Publication Date:
2015-12-24
Description:
Large earthquakes alter physical and chemical processes at Earth’s surface, triggering landslides, fracturing rock, changing large-scale permeability, and influencing hydrologic pathways. The resulting effects on global chemical cycles are not fully known. Here we show changes in the dissolved chemistry of the Min Jiang, a river in the Yangtze River (China) headwaters, following the A.D. 2008 M w 7.9 Wenchuan earthquake. Total solute fluxes transported by the Min Jiang increased after the earthquake, accompanied by an ~4 x increase in Na*/Ca ratios (where Na* is Na + corrected for atmospheric and evaporite contributions) and a 0.000644 ± 0.000146 increase in 87 Sr/ 86 Sr isotopic ratios. These changes are consistent with enhanced contribution from silicate sources. We infer that the CO 2 consumption rate via silicate-derived alkalinity increased 4.3 ± 0.4 times. If similar changes are associated with other large earthquakes, enhanced solute export could directly link tectonic activity with weathering and alkalinity fluxes that supply nutrients to ecosystems, influence seawater chemistry evolution, and steer Earth’s long-term carbon cycle and climate.
Print ISSN:
0091-7613
Electronic ISSN:
1943-2682
Topics:
Geosciences
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