The occurrences of associated elements and their genetic factors in the No. 30 coal seam in the Zhijin Coalfield were studied using instrumental neutron activation analysis, inductively coupled plasma-atomic emission ...The occurrences of associated elements and their genetic factors in the No. 30 coal seam in the Zhijin Coalfield were studied using instrumental neutron activation analysis, inductively coupled plasma-atomic emission spectroscopy, and a scanning electron microscope equipped with an energy-dispersive X-ray analyzer. And, a microscope photometer system (Leitz MPV-Ⅲ) was used to observe the characteristics of coal petrology. According to the influence degree by the siliceous low-temperature hydrothermal fluids, the organic matter is divided into four types: A, B, C, and D of the hydrothermally-altered organic matter (HAOM). The study shows that the high content of Fe (2.31%) is not from pyrite, but mostly from the siliceous low-temperature hydrothermal fluids. The occurrences of the associated elements in the four organic matter types are different. The contents of Fe, Si, and Al are decreasing, but S and Cu are increasing in the order of the HAOM-A, HAOM-B, HAOM-C, and HAOM-D. The losing rate of sulfur in organic matter is 0.35% and the content of Fe taken from the low-temperature hydrothermal fluids into the organic matter is 0.794% during the siliceous low-temperature hydrothermal fluids invading the coal seam. The above facts indicate that the low-temperature hydrothermal fluids play a crucial role in the re-distributions and occurrences of associated elements in coal.展开更多
Optical, cathodoluminescence and transmission electron microscope (TEM)analyses were conducted on four groups of calcite fault rocks, a cataclastic limestone, cataclasticcoarse-grained marbles from two fault zones, an...Optical, cathodoluminescence and transmission electron microscope (TEM)analyses were conducted on four groups of calcite fault rocks, a cataclastic limestone, cataclasticcoarse-grained marbles from two fault zones, and a fractured mylonite. These fault rocks showsimilar microstructural characteristics and give clues to similar processes of rock deformation.They are characterized by the structural contrast between macroscopic cataclastic (brittle) andmicroscopic mylonitic (ductile) microstructures. Intragranular deformation microstructures (i.e.deformation twins, kink bands and microfractures) are well preserved in the deformed grains inclasts or in primary rocks. The matrix materials are of extremely fine grains with diffusivefeatures. Dislocation microstructures for co-existing brittle deformation and crystalline plasticitywere revealed using TEM. Tangled dislocations are often preserved at the cores of highly deformedclasts, while dislocation walls form in the transitions to the fine-grained matrix materials andfree dislocations, dislocation loops and dislocation dipoles are observed both in the deformedclasts and in the fine-grained matrix materials. Dynamic recrystallization grains from subgrainrotation recrystallization and subsequent grain boundary migration constitute the major parts of thematrix materials. Statistical measurements of densities of free dislocations, grain sizes ofsubgrains and dynamically recrystallized grains suggest an unsteady state of the rock deformation.Microstructural and cathodoluminescence analyses prove that fluid activity is one of the major partsof faulting processes. Low-temperature plasticity, and thereby induced co-existence of macroscopicbrittle and microscopic ductile microstructures are attributed to hydrolytic weakening due to theinvolvement of fluid phases in deformation and subsequent variation of rock rheology. Duringhydrolytic weakening, fluid phases, e.g. water, enhance the rate of dislocation slip and climb, andincrease the rate of recovery of strain-hardened rocks, which accommodates fracturing.展开更多
基金the National NaturalScience Foundation of China(No.40072054)the Coal Science Foundation of China(No.97Geo-10205).
文摘The occurrences of associated elements and their genetic factors in the No. 30 coal seam in the Zhijin Coalfield were studied using instrumental neutron activation analysis, inductively coupled plasma-atomic emission spectroscopy, and a scanning electron microscope equipped with an energy-dispersive X-ray analyzer. And, a microscope photometer system (Leitz MPV-Ⅲ) was used to observe the characteristics of coal petrology. According to the influence degree by the siliceous low-temperature hydrothermal fluids, the organic matter is divided into four types: A, B, C, and D of the hydrothermally-altered organic matter (HAOM). The study shows that the high content of Fe (2.31%) is not from pyrite, but mostly from the siliceous low-temperature hydrothermal fluids. The occurrences of the associated elements in the four organic matter types are different. The contents of Fe, Si, and Al are decreasing, but S and Cu are increasing in the order of the HAOM-A, HAOM-B, HAOM-C, and HAOM-D. The losing rate of sulfur in organic matter is 0.35% and the content of Fe taken from the low-temperature hydrothermal fluids into the organic matter is 0.794% during the siliceous low-temperature hydrothermal fluids invading the coal seam. The above facts indicate that the low-temperature hydrothermal fluids play a crucial role in the re-distributions and occurrences of associated elements in coal.
基金partly financially supported by the State Education Commission and the NNSF(No.49872071).
文摘Optical, cathodoluminescence and transmission electron microscope (TEM)analyses were conducted on four groups of calcite fault rocks, a cataclastic limestone, cataclasticcoarse-grained marbles from two fault zones, and a fractured mylonite. These fault rocks showsimilar microstructural characteristics and give clues to similar processes of rock deformation.They are characterized by the structural contrast between macroscopic cataclastic (brittle) andmicroscopic mylonitic (ductile) microstructures. Intragranular deformation microstructures (i.e.deformation twins, kink bands and microfractures) are well preserved in the deformed grains inclasts or in primary rocks. The matrix materials are of extremely fine grains with diffusivefeatures. Dislocation microstructures for co-existing brittle deformation and crystalline plasticitywere revealed using TEM. Tangled dislocations are often preserved at the cores of highly deformedclasts, while dislocation walls form in the transitions to the fine-grained matrix materials andfree dislocations, dislocation loops and dislocation dipoles are observed both in the deformedclasts and in the fine-grained matrix materials. Dynamic recrystallization grains from subgrainrotation recrystallization and subsequent grain boundary migration constitute the major parts of thematrix materials. Statistical measurements of densities of free dislocations, grain sizes ofsubgrains and dynamically recrystallized grains suggest an unsteady state of the rock deformation.Microstructural and cathodoluminescence analyses prove that fluid activity is one of the major partsof faulting processes. Low-temperature plasticity, and thereby induced co-existence of macroscopicbrittle and microscopic ductile microstructures are attributed to hydrolytic weakening due to theinvolvement of fluid phases in deformation and subsequent variation of rock rheology. Duringhydrolytic weakening, fluid phases, e.g. water, enhance the rate of dislocation slip and climb, andincrease the rate of recovery of strain-hardened rocks, which accommodates fracturing.
