Furong, Hunan, is a large tin orefield discovered in China in recent years, which is mainly of the skarn-greisen-chlorite type. On the basis of the geological characteristics of the orefield, 40Ar-39Ar dating was perf...Furong, Hunan, is a large tin orefield discovered in China in recent years, which is mainly of the skarn-greisen-chlorite type. On the basis of the geological characteristics of the orefield, 40Ar-39Ar dating was performed on muscovite from greisen-type tin ore and biotite from related amphibole-biotite granite, which yielded three sets of age data, i.e., a plateau age of 157.5±0.3 Ma and an isochron age of 156.9±3 Ma for amphibole-biotite granite; a plateau age of 156.1±0.4 Ma and an isochron age of 155.7±1.7 Ma for the Sanmen greisen-type tin ore; and a plateau age of 160.1±0.9 Ma and an isochron age of 157.5±1.5 Ma for the Taoxiwo greisen-type tin ore. The three sets of age data coincide well with each other. They not only accurately reflect the timing of rock and ore formation but also indicate close relations between granite and tin deposits. In addition, the plateau ages of all three sets suggest that no subsequent thermal perturbation event occurred after the formation of granite and tin deposits. The Furong tin orefield is a component part of the southern Hunan large tungsten-tin polymetallic deposit concentration area and also a representative deposit formed in the time interval of 160-135 Ma in four peaks of Mesozoic tungsten-tin mineralization in the South China region. They might still correspond to the middle and late stages of the major geodynamic transition from a N-S- to an E-W-direction in eastern China.展开更多
This paper explores the influence of the local meteoric conditions, the overlying soil on the concentrations of Ca, Mg, and St, and the ratios of Mg/Ca, Sr/Ca, and Mg/Sr in soil infiltrating water （SIW）. An in situ ...This paper explores the influence of the local meteoric conditions, the overlying soil on the concentrations of Ca, Mg, and St, and the ratios of Mg/Ca, Sr/Ca, and Mg/Sr in soil infiltrating water （SIW）. An in situ monitoring program was carried out above the Furong Cave throughout 2010 to collect data on SIW, monthly temperature and rainfall, and the geochemical com- position and granularity of soils. The discharge of SIW responded quickly to the local rainfall, and its residence time was the primary factor affecting the Ca, Mg, and Sr content of the SIW. The high concentrations of Ca, Mg, and Sr in the SIW during April should be attributed primarily to the prolonged residence of SIW in the soil during the local dry seasons of winter and early spring. The maximum Mg/Sr ratio also occurred in April. The ratio of Mg/Ca in SIW is positively correlated with pro- longed residence time and with high temperatures, which do not strongly affect the ratio of Sr/Ca. The Mg/Ca ratio was lowest when the Sr/Ca ratio was highest because plant metabolism increased the absorption of Ca and Mg, but not St, and also be- cause higher temperatures enhanced the dissolution of Mg more than that of Sr. These different responses of Mg and Sr to temperature increases resulted in high Mg/Sr ratios during July and August.展开更多
采用解剖观察、组织切片及人工催情等方法,研究芙蓉鲤鲫(Cyprinus capiofurong.♀×Carassius auratus red var.♂)的性腺发育及繁殖性能。结果显示:解剖观察,芙蓉鲤鲫性腺发育异常的个体占83.64%,性腺外观基本正常的个体占16.36%...采用解剖观察、组织切片及人工催情等方法,研究芙蓉鲤鲫(Cyprinus capiofurong.♀×Carassius auratus red var.♂)的性腺发育及繁殖性能。结果显示:解剖观察,芙蓉鲤鲫性腺发育异常的个体占83.64%,性腺外观基本正常的个体占16.36%。组织学观察,芙蓉鲤鲫性腺可分三类:两性嵌合体占21.13%,其中以精巢为主的16.90%,以卵巢为主的4.23%,它们性腺发育迟缓,在繁殖季节成熟系数也没有明显变化,性腺多为一侧发育或两侧不对称,两种性腺细胞均不能成熟;雌性个体占40.84%,在生殖季节卵巢可发育到第IV时相,但未见其细胞核发生偏移;雄性个体,占38.03%,在生殖季节只能发育到精子细胞阶段,不能产生成熟的精子。经人工催产,芙蓉鲤鲫少部分个体有发情产卵行为但不能正常受精。结果表明芙蓉鲤鲫为两性败育类型。展开更多
华南是我国最重要的锡成矿省,产有大量的与花岗岩有关的大型-超大型锡多金属矿床。近年来,在湘南新探明一个超大型锡矿床—芙蓉锡矿床,其中,最重要的锡矿化产在骑田岭花岗岩体西南部的破碎蚀变带内,与绿泥石化密切相关。骑田岭花岗岩富...华南是我国最重要的锡成矿省,产有大量的与花岗岩有关的大型-超大型锡多金属矿床。近年来,在湘南新探明一个超大型锡矿床—芙蓉锡矿床,其中,最重要的锡矿化产在骑田岭花岗岩体西南部的破碎蚀变带内,与绿泥石化密切相关。骑田岭花岗岩富含角闪石,具有较高的氧逸度,显示出准铝的地球化学特征,在花岗岩形成过程中发生过壳-慢岩浆混合作用。这些特点都表明骑田岭花岗宕并不同于一般的 S 型含锡花岗岩,而显示出 A 型花岗岩的地球化学特征。同位素定年分析表明,芙蓉锡矿床主成矿阶段的形成时代要晚于骑田岭花岗岩侵位年龄近20Ma。氢、氧同位素分析表明,发生过水-岩反应的大气降水在成矿流体中占有很重要的地位。硫同位素分析表明花岗岩和地层都提供了成矿所需的硫。因此,用花岗岩浆结晶分异过程中分离出富锡的岩浆流体来形成锡矿的传统模式并不适合于解释芙蓉锡矿的形成。我们认为芙蓉锡矿的形成主要与骑田岭花岗岩的绿泥石化蚀变有关,循环的大气降水与花岗岩发生水-岩反应,富锡的铁镁矿物在蚀变成绿泥石的同时释放出 Sn 和 Ti 等金属到流体中,当物理化学条件改变时,沉淀形成锡矿体。这是一种比较独特的锡矿化模式,丰富了华南与花岗岩有关的锡矿化类型。展开更多
文摘Furong, Hunan, is a large tin orefield discovered in China in recent years, which is mainly of the skarn-greisen-chlorite type. On the basis of the geological characteristics of the orefield, 40Ar-39Ar dating was performed on muscovite from greisen-type tin ore and biotite from related amphibole-biotite granite, which yielded three sets of age data, i.e., a plateau age of 157.5±0.3 Ma and an isochron age of 156.9±3 Ma for amphibole-biotite granite; a plateau age of 156.1±0.4 Ma and an isochron age of 155.7±1.7 Ma for the Sanmen greisen-type tin ore; and a plateau age of 160.1±0.9 Ma and an isochron age of 157.5±1.5 Ma for the Taoxiwo greisen-type tin ore. The three sets of age data coincide well with each other. They not only accurately reflect the timing of rock and ore formation but also indicate close relations between granite and tin deposits. In addition, the plateau ages of all three sets suggest that no subsequent thermal perturbation event occurred after the formation of granite and tin deposits. The Furong tin orefield is a component part of the southern Hunan large tungsten-tin polymetallic deposit concentration area and also a representative deposit formed in the time interval of 160-135 Ma in four peaks of Mesozoic tungsten-tin mineralization in the South China region. They might still correspond to the middle and late stages of the major geodynamic transition from a N-S- to an E-W-direction in eastern China.
基金supported by National Natural Science Foundation of China(Grant Nos.41302138,40971122,41030103 and 41172165)the Fundamental Research Funds for the Central Universities of Southwest University(Grant Nos.XDJK2013A012 and XDJK2009C106)State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences(Grant No.SKLLQG1310)
文摘This paper explores the influence of the local meteoric conditions, the overlying soil on the concentrations of Ca, Mg, and St, and the ratios of Mg/Ca, Sr/Ca, and Mg/Sr in soil infiltrating water （SIW）. An in situ monitoring program was carried out above the Furong Cave throughout 2010 to collect data on SIW, monthly temperature and rainfall, and the geochemical com- position and granularity of soils. The discharge of SIW responded quickly to the local rainfall, and its residence time was the primary factor affecting the Ca, Mg, and Sr content of the SIW. The high concentrations of Ca, Mg, and Sr in the SIW during April should be attributed primarily to the prolonged residence of SIW in the soil during the local dry seasons of winter and early spring. The maximum Mg/Sr ratio also occurred in April. The ratio of Mg/Ca in SIW is positively correlated with pro- longed residence time and with high temperatures, which do not strongly affect the ratio of Sr/Ca. The Mg/Ca ratio was lowest when the Sr/Ca ratio was highest because plant metabolism increased the absorption of Ca and Mg, but not St, and also be- cause higher temperatures enhanced the dissolution of Mg more than that of Sr. These different responses of Mg and Sr to temperature increases resulted in high Mg/Sr ratios during July and August.
文摘采用解剖观察、组织切片及人工催情等方法,研究芙蓉鲤鲫(Cyprinus capiofurong.♀×Carassius auratus red var.♂)的性腺发育及繁殖性能。结果显示:解剖观察,芙蓉鲤鲫性腺发育异常的个体占83.64%,性腺外观基本正常的个体占16.36%。组织学观察,芙蓉鲤鲫性腺可分三类:两性嵌合体占21.13%,其中以精巢为主的16.90%,以卵巢为主的4.23%,它们性腺发育迟缓,在繁殖季节成熟系数也没有明显变化,性腺多为一侧发育或两侧不对称,两种性腺细胞均不能成熟;雌性个体占40.84%,在生殖季节卵巢可发育到第IV时相,但未见其细胞核发生偏移;雄性个体,占38.03%,在生殖季节只能发育到精子细胞阶段,不能产生成熟的精子。经人工催产,芙蓉鲤鲫少部分个体有发情产卵行为但不能正常受精。结果表明芙蓉鲤鲫为两性败育类型。
文摘华南是我国最重要的锡成矿省,产有大量的与花岗岩有关的大型-超大型锡多金属矿床。近年来,在湘南新探明一个超大型锡矿床—芙蓉锡矿床,其中,最重要的锡矿化产在骑田岭花岗岩体西南部的破碎蚀变带内,与绿泥石化密切相关。骑田岭花岗岩富含角闪石,具有较高的氧逸度,显示出准铝的地球化学特征,在花岗岩形成过程中发生过壳-慢岩浆混合作用。这些特点都表明骑田岭花岗宕并不同于一般的 S 型含锡花岗岩,而显示出 A 型花岗岩的地球化学特征。同位素定年分析表明,芙蓉锡矿床主成矿阶段的形成时代要晚于骑田岭花岗岩侵位年龄近20Ma。氢、氧同位素分析表明,发生过水-岩反应的大气降水在成矿流体中占有很重要的地位。硫同位素分析表明花岗岩和地层都提供了成矿所需的硫。因此,用花岗岩浆结晶分异过程中分离出富锡的岩浆流体来形成锡矿的传统模式并不适合于解释芙蓉锡矿的形成。我们认为芙蓉锡矿的形成主要与骑田岭花岗岩的绿泥石化蚀变有关,循环的大气降水与花岗岩发生水-岩反应,富锡的铁镁矿物在蚀变成绿泥石的同时释放出 Sn 和 Ti 等金属到流体中,当物理化学条件改变时,沉淀形成锡矿体。这是一种比较独特的锡矿化模式,丰富了华南与花岗岩有关的锡矿化类型。
