『Abstract
　The Hong (Red) River drains the prominent Red River Fault Zone that has experienced various tectonic activities - intrusion of magma, exhumation of basement rocks, and influx of thermal waters - associated with the Cenozoic collision of India and Eurasia. We report dissolved major elements and Sr isotope compositions of 43 samples from its three tributary systems (Da, Thao/Hong main channel, and Lo) encompassing summer and winter seasons. Carbonic acid ultimately derived from the atmosphere is the main weathering agent, and sulfuric acid from pyrite oxidation plays a minor role. Seasonality is manifested in higher calcite saturation index and Mg/TZ⁺ and lower Ca/Mg in summer, suggesting calcite precipitation, and in higher Si/(Na^* + K) ratios in summer suggesting more intensive silicate weathering. we quantified the input from rain, evaporite, carbonate, and silicate reservoirs using forward and inverse models and examined the robustness of the results. Carbonate dissolution accounts for a significant fraction of total dissolved cations (55-97％), and weathering of silicates makes a minor contribution (1-40％). Our best estimate of the spatially averaged silicate weathering rate in the Hong basin is 170×10³ mol/km²/yr in summer and 51×10³ mol/km²/yr in winter. We tested for correlations between the rate of CO2 consumption by silicate weathering and various climatic (air temperature, precipitation, runoff, and potential evapotranspiration) and geologic (relief, elevation, slope, and lithology) parameters calculated using GIS. Clear correlations do not emerge (except for φCO2 and runoff in winter) which we attribute to the complex geologic setting of the area, the seasonal regime change from physical-dominant in summer to chemical-dominant in winter, and the incoherent timescales involved for the different parameters tested.』

1. Introduction
2. Study area
　2.1. Geography, vegetation, and climate
　2.2. Tectonics and geology
3. Methodology
4. Results and discussion
　4.1. Major elements
　4.2. Comparison to global rivers
　4.3. Effect of different rock types
　　4.3.1. Evaporite dissolution and pyrite oxidation
　　4.3.2. Silicate weathering
　　4.3.3. Carbonate weathering
　　4.3.4. Seasonal variation
　4.4. Quantification of input sources
　　4.4.1. The forward model
　　4.4.2. The inverse model
　　　4.4.2.1. Inverse model description
　　　4.4.2.2. Inverse model sensitivity
　　4.4.3. Model results
　4.5. Flux calculations
　4.6. Factors controlling the CO2 consumption rate
5. Conclusions
Acknowledgments
References