我国东部沿海地区中生代火山岩分布十分广泛。在长江中下游地区,由碱玄岩-粗安岩-粗面岩组合构成的陆相火山岩凹陷,常有玢岩铁矿和块状黄铁矿床产出。矿床的蚀变作用极为普遍。一般由矿化中心向外,由深至浅,划分为两套蚀变带,即暗色蚀变带和浅色蚀变带。无论是垂直 The Mesozoic volcanic rocks in the eastern coastal areas of China are widely distributed. In the middle and lower reaches of the Yangtze River, the continental volcanic sags formed by a combination of basaltic rock-sorbite-trachyte rock often have the boulder iron ore and massive pyrite deposits. Deposit alteration is extremely common. Generally from the mineralization center outward, from deep to shallow, divided into two sets of alteration zone, namely dark alteration zone and light-colored alteration zone. Whether it is vertical