闽西南坳陷内石炭纪海相火山岩类的空间分布及其意义

On Spatial Distribution and Signification of Carboniferous Marine Volcanic Rocks in the Southwest Fujian Depression

闽西南坳陷在石炭纪时,演化至一个重要的发展阶段。于海盆形成初期,随着坳陷加深,发育了一条呈北东东向横贯坳陷区的横张断裂带,使盆底开裂、引起海底火山活动。此带可称为上杭—德化构造、火山活动带。该带与南平—宁化构造带基本平行,后者作为控制闽西南坳陷北部的边界性构造,很可能也控制了上杭—德化构造、火山活动带的生成。在龙岩马坑等地,断裂已深切至上地幔,导致玄武岩浆的喷溢,而马坑铁矿正处于坳陷最深部位。福建已知的重要铁矿几乎均位于此带上,因此,是重要的铁矿成矿带。

The Southwest Fuiian Depression is on an important development stage in Carboniferous period. During the early stage of forming a marine basin, the more down-warping results from a well-developed NEE-trend traverse tension rupture belt, which makes the basin floor cracking and the submarine volcanoes active. The fracture belt can be called the ShanghangDehua tectonic and volcanic active belt, which is approximately parallel to the Nanping-Dehua tectonic belt. As a boundary fault of controlling the northern part of the Southwest Fujian Depression, it is inferred that the Nanping-Ninhua tectonic belt also sets a limit to the formation of the Shanghang-Dehua tectonic-volcanic active belt. In Makeng, Longyan City, the faults reach down to the upper mantle, which results in the effusion of basaltic magma. The Makeng Iron Ore （the largest iron ore in Fujian Province） exists in the deepmost part of the Depression. The major known iron ores in Fujian Province have been discovered almost in the Shanghang-Dehua tectonic belt. Therefore, the Shanghang-Dehua tectonic belt is an important metallogenic belt of iron ores.