『Abstract
We investigated the petrography and major, trace and rare earth
element compositions of the bed sediments from the large rivers
draining the eastern Tibetan Plateau (ETP) - Huang He (Yellow),
Chang Jiang (Yangtze), Hong He (Red), Mekong and Salween. The
combined drainage spans tropical, temperate and arid climate zones.
In addition, samples from the Lena River, were also studied for
their major ad trace element composition. The sub-angular texture,
the quartz:feldspar:rock fragment classification in the lithic
arenite field, and the relatively low chemical index of alteration
(CIA: 42-79), indicate that these sediments are texturally, petrographically
and chemically immature, and immobile trace elements can be used
to obtain some information about the lithologic provenance. The
ETP river sediments are felsic and similar to the Upper Continental
Crust, with the Salween most felsic and the Lena most mafic. The
sediments show a gradation in maturity that is not clearly related
to present climatic or physiographic regime. This suggests that
maturity itself is a relict feature inherited from previous sedimentary
cycles. The high physical erosion in such high energy and relief
systems seems to inhibit intense weathering and manifests a provenance
control from local rocks on the sediment compositions.
Keywords: Hong (Red); Chang Jiang (Yangtze); Salween; Mekong;
Lena; CIA』
1. Introduction
2. Geological and hydrographical setting
2.1. Huang He (Yellow)
2.2. Chang Jiang (Yangtze)
2.3. Hong He (Red)
2.4. Mekong
2.5. Salween
2.6. Lena
3. sampling and analytical methods
4. Results and discussion
4.1. Can provenance information be retrieved?
4.1.1. Tectonic provenance
4.1.2. Lithologic provenance
4.1.3. Heavy minerals
4.2. Sediment maturity
4.2.1. Immature sediments
4.2.2. Evidence of weathering but when?
4.3. Effect of climate and physiography on sediment maturity
4.3.1. The ETP rivers
4.3.2. Global relationship
5. Conclusions
Acknowledgments
Appendix A
References