1.1 TOPIC OVERVIEW AND LEARNING OBJECTIVES

This section presents an overview of the primary landforms and geological structures of the Mekong basin, and briefly discusses the geological processes that have created these landscapes over the last 50 million years. Their setting within the larger geographic context of Southeast Asia is described first and this is followed by a more detailed account of the topography and geology in the upper, middle and lower portions of the basin. Although the topographic landscapes and the geological processes that created them are interesting in themselves, the objective of this section is to establish the relationships between the geology, topography and the Mekong River as a physical and ecological system. This river system is divided into the upper, middle and lower sections with each of these having its own particular physical and ecological characteristics that must be understood in order to understand the environment, ecology, traditional use, potential for development and management of the Mekong River and basin.

After completing this Section, the RAK user should be able to:

• Describe the major landforms that make-up the landscapes of the Mekong River basin;

• Describe the most important geological processes that created the landforms of the Mekong River basin, giving an indication of the time-frame over which they evolved;

• Describe how the basic landforms determine the drainage and other hydrological characteristics of the Mekong River system and its relation to other major rivers that have their origin in the same region;

• Explain in general terms, the relationships between the geological structure and topographic features of the Mekong River and other physical and ecological processes;

• Describe the upper, middle and lower sections of the Mekong River basin, giving an explanation of the physical features and geological origin of each;

• Explain how the geological structure and topographic features are now being incorporated into major development plans for the entire Mekong River system.