The Zhangjiakou-Xuanhua area is a mineral resource-concentrated area for gold-silver polymetallic ore deposits. The temporal and spatial distribution and origin of mineral resources have been argued for a long time. B...The Zhangjiakou-Xuanhua area is a mineral resource-concentrated area for gold-silver polymetallic ore deposits. The temporal and spatial distribution and origin of mineral resources have been argued for a long time. Based on the comprehensive studies of geochronology and sulfur, lead, oxygen, carbon and noble gas isotopes, it is considered that the temporal and spatial distribution of mineral resources in this area is obviously controlled by the Zhangjiakou-Xuanhua mantle branch structure, as is reflected by the occurrence of gold deposits in the inner parts and of Ag-Pb-Zn polymetallic ore deposits in the outer parts. The mineralization took place mainly during the Yanshanian period. Ore-forming materials came largely from the deep interior of the Earth, and hydrothermal fluids were derived predominantly from Yanshanian magmatism.展开更多
This study was conducted following research on metallogenesis in the Zhangjiajie-Xuanhua and East Hebei mantle branch structure zones. The Fuping mantle branch structure zone is one where Au, Cu and Ag poly-metallic o...This study was conducted following research on metallogenesis in the Zhangjiajie-Xuanhua and East Hebei mantle branch structure zones. The Fuping mantle branch structure zone is one where Au, Cu and Ag poly-metallic ore resources are concentrated in North Hebei. However, there has existed a long-standing controversy on the temporal-spatial distribution of ore resources and their ore-forming material sources. In terms of age dating and the comprehensive analysis of S, Pb, O, C and Si isotopes, it is considered that the temporal-spatial distribution of ore resources in this mantle branch structure zone is obviously controlled by the Fuping mantle branch structure. In space there is developed such a metallogenic pattern as to be Ag, Pb and Zn polymetallic ore deposits with gold appearing inside and copper appearing outside. Metallogenesis is dated mainly at Yanshanian, the ore-forming materials were derived predominantly from the deep interior of the Earth, and ore-forming fluids were derived largely from Yanshanian magmatism.展开更多
基金the National Natural Science Foundation of China (No. 40272088).
文摘The Zhangjiakou-Xuanhua area is a mineral resource-concentrated area for gold-silver polymetallic ore deposits. The temporal and spatial distribution and origin of mineral resources have been argued for a long time. Based on the comprehensive studies of geochronology and sulfur, lead, oxygen, carbon and noble gas isotopes, it is considered that the temporal and spatial distribution of mineral resources in this area is obviously controlled by the Zhangjiakou-Xuanhua mantle branch structure, as is reflected by the occurrence of gold deposits in the inner parts and of Ag-Pb-Zn polymetallic ore deposits in the outer parts. The mineralization took place mainly during the Yanshanian period. Ore-forming materials came largely from the deep interior of the Earth, and hydrothermal fluids were derived predominantly from Yanshanian magmatism.
基金supported by the National Natural Science Foundation of China (Grant No. 40872137)Natural Science Foundation of Hebei Province (GrantNo.D2007000751)
文摘This study was conducted following research on metallogenesis in the Zhangjiajie-Xuanhua and East Hebei mantle branch structure zones. The Fuping mantle branch structure zone is one where Au, Cu and Ag poly-metallic ore resources are concentrated in North Hebei. However, there has existed a long-standing controversy on the temporal-spatial distribution of ore resources and their ore-forming material sources. In terms of age dating and the comprehensive analysis of S, Pb, O, C and Si isotopes, it is considered that the temporal-spatial distribution of ore resources in this mantle branch structure zone is obviously controlled by the Fuping mantle branch structure. In space there is developed such a metallogenic pattern as to be Ag, Pb and Zn polymetallic ore deposits with gold appearing inside and copper appearing outside. Metallogenesis is dated mainly at Yanshanian, the ore-forming materials were derived predominantly from the deep interior of the Earth, and ore-forming fluids were derived largely from Yanshanian magmatism.
文摘为探究封育保护后具有人工经营背景森林的群落结构和物种多样性在自然更替过程中的变化规律,以鄂西南地区的百户湾林场内0.01 km^(2)针阔混交林固定监测样地为研究对象,对木本植物的物种组成、群落结构和物种多样性进行调查与分析。结果表明,样地内胸径(diameter at breast height,DBH)≥1 cm的木本植物有8702株,隶属于39科66属111种;重要值排名前10位的物种中,常绿阔叶树种占明显优势;林冠层优势种为杉木(Cunninghamia lanceolata)和枹栎(Quercus serrata),灌木层优势种为翅柃(Eurya alata);样地内个体数量随DBH值增加而逐渐减少,小径级个体较多,平均DBH为5.2 cm;样地内物种较为丰富,各层级中亚乔木层的物种多样性最高。该研究为进一步探究森林群落结构和物种多样性的动态变化提供了科学依据。