SUMMARY

Geological - geomorphological diversity forming

the Phong Nha - KÎ Bµng World Natural Heritage

TrÇn Nghi, T¹ Hoµ Ph­¬ng, NguyÔn Quang Mü,

Vò V¨n Ph¸i, §Æng V¨n Bµo, Phan Duy Ngµ

The Phong Nha - KÎ Bµng National Park is the place of concentration of diversity in geology, geomorphology, topography, ecology and biology. The developing geological history of the Earth crust of Qu¶ng B×nh area has passed through longterm development from Cambrian to present time with 4 tectonic cycles: Devonian, Late Devonian - Early Carboniferous, Carboniferous - Permian, and Mesozoic.

The Phong Nha - KÎ Bµng cave system is of oldest age among the caves of South East Asia. The Phong Nha - KÎ Bµng cave system was formed in relation to tectonic faults in Tertiary (from 35 Ma to 5 Ma BP) and sea transgressions, regressions during Quaternary (from 1.75 Ma BP to present time). Therefore, there are 8 cave steps, corresponding to 8 planation steps of the relief as follows:

- Khe Ry Cave step: 1500 - 1600 m high;

- Vßm Cave step: 360 m high;

- Ðn Cave steps: 300 m, 93 m, 43 m, 24 m high;

- Phong Nha Cave steps: 15 m, 6 m high.

Ngµy nhËn bµi: 9-1-2004

Ng­êi biªn tËp: TrÇn V¨n TrÞ