LATE PLEISTOCENE - EARLY - MIDDLE HOLOCENE TRANGRESSION IN MAINLAND AND CONTINENTAL SHELF OF VIET NAM

Abstract

Late Pleistocene - Holocene trangression started from 18 Ka (depth of 100 - 120 m watet) to 6 - 4 Ka (height of 4.5 - 6 m) according to maximum sea level.

The transgressive process has been clearly recognized by 3 important shorelines as follows:

- Shoreline situated in the depth of 50 - 60 m with the age of late Pleistocene (approximating 16 Ka).

- Shoreline situated in the depth of 25 - 30 m with the age of Early - Middle Holocene (from 12 Ka to 10 Ka).

- Shoreline situated in the elevation 4.5 - 6 m on marine terraces and notches in limestone mounts.

The shorelines are characterized by following factors:

- Abrasion - accumulation relief distributed in accordance with isobaths.

- Existence of typical lithofacies: sandy bar, lagoonal clay, peat and coastal swamp, well rounded terrigenous and lateric marly pebble and gravel and rock fragments.

-Marine terraces and notches of the same height on the mainland.