China is the third largest country in the world, with a land area of about 9.6 million km2. It is endowed with abundant mineral resources, and the metal mining activity can be traced back to ca. 8000 years ago. Howeve...China is the third largest country in the world, with a land area of about 9.6 million km2. It is endowed with abundant mineral resources, and the metal mining activity can be traced back to ca. 8000 years ago. However, due to language barrier, little has been known about the geology and tectonics to the outside world until 1980s. In the last three decades, a great deal of knowledge has been gained, enhanced by a vigorous cooperation between Chinese and Western geologists. Research papers about geological, geochemical, and geochronological features of mineral deposits of China are widely published and cited in international journals. A comprehen- sive and comprehensible English literature that summarises the features of mineral deposits in China, however, is still lacking.展开更多
An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage...An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.展开更多
The total, soluble and insoluble oxalate contents of the small, large and cauline leaves and small and large stems of miner’s lettuce (Claytonia perfoliata ) plants which had been irrigated with tap water or a solubl...The total, soluble and insoluble oxalate contents of the small, large and cauline leaves and small and large stems of miner’s lettuce (Claytonia perfoliata ) plants which had been irrigated with tap water or a soluble fertilizer were extracted and measured using HPLC chromatography. Overall, all plant parts of miner’s lettuce analyzed contained high levels of total and soluble oxalates;however plants irrigated with fertilizer contained lower levels of oxalates compared with plants irrigated with water. On a dry matter basis, the small leaves contained higher levels of total oxalate when compared to the total oxalate in the large leaves. Soluble oxalate in the leaves of plants irrigated with water ranged from 2.6 to 7.5 mg/100g dry matter (DM) and was significantly higher (P < 0.05) than the leaves of the fertilizer-watered plants, which ranged from 1.8 to 2.8 mg/100g DM. The soluble oxalate in the small and large stems of the fertilizer-watered plants ranged from 1.20 to 1.5 mg/100g DM and was significantly lower (P < 0.05) than the water-treated small and large stems, which ranged from 3.75 to 4.4 mg/100g DM. It is recommended that the leaves of miner’s lettuce should be consumed in moderation.展开更多
Relatively strongly magnetic fine components (<30μm, XS-4J and DS-4J) which are most environmentally sensitive were separated from layer S-{5-1} in the Xifeng and Duanjiapo loess sections and analyzed by MPV-3 for...Relatively strongly magnetic fine components (<30μm, XS-4J and DS-4J) which are most environmentally sensitive were separated from layer S-{5-1} in the Xifeng and Duanjiapo loess sections and analyzed by MPV-3 for their morphometric characteristics and reflectance, SEM-ESD for their element contents and XRD for their mineral phases, respectively. The results showed that minerals in both samples are dominated by detrial Fe-Ti oxides of aeolian origin. In sample XS-4J the reflectance and iron contents of magnetic minerals are usually high. In addition to magnetite (Fe-3O-4), maghemite (γFe-2O-3) and hematite (Fe-2O-3), some Fe-high oxide ({72.25 wt%}-{86.67 wt%}), ilmenite (FeTiO-3), and magnetite-ulvspinel were also detected. In sample DS-4J obvious negative linear correlations were found between Ti and Fe, and the contents of Mn, Si, Al and Ca are usually high and the minerals are dominated by magnetite (maghemite), goethite (FeOOH) and limonite (containing Si and OH). In addition, the signs of corrosion of magnetic minerals and newly crystallized magnetite (maghemite) were recognized. Differences in the composition and assemblage characteristics of magnetite minerals between XS and DS reflect significant differences in source rocks and preserving conditions.展开更多
文摘China is the third largest country in the world, with a land area of about 9.6 million km2. It is endowed with abundant mineral resources, and the metal mining activity can be traced back to ca. 8000 years ago. However, due to language barrier, little has been known about the geology and tectonics to the outside world until 1980s. In the last three decades, a great deal of knowledge has been gained, enhanced by a vigorous cooperation between Chinese and Western geologists. Research papers about geological, geochemical, and geochronological features of mineral deposits of China are widely published and cited in international journals. A comprehen- sive and comprehensible English literature that summarises the features of mineral deposits in China, however, is still lacking.
基金Supported by the Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX3-SW-151)
文摘An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.
文摘The total, soluble and insoluble oxalate contents of the small, large and cauline leaves and small and large stems of miner’s lettuce (Claytonia perfoliata ) plants which had been irrigated with tap water or a soluble fertilizer were extracted and measured using HPLC chromatography. Overall, all plant parts of miner’s lettuce analyzed contained high levels of total and soluble oxalates;however plants irrigated with fertilizer contained lower levels of oxalates compared with plants irrigated with water. On a dry matter basis, the small leaves contained higher levels of total oxalate when compared to the total oxalate in the large leaves. Soluble oxalate in the leaves of plants irrigated with water ranged from 2.6 to 7.5 mg/100g dry matter (DM) and was significantly higher (P < 0.05) than the leaves of the fertilizer-watered plants, which ranged from 1.8 to 2.8 mg/100g DM. The soluble oxalate in the small and large stems of the fertilizer-watered plants ranged from 1.20 to 1.5 mg/100g DM and was significantly lower (P < 0.05) than the water-treated small and large stems, which ranged from 3.75 to 4.4 mg/100g DM. It is recommended that the leaves of miner’s lettuce should be consumed in moderation.
文摘Relatively strongly magnetic fine components (<30μm, XS-4J and DS-4J) which are most environmentally sensitive were separated from layer S-{5-1} in the Xifeng and Duanjiapo loess sections and analyzed by MPV-3 for their morphometric characteristics and reflectance, SEM-ESD for their element contents and XRD for their mineral phases, respectively. The results showed that minerals in both samples are dominated by detrial Fe-Ti oxides of aeolian origin. In sample XS-4J the reflectance and iron contents of magnetic minerals are usually high. In addition to magnetite (Fe-3O-4), maghemite (γFe-2O-3) and hematite (Fe-2O-3), some Fe-high oxide ({72.25 wt%}-{86.67 wt%}), ilmenite (FeTiO-3), and magnetite-ulvspinel were also detected. In sample DS-4J obvious negative linear correlations were found between Ti and Fe, and the contents of Mn, Si, Al and Ca are usually high and the minerals are dominated by magnetite (maghemite), goethite (FeOOH) and limonite (containing Si and OH). In addition, the signs of corrosion of magnetic minerals and newly crystallized magnetite (maghemite) were recognized. Differences in the composition and assemblage characteristics of magnetite minerals between XS and DS reflect significant differences in source rocks and preserving conditions.
