『Abstract
Weathering of rocks takes place through complex processes involving
an intimate coupling between mechanical disintegration of the
rocks and interactions between the exposed rock surface, the hydrosphere
and the biosphere. It is still poorly understood how this coupling
affects weathering rates and patterns produced by weathering,.
Here, we show that the observed spheroidal weathering patterns
in basaltic intrusions (dolerites) in the Karoo Basin in South
Africa are created through volume expanding reactions which set
up stresses that not only lead to spalling of spheroidal layers
of rocks, but also drive a large scale hierarchical fracturing
process by which the dolerite is continuously undergoing domain
division. The fracture processes generates new reactive surface
area in a self-accelerating manner, thus providing a first-order
control on the total weathering rate.
Keywords: weathering; weathering rates; spheroidal weathering;
basalt; hierarchical fracturing; fracture patterns』
1. Introduction
2. Field observations
3. Numerical model
4. Implications for weathering rates
5. Conclusion
Acknowledgements
Appendix A. Supplementary data
References