summary
Evolution of Quaternary sediments in Qu¶ng TrÞ - Thõa ThiȘn HuÕ plain
Vò Quang L©n.
Through the analysis and synthesis of the data from geological mapping at the scale of 1:50.000, 1:25.000 and the data concerned with Quaternary sediments in Qu¶ng TrÞ - Thõa ThiȘn HuÕ plain, the author has some remarks as follows:
1. On the basis of data on lithology, paleontology, sedimentary environments and geophysics, the boundary between Neogene and Quaternary in the studied area has been preliminarily determined.
2. The Quaternary sediments in the Qu¶ng TrÞ - Thõa ThiȘn HuÕ plain have 9 types of origin: fluvio - proluvial (ap), fluvial (a), fluvio - marshy (ab), fluvio - marine (am), fluvio - marine - marshy (amb), marine - fluvial (ma), marine - fluvio - marshy (mab), marine - eolian (mv) and marine (m), that belong to 6 stratigraphic units with the age of Early Pleistocene - Late Holocene.
3. Evolution of Quaternary sedimentary formations in Qu¶ng TrÞ - Thõa ThiȘn HuÕ plain are closely related to the sea-level changes and to the local tectonic uplift and subsidence.
The historical evolution of Quaternary sediments in Qu¶ng TrÞ - Thõa ThiȘn HuÕ plain can be divided into 5 periods : 1) Early Pleistocene period (Q11); 2) Middle Pleistocene - early Late Pleistocene period (Q12-3); 3) Late Late Pleistocene period (Q13 ); 4) Early - Middle Holocene period (Q21-2 ); 5) Middle - Late Holocene and Late Holocene period (Q22-3 and Q23 ).