贺兰山断裂带的ESR年龄测定

ESR dating of Helan Mountain Fault Zone

杨帆 方成名 黄泽光 周小进 徐良发

Yang Fan Fang Chengmin Huang Zeguang Zhou Xiaojin Xu Liangfa

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China

脆性断层一般产生于低温环境中，通常不会生成新的变质矿物，因此无法用普通的测年方法来确定断层的活动年龄。由于脆性断层中常会伴生有同期生成的石英脉，可以通过热活化电子自旋共振(ESR)法测定石英脉的生成年龄，从而得出断层活动的年龄。如果断层带中发育了多期的石英脉，通过测定还可以得出断层多次活动的年龄。鄂尔多斯盆地西缘构造复杂，对其断裂发育机制历来存在较多争议，通过对贺兰山地区石英脉体的ESR测年分析，证实了该区由东向西逆冲的南北向断裂带形成于晚侏罗世之后，且具有多期次活动的特征。

It is very difficult to form new metamorphic minerals in the movement of brittle faults under shallow and low-temperature situation. Therefore it is impossible to determine the active ages of faults exactly through traditional methods. In the activation of shallow faults, homochromous quartz veins often develop. As a result, we can use thermal activated ESR dating to obtain the ages of quartz veins, and then to determine the active ages of faults. If there are several stages of quartz veins in fault belts, the corresponding active ages of faults can also be determined. The western Ordos thrust-fold belt has a complicated structure, and its development mechanism is still controversial. A case study was made in the Helan Mountain area. According to the ESR dating of quartz veins, the SN-trending fault which thrusted from east to west in the study area was formed after the Late Jurassic, and experienced several active stages.

国家科技重大专项“大型油气田及煤层气开发”(2011ZX05002-006-01)资助。

https://doi.org/10.11781/sysydz201405642