The Banfora’s birimian greenstones belt is located in the western part of Burkina Faso (west Africa). Recent petrographic and lithogeochemical studies have highlighted plutons intruding the metasedimentary and metavo...The Banfora’s birimian greenstones belt is located in the western part of Burkina Faso (west Africa). Recent petrographic and lithogeochemical studies have highlighted plutons intruding the metasedimentary and metavolcanic series. These plutonic rocks are composed of leucogranites belonging to the so-called Ferkessedougou’s or Ferké’s batholith, granites, granodiorites, monzodiorites and quartz monzonites. From the lithogeochemical studies, these plutonic rocks have a calc-alkaline and peraluminous character. The rare earth elements spectra of the Ferké’s leucogranites let distinguished two sub-facies. One of the sub-facies is composed of quartz monzonite to granite, while the other is granitic sensu stricto. However, all these plutonic rocks were emplaced in a geodynamic context of subduction followed by collision.展开更多
Objective: To analyze the caesarean section prognosis aspects according to Misgav-Ladach versus classical technique in the regional hospital of Banfora. Materials and Methods: This is about a randomized clinical test ...Objective: To analyze the caesarean section prognosis aspects according to Misgav-Ladach versus classical technique in the regional hospital of Banfora. Materials and Methods: This is about a randomized clinical test of 2 groups carried in the regional hospital in Banfora on a two-month period from 1st October to 30 November 2015. In the first group, 66 patients had benefited from a caesarean section by the Misgav-Ladach technique. In the control group, 44 patients had benefited from a caesarean in the conventional technique. Were included in our sample all patients having benefited from a cesarean in the study site during the study period and who had consented to participate in the study. All patients were followed until the postpartum healing of the surgical wound. All prognostic elements have been compared. The results were analyzed with Epi Info 3.5.1 software and the significance level was set at 5%. Results: The indications for cesarean section were dominated by maternal causes in 70 cases (63.6%). The average duration of the surgical procedure was 27.98 mm for Misgav-Ladach technique versus 28.27 mm for the conventional technique (p = 0.49). The evaluation of blood loss by the change in hemoglobin pre- and post-operative did not find statistically significant differences between the two techniques (p = 0.6). The evaluation of the number of intraoperative suture used, was in favor of the technique of Misgav-Ladach (p = 0.007). The evolutionary trend in the intensity of postoperative pain was in favor of the technique of Misgav-Ladach. The average time of wound healing was 16.33 days for group 1 versus 21, 27 days for group 2 (p = 0.0001). Postoperative morbidity was greater with the conventional technique in comparison to Misgav-Ladach’s (p = 0.046). There was no statistically significant differences in length of hospital stay (p = 0.056). Conclusion: The Misgav-Ladach cesarean section reduces operative risk. The adoption and diffusion of this technique to the national level and its effective integration into training curriculas should contribute to reducing maternal morbidity and mortality of abdominal delivery.展开更多
In the Mangodara area within the Banfora greenstone belts (Baoulé-Mossi domain of the West African Craton), our study focused on geochemical assessment of the mobility of major and trace elements. Gold and base m...In the Mangodara area within the Banfora greenstone belts (Baoulé-Mossi domain of the West African Craton), our study focused on geochemical assessment of the mobility of major and trace elements. Gold and base metal occurrences are hosted in highly metamorphic felsic (metarhyolite) and intermediate (metadacite and metaandesite) formations. Common mineral assemblages made up of staurolite - kyanite - pyrophyllite are interpreted to represent the metamorphosed equivalent of aluminous hydrothermal alteration. Associated felsic and intermediate volcanic rocks are enriched in Fe<sub>2</sub>O<sub>3</sub>, K<sub>2</sub>O (metaandesite, metarhyolite) and depleted in MgO, Al<sub>2</sub>O<sub>3</sub>, CaO, P<sub>2</sub>O<sub>5</sub>, Na<sub>2</sub>O (metarhyolite) and Fe<sub>2</sub>O<sub>3</sub>, MgO, CaO (metaandesite). Al<sub>2</sub>O<sub>3</sub> depletion in mineralized kyanite-staurotide bearing metarhyolites suggests corroded minerals. Mineralized metarhyolites show enrichment in Au, Ag, Ba, Bi, Cr, Cu, Eu, La, Mo, Ni, Pb, S, Sc, V and depletion in As Sb Co, Sn, Zn while mineralized metaandesites show enrichment in Au, Ag, As, Mo, S, Sb and depletion in Co, Sn, Zn, Bi, Cr, Cu, Eu, Ni, Pb, Sc. Ba, La, V are immobile in metaandesites. Finally, Ag, As, Sn appear as geochemical vectors for gold exploration in the study area since gold mineralization is characterized by Au + Ba + Cu + Eu + La + Mo + Ni + S association in metarhyolites and Au + S + Sb + As + Ag + Bi in metaandesites.展开更多
Metasedimentary rocks of the Banfora belt are examined for their petrography geochemistry and genesis. The main formations are pelite metapelites sandstone, and metagraywackes. The first ones show a fine interlocking ...Metasedimentary rocks of the Banfora belt are examined for their petrography geochemistry and genesis. The main formations are pelite metapelites sandstone, and metagraywackes. The first ones show a fine interlocking layering with unclear graded bedding in the sandstone compared to the metapelites, while the metagraywackes show a clearly discordant graded bedding of light grey to light pink color. The low SiO2/Al2O3 ratios (3.67 to 6.60) suggest their low sedimentary maturity. The metapelites and sandstone-pelites show moderate Na2O/K2O values (10.13 - 22.69), indicating moderate chemical maturity;in contrast, the metagraywackes show low Na2O/K2O values (1.94 - 5.80) suggesting low chemical maturity. The metapelites, sandstone-pelites and metagraywackes have Rb/Sr ratios of 0.866 - 0.004 and 0.173 - 0.607 respectively, indicating a moderate to low degree of chemical alteration. The chemical alteration index (CIA = 58 - 83) and the plagioclase alteration index (PIA = 53 - 81) suggest weak to moderate alteration of the source rocks. This alteration is different from simple alteration as the sole control of chemical composition, but is associated with metasomatism. The metapelites sandstone shows a mixture of mafic and intermediate igneous sources, which indicates that the protoliths could be basalts and andesites, but the metagraywackes would be derived from the erosion of a mixture of andesitic to granitic rocks. The studied rocks were generated from young undifferentiated to differentiated arcs. They are of low to moderate sedimentary and chemical maturity.展开更多
Regional exploration of base and strategic metals(Li,Nb,Ta,Sn)in the Kangounadéni sector,part of the Banfora Belt(Paleoproterozoic greenstone belt,West African Craton),was conducted using stream sediment and soil...Regional exploration of base and strategic metals(Li,Nb,Ta,Sn)in the Kangounadéni sector,part of the Banfora Belt(Paleoproterozoic greenstone belt,West African Craton),was conducted using stream sediment and soil sampling around the two-micas leucogranite of Ferkessédougou.In this study,a total of 281 stream sediment samples and 640 soil samples from the Kangounadéni sector were analyzed to determine the concentrations of 57 major and trace elements,by the multi-acid digestion followed by the ICP-MS multi-element analysis.We processed geochemical analysis results using multivariate statistical techniques including principal component analysis and hierarchical classification,to identify geochemical trends and anomalous zones.Geochemical enrichment in K,Rb,U,and Nb is primarily related to the Ferkessédougou two-micas leucogranite,whereas enrichment in As,Sb,light rare earth elements(LREE),and medium to high contents of Fe,Ni,Cr,and Sc is characteristic of the volcanosedimentary formations.Two types of anomalies have been identified:(i)Li±Sn anomalies within and around the two-micas Ferkessédougou leucogranite(Li up to 133 ppm in stream sediments and 194 ppm in soils,Sn up to 2.9 ppm in stream sediments and 19.2 ppm in soils),accompanied with high content in Na,K,and Rb in the granite.(ii)Pb-Zn outlying concentrations on its eastern edge,likely associated with meta-volcanosedimentary units(Pb up to 17.24 ppm in stream sediments and 523 ppm in soils,Zn up to 523 ppm in soils).Background thresholds in soils were determined for Li,Pb,Sn,W,Ta,and U at 120 ppm,109 ppm,4.1 ppm,2.3 ppm,6.6 ppm,and 9.1 ppm,respectively.The Li±Sn anomalies align with a petrogenetic LCT granite/pegmatite source,related to the two-micas Ferkessedougou leucogranite.However,Nb and Ta concentrations in soils are low,making them unreliable indicators of mineralized zones.Additionally,the Pb-Zn anomaly suggests base metal enrichment linked to a potential sulfide mineralization process within the surrounding volcano-sedimentary rocks.The behavior of HFSE(W,Ti,Nb,Ta)and U is probably controlled by accumulation of residual minerals or laterization.展开更多
文摘The Banfora’s birimian greenstones belt is located in the western part of Burkina Faso (west Africa). Recent petrographic and lithogeochemical studies have highlighted plutons intruding the metasedimentary and metavolcanic series. These plutonic rocks are composed of leucogranites belonging to the so-called Ferkessedougou’s or Ferké’s batholith, granites, granodiorites, monzodiorites and quartz monzonites. From the lithogeochemical studies, these plutonic rocks have a calc-alkaline and peraluminous character. The rare earth elements spectra of the Ferké’s leucogranites let distinguished two sub-facies. One of the sub-facies is composed of quartz monzonite to granite, while the other is granitic sensu stricto. However, all these plutonic rocks were emplaced in a geodynamic context of subduction followed by collision.
文摘Objective: To analyze the caesarean section prognosis aspects according to Misgav-Ladach versus classical technique in the regional hospital of Banfora. Materials and Methods: This is about a randomized clinical test of 2 groups carried in the regional hospital in Banfora on a two-month period from 1st October to 30 November 2015. In the first group, 66 patients had benefited from a caesarean section by the Misgav-Ladach technique. In the control group, 44 patients had benefited from a caesarean in the conventional technique. Were included in our sample all patients having benefited from a cesarean in the study site during the study period and who had consented to participate in the study. All patients were followed until the postpartum healing of the surgical wound. All prognostic elements have been compared. The results were analyzed with Epi Info 3.5.1 software and the significance level was set at 5%. Results: The indications for cesarean section were dominated by maternal causes in 70 cases (63.6%). The average duration of the surgical procedure was 27.98 mm for Misgav-Ladach technique versus 28.27 mm for the conventional technique (p = 0.49). The evaluation of blood loss by the change in hemoglobin pre- and post-operative did not find statistically significant differences between the two techniques (p = 0.6). The evaluation of the number of intraoperative suture used, was in favor of the technique of Misgav-Ladach (p = 0.007). The evolutionary trend in the intensity of postoperative pain was in favor of the technique of Misgav-Ladach. The average time of wound healing was 16.33 days for group 1 versus 21, 27 days for group 2 (p = 0.0001). Postoperative morbidity was greater with the conventional technique in comparison to Misgav-Ladach’s (p = 0.046). There was no statistically significant differences in length of hospital stay (p = 0.056). Conclusion: The Misgav-Ladach cesarean section reduces operative risk. The adoption and diffusion of this technique to the national level and its effective integration into training curriculas should contribute to reducing maternal morbidity and mortality of abdominal delivery.
文摘In the Mangodara area within the Banfora greenstone belts (Baoulé-Mossi domain of the West African Craton), our study focused on geochemical assessment of the mobility of major and trace elements. Gold and base metal occurrences are hosted in highly metamorphic felsic (metarhyolite) and intermediate (metadacite and metaandesite) formations. Common mineral assemblages made up of staurolite - kyanite - pyrophyllite are interpreted to represent the metamorphosed equivalent of aluminous hydrothermal alteration. Associated felsic and intermediate volcanic rocks are enriched in Fe<sub>2</sub>O<sub>3</sub>, K<sub>2</sub>O (metaandesite, metarhyolite) and depleted in MgO, Al<sub>2</sub>O<sub>3</sub>, CaO, P<sub>2</sub>O<sub>5</sub>, Na<sub>2</sub>O (metarhyolite) and Fe<sub>2</sub>O<sub>3</sub>, MgO, CaO (metaandesite). Al<sub>2</sub>O<sub>3</sub> depletion in mineralized kyanite-staurotide bearing metarhyolites suggests corroded minerals. Mineralized metarhyolites show enrichment in Au, Ag, Ba, Bi, Cr, Cu, Eu, La, Mo, Ni, Pb, S, Sc, V and depletion in As Sb Co, Sn, Zn while mineralized metaandesites show enrichment in Au, Ag, As, Mo, S, Sb and depletion in Co, Sn, Zn, Bi, Cr, Cu, Eu, Ni, Pb, Sc. Ba, La, V are immobile in metaandesites. Finally, Ag, As, Sn appear as geochemical vectors for gold exploration in the study area since gold mineralization is characterized by Au + Ba + Cu + Eu + La + Mo + Ni + S association in metarhyolites and Au + S + Sb + As + Ag + Bi in metaandesites.
文摘Metasedimentary rocks of the Banfora belt are examined for their petrography geochemistry and genesis. The main formations are pelite metapelites sandstone, and metagraywackes. The first ones show a fine interlocking layering with unclear graded bedding in the sandstone compared to the metapelites, while the metagraywackes show a clearly discordant graded bedding of light grey to light pink color. The low SiO2/Al2O3 ratios (3.67 to 6.60) suggest their low sedimentary maturity. The metapelites and sandstone-pelites show moderate Na2O/K2O values (10.13 - 22.69), indicating moderate chemical maturity;in contrast, the metagraywackes show low Na2O/K2O values (1.94 - 5.80) suggesting low chemical maturity. The metapelites, sandstone-pelites and metagraywackes have Rb/Sr ratios of 0.866 - 0.004 and 0.173 - 0.607 respectively, indicating a moderate to low degree of chemical alteration. The chemical alteration index (CIA = 58 - 83) and the plagioclase alteration index (PIA = 53 - 81) suggest weak to moderate alteration of the source rocks. This alteration is different from simple alteration as the sole control of chemical composition, but is associated with metasomatism. The metapelites sandstone shows a mixture of mafic and intermediate igneous sources, which indicates that the protoliths could be basalts and andesites, but the metagraywackes would be derived from the erosion of a mixture of andesitic to granitic rocks. The studied rocks were generated from young undifferentiated to differentiated arcs. They are of low to moderate sedimentary and chemical maturity.
基金financial support of the Bureau of Mines and Geology of Burkina Faso(BUMIGEB),National Geological Survey.
文摘Regional exploration of base and strategic metals(Li,Nb,Ta,Sn)in the Kangounadéni sector,part of the Banfora Belt(Paleoproterozoic greenstone belt,West African Craton),was conducted using stream sediment and soil sampling around the two-micas leucogranite of Ferkessédougou.In this study,a total of 281 stream sediment samples and 640 soil samples from the Kangounadéni sector were analyzed to determine the concentrations of 57 major and trace elements,by the multi-acid digestion followed by the ICP-MS multi-element analysis.We processed geochemical analysis results using multivariate statistical techniques including principal component analysis and hierarchical classification,to identify geochemical trends and anomalous zones.Geochemical enrichment in K,Rb,U,and Nb is primarily related to the Ferkessédougou two-micas leucogranite,whereas enrichment in As,Sb,light rare earth elements(LREE),and medium to high contents of Fe,Ni,Cr,and Sc is characteristic of the volcanosedimentary formations.Two types of anomalies have been identified:(i)Li±Sn anomalies within and around the two-micas Ferkessédougou leucogranite(Li up to 133 ppm in stream sediments and 194 ppm in soils,Sn up to 2.9 ppm in stream sediments and 19.2 ppm in soils),accompanied with high content in Na,K,and Rb in the granite.(ii)Pb-Zn outlying concentrations on its eastern edge,likely associated with meta-volcanosedimentary units(Pb up to 17.24 ppm in stream sediments and 523 ppm in soils,Zn up to 523 ppm in soils).Background thresholds in soils were determined for Li,Pb,Sn,W,Ta,and U at 120 ppm,109 ppm,4.1 ppm,2.3 ppm,6.6 ppm,and 9.1 ppm,respectively.The Li±Sn anomalies align with a petrogenetic LCT granite/pegmatite source,related to the two-micas Ferkessedougou leucogranite.However,Nb and Ta concentrations in soils are low,making them unreliable indicators of mineralized zones.Additionally,the Pb-Zn anomaly suggests base metal enrichment linked to a potential sulfide mineralization process within the surrounding volcano-sedimentary rocks.The behavior of HFSE(W,Ti,Nb,Ta)and U is probably controlled by accumulation of residual minerals or laterization.
