Goodbred, Steven L.1, Yoshiki Saito2, Zhongyuan Chen3
(1) Stony Brook University, Stony Brook, NY
(2) Geological Survey of Japan, Tsukuba, Japan
(3) East China Normal University, Shanghai, China
ABSTRACT: Toward a Unifying Model of Monsoon-driven Delta Systems: IGCP-475 DeltaMAP Project
The monsoon-influence regions of Asia give yield about 75% of the world's riverine sediment fluxes, thereby producing many major deltaic systems. Among these are a series of mega-deltas that extend from the Huanghe (Yellow) in northern China to the Indus of Pakistan, and further include the Ganges-Brahmaputra, Irrawaddy, Mekong, and Changjiang (Yangtze). The past decade of research on these deltaic lowlands of Asia have provided important new information on the behavior of deltaic systems under high sediment yield, high-energy (fluvial and marine), and climate controlled conditions. Why are so many large deltas distributed along the Asian coast? One is the presence of large rivers with a high sediment yield, which have their sources from the Himalayas and the Tibetan Plateau and high precipitation due to the seasonal monsoonal climate. The other is the stable or slightly falling sea level over the last 6-7 kys. Most of the Asian region recorded a middle Holocene sea-level highstand 2-4 m above the present sea level about 6-7 ka by hydro-isostasy. The long-stable sea level has allowed more than 200 km of shore-line migration since this period and the formation of deltas with a wide delta plain. A new IGCP project, IGCP-475 "Deltas in the Monsoon Asia-Pacific Region (DeltaMAP): Late Quaternary Development and Recent Changes Due to Natural and Human Influences" has started as a 5-year project from 2003-2007. In terms of sedimentary dynamics, active margin processes, and human-related issues, the monsoon Asia-Pacific encompasses probably the world’s most exciting region for sedimentary research. This area also includes a breadth of climatic, tectonic, and anthropogenically-altered environments. The project seeks to understand these diverse settings within the unifying theme of monsoon-driven sedimentary systems. Primary goals for the next 5 years will be to (1) develop an adaptive and comprehensive conceptual model for monsoon-driven river-delta systems and (2) enhance regional and international collaboration on delta research.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.