摘要
矽卡岩在地壳中分布广泛,其研究历史超过一百年。然而,矽卡岩的定义却相对模糊。直到近年来,具有特征性矽卡岩矿物组合被认为是确认矽卡岩的关键。对于矽卡岩的成因亦长期缺乏统一认识。从花岗岩与灰岩的接触交代成因拓展到基性-超基性岩与碳酸盐岩接触成因,再到其岩浆成因,反映出矽卡岩所包含的地质过程和意义在不断扩大。近年来对矽卡岩矿物中的熔体包裹体和岩浆混染实验等为矽卡岩的成因研究提供了新的方向。铁矿床是与矽卡岩相关度最大的一类矿床,单个矿床储量可达5000 Mt(平均品位约45%)。与矽卡岩有关的铁矿床通常与基性-超基性岩有关,流体盐度高,且碱交代发育,相对IOCG具很低的金含量。本文结合作者实际研究资料,阐明新疆哈密地区雅满苏矽卡岩型铁矿的矽卡岩化过程。
Skarn has been scientifically recognized as a distinct class of rock for more than 100 years. However, the definition of skarn is loose. Recently, mineralogy was proposed to be the key to define a skarn： a mineral assemblage including a wide variety of calc-silicate and associated minerals, but is usually dominated by garnet and pyroxene; it was formed in almost all ages and a variety of tectonic settings. This pure ＂descriptive＂ definition is not genetic and does not account for processes such as ＂metasomatism＂ and ＂replacement＂. As for the genetic aspect, diverse models have been proposed： from a general dictionary definition of contact metamorphic-metasomatic interactions with intruding granitic magma in early times to interactions with mafie- ultramafic magma and high temperature magmatic skarn in recent years. It seems that genetic geological domain of skam could be controversial and is also expanding with time. Melt inclusion in skarn minerals and assimilation experiments studies provides new insight on the skarn. Skarn-related iron deposits are of the most abundant types among the others, which may reach 5000 Mt with a grade of 45%. Skarn-related iron deposits are mostly associated with mafic-ultramafic magmatism, alkaline alteration extensively developed, and were low in Au compared to IOCG. These deposits of Precambrian age are rare. This paper also summarizes some features of skam-related iron deposits which promote our understanding of different iron ore deposits. In addition, the skamization processes in Yamansu skarn deposit were illustrated..
出处
《高校地质学报》
CAS
CSCD
北大核心
2013年第3期425-436,共12页
Geological Journal of China Universities
基金
中国地调局地质调查工作项目(1212011140056)资助
关键词
矽卡岩
与矽卡岩有关的矿床
交代岩
变质岩
岩浆矽卡岩
雅满苏铁矿
skarn
skarn-related deposit
metasomatic rock
metamorphic rock
magmatic skarn
Yamansu skarn-related deposit
