Abstract:

Jinfosi Pluton  is seismically highly  reflective medium and  it has been difficult  to obtain velocity data of  the pluton
directly. The deep structures of Jinfosi  thrust belt  revealed by  time-domain and depth-domain seismic data show significant
difference. We used the velocity data that were derived in laboratory under high temperatures and pressures simulating conditions
at depth  to quautify  the  relationship between velocity and depth underground. This allows  time-depth conversion  for  the 2-D
seismic data of  the Jinfosi pluton and comparison of  the deep structures of Jinfosi  thrust belt  revealed by  the  time-domain and
depth-domain seismic data. Based on  the new depth data and  interpretation, GOCAD software was employed  to establish a 3-D
geological model, which allowed further discussion of the deep structures. The model shows that the Mesozoic-Cenozoic rocks form
a deeply buried monocline which dips SW and structural highs are relatively deeply buried with dips diminishing toward the two
limbs.

Key words:  thrust belt, Jinfosi pluton, time-to-depth conversion, 3-D geological model