关键词: 福州盆地, 断层擦痕, 主压应力, 应力状态, 伸展构造

Abstract: Fuzhou basin is one of the typical basins on southeastern margin of China continent In the basin two groups of faults have been found. There are NNW-NW-and NNE-NE-trending faults. The NNW-trending Ba'yi reservoir-Wangjuan fault is active and also is a well-known heat-flow anomaly zone.The calculation of striats along the faults on the bedrock outcrops within the basin and its boundaries by using Etchecopar's computerized method shows that there were four important stress fields since Yanshanian phase. The first stress field was compressive in NW-SE orientation, which caused reverse fault, schistosity and mylonite zone to be formed. The second was compressive in SN or NNE orientation, but in the state of compression which produced Paleogene diabase dykes along NNE-trending faults. The third was compressive in nearly EW or WNW orientation, R = 1, σ₂=σ₃, but in a extension state. The evidence for the third stress field is tension-shear horizontal striation on the walls of the basic dyke formed from Neogene to Quarternary. For the fourth stress field maximum principal compressive stress was vertical, indicating that the basin is in an exten-sional tectonic environment.

Key words: Fuzhou basin, Fault striation, Maximum principal compressive stress, stress field, Extensional tectonics