Sequence Stratigraphy Study of the Late Quaternary Activity of the Nankou-Sunhe Fault in Its Northern Segment,Beijing

摘要

A test drilling exploration was implemented across the northern segment of the Nankou-Sunhe fault in the Beijing plain,and a combined borehole section was built by sequence stratigraphy,lithologic facies analysis,magnetic susceptibilityand absolute chronology to investigate the episodic activities of the fault since 60 ka BP. The results show that the active stages of the fault are 60 ka to 47 ka BP,36 ka to 28 ka BP,and 16 ka BP to present. Other intervals are relatively stable. The average vertical slip rate is 0.35 mm/a from 60 ka to 37 ka BP,0 mm/a from 37 ka to 32 ka BP,0.78 mm/a from 32 ka to 12 ka BP,and 0.35 mm/a since 12 ka BP. Compared with the conventional analyses on lithology and sedimentary facies,the sequence stratigraphy method has certain advantages in the studies of borehole strata comparison and episodic activity of buried faults.