Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area...Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area is identified by the high elevated zone which is remained the witness of stable zone, not affected by the ancienst erosion process. Zatua Hills are in the superior Kibalian formation dated to Neoarchaen, hosted in Upper Congo Granites Massifs of DRC covering a large central zone of NE of DRC, and consisting to dolerite, phyllade, clay rich sediment, poor Banded Iron Formations (BIFs), enriched BIFs, friable hematite, hard hematite, mineralized and unmineralized brechias. Magnetite, martite and hematite are associated to some secondary minerals such as goethite, gibbsite, kaolinite, strengite, variscite and others clay minerals present in BIFs. Petrographic analysis made from the samples collected in situ showed, as well as BIFs and iron ore associated, that magnetite was much abundant oxide mineral which is oxided to martite before to stabilize to hematite during the deposition time. Having about hundred meters of thickness, the rich iron ore of this area content, in the majority less deleterious elements which, are harmful in metallurgic process of iron. These secondary minerals were precipitated at various degrees in the leached cavities of rocks between martite and hematite aggregates to botryoidal texture and, are rich to Al, and are mainly consisting to gibbsite and solid solution series of variscite-strengite (AlPO<sub>4</sub>·2H<sub>2</sub>O and FePO<sub>4</sub>·2H<sub>2</sub>O). Low degree of metamorphism played when magnetite was converted to martite, with the presence of variscite and anatase like witnesses of this event in which, martite was crystalized to hematite.展开更多
Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has rem...Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.展开更多
司家营条带状含铁建造(Banded iron formation,BIF)型铁矿床是冀东地区规模最大的铁矿床,前人对其进行了大量的年代学、岩石学和元素地球化学工作,但目前尚未对其进行Fe同位素研究。笔者等通过Fe同位素和主微量、稀土元素相结合的方法...司家营条带状含铁建造(Banded iron formation,BIF)型铁矿床是冀东地区规模最大的铁矿床,前人对其进行了大量的年代学、岩石学和元素地球化学工作,但目前尚未对其进行Fe同位素研究。笔者等通过Fe同位素和主微量、稀土元素相结合的方法对司家营BIF的成矿物质来源和形成背景提出了有效制约,同时对司家营BIF的锆石U-Pb年龄数据进行补充。锆石U-Pb年代学显示,司家营BIF形成于2537~2531 Ma。地球化学数据显示司家营BIF矿石主要由TFe_(2)O_(3)和SiO_(2)组成,具有较低的Al_(2)O_(3)和TiO_(2)含量,富集Fe重同位素(δ^(56)Fe=0.341‰~0.525‰);稀土元素配分模式呈现轻稀土亏损、重稀土富集的特征,具有明显的Eu、Y、La正异常,Y/Ho值较高(Y/Ho=34.96~45.84)。这些特征表明司家营BIF是基本无碎屑物质参与的化学沉积岩,稀土元素来源于高温热液和海水的混合溶液,铁质来源于海相热液流体。司家营BIF缺乏真正的Ce负异常和Fe同位素组成均为正值指示其形成于缺氧环境。综合对比世界上其他地区太古宙BIF的Fe同位素特征,笔者等认为新太古代时期地球海洋含氧量逐步上升,此时海洋总体属于缺氧环境,但部分地区氧气含量较高。展开更多
文摘Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area is identified by the high elevated zone which is remained the witness of stable zone, not affected by the ancienst erosion process. Zatua Hills are in the superior Kibalian formation dated to Neoarchaen, hosted in Upper Congo Granites Massifs of DRC covering a large central zone of NE of DRC, and consisting to dolerite, phyllade, clay rich sediment, poor Banded Iron Formations (BIFs), enriched BIFs, friable hematite, hard hematite, mineralized and unmineralized brechias. Magnetite, martite and hematite are associated to some secondary minerals such as goethite, gibbsite, kaolinite, strengite, variscite and others clay minerals present in BIFs. Petrographic analysis made from the samples collected in situ showed, as well as BIFs and iron ore associated, that magnetite was much abundant oxide mineral which is oxided to martite before to stabilize to hematite during the deposition time. Having about hundred meters of thickness, the rich iron ore of this area content, in the majority less deleterious elements which, are harmful in metallurgic process of iron. These secondary minerals were precipitated at various degrees in the leached cavities of rocks between martite and hematite aggregates to botryoidal texture and, are rich to Al, and are mainly consisting to gibbsite and solid solution series of variscite-strengite (AlPO<sub>4</sub>·2H<sub>2</sub>O and FePO<sub>4</sub>·2H<sub>2</sub>O). Low degree of metamorphism played when magnetite was converted to martite, with the presence of variscite and anatase like witnesses of this event in which, martite was crystalized to hematite.
文摘Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.
文摘司家营条带状含铁建造(Banded iron formation,BIF)型铁矿床是冀东地区规模最大的铁矿床,前人对其进行了大量的年代学、岩石学和元素地球化学工作,但目前尚未对其进行Fe同位素研究。笔者等通过Fe同位素和主微量、稀土元素相结合的方法对司家营BIF的成矿物质来源和形成背景提出了有效制约,同时对司家营BIF的锆石U-Pb年龄数据进行补充。锆石U-Pb年代学显示,司家营BIF形成于2537~2531 Ma。地球化学数据显示司家营BIF矿石主要由TFe_(2)O_(3)和SiO_(2)组成,具有较低的Al_(2)O_(3)和TiO_(2)含量,富集Fe重同位素(δ^(56)Fe=0.341‰~0.525‰);稀土元素配分模式呈现轻稀土亏损、重稀土富集的特征,具有明显的Eu、Y、La正异常,Y/Ho值较高(Y/Ho=34.96~45.84)。这些特征表明司家营BIF是基本无碎屑物质参与的化学沉积岩,稀土元素来源于高温热液和海水的混合溶液,铁质来源于海相热液流体。司家营BIF缺乏真正的Ce负异常和Fe同位素组成均为正值指示其形成于缺氧环境。综合对比世界上其他地区太古宙BIF的Fe同位素特征,笔者等认为新太古代时期地球海洋含氧量逐步上升,此时海洋总体属于缺氧环境,但部分地区氧气含量较高。
