Borges,J.B., Huh,Y., Moon,S. and Noh,H.(2008): Provenance and weathering control on river bed sediments of the eastern Tibetan Plateau and the Russian Far East. Chemical Geology, 254, 52-72.

『チベット高原東部とロシア極東の河床堆積物の起源と風化によるコントロール』


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


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