural dwellers in Ghana. This is despite evidence that the world's poorest populations will bear the brunt of COVID-19 effects, and that globally, four out of five people living below the poverty line reside in rural areas. Using the Upper West Region as a case study, we discuss the differentiated vulnerabilities that agrarian communities in Ghana face regarding the pandemic. We situate our discussions within the theories of vulnerability and feminist political economy to highlight how interlocking vulnerabilities regarding historical, environmental, geopolitical, socio-economic, health, and gendered inequalities affect the disposition of agrarian communities to cope with and recover from the COVID-19 pandemic. We call for more nuanced COVID-19 responses that account for the needs and experiences of agrarian communities in Ghana.

16.
Sci Rep ; 10(1): 19925, 2020 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-33199807

RESUMEN

There has been tritium groundwater leakage to the land side of Fukushima Dai-ichi nuclear power plants since 2013. Groundwater was continuously collected from the end of 2013 to 2019, with an average tritium concentration of approximately 20 Bq/L. Based on tritium data published by Tokyo Electric Power Company Holdings (TEPCO) (17,000 points), the postulated source of the leakage was (1) leaks from a contaminated water tank that occurred from 2013 to 2014, or (2) a leak of tritium that had spread widely over an impermeable layer under the site. Based on our results, sea side and land side tritium leakage monitoring systems should be strengthened.

17.
Soc Sci Med ; 262: 113253, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32795631

RESUMEN

Maternal mortality represents one of the widest gaps between developed and developing countries. Ninety-nine percent of maternal deaths occur in developing countries, with over half occurring in sub-Saharan Africa. This health indicator became a global priority when the United Nations' Sustainable Development Goal 3.1 set out to decrease the global maternal mortality rate to less than 70 per 100 000 births by 2030. In the Democratic Republic of the Congo (DRC), 473 of every 100 000 women who give birth die due to pregnancy-related complications. These deaths could be prevented through enhanced access and utilization of antenatal care services and skilled birth attendants. However, amid prolonged conflict, violence, and authoritarian governments, the Democratic Republic of the Congo has been classified as a fragile and conflict-affected situation and women are prone to face difficulties accessing maternal health services. This study examined the utilization of antenatal care and skilled birth attendants in the Democratic Republic of Congo using logistic regressions. Our findings show that women living in regions with extremely high levels of prolonged conflict were significantly less likely than those in regions with moderate levels of conflict to have their first antenatal care visit within the first trimester (OR = 0.29, p < 0.01), and to have four visits (OR = 0.46, p < 0.01). Overall, women in regions with extremely high levels of conflict (OR = 0.41, p < 0.01) were less likely to meet the World Health Organization's antenatal care recommendations compared to those in regions with moderate levels of conflict. The findings suggest that conflict-affected countries, such as the Democratic Republic of the Congo, require context-specific interventions if progress is to be made towards achieving Sustainable Development Goal 3.1.


Asunto(s)
Servicios de Salud Materna , Atención Prenatal , República Democrática del Congo/epidemiología , Femenino , Humanos , Mortalidad Materna , Embarazo
18.
Proc Jpn Acad Ser B Phys Biol Sci ; 96(7): 322-334, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32788554

RESUMEN

Here, we report the groundwater oxygen isotope anomalies caused by the 2016 Kumamoto earthquake (MJMA7.3) that occurred in Southwest Japan on April 16, 2016. One hundred and seventeen groundwater samples were collected from a deep well located 3 km to the southeast of the epicenter in Mifune Town, Kumamoto Prefecture; they were drinking water packed in PET bottles and distributed in the area between April 2015 and March 2018. Further, the oxygen and hydrogen isotopes were evaluated via cavity ring-down spectroscopy without performing any pretreatment. An anomalous increase was observed with respect to the δ18O value (up to 0.51‰) soon after the earthquake along with a precursory increase of 0.38‰ in January 2016 before the earthquake. During these periods, there was no noticeable change in the hydrogen isotopic ratios. Rapid crustal deformation related to the earthquake may have enhanced the microfracturing of the aquifer rocks and the production of new surfaces, inducing δ18O enrichment via oxygen isotopic exchange between rock and porewater without changing δ2H.


Asunto(s)
Terremotos , Agua Subterránea/química , Oxígeno/análisis , Japón
19.
Sci Rep ; 10(1): 10897, 2020 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-32616729

RESUMEN

Nitrogen is a crucial volatile element in the early Earth's evolution and the origin of life. Despite its importance, nitrogen's behavior in the Earth's interior remains poorly understood. Compared to other volatile elements, nitrogen is depleted in the Earth's atmosphere (the so-called "missing nitrogen"), calling for a hidden deep reservoir. To investigate nitrogen's behavior in the deep Earth including how the reservoir formed, high-pressure and high-temperature experiments were conducted at 28 GPa and 1,400-1,700 °C. To reproduce the conditions in the lower mantle, the redox was controlled using a Fe-FeO buffer. We observed that depending on the temperature conditions, stishovite can incorporate up to 90-404 ppm nitrogen, experimentally demonstrating that stishovite has the highest nitrogen solubility among the deep mantle minerals. Stishovite is the main mineral component of subducted nitrogen-rich sedimentary rocks and eroded continental crust that are eventually transported down to the lower mantle. Our results suggest that nitrogen could have been continuously transported into the lower mantle via subduction, ever since plate tectonics began.

20.
Nature ; 582(7810): 67-72, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32494080

RESUMEN

Continental rifts are important sources of mantle carbon dioxide (CO2) emission into Earth's atmosphere1-3. Because deep carbon is stored for long periods in the lithospheric mantle4-6, rift CO2 flux depends on lithospheric processes that control melt and volatile transport1,3,7. The influence of compositional and thickness differences between Archaean and Proterozoic lithosphere on deep-carbon fluxes remains untested. Here we propose that displacement of carbon-enriched Tanzanian cratonic mantle concentrates deep carbon below parts of the East African Rift System. Sources and fluxes of CO2 and helium are examined over a 350-kilometre-long transect crossing the boundary between orogenic (Natron and Magadi basins) and cratonic (Balangida and Manyara basins) lithosphere from north to south. Areas of diffuse CO2 degassing exhibit increasing mantle CO2 flux and 3He/4He ratios as the rift transitions from Archaean (cratonic) to Proterozoic (orogenic) lithosphere. Active carbonatite magmatism also occurs near the craton edge. These data indicate that advection of the root of thick Archaean lithosphere laterally to the base of the much thinner adjacent Proterozoic lithosphere creates a zone of highly concentrated deep carbon. This mode of deep-carbon extraction may increase CO2 fluxes in some continental rifts, helping to control the production and location of carbonate-rich magmas.

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