Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcent...Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks.展开更多
The granite weathering in Longnan, Jiangxi, is represented by mineralogical changes of feldspars · montmorillonite, illite · kaolinite, halloysite · bauxite, with Na, Ca, Si, P, V, U and Sr being in a m...The granite weathering in Longnan, Jiangxi, is represented by mineralogical changes of feldspars · montmorillonite, illite · kaolinite, halloysite · bauxite, with Na, Ca, Si, P, V, U and Sr being in a mobile state while Ti, Al, Fe, Sc, Th, Zr and Hf remaining relatively conservative. With the exception of Zr/Hf, Nb/Ta, Th/Sc, Zr/Nd and Sm/Nb, changes are notable in ratios between most of the trace elements. Re-distribution of REE and Y has展开更多
利用江西省雷电监测系统获取的2003-2018年赣州地区范围内的地闪定位资料,对闪电的基本特性、日变化、月变化以及闪电密度的分布等方面进行了分析。结果表明,闪电强度平均值为8.27 k A;负地闪数占总闪电数的95.4%,平均闪电强度为-9.94 k...利用江西省雷电监测系统获取的2003-2018年赣州地区范围内的地闪定位资料,对闪电的基本特性、日变化、月变化以及闪电密度的分布等方面进行了分析。结果表明,闪电强度平均值为8.27 k A;负地闪数占总闪电数的95.4%,平均闪电强度为-9.94 k A;正负闪电比为4.6%,正闪平均强度为26.38 kA;闪电的月变化表现为单峰型,主要出现在4-9月,其中6-8月最为频繁;一天中闪电活跃期为13:00-19:00;闪电密度分布由北往南依次减少。展开更多
通过对龙南县1987—2016年汛期暴雨前1 d 14:00的温度、水汽压、本站气压等要素资料进行统计分析,得出分月暴雨要素变化参考指标,利用2017—2018年大雨及以上量级降水过程对指标进行检验。结果表明,指标可以有效降低暴雨过程的空报率,...通过对龙南县1987—2016年汛期暴雨前1 d 14:00的温度、水汽压、本站气压等要素资料进行统计分析,得出分月暴雨要素变化参考指标,利用2017—2018年大雨及以上量级降水过程对指标进行检验。结果表明,指标可以有效降低暴雨过程的空报率,提高预报的准确率。展开更多
文摘Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks.
文摘The granite weathering in Longnan, Jiangxi, is represented by mineralogical changes of feldspars · montmorillonite, illite · kaolinite, halloysite · bauxite, with Na, Ca, Si, P, V, U and Sr being in a mobile state while Ti, Al, Fe, Sc, Th, Zr and Hf remaining relatively conservative. With the exception of Zr/Hf, Nb/Ta, Th/Sc, Zr/Nd and Sm/Nb, changes are notable in ratios between most of the trace elements. Re-distribution of REE and Y has
文摘利用江西省雷电监测系统获取的2003-2018年赣州地区范围内的地闪定位资料,对闪电的基本特性、日变化、月变化以及闪电密度的分布等方面进行了分析。结果表明,闪电强度平均值为8.27 k A;负地闪数占总闪电数的95.4%,平均闪电强度为-9.94 k A;正负闪电比为4.6%,正闪平均强度为26.38 kA;闪电的月变化表现为单峰型,主要出现在4-9月,其中6-8月最为频繁;一天中闪电活跃期为13:00-19:00;闪电密度分布由北往南依次减少。
